Catha edulis

A slow-growing shrub up to 25 meters tall that thrives in arid environments. The young leaves and shoots contain cathinone.

[1] [2] [3] [4] [5] [6]

Propagation

Because the newest shoots and leaves are harvested for their alkaloid content before they can flower, seeds are an uncommon method of propagation.[7]

Germination

Vegetative

Edulis produces suckers that can be removed and propagated.[8]

In-Vitro

Edulis is amenable to micropropagation. In contrast, callus induction is slow and has difficulty with exudates.[7]

Micropropagation

Recommended protocol

1. cut 5-7mm shoot tip explants
2. disinfect with 70% EtOH for 1-2 min
3. rinse 3x with ddH2O
4. disinfect with ~1% sodium hypochlorite sol. + Tween 80 for 5 min
5. rinse 3x with ddH2O
6. culture 4-8 weeks on base media + 3mg/l BA + 0.3 mg/l IAA (media I) in base environment
7. transfer to base media + 0.3 mg/l BA + 3 mg/l IAA for ~4 weeks (media II)
8. separate and transfer elongated shoots (5-10 cm) to base media + 3 mg/l IAA only (media III) for 8-12 weeks
9. return leftover buds to multiplication media (I)
10. acclimatize rooted plantlets in media III to greenhouse conditions

Base media: MS inorganic salts, Gamborg B5 vitamins, 2 mg/l glycine, 30 g/l sucrose, 100 mg/l inositol, 8 g/l Bacto agar; adjusted to pH 5.7 ± 0.1; autoclaved 20 min at 121°C;

Base environment: constant temperature of 23°C; 16-h photoperiod; 22.5 u mol/s/m2 (1500lx) 4100K light;

Shoot tips (5-7mm long) can be used to establish micropropagation cultures for edulis. Explants are disinfected by dipping in 70% EtOH for 1-2 min, rinsing in dH2O, soaking in 20 % (v/v) NaOCl solution + Tween 80 for 5 minutes, the rinsing 3x in dH2O. Explants are then cultured on MS media with Gamborg vitamins plus 30g/l sucrose, 8g/l bacto agar, and PGR.[7]

Maximum shoot multiplication of 13 ± 3.5 shoots per explant was achieved after 8 weeks using 0.3 mg/l BA + 3 mg/l IAA. The author recommends using 3 mg/l BA + 0.3 mg/l IAA for multiplication, despite the data (Table 1) showing that protocol was ineffective (0 shoots ≥ 5mm per explant).[7] Two years earlier in 1994, the same research group likewise recommends 3 mg/l BA + 0.3 mg/l IAA for shoot multiplication.[9] In an earlier study (1991) by the same lead author using the same data as in the 1996 study, 0.3 mg/l BA plus 0.3 or 3.0 mg/l IAA is recommended for multiplication.[10]

Though not reported, it could be that the number of buds or bud clusters produced using 3 mg/l BA exceeds that of shoots produced at 0.3 mg/l BA. Those buds later form shoots after transfer to low BA media leading to an overall greater number of shoots.

The shoot clusters averaged 15×15 mm after 8 weeks and could be divided at that time. Replacing BA with 2iP or kinetin does not enhance multiplication.[10]

Maximum shoot elongation (35 ± 5 mm) and rooting (100% success) was achieved after 8 weeks using 3.0 mg/l IAA only. The shoot cultures were maintained on this media until they achieved sufficient height (5-10 cm) for transplanting to the soil. No details were given for the acclimatization procedure used but, “at least 30% of rooted plantlets were acclimatized and established in the soil in the greenhouse.”[7]

Callus

Recommended protocol

1. remove whole leaf explant
2. disinfect with 70% EtOH for 1-2 min
3. rinse 3x with ddH2O
4. disinfect with ~1% sodium hypochlorite sol. + Tween 80 for 5 min
5. rinse 3x with ddH2O
6. divide into 10mm×2mm sections
7. culture on base media + 4.8 mg/l (20 uM) picloram + 0.19 mg/l (0.9 uM) kinetin with optional 0.1% PVP for 8-10 weeks in the base environment subculture on the same media every 4-6 weeks

alternative PGRs: 2 mg/l IBA + 0.5 mg/l NAA;

base media: MS inorganic salts, Gamborg B5 vitamins, 2 mg/l glycine, 20 g/l sucrose, 100 mg/l inositol, 8 g/l Bacto agar; adjusted to pH 5.7 ± 0.1; autoclaved 20 min at 121°C;

Base environment: constant temperature of 25±2°C; 16-h photoperiod; 0-40 umol/s/m2 4100K light;

Callus culture can be induced from young leaf explants using 9.8 uM IBA + 2.7 uM NAA, 20.7 uM picloram + 0.9 uM kinetin, or 8.3/12.4 uM picloram on 0.8% agar MS media. A higher fresh weight of calli was obtained with picloram + kinetin treatments. Sucrose concentration was not given. Explants were disinfected using 0.2% HgCl2 for 7 minutes.[11]

Similarly, callus culture can be induced slowly with 0.1 mg/l kinetin and 3.0 mg/l of either NAA or IBA from leaf sections of either greenhouse plants or established in-vitro shoot cultures. [7] The sucrose concentration is not stated directly, however, the same research group recommends 20 g/l in an earlier study.[9]

2,4-D did not induce callus formation in isolation, but it did in combination with 0.1 mg/l kinetin. Either IBA or NAA in combination with kinetin was superior in inducing callus formation compared to 2,4-D, however.[9][7]

Calli will also be produced at the base of shoot cultures derived from shoot tips on a medium containing IBA in isolation. However, these calli will produce roots.[7][9] It is worth investigating shoot formation from leaf-derived calli.

Pigment exudates inhibit further callus growth.[11] PVP added at 0.1% can be used to reduce but not eliminate the problem.[7] Activated charcoal at 0.3% was not effective at absorbing pigments.[9] After subculturing every 4-6 weeks, PVP can be excluded.[12]

Preliminary attempts at establishing callus culture in liquid media only produced a “dark concoction” with disintegrated calli.[7]

Cultivation

[13] [14] [15] [16] [17] [18] [19] [20] [6] [21] [22] [23] [24] [25] [26]

Harvest

Drying and storage result in the loss of cathinone by conversion to the less desirable cathine.[27][28][29][30]

[31]

Yield

[32] [15] [33] [34]

Soilless

Soil

Fertilization

[35] [24]

Pests

[36] [37] [38] [39] [40]

Morphology

The complete chloroplast genome of edulis has been sequenced.[41]

[42] [43] [44] [45] [46] [47] [25] [48] [49] [50]

Roots

Stem

Leaves

[51]

Inflorescence

Seeds

[52]

Ecology

If not pruned, edulis can live up to 40 years and grow to 25m in height.[7]

Indigenous to East Africa and Southern Arabia.[7]

[53] [54] [20] [55]

Phytochemistry

Edulis contains many tannins, flavonoids, glycosides, and alkaloids. Most notably, edulis contains the phenylalkylamines cathinone, cathinenorephedrine, merucathinone, pseudomerucathine, and merucathine.[56][57]

[58] [27] [28] [59] [60] [61] [13] [62] [14] [63] [64] [65] [66] [67] [16] [68] [56] [69] [70] [57] [45] [71] [72] [73] [74] [75] [37] [76] [38] [21] [77] [78] [79] [29] [80] [81] [82] [24] [83] [84] [85] [86] [87] [88] [89] [90] [91] [92] [93] [94] [95] [5] [96] [39] [97] [98] [99] [100] [101] [102] [103] [104] [105] [106] [9] [107] [108] [109] [110] [111] [112] [113] [114] [115] [116] [117] [118] [119] [120] [121] [122] [123] [124] [125] [126] [127] [128] [129] [130] [131] [132] [133] [134] [12] [50] [135] [11]

Cathinone can be detected in micropropagated plantlets of edulis but not in callus cultures.[7] The concentration of cathinone increased with the increasing age of shoots. The trend continued in greenhouse plants derived from micropropagation, approaching the concentration in the original explant source.[9]

[42] [44] [43] [74] [47] [111] [112] [49]

Infraspecific Variation

Biosynthesis

Distribution

Timecourse

Improvement

Identification

Inheritance

Methods

History & Society

[136] [137] [138] [139] [140] [22] [23] [141] [142] [88] [143] [144] [145] [146] [147] [148]

Work Log

Bibliography

1. Hill, Bob G., Č̣at (Catha Edulis Forsk), Journal of Ethiopian Studies, vol. 3, no. 2, pp. 13--23, 1965. url: https://www.jstor.org/stable/41965724.
2. Hocking, George M., Catha Edulis (“Kath” or “Kat”), Quarterly Journal of Crude Drug Research, vol. 3, no. 1, pp. 338--340, January 1963. doi: 10.3109/13880206309102224.
3. Bally, P. R. O., Catha Edulis., East African Medical Journal, vol. 22, no. 1, pp. 2--3, 1945. url: https://www.cabdirect.org/cabdirect/abstract/19452901074. Abstract
   i. Miraa is one of several local names (others are muirugi, khat, cafta) of a tree (Catha eduhs), usually some 20 feet in height, occasionally three to four times this, indigenous in Africa. Its leaves and twigs may be chewed, or infused as Bushman's Tea, or smoked, or the leaves may be made into a sweet with honey. It induces, particularly when chewed, " a happy and mellow friendliness and an...
4. Abdulwaheb, Mohammedberhan and Muche, Abebe, Khat (Catha Edulis Foresk)—an Updated Review, pp. 14, 2007. Abstract
   Khat (Catha edulis Forsk) is an evergreen plant that grows at high altitudes in East Africa and Arabian Peninsula. Chewing its fresh leaves is a widespread habit in the local populations, with several million people consuming khat regularly in social sessions that often last for hours. This review describes the history, cultivation and chemical composition of khat. The pharmacology of (-)-cathinone (the main active component) in the central nervous system and the peripheral effects are described. (-)-cathinone is regarded as an amphetamine- like sympathomimetic amine and this mechanism of action is discussed in relation to the central stimulant actions. The medical, psychological and social and epidemiological aspects are emphasized, and the current knowledge about the reproductive effects of khat is also presented.
5. Feyissa, Anteneh M. and Kelly, John P., A Review of the Neuropharmacological Properties of Khat, Progress in Neuro-Psychopharmacology and Biological Psychiatry, vol. 32, no. 5, pp. 1147--1166, July 2008. doi: 10.1016/j.pnpbp.2007.12.033. Abstract
   Background The psychostimulant khat (Catha edulis Forsk), is a herbal drug cultivated and chewed as a recreational and socializing drug in East Africa and the Arabian Peninsula for centuries. Due to increasing air transportation and the loosening of customs restrictions, it is now readily available in the Western Countries mainly used by immigrants from khat growing areas causing a concern to policy-makers. Objective We conducted this review to further gain an insight to the neuropharmacological effects of khat. Methodology PubMed search engine with key terms ‘khat’ or ‘qat’ or ‘mirra’ or’qaad/jaad’ or ‘cathinone’ was used to obtain articles relevant to khat chewing. In total 284 English written articles published from 1959 to 2007 were screened. Results Most of the studies focused on cathinone, the postulated active psychostimulant alkaloid in khat. There were few studies which investigated the entire plant extract in either in vitro or animal studies. In the majority of the studies it was reported that both cathinone and cathine, another psychoactive constituent, have actions that are similar to those of amphetamine. Conclusions It seems that the well investigated khat alkaloids have many features similar to amphetamines; however there is a need for a more thorough examination of khat itself in well designed in vitro, animal and human studies with a range of comparator drugs before confirming the claim that khat is a “natural amphetamine”.
6. {Ben-Shabat}, Shimon and Goloubinoff, Pierre and Dudai, Nativ and Lewinsohn, Efraim, Farming Amphetamines: Khat (Catha Edulis Forsk.) a Traditional Plant with Mild Stimulating Psychoactive and Medicinal Properties, pp. 181--197, 2014. doi: 10.1007/978-94-017-9276-9_9. Abstract
   Khat (Catha edulis Forsk., Celastraceae) is a flowering perennial shrub with a long history of use and cultivation in East Africa and the Arabian Peninsula. Young khat leaves are traditionally chewed in social gatherings to attain special states of mind, aimed especially at awakeness and enhanced mind focus. Since khat chewing contains amphetamine-like molecules and reportedly causes addiction among users it is banned in most countries, but it is part of social life and legal in some countries. The main pharmacoactive compounds present in khat leaves are the phenylpropylamino alkaloids (S)-cathinone and (S)-cathine.
7. Elhag, H. M. and Mossa, J. S., Catha Edulis (Khat): In Vitro Culture and the Production of Cathinone and Other Secondary Metabolites, pp. 76--86, 1996. doi: 10.1007/978-3-662-08618-6_5. Abstract
   Khat, Catha edulis (Vahl) Forssk. ex Endl. (Celasteraceae), is an evergreen shrub or tall tree that may reach up to 25 m in height if not pruned (Fig. 1). Extensive pruning makes it a small shrub, as it is usually described. Its life span may extend for 40 years. The plant is indigenous to East Africa and southern Arabia, but may have originated in the Harar district of Ethiopia, according to earlier reports (Getahun and Krikorian 1973). Its habitat extends from northern Ethiopia to the mountainous regions of East Africa and Yemen, all the way to south Africa, between latitudes 18 °N and 30 °S. It is cultivated mostly on hillsides and mountain slopes at altitudes of 1500–2000 m above sea level (Nordal 1980; Krikorian 1984). Besides Ethiopia and Yemen, the khat plant is now grown in Djibouti, Somalia, Kenya, Tanzania, Uganda, and Madagascar. However, the use of the plant is by no means restricted to the natives of these countries, but extends to other Asian countries and immigrant communities in several Western countries (Kalix 1990).
8. {karode13M}, Khat, Catha Edulis Root Sucker Propagation, Shroomery, November 14. url: https://www.shroomery.org/forums/showflat.php/Number/20909793. Abstract
   Catha edulis is one of the entheogens that can be propagated via root sucker division. This basically means the plant will put out shoots at the base of the plant, these shoots end up sprouting roots and this makes making new plants quite easy. Here's a quick how to:
9. {El-Domiaty}, {\relax Mm}. and Elhag, H. M. and {El-Feraly}, F. S. and {Al-Meshal}, I. A. and {El-Olemy}, M. M., Studies on (-)-Cathinone Formation in Micropropagated Plants and Tissue Cultures of Catha Edulis (Khat), International Journal of Pharmacognosy, vol. 32, no. 2, pp. 135--141, January 1994. doi: 10.3109/13880209409082984. Abstract
   A highly sensitive HPLC method (minimum detection limit 150 ng) is reported for the determination of (-)-cathinone in micropropagated plants and in tissue cultures of Catha edulis (khat). Callus was initiated from leaves or shoot tips of khat on MS media containing either IB A (indolebutyric acid) or NAA (naphthalene acetic acid). Callus growth was best obtained in the light on media containing 3.0 mg/1 IBA or NAA. The inclusion of 1.0 g/1 of PVP in the medium was found necessary to reduce the effects of pigments and to enhance callus growth. (-)-Cathinone was found in micropropagated plantlets and plants, but not in the corresponding callus cultures. Its content in micropropagated plants was found to increase with age.
10. Elhag, Hamid M., In Vitro Propagation of Catha Edulis, HortScience, vol. 26, no. 2, pp. 212, February 1991. doi: 10.21273/HORTSCI.26.2.212. Abstract
    Khat [Catha edulis (Vahl) Forssk. ex Endl., Celastraceae] is a perennial shrub or small tree that grows wild and is cultivated in certain regions of the Middle East and eastern Africa. The leaves are commonly chewed while fresh to alleviate hunger and to produce stimulating effects, but habitual use is often associated with social and medical problems (Shadan and. Shellard, 1962). Because khat may have other pharmacological properties (Al-Meshal et al., 1986; Nordal, 1980), there is a need to provide reliable and uniform plant material for further studies on secondary plant products. This report describes in vitro propagation of khat.
11. Kumari, Aloka and Baskaran, Ponnusamy and Van Staden, Johannes, Enhanced HIV-1 Reverse Transcriptase Inhibitory and Antibacterial Properties in Callus of Catha Edulis Forsk., Phytotherapy Research, vol. 29, no. 6, pp. 840--843, 2015. doi: 10.1002/ptr.5318. Abstract
    Developing tissue culture systems for medicinal plants is important in that they may offer an alternative to protect wild populations. However, analysis of bioactivity for tissue culture developed plant tissues is required to offer support and allow acceptance in traditional medicine. The use of propagated callus could provide potential material for therapeutic purposes. This study was aimed at evaluating the anti-HIV and antibacterial properties of a three-month-old tissue culture-derived calli and leaves of cultivated mother plants of Catha edulis Forsk. The calli were derived from leaf explants using different plant growth regulators. The calli obtained from callus cultured on 9.8 μM indole-3-butyric acid plus 2.7 μM naphthalene acetic acid exhibited the highest HIV-1 reverse transcriptase inhibitory effects when compared with other treatments and the mother plants. Different extracts of callus exhibited high antibacterial activity ({$<$}1 mg/mL: minimum inhibitory concentration from 0.098 to 0.78 mg/mL) against both gram-positive and gram-negative bacteria. Leaf acetone extracts showed moderate activity (minimum inhibitory concentration of 0.78 mg/mL) against Staphylococcus aureus. The present study indicated that tissue culture-derived calli could be used as therapeutic agents for traditional medicine. The choice of treatment used in the tissue culture system and the age of the callus for production of biomass may significantly influence its therapeutic potential. Copyright © 2015 John Wiley \& Sons, Ltd.
12. Elhag, Hamid and Mossa, Jaber S and {El-Olemy}, Mahmoud M, Antimicrobial and Cytotoxic Activity of the Extracts of Khat Callus Cultures, Perspectives on New Crops and New Uses, pp. 463--466, 1999. url: https://www.hort.purdue.edu/newcrop/proceedings1999/v4-463.html. Abstract
    Khat, (Catha edulis Forssk., Celastraceae) is an evergreen tree indigenous to East Africa and Yemen. The fresh young leaves are commonly chewed, known as the Khat habit, to alleviate hunger and to produce stimulating effects (CNS). Such effects were shown to be due to phenylalkylamine alkaloids, primarily cathinone (Kalix 1990; Crombie et al. 1990). Habitual use of khat is often associated with social and medical problems (Shadan and Shellard 1972). Previous work on khat cultures, in our laboratories, has dealt with in vitro micropropagation (Elhag 1991) and the production of secondary metabolites by micropropagated plantlets and callus cultures (El-Domiaty et al. 1994). In the course of our work with khat tissue cultures, the production of dark colored pigments was observed as a typical characteristic of the callus culture (Elhag and Mossa 1996). The present investigation deals with the isolation, identification, and biological effects of such pigments.
13. Ademe, Beyene Wondafrash and Brimer, Leon and Dalsgaard, Anders and Belachew, Tefera and Ademe, Beyene Wondafrash and Brimer, Leon and Dalsgaard, Anders and Belachew, Tefera, Chemical and Microbiological Hazards of Khat (Catha Edulis) from Field to Chewing in Ethiopia, GSC Biological and Pharmaceutical Sciences, vol. 11, no. 1, pp. 024--035, 2020. doi: 10.30574/gscbps.2020.11.1.0038. Abstract
    Catha edulis of the plant family Celastraceae commonly named as Khat in Ethiopia is a stimulant plant containing amphetamine-like substances. Fresh Khat leaves described to contain some 60 different constituents. Consumers chew leaves and masticate it for hours. Some users make a paste from dried leaf powder, mixing with sugar and water which is easily chewed and swallowed. In some areas, dried leaves are used as a tea, and also crushed and rolled into cigarettes. Less attention has been directed toward possible chemical and microbial contamination and risky pathways. The aims of this study are 1.Identify the actual Khat production-consumption process from farm to use. 2. Detect chemical and microbial contamination risk of consumable Khat leaf in process 3. Assess the microbiological qualities chewable Khat leaf. Descriptive statistics from the main dataset, for Khat consumption, showed that out of 1169, 564 household heads were Khat consumers and out of these consumers, 347 (62.52\%) consume daily. Majority of the pilot study participants (retailers and consumers) confirmed that pesticide chemicals are sprayed on Khat bushes and trees, and Khat farmers disclosed the use of Dichlorodiphenyltrichloroethane (DDT) and Malathion on their farm. The mean CFU/gm was 1.69*10\textasciicircum 5 which indicate poor hygiene /handling. Our observation showed that the processes from farming, Transporting, collection, distribution (whole-sellers, retailers) to consumption indicate a potential risk for Khat leaf to become contaminated with Chemicals/ microorganisms.
14. Adamu, Dagne Bayih and Muluye, Tesfaye and Gonfa, Teshome and Achamo, Temesgen and Tana, Tamado, Determination of Pesticide Residue in Water and Khat (Catha Edulis) Leaves Using GC-ECD, Journal of Applied Chemistry and Environment Protection, vol. 4, no. 1, December 2019. url: https://revues.imist.ma/index.php/JACEP/article/view/18700. Abstract
    In this work the concentration of some selected pesticides such as aldrin, dialdrin, BHC, diazinon, DDT, 4,4-DDE and heptachlor were investigated in water and khat samples that were collected from five different sites. The pesticides were extracted using liquid-liquid and solid phase extraction technique and analyzed by GC-ECD. The recovery test, linearity cure and extraction efficiency were tested by using standard pesticide samples. The highest concentration of pesticide obtained in water samples is diazinon in WS2 (0.0698mg/L), and the lowest concentration is heptachlor in WS3 (0.0006mg/L). The highest and lowest concentrations of pesticides obtained in Khat samples are diazinon in KS1 (0.0323mg/L) and KS3 (0.0001mg/L) respectively. The concentration of diazinon and four isomers of BHC detected in each water sample are higher than the recommended limits set by WHO which shows contamination of the lake water. Diazinon and DDT levels in KS1 (0.0323mg/L), KS2 (0.0293mg/L) and KS1 (0.0134mg/L), KS2 (0.0173mg/L) respectively are above the maximum residue level.
15. Ademe, Beyene Wondafrash and C, Jennifer Coates and Dalsgaard, Anders and Brimer, Leon and Lema, Tefera Belachew, Khat Production and Consumption; Its Implication on Land Area Used for Crop Production and Crop Variety Production among Rural Household of Ethiopia, Journal of Food Security, vol. 5, no. 4, pp. 148--154, August 2017. doi: 10.12691/jfs-5-4-5. Abstract
    Khat (Catha edulis Forsk), is a stimulant plant grown mainly in Ethiopia, Yemen and Kenya. Currently it is a ubiquitous commodity cultivated and chewed; imbedded in Ethiopian culture and agriculture. In a circumstance of land degradation and scarcity farmers consider Khat as a better small-scale faming alternative; however land disposition for Khat-mono-cropping can be a disadvantage. Adjusting for the sets of alternatives on the land area to be used for crop production and on-farm crop variety is a factor that determines Khat farmers’ household sustainable agriculture and livelihood. The dynamics in relation with rural households Khat production/consumption is not well explored. This study sets out to document the implication of farmers’ choice of Khat production and / or consumption on land use for crop production and crop variety production in rural households of Ethiopia. A panel survey using quantitative method was adopted. Data were collected in two regions of Ethiopia using pre-tested interviewer-administered questionnaire using Open Data Kit (ODK). Data were exported to STATA version SE 12(Stata Corp LP, College Station, Texas, USA). Multivariable linear regression model was run. A significantly higher proportion of Khat consumers were producers (P{$<$}0.001). Land size used for crop production increased by 0.2 units (hectares) for Khat consumers and producers as compared with No-Khat consumers and no-Khat producers’ households (β=0.20, p{$<$}0.001). The likely hood of having variety of crops is two times higher for Khat consumer and Khat producer households as compared with no-Khat consumers and no-Khat producers households (AOR: 2.00 [95\%CI: 1.38, 2.91], p{$<$}0.001). Land tenure system and agricultural policy and interventions should consider this Khat cropping effect among households in Khat producing areas of the country. Khat cultivation and use should be understood in a proper context in association with economical; social, cultural and environmental reality.
16. Mekonen, Seblework and Ambelu, Argaw and Negassa, Belay and Spanoghe, Pieter, Exposure to DDT and Its Metabolites from Khat (Catha Edulis) Chewing: Consumers Risk Assessment from Southwestern Ethiopia, Regulatory Toxicology and Pharmacology, vol. 87, pp. 64--70, July 2017. doi: 10.1016/j.yrtph.2017.05.008. Abstract
    Khat (Catha edulis) is one of the most consumed plant in the horn of African countries. However, it is a stimulant plant that has several side effects on the health of consumers. On top of that, the khat leaves used for human consumption are often contain contaminants such as pesticide residues. The present study aims to investigate the level of DDT residue and its metabolites (p'p-DDE, p'p-DDD, o'p-DDT and p'p-DDT) in khat samples and to undertake exposure assessment to consumers. The khat samples were collected from local markets in southwestern Ethiopia. Consumption survey was undertaken using 24~h recall method for both male and female khat consumers. The finding showed that 80\% of the khat samples contained DDT and its metabolites. Some of the residues were above the maximum residue limit (MRL) set by Food and Agricultural Organization (FAO). The concentration of p'p-DDE and p'p-DDT in khat were in the range of 0.033–0.113 and 0.010–0.026~mg/kg, respectively. High concentration of the metabolite (p'p-DDE) compared to the parent compound (p'p-DDT) revealed the historical use of DDT in the study area. Probabilistic exposure analysis indicated that the mean and 97.5 percentile (P97.5), of the estimated daily intake of total DDT were 0.002 and 0.006~mg/kg~bw/day, respectively. The study concluded that khat consumers are exposed to the stimulant effect of the plant as well as DDT and its metabolites in Jimma zone.
17. Amos, Gyau and Catherine, Muthuri, The Socio-Economic Potential of under-Utilized Species to Small Holder Farmers: The Case of Khat (Catha Edulis) in Ethiopia, African Journal of Business Management, vol. 10, no. 11, pp. 279--287, June 2016. doi: 10.5897/AJBM2015.7950.
18. Gebrehiwot, Mersha and Elbakidze, Marine and Lidestav, Gun and Sandewall, Mats and Angelstam, Per and Kassa, Habtemariam, From Self-Subsistence Farm Production to Khat: Driving Forces of Change in Ethiopian Agroforestry Homegardens, Environmental Conservation, vol. 43, no. 3, pp. 263--272, September 2016. doi: 10.1017/S0376892916000035. Abstract
    Traditional agroforestry homegardens deliver multiple products and benefits, including food security and livelihoods for rural households in Ethiopia. However, this land use has been changing towards monoculture production of khat (Catha edulis). This study analyses the development trajectories and causes of change in agroforestry homegardens. In total, 84 interviews, including key informant and semi-structured household interviews, and eight focus group discussions were conducted in the Southern Nations, Nationalities and Peoples' Regional State. It was found that khat production was increasing regardless of household wealth status. The proximate causes included better financial income for households, smaller sizes of farms due to farm land redistribution, favourable market conditions for khat, access to irrigation, decrease in governmental subsidies to buy fertilizer and quality seeds for food crop production, a positive experience of other farmers in khat production, and minimizing risks of theft and wildlife damage. Khat production challenges the implementation of national policies towards eradication of poverty and hunger.
19. Mekonen, Tefera and Giday, Mirutse and Kelbessa, Ensermu, Ethnobotanical Study of Homegarden Plants in Sebeta-Awas District of the Oromia Region of Ethiopia to Assess Use, Species Diversity and Management Practices, Journal of Ethnobiology and Ethnomedicine, vol. 11, no. 1, pp. 64, August 2015. doi: 10.1186/s13002-015-0049-8. Abstract
    Homegardens in Ethiopia are currently facing different threats mainly due genetic erosion, loss of traditional knowledge on their use and management and drought. On the other hand, research and documentation works on homegardens in the country are very limited. There is no previous report indicating conduct of ethnobotanical study on homegardens in selected study district. The present study thus attempted to document knowledge on uses and management practices of homegardens by people in study district.
20. Zahran, M. A. and Khedr, A. and Dahmash, A. and {El-Ameir}, Y. A., Qat Farms in Yemen: Ecology, Dangerous Impacts and Future Promise, Egyptian Journal of Basic and Applied Sciences, vol. 1, no. 1, pp. 1--8, January 2014. doi: 10.1016/j.ejbas.2013.09.002. Abstract
    Qat (Catha edulis) is an ever green tree/shrub naturally growing in Abysssinian mountains as well as in the other countries of East Africa. It has been introduced to Yemen before the Islamic Era, nowadays it is widely cultivated in the mountains of Sanaa and Taiz. The dark green leaves of qat are chewed in fresh condition by more than 90\% of Yemen people. These leaves contain alkaloids similar to cafffein having pleasurable and mildly stimulating effects. Qat is, thus, classified by WHO as a “drug of abuse”. The present study describes the ecological features, including the physical environment and floristic composition, of qat farms in 12 sites in the mountains of Taiz (3 sites) and Sanaa (9sites) having altitudes of 1450~m and 2440~m, respectively. The chemical constituents of qat's leaves collected from these mountains and the dangerous medicinal and socioeconomic impacts of qat's cultivation on the Yemen's people are described. A proposal that may help to control chewing and changing its cultivation from being harmful to be useful and profitable for Yemen's people is discussed.
21. Ligani, Shemsu and Hussen, Ahmed, Determination of Organochlorine Pesticide Residue Levels in Chewable Parts of the Khat (Catha Edulis) Plant, Bulletin of Environmental Contamination and Toxicology, vol. 93, no. 5, pp. 591--595, November 2014. doi: 10.1007/s00128-014-1385-4. Abstract
    In this study, the levels of DDT and its metabolite residues were determined in chewable parts of Catha edulis plants grown in the southern part of Ethiopia. The levels of p,p′-DDT and p,p′-DDE were found to be in the range of 10.8–19.7 and 3.5–18.6~μg/kg, respectively. These data revealed that the residue being detected is from recent applications. The estimated daily intake of total DDT from C. edulis consumption was calculated to be in the range between 0.0278 and 0.0747~μg/kg, which is significantly lower than the FAO/WHO guideline. However, this may not guarantee safety, as the application of DDT extends to vegetables as well. Even though the use of DDT was banned in Ethiopia for agriculture purposes, detectable levels are still being observed. The results of the study necessitate the need for awareness creation among the people in the community.
22. Kandari, Laxman S. and Yadav, Hiranmai R. and Thakur, Ashok K. and Kandari, Tripti, Chat (Catha Edulis): A Socio Economic Crop in Harar Region, Eastern Ethiopia, SpringerPlus, vol. 3, no. 1, pp. 579, October 2014. doi: 10.1186/2193-1801-3-579. Abstract
    Chat (Catha edulis) is an important perennial crop and its leaves are chewed for a stimulating effect. It is widely cultivated in the Ethiopian highlands of Oromia region and is figured as Ethiopia’s second largest foreign exchange earner. Its cultivation accounts for about 70\% of farmer’s income in the study area. The common effect of its consumption leads to insomnia, a condition that the users sometimes try to overcome with sedatives or alcohol. The present study is an attempt to survey and assess the impact of crop on the community. It has been observed to implicate health problems, reduces savings and nutritional standards of the family members. The chat yields in the area ranges from 1500–1800 kg/ha through monoculture. During the study, the average monthly income of the family practicing chat cultivation was from Birr 8, 533.00 to 13, 166.00 kg/ha per year in Baate and Genede cultivating areas. When the average cost per/ha was rupees 60/kg. The present study shows that during the recent past, leaf consumption has increased significantly. Chat growers are not only producers but also traders and consumers. Its consumption has become a widespread habit from secondary schools. Highest number of consumers was found to be among drivers followed by students and shopkeepers. The consumption of the plant is not considered a taboo but on contrary a status symbol in the region. It has no legal or moral implications and is considered as a part of custom and habit of local people. High value cash crop like vegetables and orchard fruits needs to be used as a replacement for chat which could be a regular source of income to farmers. Alternative sources of income for farmers needs to be scientifically worked out and proposed keeping in view the proportion of agricultural land reserved under chat cultivation and to increase the production of food grains being produced.
23. Unravelling the Potential of Neglected Tree Species for Income Generation: The Case of Catha Edulis in West Shewa Zone of Ethiopia, 2013. doi: 10.22004/ag.econ.160549. Abstract
    Agriculture is an important part of Ethiopia’s economy constituting a significant proportion of Gross Domestic Product (GDP) and total export. The method of agricultural production in Ethiopia has resulted in increasing deforestation and degradation. Among others, Agroforestry has been considered as a potential alternative to address the increasing deforestation and degradation. Khat (Catha edulis), an indigenous shrub species offers the potential to be intercropped with other food crops in an agroforestry system. The aim of this article is to assess the competitiveness of Khat production as a complementary source of income for farmers in the West Shaw region of Ethiopia. Three focus group discussions (FGD) with 14 Khat producers per FGD were conducted in 3 villages in West Shewa and East Wollega zones in the Oromia region of Ethiopia. In addition, key informant interviews with traders were conducted to obtain further information about Khat production and marketing. Data was analyzed using Porters’ five forces framework. The results indicate that demand exceeds its current supply and farmers have power to determine the price. However, there is high level of competition among traders in sourcing from the farmers leading to price war among traders. The agro ecological suitability for Khat production in the area indicates that more farmers can produce it if the awareness of its market potential is built. However, with the high level of demand and existence of export market, supply can be absorbed. We conclude that Khat can be promoted as a profitable crop for agroforestry practice in Ethiopia
24. Atroosh, K. B. and {Al-Moayad}, M. A., Water Requirements of Qat (Catha Edulis) Cultivation in the Central Highlands of Yemen, Journal of Scientific Research, vol. 4, no. 1, pp. 77--77, 2012. doi: 10.3329/jsr.v4i1.7544. Abstract
    Water requirements of qat (Catha edulis) under irrigated and rainfed production systems in the central highlands in Yemen were studied during 2003 and 2004 at 6 sites. The crop evapotranspiration of qat was calculated by balancing method, where the sources of evapotranspiration were irrigation water and rainfall. The amounts of crop evapotranspiation of qat during winter months were less than other months of the year under both irrigated and rainfed conditions. The maximum daily evapotranspiration was 2.5 mm during summer season. The annual crop evapotranspiration for the irrigated qat in the Yemeni central highlands was 602.8 to 786.7 mm and 412.8 to 506.2 mm for the rainfed qat. The average annual crop evapotranspiration of qat for both production systems (irrigated and rainfed) was about 553.6 mm/year.Keywords: Crop water requirement; Evapotranspiration; Qat; Central highlands; Yemen.\© 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v4i1.7544J. Sci. Res. 4 (1), 77-82 (2012)
25. Getahun, Amare and Krikorian, A. D., Chat: Coffee’s Rival from Harar, Ethiopia. I. Botany, Cultivation and Use, Economic Botany, vol. 27, no. 4, pp. 353--377, October 1973. doi: 10.1007/BF02860690. Abstract
    The early history, botany, cultivation, economics and sociological aspects of the use ofCatha edulis (Vahl) Forsk. ex Endl., commonly known as chat, have been presented in some detail with special emphasis being given to agricultural practice around Harar, Ethiopia, an area where the plant is probably native. Chat attains an average height of 2.5 to 3 meters but may occasionally reach 15–20 meters. Its tender leaves and twigs are used exclusively as a masticatory in this area although its name Abyssinian, Somali or Arabian tea indicates its use as a beverage in earlier days and some localities. Indeed, it is held that prior to the introduction of coffee and its use, people in Yemen made a decoction of chat and the use of chat even disappeared for a while from Aden and coffee drinking was substituted. The twigs of chat, with leaves attached, in bundles of fifty or so and in pieces from about 30 to 40 cm in length, form a very considerable article of commerce. The effects produced by chewing the fresh leaves are described as similar to those produced by an amphetamine or amphetamine-like stimulant, only more pleasant and agreeable when not used in excess. Chat is also an anorexiant. Chewers in rural areas use the leaves to give them energy to work and suppress the appetite and keep them from feeling drowsy; in urban areas users chew chat as a “past-time” stimulant, appetite suppressant or as a study aid. Although chat was originally used exclusively by Moslems, its use now pervades all religions and socio-economic groups although Moslem males are still the prime consumers.
26. Brooke, Clarke, Khat (Catha Edulis): Its Production and Trade in the Middle East, The Geographical Journal, vol. 126, no. 1, pp. 52--59, 1960. doi: 10.2307/1790429.
27. Arimi, Joshua, Green Gold: Refining Crude Miraa (Catha Edulis) into a Real Green Gold, African Journal of Science, Technology and Social Sciences, vol. 1, no. 1, September 2022. url: http://41.89.229.52/index.php/AJSTSS/article/view/26. Abstract
    Miraa (Catha edulis) is a very lucrative psychoactive crop for the farmers in lower parts of Meru county and Embu county. However, its handling is unhygienic and it’s a perishable crop. Withering and drying leads to conversion of the stimulating compound; cathinone to a less stimulating compound; cathine. Therefore, it has to be transported to the market within the shortest time possible. This has led to culture of high speed driving of miraa delivery pick-ups and lorries. This is both unsafe to the miraa transporters as well as other road users leading to high records of fatal road accidents. Once in the market, the twigs are chewed raw without any value addition. This form of presentation and chewing makes it look unaesthetic, archaic and primitive. The objective of this study was to determine microbial load and evaluate the possibility of extending the shelf-life and development of various processed products from miraa while retaining the active ingredients.\  The miraa twigs for all the studies were purchased from the local vendors in Meru. Microbial load of miraa from different miraa vending points around Meru town, these are; Nchiru, Kianjai, Ruiri, Makutano and Meru town was studied. Shelf-life of miraa was studied by storing miraa at ambient temperature, refrigerated conditions (4-8 °C) and humidity chamber. Weight loss and total phenolic compounds were monitored. Miraa was processed into unflavoured and flavoured infusion bags. Miraa sourced from Meru town exhibited the highest microbial load compared to the other vending points. This is associated to environmental contaminants and high number of handlers. Miraa stored at ambient temperature exhibited the highest weight loss and reduction in total phenolic compounds while that stored in humidity chamber showed the lowest weight loss and highest retention of phenolic compounds after 72 hours. Consumer tests preferred miraa infusion bags as hygienic with moderate stimulation effects. The results showed that it’s possible to store miraa for up to 72 hours and to prepare miraa infusion bag with stimulatory effects.\ \ 
28. Pendl, Elisabeth and Pauritsch, Udo and Kollroser, Manfred and Schmid, Martin G., Determination of Cathinone and Cathine in Khat Plant Material by LC–MS/MS: Fresh vs. Dried Leaves, Forensic Science International, vol. 319, pp. 110658, February 2021. doi: 10.1016/j.forsciint.2020.110658. Abstract
    The consumption of Khat leaves represents an ancient kind of drug abuse mainly observed in Eastern Africa and the Arab Peninsula among adult men. For this purpose, the leaves are directly collected from the shrub “Catha edulis” prior to extensive chewing process. Seizures in Europe are rare, since the leaves have to undergo quick transportation: After a short period of time, the harvested leaves decompose and suffer in decrease of concentration of the active ingredient cathinone, which makes long term transportation difficult. As an alternative, plant material can be dried to increase life period. In the past years, an increasing number of seizures were made by Austrian police, however, the content of cathinone and cathine in dry material is widely unknown. In this work, a seizure of fresh Khat leaves was compared with two seizures of dried material in terms of concentration of cathinone and cathine using LC–MS/MS analysis. For fresh leaves, a purity grade was found to be 0.115-0.158\% for cathinone and 0.172-0.192\% for cathine, respectively. In contrast, subsequent storage of dried Khat leaves over months led to a dramatic loss of cathinone: Analysis of two seizures revealed that concentration of cathinone dropped to 0.021-0.023\%. These findings are intended to serve as a guideline for Justice authorities to estimate the content of the controlled ingredients of Khat leaves in future.
29. Atlabachew, M. and Chandravanshi, B. S. and {Redi-Abshiro}, M. and Torto, N. and Chigome, S. and Pule, B. O., Evaluation of the Effect of Various Drying Techniques on the Composition of the Psychoactive Phenylpropylamino Alkaloids of Khat (Catha Edulis Forsk) Chewing Leaves, Bulletin of the Chemical Society of Ethiopia, vol. 27, no. 3, pp. 347--358, September 2013. doi: 10.4314/bcse.v27i3.3. Abstract
    The study demonstrated that by freezing or drying under different conditions, cathinone could be detected in the khat (Catha edulis Forsk) samples that have been harvested for more than four months. Freeze drying or freezing in the refrigerator (-20 oC) yielded more than 73\% of cathinone. Air drying, sun drying or oven drying at 60 oC resulted in a cathinone composition of 57\%, 42\% and 36\%, respectively. The study confirmed that, freshly harvested tender leaves of khat contained exclusively of cathinone but upon sun drying, part of it decomposes to cathine and norephedrine leaving cathinone as a major component. Thus it is wrong to assume that sun drying the leaves can result complete conversion of cathinone to cathine and norephedrine. Furthermore, the results of the study confirmed that it was possible to preserve khat samples for longer periods after freeze drying or deep freezing without significant loss of cathinone.~KEY WORDS: Khat, Alkaloids, Cathinone, Cathine, Norephedrine, Storage~Bull. Chem. Soc. Ethiop. 2013, 27(3), 347-358.DOI: http://dx.doi.org/10.4314/bcse.v27i3.3
30. Chappell, John S. and Lee, Marsha M., Cathinone Preservation in Khat Evidence via Drying, Forensic Science International, vol. 195, no. 1, pp. 108--120, February 2010. doi: 10.1016/j.forsciint.2009.12.002. Abstract
    A primary concern with the forensic analysis of the khat plant (Catha edulis) has been the need to preserve the principle psychoactive component, cathinone, which converts to the less-active substance, cathine, after harvesting. The loss of cathinone has serious legal implications since it is a Schedule I controlled substance under federal regulations in the United States, while cathine is Schedule IV. A common misconception is that cathinone is highly unstable once the plant is harvested, and may be undetectable upon drying and prolonged storage. However, drying the plant material will preserve cathinone. Numerous seizures of a dried form of khat (referred to as “graba” in the United States) have been made in recent years, suggesting that drying the plant material is a viable approach to preserve khat evidence for both storage and reanalysis. A qualitative and quantitative study of the composition of khat samples seized as dried plant material has found the khat alkaloids to be relatively stable for a monitored period of 3 years, and cathinone has remained identifiable while stored at room temperature for over 10 years. Studies of green khat (received moist) have also determined that drying the moist leaves at either room temperature or by the application of heat are suitable methods to preserve cathinone in the dried material. These findings demonstrate that cathinone persists in dried khat for a time frame of several years, and simple drying techniques are an effective means to preserve seized khat evidence for long-term storage.
31. Botha, J. and Witkowski, E. T. F. and Shackleton, C. M., Harvesting Impacts on Commonly Used Medicinal Tree Species ( Catha Edulis and Rapanea Melanophloeos ) under Different Land Management Regimes in the Mpumalanga Lowveld, South Africa, Koedoe, vol. 47, no. 2, pp. 1--18, December 2004. doi: 10.4102/koedoe.v47i2.77. Abstract
    Harvesting of products from plants in the wild is widespread throughout southern Africa. Particularly important products are plant parts used in traditional medicine. However, the impacts of harvesting practices are rarely quantified, with as yet insufficient generic rules across species and life forms. This limits the predictive ability to monitor and manage the affected populations. This paper examines the harvesting impact on two popular woody medicinal species used throughout sub-Saharan Africa, namely Catha edulis (Vahl) Forssk. ex Endl. (bushman’s tea) and Rapanea melanophloeos (L.) Mez. (Cape beech). In both species, basal diameters, heights, and the number of size classes in the harvested populations were lower than in unharvested. Densities of harvested populations were higher in both species, including densities of young plants, but the frequency of individuals in larger size classes was lower. The populations of both species being harvested for medicinal products appeared to be withstanding the current levels of harvesting, but the population structure of C. edulis populations being harvested for poles on the roadside and near human settlements had been substantially altered. Despite the resilience of the two species to harvesting for medicinal products, loss of habitat or changes in land use pose a threat to a number of the assessed populations.
32. Getnet, Desalegn and Negash, Mesele, Allometric Equations for Estimating Aboveground Biomass of Khat (Catha Edulis)-Stimulate Grown in Agroforestry of Raya Valley, Northern Ethiopia, Heliyon, vol. 7, no. 1, pp. e05839, January 2021. doi: 10.1016/j.heliyon.2020.e05839. Abstract
    Khat plant (Catha edulis Forsk) is an evergreen perennial cash crop cultivated in east Africa, southwest Arabia, and Madagascar. The plant is known for its production of stimulant fresh leaves, and expanding as expense of other land uses for its short-term financial returns. We, therefore, developed allometric equations for estimating aboveground biomass and carbon (C) removal of khat grown in farmlands of Raya Valley, Northern Ethiopia. A total of 31 plant individuals were harvested destructively on the basis of their diameters and age ranges. The equations were parametrized using biometric variables such as basal diameter (d10), diameter at breast height (d), dominate height (doh) and mean height (h). Results of the analysis showed that, stem accounted for 58\%, branch 32\% and foliage 10\% of the aboveground biomass (AGB). Commercial foliage biomass C removal ranged from 2.3 to 2.7 Mg ha−1. The power equation, AGB = b1×d10b2×dohb3, was the best (highest ranked using goodness-of-fit statistics), explaining 96\% of the variation in aboveground biomass (p {$<$} 0.01). Models comparisons showed that our best ranked equation (M6) improved the aboveground biomass estimate by 44\% and 48 \% that of generic and other species-site specific equations developed in the tropics, respectively. Thus, our best species-site specific equation developed in this study can accurately estimate aboveground of khat plant biomass in the study region.
33. Tolera, Motuma and Teklu, Beyene and Derese, Ararsa, Traditional Home Gardens System Change to Commercialization of Khat (Catha Edulis) Reduced Woody Species Conservation and Climate Change Mitigation Potentials of Sidama Landscape in Southern Ethiopia, no. 4259828, October 2022. doi: 10.2139/ssrn.4259828. Abstract
    Increasing population pressure induced farmland constraints which pushed smallholder farmers in Sidama region to shift from age-old traditional homegardens that is characterized by diversity to monoculture khat cultivation. Although change from polyculture homegardens to monoculture is expected to cause decline in woody species composition and biomass carbon stock, yet there is little quantitative information to testify this pattern. This study was therefore initiated to assess effect of khat expansion at the expenses of homegardens on woody species composition and biomass carbon stock in southern Ethiopia. Woody species were inventoried within 10m x 10m (100m2) plots from sixty three adjacent land use types of homegardens and khat and the total number of tree and shrub species counted and height and diameter of each species were measured. Both generic and species specific allometirc equations were used to calculate biomass carbon stock of each land use types. Woody species diversity was assessed using Simpson's diversity index, Shannon-Wiener and Shannon equitability. A total of 27 plant species that belong to 21 families were recorded and among the woody plant species, trees constituted 67\% and shrubs 33\%. The woody species richness and Shannon and Simpson diversity recorded from khat were by half lower than homegardens. The mean Evenness value was 0.942, 0.390 for homegardens and khat respectively. Coffea arabica was the most important woody species in the home gardens followed by Cordia africana Lam., Persea americana and Grevillea robusta while Catha edulis was the most important woody species in khat land use ttype followed by Coffea arabica, Croton macrostachyus Del and Cordia africana Lam. The aboveground, belowground and total biomass carbon recorded in khat land use types were lower by 18\%, 63\% and 42\% respectively compared to the homegardens.In the home gardens, Grevillea together with Eucalyptus species accounted for 51\% total biomass carbon stock, which implies the replacement of indigenous woody species by not only khat but also fast growing introduced species. Given the multiple role of multipurpose woody species, further study on implication of the decline in woody species diversity and biomass carbon stock on soil fertility, demand for services provided by woody species is vital to understand the socioeconomic and ecological sustainability of farming systems the study area.
34. Mellisse, B.t. and Descheemaeker, K. and Mourik, M.j. and {van de Ven}, G.w.j., Allometric Equations for Yield Predictions of Enset (Ensete Ventricosum) and Khat (Catha Edulis) Grown in Home Gardens of Southern Ethiopia, Annals of Applied Biology, vol. 171, no. 1, pp. 95--102, 2017. doi: 10.1111/aab.12350. Abstract
    Enset is a large, single-stemmed perennial herbaceous plant domesticated as a staple food crop only in Ethiopia. Khat is a perennial plant cultivated for its economically important leaves and twigs that are the sources of stimulant when chewed. We address the issue of yield estimation of both crops, as they are important for the livelihoods of smallholders in the home garden systems in Southern Ethiopia and have received little attention so far. The objective of this study was to develop linear allometric models for estimating the edible (food and feed) and commercial yields of enset and khat plants, respectively. Data were collected from 20 enset and 100 khat plants. Diameter at 50-cm height (d50), pseudostem height (hp) and their combination were good predictor variables for the food products of enset with adjusted R2 values above 0.85, while d50, hp, edible pseudostem height (hep), total height (ht) and their combination were good predictor variables for the feed products of enset with adjusted R2 values above 0.70. For dwarf khat plants crown area (ca) combined with total height (ht) resulted in the best prediction with an adjusted R2 of 0.77, while the leaf and twig dry weight for tall khat plants was best predicted by ca with adjusted R2 of 0.43. In all cases linear models were used.
35. Dobo, Beyene and Asefa, Fassil and Asfaw, Zebene, Phosphorus Requirement for Colonization by Arbuscular Mycorrhizal Fungi (AMF) and Effect of AMF Inoculants on Growth of Perennial Crops and Agroforestry Trees, East African Journal of Sciences, vol. 10, no. 2, pp. 77--86, 2016. doi: 10.4314/eajsci.v10i2. Abstract
    In most tropical soils, phosphorus is deficient and high costs of phosphorus fertilizer made it difficult for smallholder farmers to use it when needed. Arbuscular mycorrhizal fungi is known to improve particularly P in P deficient soils. However, response of plant species to mycorrhizal fungi inoculation and application of different rates of P varies. Therefore, this study was conducted to investigate the effect of phosphorus (P) concentrations on arbuscular mycorrhizal fungi (AMF) colonization and growth of two perennial crops (Catha edulis and Ensete ventricosum) and four multipurpose agroforestry trees (Cordia africana, Croton macrostachyus, Erythrina brucei and Millettia ferruginea). The experiment was conducted in a glasshouse. The treatment consisted of 0, 0.005, 0.01, 0.02, 0.05, and 0.1 mg P/g substrate and three species of AMF. The experiment was laid out in CRD design in a factorial arrangement. The results showed that plant growth parameters (shoot length and dry weight) and P uptake increased significantly after inoculations with AMF, namely Rhizophagus clarus, and Rhizophagus intraradices, and the mixed AMF species. Results on effect of P application on total mycorrhizal dependency (MD) of the studied crops and agroforestry tree species showed that maximum (41.71\%) MD value was recorded for Rhizophagus clarus in khat (Catha edulis Forsk.), followed by 34.85 and 34.45\% MD values for the same Rhizophagus clarus in Birbira (Millettia ferruginea) and Bisana (Croton macrostachyus), respectively. The next MD values, ranging from 2.57\% for Catha edulis to 30.67\% in Ensete ventricosum, were recorded for inoculation with the mixed AMF species. The least MD values of 3.51, 16.46, 10.51, 7.71, 4.34, and 14.32 were recorded for treatments with Rhizophagus intraradices for all plant species (Catha edulis, Cordia africana, Croton macrostachyus, Ensete ventricosum, Erythrina brucei and Millettia ferruginea) under the study respectively. Optimum P concentrations for maximum benefits from the AMF symbiosis in the aforementioned six plant species varied from 0.005 to 0.02 mg P g-1 substrate and the corresponding peaks of arbuscules, vesicles, percent colonization, and spore count per 50 cm3 sand were noticed at similar P concentrations. Thus, the current research results revealed that the recorded plant growth peaks were attributed to AMF colonization of the perennial crops and agroforestry trees. Therefore, inoculating plant species with a suitable AMF inoculant could result in a benefit comparable to high P fertilizer input and lead to a significant cost saving from expenditure on inorganic P fertilizer. The information obtained on minimum P requirement for perennial crops and shade trees in Sidama agroforestry can form the basis for further pot/field experiments involving integration of chemical fertilizers with AMFKeywords: Agroforestry; Crops; Inoculation; Phosphorus; Root colonization; Spore density; Trees.
36. Seid, A. and Goftishu, M. and Degebassa, L. and Mekete, T., Occurrence, Distribution, and Abundance of Plant-Parasitic Nematodes Associated with Khat (Catha Edulis Forsk) in East Hararghe Zone, Ethiopia, Nematropica, vol. 45, no. 2, pp. 208--214, December 2015. url: https://journals.flvc.org/nematropica/article/view/87382. Abstract
    Plant-parasitic nematodes have received little research attention in the tropics particularly in sub-Saharan Africa as compared to temperate countries. Despite the daily use and consumption of khat (Catha edulis Forsk) by millions of people across Ethiopia and other countries, very little is known about the associated plant-parasitic nematodes. Consequently, this survey was initiated to study the occurrence, distribution, and abundance of plant-parasitic nematodes associated with C. edulis in East Hararghe Zone, Ethiopia. A total of 300 composite soil and root samples (150 each) were collected from 15 major khat-growing districts in East Hararghe Zone during the 2013/14 growing season. This survey documented eight plant-parasitic nematode genera: Criconema spp., Helicotylenchus spp., Hemicyclophora spp., Longidorus spp., Meloidogyne spp., Paratylenchus spp., Pratylenchus spp., and Rotylenchulus spp. associated with khat crop. Among these, Pratylenchus, Meloidogyne, Helicotylenchus, and Longidorus were the most frequently encountered and abundant plant-parasitic nematode genera with 80, 60, 53.3, and 46.6\% frequency of occurrence from soil, respectively. This diversity could be attributed to the cropping pattern of khat, which is mostly intercropped with solanaceous and other vegetables (mainly tomato, pepper, cabbage, potato, and sweet potato), cereals (mainly maize and sorghum), and groundnut by Hararghe farmers. These findings suggest that producers need to monitor and carefully select their cropping pattern. Furthermore, research should focus on the damage potential of these nematode species on khat crop performance to determine the economic threshold level and estimate a cost-benefit analysis on management practices.
37. {AL-Jalali}, Muhammad A and Shaltout, Abdallah A, Natural Radioactivity of Catha Edulis (Khat) and Tobacco Plants Collected from Yemen, vol. 2, no. 5, pp. 6, 2014. Abstract
    Chewing Catha edulis (Khat) and smoking tobacco at the same time cause a severe problem to human health. This behavior could be responsible for an array of cancer diseases, which leads to human death. For this reason, the present work aims to demonstrate the natural radioactivity distribution of Catha edulis (Khat) and tobacco plants grown in Yemen. Wavelength Dispersive X-ray Fluorescence (WDXRF) spectrometer was used to specify the chemical composition of Catha edulis and tobacco plants. The results of X-ray fluorescence experiments revealed the presence of heavy minerals in Catha edulis and Tobacco with different concentrations. In addition, the radioactivity concentrations of 226Ra, 238U, 232Th and 40K were quantified in Bq/kg for these plants using -spectrometry connected with high pure germanium detector. The average concentration of 226Ra, 238U, 232Th and 40K in Catha edulis were 59.5±2.40, 0.285±0.05, 50.25±4.88, 687±38.18 Bq/kg respectively. For the collected Tobacco plants the average concentrations of 226Ra, 238U, 232Th and 40K in were 71.0±2.26, 0.81±0.04, 71.35±8.84, 1126.5±50.20 Bq/kg respectively. It was found that the concentrations of the natural radioactivity of tobacco plants are higher than their level in the Catha edulis plants.
38. {AL-Jalali}, Muhammad, Effects of Low Radioactivity of the Yemeni’s Catha Edulis (Khat) and Tobacco Plants, International Journal of Physical Research, vol. 2, no. 2, pp. 32--36, June 2014. doi: 10.14419/ijpr.v2i2.2843. Abstract
    The present work aims to shed light on the relationship between the cause of cancer and low radioactivity distribution of Catha edulis (Khat) and tobacco grown in Yemen, whereas they have a remarkable relationship with human health, due chewing of Catha edulis and smoking tobacco simultaneously. The complicated behavior of smoking tobacco and chewing Catha edulis at the same time could be responsible for different kinds of cancer diseases. Wavelength Dispersive X-ray Fluorescence (WDXRF) spectrometer was used to specify the chemical composition of Catha edulis and tobacco plants. In addition, radioactive detectors reveal the distribution of the radioactivity of Catha edulis and Tobacco plants is higher than the natural radioactivity distribution, because of the presence of the heavy minerals and different radioisotopes in Catha edulis and Tobacco plants.
39. Awadh, Ali N. A. and Lemme, D. and Jira, Th and Attef, O. and {Al-rahwi}, K., Determination of Pesticide Residues in Khat Leaves by Solid-Phase Extraction and High-Performance Liquid Chromatography, African Journal of Traditional, Complementary and Alternative Medicines, vol. 3, no. 1, pp. 1--10, January 2006. url: https://journals.athmsi.org/index.php/ajtcam/article/view/19. Abstract
    The purpose of this investigation is to develop a simple method for the assessment of pesticides in Khat leaves, Catha edulis FORSK. (Celastraceae) shrub, chewed by about 60 \% of the Yemeni people, producing amphetamine-like psychostimulation. The first procedures involve solid-phase extraction using Adsorbex® RP-C18 and Bakerbond® RP-C18 disposable cartridges with 40 \% acetonitrile for elution. Isocratic and gradient analysis was carried out by means of high-performance liquid chromatography using different stationary phases to analyse methidathion, peconazole and dimethoate. An UltrasphereODS RP-18-column with UV-detection at 210 nm and 80/20 \% (v/v) acetonitrile/water as mobile phase (isocratic) was used to determine the content of methidathion, peconazole and dimethoate (detection limit 20-25 ng). The method was validated with fortified samples at pesticide concentration of 0.1 mg/ml. Average recoveries ranging from 97.9 and 101.6\% with a relative standard deviation (RSD) of 1.7-3.8 \%. Each recovery analysis was repeated four times. Limits of detection ranged from the analytical procedures were applied to 5 samples of khat and no detectable amounts of pesticides were found in any sample under the conditions described.
40. Nthiga, J. N. and Mbugua, Amos and Anjili, Christopher, An Investigation on and Isolation of Human Parasites Associated with Contaminated Catha Edulis Leaves Sold in Selected Parts of Nairobi City County, Kenya, International Academic Journal of Health, Medicine and Nursing, vol. 1, no. 2, pp. 132--144, 2019. url: https://www.iajournals.org/subject/661.html. Abstract
    Introduction: Catha edulis (Khat) is a stimulant containing the alkaloid, cathione. The most common form of C. edulis is as dried leaves which can be chewed, brewed into tea, sprinkled on food or smoked. Contamination of leaves can lead to widespread diorrhoeal diseases among the vendors and consumers. Broad objective: The main objective was to investigate and isolate human parasites associated with contaminated c.edulis leaves sold in selected streets of Nairobi City County. Study design and site. The study Design was descriptive Cross Sectional. The study sites was include selected street of Nairobi City County where the leaves are highly sold and consumed, and include East Leigh, Kawangware, Kibra, Mathare, Dandora. Material and methods: Authority to conduct the study was obtained from JKUAT/ KNH/UoN ERC. The study population was vendors of Khat in selected city streets. An administered structured questionnaire was used to collect data from a sample of 155 vendors across the study sites. Khats leaves were collected in aerated bags. The leaves were processed in Jomo Kenyatta University of Agriculture and technology Labs. Concentration and Direct method were carried out to isolate human parasites on the leaves. Data analysis was conducted using SPSS version 23.0 and STATA 12. A statistical analysis was done using the chi square; P {$<$} 0.05 was considered significant. Results: Parasites were isolated in 15.4\% (n=24) of the study sites. G. lamblia 6.5\% (N=10), E. hystolitica 5.8\% (n=9) were the main parasites. Others were A. lumbricoides 1.9 (n=3), and strongyloides 1.3\% (n=2). Majority 54.8\% (n=85) stored the leaves on the ground uncovered. Stagnation wastes were in 70.3\% (n=109) of the study sites. Toilets were mainly public open sharing and water vendors with open communal taps 84.2\% (n=130 were the main) water suppliers. E. hystolitica and G. lamblia were mainly isolated in Eastleigh. G. lamblia was found in all areas except Kibra. Presence of parasites was statistically found to be associated with the area/ site, p=0.011 and the type of wates (p=0.043). Conclusion: The main contaminants of C. edulis leaves were G. lamblia and E. Hystolitica with a wide spread across Nairobi county. Parasites were associated with stagnation wastes poor hygiene, and poor storage of the leaves especially on the ground uncovered. Recommendations: Setting up of standard shops with required level of hygiene by the county government for vending C. edulis leaves, ensuring that vendors undergo regular medical checkup and proper disposal of wastes will reduce contaminations of the leaves, government to facilitate value addition mechanism to reduce contamination of leaves
41. Gu, Cuihua and Tembrock, Luke R. and Zheng, Shaoyu and Wu, Zhiqiang, The Complete Chloroplast Genome of Catha Edulis: A Comparative Analysis of Genome Features with Related Species, International Journal of Molecular Sciences, vol. 19, no. 2, pp. 525, February 2018. doi: 10.3390/ijms19020525. Abstract
    Qat (Catha edulis, Celastraceae) is a woody evergreen species with great economic and cultural importance. It is cultivated for its stimulant alkaloids cathine and cathinone in East Africa and southwest Arabia. However, genome information, especially DNA sequence resources, for C. edulis are limited, hindering studies regarding interspecific and intraspecific relationships. Herein, the complete chloroplast (cp) genome of Catha edulis is reported. This genome is 157,960 bp in length with 37\% GC content and is structurally arranged into two 26,577 bp inverted repeats and two single-copy areas. The size of the small single-copy and the large single-copy regions were 18,491 bp and 86,315 bp, respectively. The C. edulis cp genome consists of 129 coding genes including 37 transfer RNA (tRNA) genes, 8 ribosomal RNA (rRNA) genes, and 84 protein coding genes. For those genes, 112 are single copy genes and 17 genes are duplicated in two inverted regions with seven tRNAs, four rRNAs, and six protein coding genes. The phylogenetic relationships resolved from the cp genome of qat and 32 other species confirms the monophyly of Celastraceae. The cp genomes of C. edulis, Euonymus japonicus and seven Celastraceae species lack the rps16 intron, which indicates an intron loss took place among an ancestor of this family. The cp genome of C. edulis provides a highly valuable genetic resource for further phylogenomic research, barcoding and cp transformation in Celastraceae.
42. Tembrock, Luke R. and Simmons, Mark P. and Richards, Christopher M. and Reeves, Patrick A. and Reilley, Ann and Curto, Manuel A. and Meimberg, Harald and Ngugi, Grace and Demissew, Sebsebe and {Al-Khulaidi}, Abdul Wali and {Al-Thobhani}, Mansoor and Simpson, Sheron and Varisco, Daniel M., Clonal Diversity, Cultivar Traits, Geographic Dispersal, and the Ethnotaxonomy of Cultivated Qat (Catha Edulis, Celastraceae), Economic Botany, vol. 74, no. 3, pp. 273--291, September 2020. doi: 10.1007/s12231-020-09501-4. Abstract
    Farmers and traders have developed a system of names to refer to different qat (Catha edulis) cultivars, using stem color as the primary trait to differentiate them. In this study, we tested if the named cultivars from Ethiopia, Kenya, and Yemen represent genetic clusters. We also quantified clonal reproduction and tracked the geographic dispersal of cultivated–qat genotypes using microsatellite genotypes of specimens collected from across the major qat growing regions (Ethiopia, Kenya, and Yemen). Specimens were mapped to determine whether names, morphology, genetic clusters, or genotypes (in particular clones) were geographically restricted. Stem color was found to be a plastic trait because specimens of the same genotype have different colored stems. A single cultivar name was often applied to numerous clonal groups and genetic clusters, creating widespread homonymy in the ethnotaxonomy of qat cultivars. The East African Rift (EAR) in central Ethiopia was found to be a barrier to the exchange of both clonal groups and certain cultivar names. In Kenya, both cultivar names and clonal groups were broadly dispersed geographically. Nearly all of these clonal groups originated from the Mt. Kenya/Meru area in central Kenya.
43. Ngari, Loise N and Njagi, Shadrack N and Kamau, James K and Lagat, Rose C and Musyoki, Amos M and Muiruri, Joseph K and Ngugi, Mathew P, Genotypic Characterization of Catha Edulis in Mt. Kenya Region, Kenya, Journal of Phylogenetics \& Evolutionary Biology, vol. 06, no. 03, 2018. doi: 10.4172/2329-9002.1000203. Abstract
    Khat (Catha edulis Vahl) is a plant that is habitually ingested for its euphoric and stimulatory effects. This study aimed at evaluating genetic diversity of selected khat cultivars grown in Embu and Meru Counties Mt Kenya region. This will ensure that genetic resources are preserved and secured for future so that benefits from such plants continue to flow. DNA extraction was done using CTAB method and genetic diversity determined using 5 SSR markers. The number of alleles per locus ranged from 2 to 4 with an average of 2.4 across the 5 markers used. Gene diversity per locus ranged from 0.2296 (CE50) to 0.3344 (CE64) with an average of 0.2883 and Polymorphic Information Content (PIC) ranged from 0.2024 (CE50) to 0.2878 (CE37) with an average of 0.2475. A two dimensional scatter plot was generated and the two PCoA axis accounted for 43.33 and 28.19\% of genetic variation. The AMOVA indicated intra-population variation of 93\% while inter-population variation was 7\%. The unweighted neighbour joining tree clustered khat cultivars into three major clusters and subsequent sub-clusters. This study revealed that there is a considerable level of genetic diversity among the Mt. Kenya khat cultivars. This was indicated by the alleles observed and clusters generated.
44. Tembrock, Luke R. and Simmons, Mark P. and Richards, Christopher M. and Reeves, Patrick A. and Reilley, Ann and Curto, Manuel A. and Meimberg, Harald and Ngugi, Grace and Demissew, Sebsebe and Al Khulaidi, Abdul Wali and {Al-Thobhani}, Mansoor and Simpson, Sheron and Varisco, Daniel M., Phylogeography of the Wild and Cultivated Stimulant Plant Qat (Catha Edulis, Celastraceae) in Areas of Historical Cultivation, American Journal of Botany, vol. 104, no. 4, pp. 538--549, 2017. doi: 10.3732/ajb.1600437. Abstract
    PREMISE OF THE STUDY: Qat (Catha edulis, Celastraceae) is a woody plant species cultivated for its stimulant alkaloids. Qat is important to the economy and culture in large regions of Ethiopia, Kenya, and Yemen. Despite the importance of this species, the wild origins and dispersal of cultivars have only been described in often contradictory historical documents. We examined the wild origins, human-mediated dispersal, and genetic divergence of cultivated qat compared to wild qat. METHODS: We sampled 17 SSR markers and 1561 wild and cultivated individuals across the historical areas of qat cultivation. KEY RESULTS: On the basis of genetic structure inferred using Bayesian and nonparametric methods, two centers of origin in Kenya and one in Ethiopia were found for cultivated qat. The centers of origin in Ethiopia and northeast of Mt. Kenya are the primary sources of cultivated qat genotypes. Qat cultivated in Yemen is derived from Ethiopian genotypes rather than Yemeni wild populations. Cultivated qat with a wild Kenyan origin has not spread to Ethiopia or Yemen, whereas a small minority of qat cultivated in Kenya originated in Ethiopia. Hybrid genotypes with both Ethiopian and Kenyan parentage are present in northern Kenya. CONCLUSIONS: Ethiopian cultivars have diverged from their wild relatives, whereas Kenyan qat has diverged less. This pattern of divergence could be caused by the extinction of the wild-source qat populations in Ethiopia due to deforestation, undersampling, and/or artificial selection for agronomically important traits.
45. Atlabachew, Minaleshewa and Combrinck, Sandra and Sandasi, Maxleene and Chen, Weiyang and Viljoen, Alvaro, Rapid Differentiation of Khat (Catha Edulis Vahl. Endl.) Using Single Point and Imaging Vibrational Spectroscopy, Vibrational Spectroscopy, vol. 81, pp. 96--105, November 2015. doi: 10.1016/j.vibspec.2015.10.005. Abstract
    The leaves of Catha edulis Vahl. Endl., known as Khat, are widely used as a “natural amphetamine” stimulant in Africa and in the Arabian Peninsula. In recent years, there has been an increase in the amounts exported to the USA, Australia and Europe. Although the dried, powdered form of the young and mature leaves, as well as samples from different geographical origins, have similar physical appearance, they have not been proven to exhibit equipotent stimulatory activity. In this study, powdered young and mature leaves were differentiated using vibrational spectroscopy, which included mid-infrared (MIR) and near-infrared (NIR) spectroscopy and hyperspectral imaging (HSI), and ultra performance liquid chromatography-mass spectrometry (UPLC–MS), in combination with chemometric data analysis. Samples originating from Ethiopia or South Africa could also be distinguished using chemometric models constructed from HSI data. Principal component analysis (PCA) and orthogonal projection to latent structures discriminant analysis (OPLS-DA) was successfully applied to classify powdered Khat samples according to their geographical origin and level of maturity. The OPLS-DA model constructed from the MIR and UPLC–MS data displayed the ability to clearly distinguish between young and mature leaves, as illustrated by the model statistics (R2Xcum and Q2cum{$>$}80\% and R2Y{$>$}90\%). Shortwave infrared hyperspectral imaging could distinguish Khat samples from two distinct geographical regions with good model statistics (R2Xcum=0.91 and Q2cum=0.92) and discriminate between the maturity levels (R2Xcum=0.85 and Q2cum=0.80). These models could prove valuable as rapid techniques for identifying confiscated Khat in forensic environments.
46. Curto, Manuel A. and Tembrock, Luke R. and Puppo, Pamela and Nogueira, Marcos and Simmons, Mark P. and Meimberg, Harald, Evaluation of Microsatellites of Catha Edulis (Qat; Celastraceae) Identified Using Pyrosequencing, Biochemical Systematics and Ecology, vol. 49, pp. 1--9, August 2013. doi: 10.1016/j.bse.2013.02.002. Abstract
    The use of Next Generation Sequencing (NGS) techniques to identify microsatellite markers has replaced more time intensive methods such as molecular cloning. The main advantage of NGS over traditional methods of identifying microsatellite markers is the generation of many more sequences with less effort. It is possible to design primers from unenriched DNA, thereby further reducing the workload and also allowing the use of SSRs that are difficult to enrich (e.g., TA/AT and TAA/ATT). We present microsatellite primer pairs that may be used for phylogeographic analysis as well as to infer the geographical origin of traded material of Catha edulis, which contains two amphetamines that are controlled substances in many counties. We used data from two partial 454 pyrosequencing runs that generated about 2000 sequences containing microsatellites (3\% of all sequences) as well as flanking regions sufficient for primer design. Using 23 samples of C. edulis we identified 27 single-copy markers that were broadly amplified across the sampled individuals; 18 showed polymorphism information content (PIC) higher than 0.5. The genetic structure in wild individuals is concordant with their geographic origins; wild samples from northern Kenya are more closely related to Ethiopian samples than are other wild samples from Kenya. The geographic differences in allele frequencies indicate that microsatellite analysis can be used to determine the geographic source of cultivated and wild collected material.
47. Simmons, Mark P. and Cappa, Jennifer J. and Archer, Robert H. and Ford, Andrew J. and Eichstedt, Dedra and Clevinger, Curtis C., Phylogeny of the Celastreae (Celastraceae) and the Relationships of Catha Edulis (Qat) Inferred from Morphological Characters and Nuclear and Plastid Genes, Molecular Phylogenetics and Evolution, vol. 48, no. 2, pp. 745--757, August 2008. doi: 10.1016/j.ympev.2008.04.039. Abstract
    The phylogeny of Celastraceae tribe Celastreae, which includes about 350 species of trees and shrubs in 15 genera, was inferred in a simultaneous analysis of morphological characters together with nuclear (ITS and 26S rDNA) and plastid (matK, trnL-F) genes. A strong correlation was found between the geography of the species sampled and their inferred relationships. Species of Maytenus and Gymnosporia from different regions were resolved as polyphyletic groups. Maytenus was resolved in three lineages (New World, African, and Austral-Pacific), while Gymnosporia was resolved in two lineages (New World and Old World). Putterlickia was resolved as nested within the Old World Gymnosporia. Catha edulis (qat, khat) was resolved as sister to the clade of Allocassine, Cassine, Lauridia, and Maurocenia. Gymnosporia cassinoides, which is reportedly chewed as a stimulant in the Canary Islands, was resolved as a derived member of Gymnosporia and is more closely related to Lydenburgia and Putterlickia than it is to Catha. Therefore, all eight of these genera are candidates for containing cathinone- and/or cathine-related alkaloids.
48. Shadan, Parirokh and Shellard, E J, An Anatomical Study of Ethiopian Khat (Leaf of Catha Edulis Forsk), Journal of Pharmacy and Pharmacology, vol. 14, no. 1, pp. 110--118, September 1962. doi: 10.1111/j.2042-7158.1962.tb11062.x. Abstract
    The morphology and anatomy of the leaves of Catha edulis Forsk. obtained from Ethiopia is described and illustrated. A list of the characters of powdered Khat is also given.
49. Ngari, Loise N and Njagi, Shadrack N and Kamau, James K and Lagat, Rose C and Musyoki, Amos M and Akoth, Beryl O and Kioko, Festus and Okwany, Zedekiah-A and Ngugi, Mathew P, Phenotypic Characterization of Selected Kenyan Khat (Catha Edulis) Cultivars Based on Morphological Traits, African Journal of Biotechnology, vol. 18, no. 29, pp. 865--874, 2019. doi: 10.5897/AJB2019.16757. Abstract
    Khat (Catha edulis Vahl) is an evergreen shrub habitually ingested for its euphoric and stimulatory effects. The crop is grown in the Middle East, Somalia, East Africa and Ethiopia. It is referred to as Miraa in Kenya, while in Yemen it has several names like Qat, Kat, Kath, Gat, Chat and Tschat. It belongs to the sub-order Rosidae, family Celastraceae and characterized by astringent taste. Despite the daily use and consumption of khat by millions of people in Kenya, little is known about its phenotypic. Phenotypic characterization is an essential approach for assessment of khat diversity; however, it is limited by morphological plasticity and multiple lineage evolution. The study aimed at evaluating the phenotypic diversity of selected khat cultivars grown in Embu and Meru Counties. Ninety samples from 18 cultivars were collected for phenotypic characterization. MINITAB 17 Software was used for description of principal component and construction of dendrogram using the Euclidean distance tool where 58.7\% variability was observed among 13 traits studied in 90 samples of khat. Phenotypes grouped into 2 clusters phenotypic diversity showed considerable variability based on 13 khat traits. This will be useful in breeding and characterization programmes of khat cultivars.
50. Kiunga, Josphat K., Ethnobotanical and Taxonomic Study of Catha Edulis Plant Grown in Embu and Meru Counties, Kenya., 2017. url: http://erepository.uonbi.ac.ke/handle/11295/101262.
51. Krikorian, A. D., Growth Mode and Leaf Arrangement inCatha Edulis (Kat), Economic Botany, vol. 39, no. 4, pp. 514--521, October 1985. doi: 10.1007/BF02858759. Abstract
    Chewing fresh leaves and tender twigs ofCatha edulis, commonly known as kat, in order to experience their amphetamine-like stimulant action is on the increase in regions of traditional use—e.g., southern part of the Arabian Peninsula, the Horn of Africa (Somalia, Djibouti), Ethiopia, Kenya, and Madagascar. Although the genus Catha was first delineated nearly 200 yr ago, botanical descriptions rarely mention that plants may bear alternate or opposite leaves and never include an explanation for the presence of shoots with opposite leaves and shoots with alternate leaves on the same plant. An obscure paper (1903) by the late Sir David Prain in a long defunct journal goes into considerable detail on the matter. Extensive excerpts from that paper are reprinted. The association of various market grades of kat with morphological origin and age is suggested. The extensive polymorphism of the kat plant is described. More work is needed to understand kat from morphological, chemical, and pharmacological perspectives.
52. Zhang, Xin and Zhang, Zhixiang and Stützel, Thomas, Ontogeny of the Ovule and Seed Wing in Catha Edulis (Vahl) Endl. (Celastraceae), Flora - Morphology, Distribution, Functional Ecology of Plants, vol. 209, no. 3, pp. 179--184, March 2014. doi: 10.1016/j.flora.2014.01.002. Abstract
    The seed wing of Catha edulis (Vahl) Endl. (Celastraceae) has been described as an aril derived from the funiculus. However, the aril-like structure of other Celastraceae has been shown to originate from the micropyle instead of the funiculus. It is therefore of interest whether the seed appendages in Catha are not only functionally but also developmentally different from those in other Celastraceae. To clarify this, the ontogeny of ovule and seed wing in Catha edulis has been studied. It is shown that the wing is a modified caruncula derived from the micropylar region. Seed wings are thus not only interesting in respect to function but may also carry interesting and important evolutionary signals. The evolution of different micropylar appendages within Celastraceae is discussed.
53. Mostert, Theo H. C. and Bredenkamp, George J. and Klopper, Hannes L. and Verwey, Cornie, Major Vegetation Types of the Soutpansberg Conservancy and the Blouberg Nature Reserve, South Africa : Original Research, Koedoe : African Protected Area Conservation and Science, vol. 50, no. 1, pp. 32--48, January 2008. doi: 10.10520/EJC139700. Abstract
    The Major Megetation Types (MVT) and plant communities of the Soutpansberg Centre of Endemism are described in detail, with special reference to the Soutpansberg Conservancy and the Blouberg Nature Reserve. Phytosociological data from 442 sample plots were ordinated using a DEtrended CORrespondence ANAlysis (DECORANA) and classified using TWo-Way INdicator SPecies ANalysis (TWINSPAN). The resulting classification was further refined with table-sorting procedures based on the Braun-Blanquet floristic-sociological approach of vegetation classification using MEGATAB. Eight MVT's were identified and described as Eragrostis lehmanniana var. lehmanniana-Sclerocarya birrea subsp. caffra Blouberg Northern Plains Bushveld, Euclea divinorum-Acacia tortilis Blouberg Southern Plains Bushveld, Englerophytum magalismontanum-Combretum molle Blouberg Mountain Bushveld, Adansonia digitata-Acacia nigrescens Soutpansberg Arid Northern Bushveld, Catha edulis-Flueggia virosa Soutpansberg Moist Mountain Thickets, Diplorhynchus condylocarpon-Burkea africana Soutpansberg Leached Sandveld, Rhus rigida var. rigida-Rhus magalismontanum subsp. coddii Soutpansberg Mistbelt Vegetation and Xymalos monospora-Rhus chirendensis Soutpansberg Forest Vegetation.
54. Feyisa, Taye Hailu and Aune, Jens B., Khat Expansion in the Ethiopian Highlands, Mountain Research and Development, vol. 23, no. 2, pp. 185--189, May 2003. doi: 10.1659/0276-4741(2003)023[0185:KEITEH]2.0.CO;2. Abstract
    Khat (Catha edulis) is a rapidly expanding perennial crop in the Ethiopian highlands, and it is Ethiopia's second largest export item. The leaves of the crop are used for their stimulating effect. The present study was undertaken in Habro district in western Hararghie. Khat production in this district is rapidly replacing cereal production and to some extent coffee production. About 70\% of farmers' income in the study area is currently obtained from khat. One important reason for the expansion of khat production is that the khat–maize intercropping system is 2.7 times more profitable per hectare than maize monocropping. Khat is also less risky to grow than cereals and coffee because it is less vulnerable to drought. Increased production leads to changes in livestock composition because oxen are far less needed for plowing in the khat-based system; moreover, availability of crop residues for fodder is reduced when khat expands. Khat growing farmers, therefore, give more emphasis to milk-producing animals such as cows and goats. It was found that khat producers also are consumers of khat and that khat consumption has become widespread in the nearby secondary school. Khat consumption negatively affects people's working capacity. Hence, unskilled khat consumers in urban areas are paid 7 birr (US\$0.84) per day, whereas nonkhat users are paid 10 birr (US\$1.22). Measures to control further khat expansion will need to address both supply and demand.
55. Teketay, D. and Tegineh, A., Traditional Tree Crop Based Agroforestry in Coffee Producing Areas of Harerge, Eastern Ethiopia, Agroforestry Systems, vol. 16, no. 3, pp. 257--267, December 1991. doi: 10.1007/BF00119322. Abstract
    A preliminary survey of seven coffee producing Awrajas (Provinces) in eastern Ethiopia revealed that there is a traditional tree crop based agroforestry system being practised by the farmers. Coffee (C. arabica) was found to grow under the shade of several trees, 16 species, usually intercropped by one or several, a total of 15, important grain, fruit, vegetable, stimulant, oil-seed and spice crops. The majority of the trees, 69\%, is leguminous and Ficus spp. The system is characterized by the integration of crops, livestock and sometimes apiculture. Recommendations are made for future studies.
56. Getasetegn, Million, Chemical Composition of Catha Edulis (Khat): A Review, Phytochemistry Reviews, vol. 15, no. 5, pp. 907--920, October 2016. doi: 10.1007/s11101-015-9435-z. Abstract
    Khat (Catha edulis) belongs to Celastraceae family which contains 60–70 genera and 850–900 species. It is an indigenous plant to Ethiopia and Yemen as the countries of origin. It is also found in many other east and southern African countries. Khat leaves are chewed by the local people for their stimulant action. The main active ingredient compounds those are responsible for this action is cathinone and a mild stimulant cathine. In addition to these khat contains several phytochemicals such as alkaloids (phenylalkylamines and cathedulins), flavonoids, steroid and triterpenoids, monoterpenes and volatile aromatic compounds, and other miscellaneous compounds like vitamins and amino acids. Hence, this paper presents a comprehensive and unified review of literatures which concerned on the phytochemical composition of khat plant. And it also provides the isolated compounds with their chemical structures.
57. Nichols, Tyler and Khondkar, Proma and Gibbons, Simon, The Psychostimulant Drug Khat (Catha Edulis): A Mini-Review, Phytochemistry Letters, vol. 13, pp. 127--133, September 2015. doi: 10.1016/j.phytol.2015.05.016. Abstract
    Khat (Catha edulis Forsk) is a shrub native to the Horn of Africa and the Middle East. The leaves of this small tree are chewed by millions worldwide as a mild, amphetamine-like psychostimulant drug. Whilst khat has enjoyed grey-area legality in many countries including the United Kingdom that otherwise prohibit the use of recreational drugs, recent years have seen the appearance of new legislation to control its production, importation and consumption. This mini-review will consolidate what is known about the pharmacology, chemistry, and effects on health of khat to provide a brief synopsis of the properties of this plant stimulant.
58. Silva, Bárbara and Soares, Jorge and {Rocha-Pereira}, Carolina and Mladěnka, Přemysl and Remião, Fernando and {on behalf of The OEMONOM Researchers}, Khat, a Cultural Chewing Drug: A Toxicokinetic and Toxicodynamic Summary, Toxins, vol. 14, no. 2, pp. 71, February 2022. doi: 10.3390/toxins14020071. Abstract
    Khat (Catha edulis) is a recreational, chewed herbal drug that has been used as a psychostimulant for centuries in East Africa and the Arabian Peninsula, namely in Somalia, Ethiopia, and Yemen. However, the growing worldwide availability of khat has produced widespread concern. The plant comprises a large number of active substances, among which cathinone, cathine, and norephedrine are the main constituents, which can be included in the group of sympathomimetics of natural origin. In fact, these compounds are amphetamine analogues, and, as such, they have amphetamine-like nervous system stimulant effects. Chewing the leaves gives people a sensation of well-being and increases energy, alertness, and self-confidence. The chronic use of khat is, however, associated with severe cardiac, neurological, psychological, and gastrointestinal complications. The psychological dependence and withdrawal symptoms of khat are the reasons for its prolonged use. The aim of this paper is to review current knowledge on the khat plant with toxicokinetic and toxicodynamic perspectives. Namely, this review paper addresses in vitro, in vivo, and human studies. The models used, as well as the concentrations and doses with the respective biological effects, are discussed. Additionally, the main drug interactions involved with khat are described.
59. Alsanosy, Rashad and Alhazmi, Hassan A. and Sultana, Shahnaz and Abdalla, Ashraf N. and Ibrahim, Yassin and Al Bratty, Mohammed and Banji, David and Khardali, Ibrahim and Khalid, Asaad, Phytochemical Screening and Cytotoxic Properties of Ethanolic Extract of Young and Mature Khat Leaves, Journal of Chemistry, vol. 2020, pp. e7897435, March 2020. doi: 10.1155/2020/7897435. Abstract
    The khat plant has been culturally used in many parts of Africa and the Arabian Peninsula for many years to induce psycho-stimulating effect. Because of the global wide-spreading nature, khat chewing is being considered as a universally growing problem. Catha abbottii, Catha edulis, and Catha transvaalensis are the three species of khat commonly chewed in Saudi Arabia and nearby regions. Khat users usually prefer to chew young leaves over mature ones due to the diverse effects produced by both. Though many of the constituents of khat leaves have been identified, the complete phytochemical profile of young and mature leaves was not performed or compared; also, no evidence is available to affirm the cytotoxicity of young or mature leaves. Therefore, this study aimed to investigate the phytochemical basis of the differential response of the young and mature leaves and to assess the cytotoxicity of young and mature khat leaves. Ethanolic extracts of young and mature leaves of three khat cultivars were subjected to GC-MS. Hierarchical cluster analysis revealed the existence of two major clusters. The extracts of young leaves were found to contain the maximum content of cathinone; however, methoxyamphetamine was found in only one extract of young leaves. Cytotoxicity investigations were also conducted on both types of leaves using three cancer cell lines, human breast adenocarcinoma, human ovary adenocarcinoma, and human colon adenocarcinoma and also normal human fetal lung fibroblast cell line was used. All extracts showed comparable cytotoxicity, IC50 ranging from 22–59\,μg/mL on the cancer cells; however, we observed more cytotoxicity against normal cells (IC50: 6–41\,μg/mL). The predominant cytotoxicity on normal cells may pose many health hazards to khat consumers.
60. Kiros, Tsegu, Non-Alkaloidal Compounds from Khat (Catha Edulis) Leaves, Biology, Medicine, \& Natural Product Chemistry, vol. 9, no. 2, pp. 81--89, November 2020. doi: 10.14421/biomedich.2020.92.81-89. Abstract
    Khat belongs to the family Celastraceae, genus Catha, and species edulis. More than 200 compounds have previously been identified in Khat leaves, including: 40 alkaloids, terpenoids and sterol, flavonoids, glycosides, tannins, amino acids, vitamins and minerals. Researchers have spent their effort and time merely on study of the alkaloidal components (mainly the stimulant agents, cathinone and cathine) of Khat both qualitatively and quantitatively. The two principal Khat stimulant compounds, cathinone and cathine, by now are well established. But, on the contrary, previous studies on the non-alkaloidal constituents of the plant were limited. The objective of this work was therefore to isolate and characterize compounds from non-alkaloidal fractions of the plant’s leaves.Â~ In this work, two non-alkaloidal compounds (KNA-1 and KNA-2) were isolated and characterized from the acid-EtOAc extract of fresh and oven-dried leaves of Khat (Catha edulis). From the present study, it is possible to conclude that investing more effort and time on searching additional non-alkaloidal principles from the leaves of Khat is so necessary. And further works could be done in the future to isolate extra non-alkaloidal compounds from the leaves and other parts of Khat and evaluate their biological activity.
61. Dhabbah, Abdulrhman M., Determination of Chiral Cathinone in Fresh Samples of Catha Edulis, Forensic Science International, vol. 307, pp. 110105, February 2020. doi: 10.1016/j.forsciint.2019.110105. Abstract
    The main psychoactive compound in Khat is cathinone which consists of two enantiomers, S-(-)-cathinone being more stimulant than its R antipode. This study aimed to the enantioseparation and determination of these two stereoisomers in different parts of fresh Catha edulis. The samples were solvent extracted and cathinone was derivatized with menthyl chloroformate. The separation of the two diastereomeric derivatives was carried out by gas chromatography and showed an excellent resolution, while their structure was confirmed by mass spectrometry. The quantitative determination of both enantiomers showed a different distribution in various investigated parts of the plant, as shown in their enantiomeric excess. Unlike the results published in some previous articles, the current study confirmed the presence of both S and R cathinone in all parts of the fresh plant. The concentration of S-cathinone was higher in stems while its values were lower in leaves. The obtained concentrations were in the ranges 0.081-0.290 and 0.087-0.211\,mg/g for S and R antipodes, respectively. Also, S-cathinone which is the most psychoactive stereoisomer showed an increasing concentration from lower to upper stems of the plant. The present study is the first quantitative investigation of the two cathinone enantiomers in different parts of fresh Catha edulis.
62. Bratty, Mohammed Al and Ahsan, Waquar and Alhazmi, Hassan A. and Attafi, Ibraheem M. and Khardali, Ibrahim A. and Abdelwahab, Siddig I., Determination of Trace Metal Concentrations in Different Parts of the Khat Varieties (Catha Edulis) Using Inductively Coupled Plasma-Mass Spectroscopy Technique and Their Human Exposure Assessment, Pharmacognosy Magazine, vol. 15, no. 63, pp. 449, July 2019. doi: 10.4103/pm.pm_658_18. Abstract
    {$<$}br{$>$}\textbf{Background:} Khat (\emph{Catha edulis}, family: \emph{Celastraceae}) is a plant that is native to Africa and Arab peninsula and is used for their amphetamine-like properties. Although the use of Khat is banned in Saudi Arabia, people particularly in southern Jazan province manage to get it from Yemen, and the use is increasing steadily. \textbf{Objective:} Five most commonly used varieties of Khat namely Gaifi, Kofat, Jahasha, Faqarah Menjed, and Faqarah Aswad were selected for the study. \textbf{Materials and Methods:} Metal ion concentrations were determined using inductively coupled plasma-mass spectroscopy. Since Khat is available as one bundle consisting of three parts of the plant, metal ions in all three parts were determined separately for comparison purpose. The concentrations (mg/kg) of 20 metal ions were determined in Nwaif leaves (new and smaller in size), Gafra leaves (old and larger in size), and stem of the plant and compared with the Provisional Tolerable Weekly Intake (PTWI) and acceptable daily intake (ADI) of metal ions to study the health hazards posed by them. \textbf{Results:} The non-essential metal ion Strontium (Sr) was present in highest abundance in all the samples with a concentration range of 498.6 ± 18.9–3837 ± 52.1 mg/kg followed by Copper (215.4 ± 12.3–3054 ± 45.2 mg/kg), Zinc (23.17 ± 0.4–1490 ± 32.6 mg/kg), and Manganese (108 ± 5.8–1357 ± 18.6 mg/kg). Several toxic heavy metal ions including Arsenic, Lead, and Cadmium were also present in trace concentrations in many samples. \textbf{Conclusion:} Many metal ions were observed to be present in concentrations much higher than their PTWI and ADI which further allude to the extremely hazardous nature of Khat plants. Multicomponent variate analyses were also performed using chemometric methods to establish the possible correlation between samples.{$<$}br{$>$}
63. Int, Chem, Composition of Essential Oil and Antioxidant Activity of Khat (Catha Edulis Forsk), Ethiopia, May 2019. doi: 10.31221/osf.io/w7h8j. Abstract
    In this study, we determined the chemical composition and antioxidant activities of the essential oils from two different varieties of khat (Catha edulis Forsk) cultivated in Ethiopia. The essential oils were extracted by hydrodistillation using the Clevenger type apparatus, identifications of compounds were made by gas chromatography and gas chromatography-mass spectrometry (GC-MS). Seventy seven different compounds were identified from essential oils of the two different khat cultivars. The essential oils in the samples from Bahir Dar and Wendo were composed of 50 and 34 compounds, respectively. The major compound identified in khat essentials oils include: limonene, 1-phenyl-1,2-propanedione, 1-hydroxy,1-phenyl-2-propanone, camphor, (sulfurous acid)-2-propylundecyl ester, hexadecane, O-mentha-1(7), 8-dien-3-ol, heptadecane, 10-methylnonadecane, (phthalic acid)-isobutyl octadecyl ester, and tritetracontane. The antioxidant and free radical scavenging activity of the oils were assessed by means of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assay. The scavenging activities of the oils were 23.5-23.6 μg AAE/kg of fresh khat sample.
64. Patel, Nilesh B., Khat—A Natural Source of Cathinone, pp. 25--40, 2018. doi: 10.1007/978-3-319-78707-7_3. Abstract
    Recently, a class of new psychoactive substancesNew psychoactive substances(NPS) has appeared as drugs of abuse. NPS comprise different drug classes; the most popular are synthetic cannabinomimeticsSynthetic cannabinomimeticsand designer analogues of cathinoneCathinone, an intermediate metabolite in a biosynthetic pathway, and a psychostimulant, found in the plants Catha edulis Forsk., Ephedra gerardiana sikkimensis, and Ephedra sinica. In C. edulis and E. gerardiana sikkimensis, cathinoneCathinoneis converted to norpseudoephedrine (cathine) and norephedrine, while in E. sinica the pathway continues to pseudoephedrine and ephedrine. While cathinoneCathinoneanalogues are used for recreational purposes, cathinoneCathinone, itself, is consumed only through chewing khat, i.e., the fresh leaves and twigs of the plant C. edulis Forsk., a practice similar to chewing of coca leaves. The use of khat is common among people living in Southwestern Arabia and Eastern Africa with an estimated 10–20~million daily users. This chapter describes the use of khat, its distribution and cultivation, the biosynthetic pathway that involves cathinoneCathinone, the long delay in the discovery of cathinoneCathinone, the neurochemistry of khat and cathinoneCathinone, its effects on humans, and its dependency and addiction potential.
65. Atlabachew, Minaleshewa and Chandravanshi, Bhagwan Singh and {Redi-Abshiro}, Mesfin, Preparative HPLC for Large Scale Isolation, and Salting-out Assisted Liquid–Liquid Extraction Based Method for HPLC–DAD Determination of Khat (Catha Edulis Forsk) Alkaloids, Chemistry Central Journal, vol. 11, no. 1, pp. 107, October 2017. doi: 10.1186/s13065-017-0337-6. Abstract
    Khat (Catha edulis Forsk) is an evergreen shrub of the Celastraceae family. It is widely cultivated in Yemen and East Africa, where its fresh leaves are habitually chewed for their momentary pleasures and stimulation as amphetamine-like effects. The main psychostimulant constituents of khat are the phenylpropylamino alkaloids: cathinone, cathine and norephedrine.
66. Jenčič, Boštjan and Jeromel, Luka and Ogrinc Potočnik, Nina and {Vogel-Mikuš}, Katarina and Vavpetič, Primož and Rupnik, Zdravko and Bučar, Klemen and Vencelj, Matjaž and Kelemen, Mitja and Matsuo, Jiro and Kusakari, Masakazu and Siketić, Zdravko and {Al-Jalali}, Muhammad A. and Shaltout, Abdallah and Pelicon, Primož, Molecular Imaging of Alkaloids in Khat (Catha Edulis) Leaves with MeV-SIMS, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, vol. 404, pp. 140--145, August 2017. doi: 10.1016/j.nimb.2017.01.063. Abstract
    Imaging Mass Spectroscopy (IMS) is a unique research tool providing localization and identification of a wide range of biomolecules as essential data to understand biochemical processes in living organisms. Secondary Ion Mass Spectrometry with high-energy heavy ions (MeV-SIMS) is emerging as a promising IMS technique for chemical imaging of biological tissue. We measured the molecular mass spatial distributions in leaves of khat (Catha edulis). Khat is a natural drug plant, native to eastern Africa and the Arabian Peninsula. In these countries, fresh leaves are being chewed by significant part of population. It was reported that 80\% of the adult population in Yemen chew the khat leaves. The main stimulating effects of khat are induced by a monoamine alkaloid called cathinone. During leaf ageing, cathinone is further metabolised to cathine and norephedrine. Earlier studies identified the alkaloids in khat, however little is known on their spatial distribution, reflecting the biosynthesis and accumulation in the tissue. Chemical mapping of alkaloids on cross-sections of khat leaves by MeV-SIMS was done at JSI by a pulsed 5.8MeV 35Cl6+ beam, focused to a diameter of 15μm, using a linear time-of-flight (TOF) spectrometer with a mass resolution of 500. In addition, measurements of MeV-SIMS mass spectra were performed at Kyoto University by a continuous broad beam of 6MeV 63Cu4+ ions at an orthogonal TOF spectrometer with a high mass resolution of 11,000. Sections of leaves were analysed and mass spectra obtained at both MeV-SIMS setups were compared. Tissue-level distributions of detected alkaloids are presented and discussed.
67. Fatima, Nuzhath and Rizwan, Mohammed and Hobani, Yahya Hasssan and Marwan, Amany El Sayed and Kumar, Basode Vinod and Sunosi, Rashad Al and Abdulwahab, Siddig Ibrahim and Areeshi, Mohammed Yahya and Alvi, Ayesha and Oriaby, Magbool Essa, Gas Chromatography/Mass Spectroscopy Analysis of Catha Edulis Forsk, A Psycho Stimulant Revealed Potent Solvent Dependent Antimicrobial Activity, Journal of Pharmacognosy and Phytochemistry, vol. 6, no. 2, pp. 197--204, 2017. url: https://www.phytojournal.com/archives/2017.v6.i2.1151/gas-chromatographymass-spectroscopy-analysis-of-catha-edulis-forsk-a-psycho-stimulant-revealed-potent-solvent-dependent-antimicrobial-activity. Abstract
    Aim: The present study was aimed to identify the best solvent system for the extraction of bioactive compound of Catha edulis Forsk (Also Known as Khat, qat) and to validate the antimicrobial activity of these extract against the clinically isolated resistant bacterial strains. Background: Catha edulis Forsk is by far the most commonly cultivated shrub native to East Africa and Arabian Pennisula. The fresh leaves of this plant are chewed traditionally for feeling of wellness, mental alertness and euphoria by the people in Saudi Arabia. Studies demonstrated the cytotoxic and therapeutic effect of Catha edulis, however this study is first of its kind to demonstrate the solvent dependent antimicrobial activity in clinically isolated microbial strains. Methodology and Results: The extract was prepared in three different polar solvents (Methanol, DMSO and Water) to determine their relative capacity to fish out the phytoconstituents with good antimicrobial, antioxidant and anti-inflammatory activity by performing a comparative phytoconstituent analysis using GC/MS. The antimicrobial activity of these extracts was tested against the clinical isolates such Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Klebseilla pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Candida albicans by agar well diffusion assay. For all the isolates, identification and antibiotic susceptibility was determined by Vitek-2 system. The results showed that out of three polar solvents, extract prepared in DMSO and methanol showed significant antimicrobial activity. Notably, the extract in DMSO was active against the multi-drug resistant isolates. This differential antimicrobial activity is concurrent with phytoconstituents detected by GC/MS. Conclusion: The study unveils Catha edulis Forsk as a potential source of natural antimicrobial compound against both sensitive and MDR bacteria. Moreover, this is the first report to demonstrate the effect of solvent on the differential extraction of various phytoconstituents of Catha edulis by GC/MS. Significance and impact of the study: Study distinct itself by corroborating observed differential antibacterial activity with the phytoconstituent detected by GC/MS analysis. Also, this is the first report to demonstrate the effect of solvent on differential extraction of phytoconstituent showing strong antimicrobial, anti-inflammatory and antioxidant activity of Catha edulis Forsk.
68. Groves, Ryan A., Transcriptome Profiling in Ephedra Sinica and Catha Edulis Reveals Enzymes Putatively Involved in Ephedrine Alkaloid Biosynthesis, January 2016. doi: 10.11575/PRISM/28507. Abstract
    Amphetamine analogs are a class of medicinal compounds produced by Ephedra sinica and Catha edulis. Two commonly used members of this class of compounds include the cough suppressant (1S-2S)-pseudoephedrine, and the stimulant (1R-2S)-ephedrine. These secondary metabolites are produced in planta through a L-phenylalanine derived multi-step pathway. Despite the importance of this biosynthetic pathway, only one enzyme in the pathway has been characterized at the molecular level. Recently, two new transcriptomes have been created for E. sinica and C. edulis with the hopes of facilitating future gene discovery in this untapped pathway. In this investigation, I outlined an efficient transcriptomics based approach to potential gene candidate selection for all putative stages of the amphetamine analog biosynthetic pathway. This investigation also describes a complete approach to molecular cloning, protein expression, and assaying of gene candidates, resulting in the discovery of a key biosynthetic enzyme involved in amphetamine analog biosynthesis in E. sinica.
69. Murthy, H. Niranjana and Joseph, K. S. and Madiwal, A. and Rajan, G. Dinesh and Badiger, M. and Kolkar, Laxmi and Hiremath, R. and Shirugumbi, M., Chemical Composition and Fatty Acid Profile of Khat (Catha Edulis) Seed Oil, Journal of the American Oil Chemists' Society, vol. 93, no. 3, pp. 405--409, March 2016. doi: 10.1007/s11746-015-2782-5. Abstract
    The proximate, physicochemical, and fatty acid compositions of seed oil extracted from khat (Catha edulis) were determined. The oil, moisture, crude protein, crude fiber, crude carbohydrate, and ash content in seeds were 35.54, 6.63, 24, 1.01, 30.4~\%, and 1.32~g/100~g DW respectively. The free fatty acids, peroxide value, saponification value, and iodine value were 2.98~\%, 12.65~meq~O2/kg, 190.60~mg~KOH/g, and 145~g/100~g oil, respectively. Linolenic acid (C18:3, 50.80~\%) and oleic (C18:1, 16.96~\%) along with palmitic acid (C16:0, 14.60~\%) were the dominant fatty acids. The seed oil of khat can be used in industry for the preparation of liquid soaps and shampoos. Furthermore, high levels of unsaturated fatty acids make it an important source of nutrition especially as an animal product substitute for omega-3 fatty acids owing to the high content of linolenic acid.
70. Groves, Ryan A. and Hagel, Jillian M. and Zhang, Ye and Kilpatrick, Korey and Levy, Asaf and Marsolais, Frédéric and Lewinsohn, Efraim and Sensen, Christoph W. and Facchini, Peter J., Transcriptome Profiling of Khat (Catha Edulis) and Ephedra Sinica Reveals Gene Candidates Potentially Involved in Amphetamine-Type Alkaloid Biosynthesis, PLOS ONE, vol. 10, no. 3, pp. e0119701, March 2015. doi: 10.1371/journal.pone.0119701. Abstract
    Amphetamine analogues are produced by plants in the genus Ephedra and by khat (Catha edulis), and include the widely used decongestants and appetite suppressants (1S,2S)-pseudoephedrine and (1R,2S)-ephedrine. The production of these metabolites, which derive from L-phenylalanine, involves a multi-step pathway partially mapped out at the biochemical level using knowledge of benzoic acid metabolism established in other plants, and direct evidence using khat and Ephedra species as model systems. Despite the commercial importance of amphetamine-type alkaloids, only a single step in their biosynthesis has been elucidated at the molecular level. We have employed Illumina next-generation sequencing technology, paired with Trinity and Velvet-Oases assembly platforms, to establish data-mining frameworks for Ephedra sinica and khat plants. Sequence libraries representing a combined 200,000 unigenes were subjected to an annotation pipeline involving direct searches against public databases. Annotations included the assignment of Gene Ontology (GO) terms used to allocate unigenes to functional categories. As part of our functional genomics program aimed at novel gene discovery, the databases were mined for enzyme candidates putatively involved in alkaloid biosynthesis. Queries used for mining included enzymes with established roles in benzoic acid metabolism, as well as enzymes catalyzing reactions similar to those predicted for amphetamine alkaloid metabolism. Gene candidates were evaluated based on phylogenetic relationships, FPKM-based expression data, and mechanistic considerations. Establishment of expansive sequence resources is a critical step toward pathway characterization, a goal with both academic and industrial implications.
71. Ad, Fenta, Profile of Essential and Non-Essential Metals in Soil and in Khat (Catha Edulis Forsk) Leaves Cultivated in Southern Region, Ethiopia, Chemical Sciences Journal, vol. 6, no. 3, 2015. doi: 10.4172/2150-3494.1000107. Abstract
    This study was conducted with the objective of determining the quantity of selected essential and nonessential metals; Co, Mg, Ca, Cu, Mn, Cr, Cd, Fe, Zn and K in the leaf and supporting soil of Khat (Catha edulis Forsk). Samples of three Khat types (Konso, Gidole and Koyra) and soils from their root zone collected from three different sites in southern Ethiopia region were analyzed by flame atomic absorption spectrometry. K in soil and Khat sample were also determined by flame atomic emission spectroscopy. Known weight of oven-dried Khat samples were wetdigested using 2 mL of (69-72\%) HNO3 and 2 mL of (70\%) HClO4 for 130 min at variable temperatures (120-268°C). Soil was digested by the procedure, 0.5 g samples of soil were digested with concentrated nitric acid, concentrated hydrochloric acid and hydrogen peroxide, using Kjeldahl digestion block under reflux condenser for 3 h at 300°C. Both the edible portion of Khat leaves and the soils of the study farms showed similar accumulation patterns to some extent, in their contents of the studied macro and micronutrients. Regression analysis and pearson correlation (r) results show a positive correlation Coffecient (R2) values ranging from 0.281 up to 0.991 and for pearson correlation (r) values ranging from 0.244-0.951. Although regressions based on the pooled data from the three Khat types are not adequately correlated with total metal soil levels, better fits were obtained when regression models were used for Konso Khat separately. However, no strong correlations between the leaves and other variables are evident except for Ca and Mg metal contents which have r values of 0.971 and 0.991 respectively with (p{$<$}0.01) levels. The concentrations of the metals were also compared with recommended maximum permissible limits and some international reports.
72. Desta, Adane, Profile of Essential and Non-Essential Metals in Soil and in Khat (Catha Edulis Forsk) Leaves Cultivated in Southern Region, Ethiopia, American Journal of Physical Chemistry, vol. 4, no. 6, pp. 58, 2015. doi: 10.11648/j.ajpc.20150406.13. Abstract
    This study was conducted with the objective of determining the quantity of selected essential and nonessential metals; Co, Mg, Ca, Cu, Mn, Cr, Cd, Fe, Zn and K in the leaf and supporting soil of Khat (Catha edulis Forsk). Samples of three Khat types (Konso, Gidole and Koyra) and soils from their root zone collected from three different sites in southern Ethiopia region were analyzed by flame atomic absorption spectrometry. K in soil and Khat sample were also determined by flame atomic emission spectroscopy. Known weight of oven-dried Khat samples were wet-digested using 2 mL of (69–72\%) HNO3 and 2 mL of (70\%) HClO4 for 130 min at variable temperatures (120–268 °C). Soil was digested by the procedure, 0.5 g samples of soil were digested with concentrated nitric acid, concentrated hydrochloric acid and hydrogen peroxide, using Kjeldahl digestion block under reflux condenser for 3 h at 300 °C. Both the edible portion of khat leaves and the soils of the study farms showed similar accumulation patterns to some extent, in their contents of the studied macro and micronutrients. Regression analysis and pearson correlation (r) results show a positive correlation Coffecient (R2) values ranging from 0.281 up to 0.991 and for pearson correlation (r) values ranging from 0.244-0.951. Although regressions based on the pooled data from the three Khat types are not adequately correlated with total metal soil levels, better fits were obtained when regression models were used for Konso Khat separately. However, no strong correlations between the leaves and other variables are evident except for Ca and Mg metal contents which have r values of 0.971 and 0.991 respectively with (p{$<$}0.01) levels. The concentrations of the metals were also compared with recommended maximum permissible limits and some international reports.
73. Fentie Tadesse, Sleshi, Determination of the Level of Selected Heavy Metals from Khat Leaves (Cata Edulis Forsk) Grown in Gidolle, Konso and Koyira, Southern Ethiopia, Science Journal of Analytical Chemistry, vol. 3, no. 6, pp. 115, 2015. doi: 10.11648/j.sjac.20150306.16. Abstract
    Khat (Catha edulis forsk), a plant used as a stimulant is grown in certain areas of East Africa and the Arab Peninsula. In Ethiopia, it is cultivated in most parts of the country and distributed to local consumers and in other countries. Many farmers have adopted modern farming methods such as application of fertilizers, pesticides and irrigation for Khat cultivation. These agricultural practices are known to increase the concentration of heavy metals in soil and khat. Some of these heavy metals such as Pb and Cd are toxic even at low concentrations while Zn, Cu, Fe and Cr though essential in the body, are toxic at high levels. Therefore this study determined the levels of Zn, Cu, Fe, Pb, Cd and Cr in khat where the plant is grown. Three different types of Khat samples grown in Gidolle, Konso and Koyira were collected from the growing area.0.5 g of oven dried Khat samples were digested by wet digestion using 3 mL of HNO3, 1 mL of HClO4 and 1 mL of H2O2 by setting the temperature first to 60°C for 30 min and then increased to 210°C for the next 2 h and 30 min.. The digests were analyzed for selected heavy metals using flame atomic absorption spectrophotometer. The following concentration ranges in dry weight (µg/g) were obtained in khat: Fe (180-222), Zn (25.23-33.69), Cu (12.64-15.74), Cr (4.01-4.53). The toxic metals (Pb and Cd) were not detected in all the samples analyzed. The ANOVA results suggested that there was significant difference (p{$<$}0.05) in the levels of heavy metals between khat varieties. Levels of studied heavy metals in khat were within in the range of maximum recommended RDA value. Based on this study the analyzed khat are free from toxic heavy metals and do not pose a health risk rather it is a source of essential nutrients for the chewers.
74. Abdelwahab, Siddig Ibrahim and Hassan, Fouad Abdulrahman and Adam, Abdalbasit and {Al-Sheraji}, Sadeq Hasan and Namrima, Putri and Mohamed, Manal and Taha, Elhassan and Ismail, Amin and Khalid, Asaad, Catha Edulis Forsk. (Khat): Antioxidative Activities and Chemical Diversities Using Hplc- Dad-Ms/Ms Analysis of Some Ethiopian and Yemenis Varieties, vol. 30, no. 10, pp. 26, 2015. Abstract
    This study aims to determine the phenolic profile of Khat (Catha edulis Forsk.). Khat was randomly collected from different places in Yemen [Dhamar (DMR), Ibb (IB), Taiz (TZ) cities] and Ethiopia (HAR). Extraction was done using 60\% methanol to determine total phenolic content (TPC), antioxidant activity [1,1-Diphenyl-2picrylhydrazyl (DPPH) radical scavenging activity, oxygen radical absorbance capacity (ORAC) and Ferric reducing/antioxidant power (FRAP)] of Khat. Quantification of phenolic compounds in khat (Catha edulis Forsk.) extracts was also performed using HPLC-DAD and confirmed using LCMS-IT-TOF system. The results showed a strong potency of antioxidants in DPPH, ORAC and FRAP assays and were significantly correlated in all samples tested. This may be due to the higher proportion of TPC. Seven phenolic compounds were quantified. HAR IB and TZ samples demonstrated similar components (5 phenolic compounds). However, DAM sample showed 6 compounds. Thus, Catha edulis Forsk rich source of phenolic content and has high antioxidant activity.
75. Atlabachew, Minaleshewa and Chandravanshi, Bhagwan Singh and Redi, Mesfin, Selected Secondary Metabolites and Antioxidant Activity of Khat (Catha Edulis Forsk) Chewing Leaves Extract, International Journal of Food Properties, vol. 17, no. 1, pp. 45--64, January 2014. doi: 10.1080/10942912.2011.614367. Abstract
    Total phenolic, flavonoid, and tannin contents of 21 Ethiopian khat (Catha edulis Forsk) leaves and their related antioxidant activities were determined in the extracts of the young leaves, matured leaves, and tips of tender stem near the young shoots. A simplified, rapid, and robust method was also optimized for the analysis of total tannins using ovalbumin as a precipitating agent and Folin Denis reagent as the quantification technique. Among the solvents tested, aqueous mixtures of 70 and 80\% acetone and 80\% methanol provided higher phenolic compounds extraction efficiency than the corresponding pure solvents and other binary mixtures. Results of the analysis revealed that total phenols ranged from 129 to 274 mg tannic acid equivalent/g of dried young leaves and 89.3 to 175 mg tannic acid equivalent/g of dried tender stem tips. Total tannin content ranged between 70.2−153 mg tannic acid equivalent/g and 49.4−103 mg tannic acid equivalent/g of the dried young leaves and tips of tender stems, respectively. Similarly, total flavonoids concentration as catechin equivalent varied between 26 to 75 and 26 to 56 mg catechin equivalent/g of dried young leaves and tips of tender stems, respectively. Khat cultivars were found to pose a substantial antioxidative activity (as ascorbic acid equivalent) ranging between 173−290 and 118−211 mg ascorbic acid equivalent/g of dried young leaves and tips of tender stems near the young shoot, respectively. Matured leaves of khat accumulated a significantly lower concentration of secondary metabolites compared to the corresponding young leaves. This study reveals that khat leaves and tender stems accumulated a substantial amount of secondary metabolites, particularly tannins.
76. Ashenef, A. and Birhanu, G. and Engidawork, E., Levels of Essential and Toxic Metals in Ethiopian Khat, (Catha Edulis Forsk.), Ethiopian Journal of Environmental Studies and Management, vol. 7, no. 3, pp. 289--297, May 2014. doi: 10.4314/ejesm.v7i3.8. Abstract
    Khat chewing is a common habit in East Africa and Arabian Peninsula. However, detail of in-organic elemental content of this plant is scarcely known. Samples of khat (Catha edulis) were collected from different parts ofEthiopia. The leaf parts, which are chewed, were separated and air dried at room temperature. The dried samples were grounded to a fine size by the use of stainless steel mills. One gram was mineralized for metal analysis via digestion in aqua regia under reflux. Spiking was performed to check the accuracy of the digestion procedure. Recoveries varied from 84.5 \% to 109.6 \%. Thirteen metal concentrations were measured by Flame Atomic Absorption/Emission Spectrometer and Graphite Furnace Atomic Absorption Spectrometer employing an external calibration curve. Levels of metals (mg/kg) on Dried Weight Basis were recorded as follows; Cu: 5.11-9.55 Cd: 0.03-6.54 Pb: non detectable to 1.57 Zn: 4.15-89.3 Mn:6.45-20 K: 5929.65-10948 Na: 218.2-842.25 Li: 0.1-0.85 Al: 2448.15-8556.45 Ba: 12.13-1479 Mg: 1798.5.5-3098.75 Fe: 260.95-1551.8 Ca: 2190.9- 10985.8. The possible consumption for the measured elements by chewing khat on regular basis lies within the recommended daily allowance (RDA) except for Al, Fe and Ba. Detection of toxic elements like Cd and Pb in khat plant samples investigated might be related to possible introduction of artificial contaminants to the ecosystem of Ethiopia. But the quantities found are in very small amounts thus there should not be an alarm~ although usual precautions of keeping the environment safe from artificial hazards is necessary. The levels of the analyzed elements in khat that surpassed the RDA i.e. Barium may expose the khat users to damages toheart, blood vessels and nervous system, Iron may facilitate growth of certain pathogenic microorganisms and Aluminium also had unconfirmed correlations under study with neuro-disorders.Key Words: Khat, Catha edulis, Metals, Flame Atomic Absorption/Emission Spectrometer (FAAS), Graphite Furnace Atomic Absorption Spectrometer (GFAAS), Ethiopia.
77. Atlabachew, Minaleshewa and Torto, Nelson and Chandravanshi, Bhagwan Singh and Redi, Mesfin, Matrix Solid-Phase Dispersion for the HPLC–DAD Determination of Psychoactive Phenylpropylamino Alkaloids from Khat (Catha Edulis Forsk) Chewing Leaves, Chromatographia, vol. 76, no. 7, pp. 401--408, April 2013. doi: 10.1007/s10337-013-2438-2. Abstract
    A fast and simple procedure based on matrix solid-phase dispersion was developed for the extraction of psychoactive phenylpropylamino alkaloids; cathinone, cathine and norephedrine, from khat (Catha edulis Forsk) chewing leaves, a stimulant and drug of abuse plant. Determination of the alkaloids was carried out by high performance liquid chromatography with diode array detection. Several extraction parameters, such as type of dispersant, type and volume of elution solvent and the ratio of sample to sorbent material were evaluated and optimized. Mean recoveries ranging from 89 to 92~\% with relative SD of less than 6~\% were obtained. A marked diversity in the phenylpropylamino alkaloid content and composition was found in seventeen different cultivars of Ethiopian khat. ANOVA results showed the existence of significant differences between the alkaloids profiles among samples of different varieties from different geographical locations in Ethiopia. The proposed method is simpler, faster and comparably more efficient than the frequently reported maceration followed by liquid–liquid extraction but as good and efficient as ultrasonic assisted extraction followed by solid-phase extraction.
78. Dell’Acqua, Lucia and Roda, Gabriella and Arnoldi, Sebastiano and Rusconi, Chiara and Turati, Lorenzo and Gambaro, Veniero, Improved GC Method for the Determination of the Active Principles of Catha Edulis, Journal of Chromatography B, vol. 929, pp. 142--148, June 2013. doi: 10.1016/j.jchromb.2013.04.012. Abstract
    The GC method previously reported by our research group for the analysis of the active principles of Catha edulis, i.e. cathine, cathinone and phenylpropanolamine, was considerably improved. N-methyl-N-trimethylsilyl-trifluoroacetamide (MSTFA) as derivatizing agent was employed, thus allowing an accurate determination of the analytes and a suitable internal standard for quantitative analyses (nicotinamide) was introduced. Moreover the chromatographic conditions were carefully studied to improve the separation of the alkaloids and sensitivity. To this end different chromatographic capillary columns and temperature gradients were investigated. The optimized GC method was validated and resulted adequate for the application in forensic analysis. Finally on behalf of the Tribunal, C. edulis vegetable material seized by the police in northern Italy was analyzed, the quantity of cathine ranging from 0.095 to 0.29\%, the quantity of PPA from 0.010 to 0.21\% and the quantity of cathinone from 0.025 to 0.374\% of the weight of the vegetable material.
79. Ashenef, A. and Engidawork, E., Fluoride Levels and Its Safety in Tea (Camellia Sinensis) and Khat (Catha Edulis) Imported and Produced in Ethiopia, Ethiopian Journal of Environmental Studies and Management, vol. 6, no. 2, pp. 149--158, March 2013. doi: 10.4314/ejesm.v6i2.5. Abstract
    The fluoride contents of sixteen(16) different packed tea leaves (Camellia sinensis) available in Ethiopian market and ten(10) samples of Khat leaves (Catha edulis) obtained from different localities were assessed using fluoride ion selective electrode. Amounts measured varies from 33.29 to 946 μg/gm on dried weight basis (DW) with an average value of 321.27±234.1 in tea samples and 13 to 20.01 μg/gm with a mean quantity of 14.94 ±1.45 in khat Samples. Based on the common practice of drinking tea three times a day by most people which is usually prepared using six grams of tea leaves and 100 to 200 gm chewing of khat leaves for those habitual users, possible daily intake of fluoride is calculated to be 1972.62 μg and 224.1-448.2 μg from tea and khat respectively based on the average fluoride quantity data from all the samples investigated. These values alone are within acceptable range of RDA (recommended daily allowance) of 2-4 mg fluorine by World Health Organization (WHO) except in one Ethiopian brand of tea where in its possible consumption the RDA limit was surpassed. Although dental problems were commonly reported in habitual khat chewers, the fluoride content of this plant is insignificant thus the chemical principle associated with such problems might be due to other ingredient(s) than fluorine. However the contribution of these plants to the overall dietary fluoride exposure should not be undermined and attention should be given to that of high values reported in tea leaves. Therefore drinking tea in areas with high fluoride levels from water sources should be cautioned to avoid the potential acute and chronic effects of fluoride.Key Words: Fluoride, Tea, Khat, Ethiopia, Ion selective electrode
80. Roda, Gabriella and Liberti, Vincenzo and Arnoldi, Sebastiano and Argo, Antonella and Rusconi, Chiara and Suardi, Sonia and Gambaro, Veniero, Capillary Electrophoretic and Extraction Conditions for the Analysis of Catha Edulis FORKS Active Principles, Forensic Science International, vol. 228, no. 1, pp. 154--159, May 2013. doi: 10.1016/j.forsciint.2013.02.034. Abstract
    A capillary electrophoretic method, which allowed the detection and separation of the active principles of Catha edulis, i.e. cathinone, cathine and phenylpropanolamine, was developed. A suitable internal standard (nicotinamide), which permitted the quantification of the analytes reducing the variability of the migration times due to EOF changes, was identified. The analytical method was validated, assessing linearity, sensitivity and repeatability, showing optimal features for the analysis of the vegetable material. Moreover extraction conditions were investigated to achieve the exhaustion of the plant material in the fastest and most efficient way to meet the requirements of the Court.
81. Wabe, Nasir and Mohammed, Mohammed, What Science Says about Khat (Catha Edulis Forsk)? Overview of Chemistry, Toxicology and Pharmacology, Journal of Experimental and Integrative Medicine, vol. 2, no. 1, pp. 29, 2012. doi: 10.5455/jeim.221211.rw.005. Abstract
    Catha edulis (khat) is a plant grown commonly in the horn of Africa. The leaves of khat are chewed by the people for its stimulant action. Khat is an evergreen shrub, which is cultivated as a bush or small tree. The leaves have an aromatic odour. The taste is astringent and slightly sweet. The plant is seedless and hardy, growing in a variety of climates and soils.
82. Shaltout, Abdallah A. and Moharram, Mohammed A. and Mostafa, Nasser Y., Wavelength Dispersive X-Ray Fluorescence Analysis Using Fundamental Parameter Approach of Catha Edulis and Other Related Plant Samples, Spectrochimica Acta Part B: Atomic Spectroscopy, vol. 67, pp. 74--78, January 2012. doi: 10.1016/j.sab.2012.01.004. Abstract
    This work is the first attempt to quantify trace elements in the Catha edulis plant (Khat) with a fundamental parameter approach. C. edulis is a famous drug plant in east Africa and Arabian Peninsula. We have previously confirmed that hydroxyapatite represents one of the main inorganic compounds in the leaves and stalks of C. edulis. Comparable plant leaves from basil, mint and green tea were included in the present investigation as well as trifolium leaves were included as a non-related plant. The elemental analyses of the plants were done by Wavelength Dispersive X-Ray Fluorescence (WDXRF) spectroscopy. Standard-less quantitative WDXRF analysis was carried out based on the fundamental parameter approaches. According to the standard-less analysis algorithms, there is an essential need for an accurate determination of the amount of organic material in the sample. A new approach, based on the differential thermal analysis, was successfully used for the organic material determination. The obtained results based on this approach were in a good agreement with the commonly used methods. Depending on the developed method, quantitative analysis results of eighteen elements including; Al, Br, Ca, Cl, Cu, Fe, K, Na, Ni, Mg, Mn, P, Rb, S, Si, Sr, Ti and Zn were obtained for each plant. The results of the certified reference materials of green tea (NCSZC73014, China National Analysis Center for Iron and Steel, Beijing, China) confirmed the validity of the proposed method.
83. Krizevski, Raz and Bar, Einat and Dudai, Nativ and Levy, Asaf and Lewinsohn, Efraim and Sitrit, Yaron and {Ben-Shabat}, Shimon, Naturally Occurring Norephedrine Oxazolidine Derivatives in Khat (Catha Edulis), Planta Medica, vol. 78, no. 8, pp. 838--842, May 2012. doi: 10.1055/s-0031-1298430. Abstract
    Khat (Catha edulis Forsk.) is a perennial shrub whose young leaves are chewed for their psychostimulating and anorectic properties. The main active principles of khat are believed to be the phenylpropylamino alkaloids, primarily (−)-cathinone [(S)-α-aminopropiophenone], (+)-cathine [(1S)(2S)-norpseudoephedrine], and (−)-norephedrine [(1R)(2S)-norephedrine]. GC-MS analyses of young leaf extracts indicated the presence of two oxazolidine derivatives, 2,4-dimethyl-5-phenyloxazolidine and 4-methyl-2-(trans-1-pentenyl)-5-phenyloxazolidine. To ascertain the chemical identity of these compounds, we synthesized the putative compounds by condensation of norephedrine and acetaldehyde or trans-2-hexenal, respectively. Spectroscopic analyses (GC-MS, NMR) of the structures of these synthetic compounds showed them to have identical retention indexes and mass spectra characteristic to 2,4-dimethyl-5-phenyloxazolidine and 4-methyl-2-(trans-1-pentenyl)-5-phenyloxazolidine. Marked differences in the ratios between each of these two norephedrine oxazolidine derivatives and total phenylpropylamino alkaloids were found among thirteen different khat accessions further indicating polymorphism in alkaloid ratios and content in C. edulis.
84. Gambaro, Veniero and Arnoldi, Sebastiano and Colombo, Maria Laura and Dell’Acqua, Lucia and Guerrini, Katia and Roda, Gabriella, Determination of the Active Principles of Catha Edulis: Quali–Quantitative Analysis of Cathinone, Cathine, and Phenylpropanolamine, Forensic Science International, vol. 217, no. 1, pp. 87--92, April 2012. doi: 10.1016/j.forsciint.2011.09.028. Abstract
    In the last years, all the vegetable material supposed to belong to the Catha Edulis species, seized at the Malpensa and Orio al Serio airports, were analyzed in our laboratory on behalf of the Tribunals of Busto Arsizio and Bergamo, respectively. After a preliminary botanic examination, the quali–quantitative determination of the active principles cathinone, cathine and phenylpropanolamine (PPA) was carried out by means of GC/MS and GC/FID techniques, which meet the requirements of the forensic analyses. We developed a fast, effective and reliable derivatization procedure which allowed to simultaneously detect cathine and PPA, whose discrimination is mandatory since PPA is not a psychoactive agent. Cathine was distributed in the various parts of the plant (leaves and stems) and its quantity ranged from 0.03\% to 0.17\% of the weight of the vegetable material; PPA was not detected in the twigs and its quantity in the leaves ranged from 0.07\% to 0.16\%. The quantitative determination of cathinone was carried out directly on the methanol solution after maceration of the vegetable material, its quantity ranging from 0.02\% to 0.10\%. No significant difference in the content of the two active principles was found between the fresh and the dried material.
85. Hagel, Jillian M. and Krizevski, Raz and Marsolais, Frédéric and Lewinsohn, Efraim and Facchini, Peter J., Biosynthesis of Amphetamine Analogs in Plants, Trends in Plant Science, vol. 17, no. 7, pp. 404--412, July 2012. doi: 10.1016/j.tplants.2012.03.004. Abstract
    Amphetamine analogs are produced by plants in the genus Ephedra and by Catha edulis, and include the widely used decongestants and appetite suppressants pseudoephedrine and ephedrine. A combination of yeast (Candida utilis or Saccharomyces cerevisiae) fermentation and subsequent chemical modification is used for the commercial production of these compounds. The availability of certain plant biosynthetic genes would facilitate the engineering of yeast strains capable of de novo pseudoephedrine and ephedrine biosynthesis. Chemical synthesis has yielded amphetamine analogs with myriad functional group substitutions and diverse pharmacological properties. The isolation of enzymes with the serendipitous capacity to accept novel substrates could allow the production of substituted amphetamines in synthetic biosystems. Here, we review the biology, biochemistry and biotechnological potential of amphetamine analogs in plants.
86. Atlabachew, Minaleshewa and Chandravanshi, Bhagwan Singh and Zewge, Feleke and Redi, Mesfin, Fluoride Content of Ethiopian Khat (Catha Edulis Forsk) Chewing Leaves, Toxicological \& Environmental Chemistry, vol. 93, no. 1, pp. 32--43, January 2011. doi: 10.1080/02772248.2010.501032. Abstract
    The levels of water soluble and total fluoride concentration in 11 different varieties of Ethiopian khat (Catha edulis Forsk, an evergreen stimulant plant) commonly consumed in the country and exported to the neighboring countries were determined by fluoride ion-selective electrode. Known amounts of fresh khat samples were suspended in deionized water, stirred, and the supernatants exposed to a chelator that decomplexes fluoride were assayed. The total fluoride concentration in the leaves was also analyzed after the leaves were dried, charred, and ashed. Water soluble and total fluoride concentration in khat varieties varied, ranging from 0.19 to 0.43 µg g−1 fresh weight and 3.4 to 7.1 µg g−1 dry weight, respectively. The fluoride concentration in matured leaves (12 µg g−1) was higher than that in young leaves (6.5 µg g−1) dry weight. Assuming that daily khat leaves chewing for an adult is 100 g, fluoride intake from chewing leaves of the analyzed khat varieties is far below the daily fluoride tolerable upper limit. The safe intake of fluoride is recommended to be 1.5–4.0 mg day−1 for adults and less for children. However, chewing khat leaves may contribute a significant amount of fluoride for the total daily intake of an individual and should not be overlooked while estimating the total dietary intake of fluoride for individuals chewing khat leaves regularly.
87. Hagel, Jillian M. and Krizevski, Raz and Kilpatrick, Korey and Sitrit, Yaron and Marsolais, Frédéric and Lewinsohn, Efraim and Facchini, Peter J., Expressed Sequence Tag Analysis of Khat (Catha Edulis) Provides a Putative Molecular Biochemical Basis for the Biosynthesis of Phenylpropylamino Alkaloids, Genetics and Molecular Biology, vol. 34, pp. 640--646, 2011. doi: 10.1590/S1415-47572011000400017. Abstract
    Khat (Catha edulis Forsk.) is a flowering perennial shrub cultivated for its neurostimulant properties resulting mainly from the occurrence of (S)-cathinone in young leaves. The biosynthesis of (S)-cathinone and the related phenylpropylamino alkaloids (1S,2S)-cathine and (1R,2S)-norephedrine is not well characterized in plants. We prepared a cDNA library from young khat leaves and sequenced 4,896 random clones, generating an expressed sequence tag (EST) library of 3,293 unigenes. Putative functions were assigned to {$>$} 98\% of the ESTs, providing a key resource for gene discovery. Candidates potentially involved at various stages of phenylpropylamino alkaloid biosynthesis from L-phenylalanine to (1S,2S)-cathine were identified.
88. Wabe, Nasir Tajure, Chemistry, Pharmacology, and Toxicology of Khat (Catha Edulis Forsk): A Review, Addiction \& Health, vol. 3, no. 3-4, pp. 137--149, 2011. url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3905534/. Abstract
    Catha edulis (khat) is a plant grown commonly in the horn of Africa. The leaves of khat are chewed by the people for its stimulant action. Its young buds and tender leaves are chewed to attain a state of euphoria and stimulation. Khat is an evergreen shrub, which is cultivated as a bush or small tree. The leaves have an aromatic odor. The taste is astringent and slightly sweet. The plant is seedless and hardy, growing in a variety of climates and soils., Many different compounds are found in khat including alkaloids, terpenoids, flavonoids, sterols, glycosides, tannins, amino acids, vitamins and minerals. The phenylalkylamines and the cathedulins are the major alkaloids which are structurally related to amphetamine., The major effects of khat include those on the gastro-intestinal system and on the nervous system. Constipation, urine retention and acute cardiovascular effects may be regarded as autonomic (peripheral) nervous system effects; increased alertness, dependence, tolerance and psychiatric symptoms as effects on the central nervous system. The main toxic effects include increased blood pressure, tachycardia, insomnia, anorexia, constipation, general malaise, irritability, migraine and impaired sexual potency in men., Databases such as Pubmed, Medline, Hinary, Google search, Cochrane and Embase were systematically searched for literature on the different aspects of khat to summarize chemistry, pharmacology, toxicology of khat (Catha edulis Forsk).
89. Laussmann, Tim and {Meier-Giebing}, Sigrid, Forensic Analysis of Hallucinogenic Mushrooms and Khat (Catha edulisForsk) Using Cation-Exchange Liquid Chromatography, Forensic Science International, vol. 195, no. 1, pp. 160--164, February 2010. doi: 10.1016/j.forsciint.2009.12.013. Abstract
    Hallucinogenic mushrooms (e.g. Psilocybe and Panaeolus species) as well as leaves and young shoots of the khat tree (Catha edulisForsk) are illicit drugs in many countries. The exact concentration of the hallucinogenic alkaloids psilocin and psilocybin in mushrooms and the sympathomimetic alkaloids cathinone and cathine in khat is usually essential for jurisdiction. Facing an increasing number of mushroom and khat seizures by German customs authorities, a convenient comprehensive quantitative HPLC method based on cation-exchange liquid chromatography for these rather “exotic” drugs has been developed which avoids time-consuming multi-step sample preparation or chemical derivatization procedures. Using this method a number of different hallucinogenic fungi species and products that are mainly distributed via the internet have been analysed (dried and fresh Psilocybe cubensisSinger as well as P. cubensis collected from “grow boxes”, Panaeolus cyanescensBerkeleyandBroome and so-called “philosopher stones” (sclerotia of Psilocybe species)). Highest total amounts of psilocin have been detected in dried P. cyanescens reaching up to 3.00±0.24mg per 100mg. The distribution of khat alkaloids in different parts of the khat shoots has been studied. High concentrations of cathinone have not only been detected in leaves but also in green parts and barks of stalks. Additionally, the sample treatment for fresh mushroom and khat samples has been optimised. Highest amounts of alkaloids were found when fresh material was freeze-dried.
90. Adugna, Yirga and Dagne, Ermi and Kebede, Eshetu and Atilaw, Yoseph, Determination of Levels of Cathine in Khat (Catha Edulis) Leaves and Its Detection in Urine of Khat Chewers: A Preliminary Report, Ethiopian e-Journal for Research and Innovation Foresight (Ee-JRIF), vol. 2, no. 1, pp. 7--22, August 2010. url: https://journals.bdu.edu.et/index.php/eejrif4/article/view/1108. Abstract
    Analysis of the different parts of the Khat plant revealed that the tender leaves, that areusually preferred by Khat chewers contain the psychoactive alkaloid cathinone, whereasthe older and harder leaves contain cathine, also known as d-norpseudoephedrine. In thisstudy we used proton nuclear magnetic resonance method not only to establish presenceor absence of these compounds in the leaves, but also to determine their levels. Using thismethod no cathine was detected in the fresh twigs and young leaves. On the other handthe harder and older leaves from the branches gave upto 1.5\% cathine. When the youngleaves were dried in the sun and analysed, cathine appeared to be the major component(1.5\%), clearly showing the gradual conversion of cathinone to cathine. The sameanalytical method was also used to establish presence or absence of cathine in urine ofKhat chewers.
91. Atlabachew, Minaleshewa and Chandravanshi, Bhagwan Singh and Redi, Mesfin, Concentration Levels of Essential and Non-Essential Metals in Ethiopian Khat (Catha Edulis Forsk), Biological Trace Element Research, vol. 138, no. 1, pp. 316--325, December 2010. doi: 10.1007/s12011-010-8617-1. Abstract
    The levels of essential (Ca, Mg, Mn, Fe, Zn, Cr, Cu, and Co) and non-essential (Cd and Pb) metal in six different varieties of Ethiopian khat (Catha edulis Forsk, an evergreen stimulant plant) commonly consumed in the country and exported to the neighboring countries were determined by flame atomic absorption spectrometry. Known weight of oven-dried khat samples were wet-digested using 2~mL of (69–72\%) HNO3 and 2~mL of (70\%) HClO4 for 2~h and 30~min at variable temperature (120–270°C). The mineral contents in the digests were analyzed using flame atomic absorption spectrometer. The following concentrations ranges in fresh-weight basis were recorded in decreasing order: Ca (1,038–2,173~µg/g)\,{$>$}\,Mg (478.2–812.3~µg/g)\,{$>$}\,Fe (53.95–82.83~µg/g)\,{$>$}\,Zn (5.18–9.40~µg/g)\,{$>$}\,Mn (6.98–8.66~µg/g)\,{$>$}\,Cu (1.85–5.53~µg/g)\,{$>$}\,Cr (0.66–3.47~µg/g)\,{$>$}\,Co (0.41–0.80~µg/g). A wide variation in the mineral contents of khat from different region of Ethiopia was noticed. The toxic metals (Pb and Cd) were not detected in all the samples analyzed.
92. Tilahun, Ephrem, Determination of Trace Metals in Commercially Available Khat (Catha Edulis Forsk) in Addis Ababa, June 2009. url: http://thesisbank.jhia.ac.ke/6195/. Abstract
    Khat (Catha edulis Forsk) is a plant that grows in certain areas of East Africa and the Arab Peninsula. A large number of people in Ethiopia chew khat leaves because of its pleasurable and stimulating effects. In the present study the level of selected Trace metals ( Cu, Zn, Mn, Ni, Co, Cr, Cd and Pb) in four different kinds of khat sampled from different khat shops in Adiss Abeba were analyzed. Known weights of oven dried Khat samples were digested by wet digestion using 3 mL of HNO3 ,1 mL of HCLO4 and 1 mL of H2O2 by setting the temperature first to 60 0C for 30 min and then increased to 210 0C for the next 2 h and 30 min. The contents of the minerals in the digests were analysed using flame atomic absorption spectrometry. The following concentration ranges in dry weight (μg/g) were obtained in the khat samples: Cu (19.2 - 24.4); Zn (24.1 – 46.9); Mn (14.92 – 20.6); Ni (4.7 – 7.7); Co (3.1 – 7.76); Cr (3.1 – 6.76); Cd (1.3 – 2.9) and Pb (4.8 – 9.1). Among the essential metal analyted Zn was the most abundant one followed by Cu,Mn,and Ni Whereas Co and Cr were less than Pb. Generally ‘Bahirdar’ Khat contained higher concentration compared to Gelemso, Gurage and Wondo for the majority of the mineral nutrients identified. The tested four kinds of khat proved high variability (p{$<$}0.05) in their content of trace metals. The possible uptake by the human body from fresh khat has also been determined. Except Cd and Pb the amount of metal that one may take through consumption of fresh khat alone were found to be below the recommended daily allowance
93. Krizevski, Raz and Dudai, Nativ and Bar, Einat and Dessow, Ilana and Ravid, Uzi and Lewinsohn, Efraim, Quantitative Stereoisomeric Determination of Phenylpropylamino Alkaloids in Khat (Catha Edulis Forsk.) Using Chiral GC-MS, Israel Journal of Plant Sciences, vol. 56, no. 3, pp. 207--213, May 2008. doi: 10.1560/IJPS.56.3.207. Abstract
    Khat (Catha edulis Forsk., Celastraceae) is a perennial shrub that was introduced to Israel by Yemenite immigrants. Its young leaves are chewed for their psycho-stimulating properties. Young khat leaves contain the phenylpropylamino alkaloids (-)-cathinone [(S)-α-aminopropiophenone], (+)-cathine [(1S)(2S)-norpseudoephedrine], and (-)-norephedrine [(1R)(2S)-norephedrine] as the main active principles. A novel GC-MS analysis method for the quantitative determination of phenylpropylamino alkaloids and their putative biosynthetic precursor 1-phenylpropane-1,2- dione in khat leaves was developed. We utilized an alkaline-organic extraction, coupled with gas chromatography and a chiral permethylated beta cyclodextrin phase, to allow a full separation between the two diastereoisomers (1S)(2S)-cathine and (1R)(2 S)-norephedrine. We found a marked diversity in the phenylpropylamino alkaloid content and composition in three different locally grown accessions and the commercial cultivar ‘Mahanaim’.
94. {Vinokur et al.}, Yakov, Hydrophilic and Lipophilic Antioxidant Capacity and Content of Phenolic Compounds in Fresh Khat Leaves ({$<$}em{$>$}Catha Edulis{$<$}/Em{$>$} Forsk.), Ethnobotanical Leaflets, vol. 2008, no. 1, July 2008. url: https://opensiuc.lib.siu.edu/ebl/vol2008/iss1/73.
95. Dudai, N. and Fischer, R. and Segev, D. and Chaimovitsh, D. and Rosenzweig, N. and Shimoni, M., Antioxidative Activity of Khat (Catha Edulis Forsk.), Acta Horticulturae, no. 778, pp. 85--92, January 2008. doi: 10.17660/ActaHortic.2008.778.8. Abstract
    Catha edulis Forsk. (khat) is an evergreen tree growing wild in high altitudes in East Africa and the Arabian Peninsula. Due to its stimulating effect, chewing fresh young leaves of khat has become a common habit in several countries in those regions, which later spread to the Western world. The stimulating activity of khat is attributed to its alkaloid fraction, comprising mainly of cathine and cathinone. In addition to its everyday use, khat has been known as a traditional medicinal plant for centuries. Therefore, additional aspects concerning this species secondary metabolism and its related biological activity are currently examined. In an attempt to identify new potential plant sources for antioxidants, khat varieties were found to posses a substantial antioxidative activity, ranging 175–204 mg/g DW chlorogenic acid equivalent. Cathine and cathinone were found to have a negligible contribution to the antioxidative activity. In order to estimate the potential use of Catha edulis as a natural antioxidant source, further aspects such as plant material availability, extraction efficiency and safety issues are yet to be evaluated.
96. Krizevski, Raz and Dudai, Nativ and Bar, Einat and Lewinsohn, Efraim, Developmental Patterns of Phenylpropylamino Alkaloids Accumulation in Khat (Catha Edulis, Forsk.), Journal of Ethnopharmacology, vol. 114, no. 3, pp. 432--438, December 2007. doi: 10.1016/j.jep.2007.08.042. Abstract
    Khat (Catha edulis Forsk., Celastraceae) is a perennial shrub that was introduced to Israel by Yemenite immigrants. Khat young leaves are chewed as a stimulant. The main stimulating active principles in this plant are the phenylpropylamino alkaloids (−)-cathinone [(S)-α-aminopropiophenone], (+)-cathine [(+)-norpseudoephedrine] and (−)-norephedrine. A novel GC–MS analysis method for the quantitative determination of phenylpropylamino alkaloids and their putative precursor 1-phenyl-1,2-propanedione in khat leaves was developed. We found a marked diversity in the phenylpropylamino alkaloids content and composition in 9 different accessions originated in seedlings and in the commercial cultivar “Mahanaim”. The highest 1-phenyl-1,2-propanedione and (−)-cathinone levels occur in young leaves, the part traditionally chewed for its psycho-stimulating properties. Older leaves lack (−)-cathinone but contain the less active (+)-cathine and (−)-norephedrine. Young stems and flowers also contain 1-phenyl-1,2-propanedione, (−)-cathinone, (+)-cathine and (−)-norephedrine. We report the presence of a (−)-cathinone reductase in khat leaves capable of reducing (−)-cathinone to (+)-cathine in the presence of NADPH. We propose that (−)-cathinone is a biosynthetic precursor of (+)-cathine and (−)-norephedrine in khat leaves.
97. {Al-Flahi}, Abdulsalam and Zou, Jian-kai and Yin, Xue-feng, Solid-Phase Microextraction for Flavor Analysis in Harari Khat (Catha Edulis) Stimulant, Journal of Zhejiang University-SCIENCE A, vol. 5, no. 4, pp. 428--431, April 2004. doi: 10.1631/jzus.2004.0428. Abstract
    This research examined the typical flavor compounds in the commonest type of Khat called Harari Khat grown in the region of Ethiopia. Twenty-eight compounds, which includes 1,2-Propanedione, 1-Phenyl, Hexanol, Hexanal compounds, Limonene, Benzaldehyde with other flavors, were extracted by polydimethylsiloxane at room temperature for 30 min from Khat samples, and identified by solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). This method needs no organic solvents and required minimal sample.
98. Brenneisen, Rudolf and Geisshüsler, Stefan, Phenylpentenylamines from Catha Edulis, ACS Publications, July 2004. doi: 10.1021/np50054a041.
99. {Al-Meshal}, Ibrahim A. and Hifnawy, Mohamed S. and Nasir, Mohammad, Myricetin, Dihydromyricetin, and Quercetin Glycosides from Catha Edulis, ACS Publications, July 2004. doi: 10.1021/np50043a032.
100. Banjaw, Mehret Yerdaw and Schmidt, Werner J., Lyophilization and Freeze-Precipitation as a Method for Crude Extraction of Cathinone from Catha Edulis Leaves with Minimum Thermal Injury, Chemistry of Natural Compounds, vol. 40, no. 6, pp. 611--612, November 2004. doi: 10.1007/s10600-005-0056-4.
101. Kite, Geoffrey C. and Ismail, Muna and Simmonds, Monique S. J. and Houghton, Peter J., Use of Doubly Protonated Molecules in the Analysis of Cathedulins in Crude Extracts of Khat (Catha Edulis) by Liquid Chromatography/Serial Mass Spectrometry, Rapid Communications in Mass Spectrometry, vol. 17, no. 14, pp. 1553--1564, 2003. doi: 10.1002/rcm.1085. Abstract
     Analysis of crude methanolic extracts of fresh khat (Catha edulis) by liquid chromatography/mass spectrometry (LC/MS) revealed the presence of 62 cathedulin alkaloids (compared with 15 published structures). Many cathedulins generated doubly protonated molecules following electrospray ionisation and the ratio of doubly to singly protonated species could be manipulated by adjusting the electrospray capillary position and source conditions. By selecting the doubly protonated species for serial mass spectrometric analysis (MS/MS), it was possible to use an ion trap mass spectrometer to observe singly charged product ions at lower m/z values than ion trap MS/MS analysis of [M+H]+ would have allowed. These spectra were particularly valuable in elucidating the acylation patterns of cathedulins where MS/MS analysis of [M+H]+ resulted in loss of a large neutral species to yield a small singly charged fragment below the lower limit for ion trapping. Acylation patterns for most of the 62 cathedulins are proposed from mass spectrometric analysis, and the data obtained for a major unreported cathedulin of mass 1001 Da suggest that it belongs to a new group of cathedulins having a cathate dilactone bridge but not an evoninate bridge. Copyright © 2003 John Wiley \& Sons, Ltd.
102. Alles, Gordon A. and Fairchild, M. David and Jensen, Mark and Alles, A., Chemical Pharmacology of Catha Edulis, ACS Publications, May 2002. doi: 10.1021/jm50015a010.
103. Field, Courtney Robin, Alkaloids of Catha Spp., 2001. url: https://researchspace.ukzn.ac.za/handle/10413/10206. Abstract
     The levels of the psychoactive alkaloids S-(-)-cathinone and its primary metabolite cathine, consisting of the diastereomers (+) -norpseudoephedrine and (-)- norephedrine were determined in Catha edulis (Vahl) Forssk. ex Endl., Catha transvaalensis Codd and Catha abbottii Van Wyk \& Prins. Alkaloid levels were investigated in C. edulis plants collected from three different localities in South Africa, and one from a Nairobi khat market. The efficiency of three different methods for the extraction and isolation of cathinone and cathine were investigated, viz. an aqueous acid extraction, an organic solvent extraction and an aqueous acid extraction using the commercially available Extrelutᴿ procedure. The aqueous acid extraction resulted in the rapid loss of cathinone and yielded variable alkaloid levels in replicate studies. This was also observed when this method was coupled with the Extrelutᴿ procedure. In contrast, the organic solvent extraction did not result in a loss of cathinone and provided consistent results over a number of replicates; it also proved to be a simple and rapid method for extracting and isolating cathinone and cathine. A trifluoroacetic acid (TFA) derivatization procedure which has been suggested to produce characteristic diagnostic fragments for gas chromatography / mass spectrometry (GC/MS) identification, was investigated, but failed to produce consistent TFA derivatives of cathinone and cathine. However, underivatized cathinone and cathine were easily identified by GCMS due to their unambiguous mass spectra. All subsequent studies were undertaken using the organic solvent extraction and isolation method, coupled with GC analysis and GC/MS identification of underivatized cathinone and cathine. Leaves of C. edulis were found to contain cathinone and cathine at levels 100 times higher than those of C. transvaalensis. The alkaloids were undetectable in C. abbottii. Plants grown from cuttings of C. edulis collected from the Durban Botanical Gardens were found to contain cathinone and cathine at levels of 0.410 mg per gram fresh weight and 0.157 mg per gram fresh weight in leaves, respectively, while these levels in plants derived from different localities decreased in the order: Eastern Cape (0.319 mg/g f.w cathinone and 0.029 mg/g f.w cathine), Mpumalanga (0.139 mg/g f.w. cathinone and 0.171 mg/g f.w. cathine) and Nairobi (0.032 mg/g f.w. cathinone and 0.025 mg/g f. w. cathine). In an investigation of the cathinone levels in the different plant parts it was found that the highest levels were found in leaves of the shoot tip (0.243 mg/g f.w.) but decreased with the age of the leaf and developmental stage of the plant in the order: juvenile leaves (0.124 mg/g f.w.), mature leaves (0.035 mg/g f.w.), young stem (0.033 mg/g f.w.) and mature stem (0.004 mg/g f.w.). Concomitantly, cathine levels increased with the age of the leaf: leaves of the shoot tip (0.006 mg/g f.w.), juvenile leaves (0.011 mg/g f.w.), mature leaves (0.019 mg/g f.w.). The cathine level in the young stem material was found to be the highest in the entire plant (0.270 mg/g f.w.) but decreased markedly in the mature stem (0.052 mg/g f.w.). Both cathinone and cathine levels in the mature root were greater than levels in the mature stern, being 0.012 mg cathinone per gram fresh weight, and 0.063 mg cathine per gram fresh weight. Neither cathinone nor cathine were detectable in young root material.
104. Mahmoud, A.-L. E., Mycotoxin-Producing Potential of Fungi Associated with Qat (Catha Edulis) Leaves in Yemen, Folia Microbiologica, vol. 45, no. 5, pp. 452--456, October 2000. doi: 10.1007/BF02817620. Abstract
     Forty-four fungal species belonging to 20 genera were isolated from 30 samples of qat leaves. The most frequent genera wereAspergillus, Alternaria, Penicillium, andCladosporium followed byFusarium, Drechslera, Chœtomium, andMucor. The most prevalent species in above genera wereAspergillus niger, A. flavus, A fumigatus, Alternaria alternata, Penicillium chrysogenum, P. citrinum, Cladosporium cladosporioides, andFusarium verticillioides. From these fungi, 17 species (39\%) related to 7 genera (35\%) proved to be true endophytes. Eleven out of 75 isolates were mycotoxigenic.A. alternata produced alternariol and alternariol monomethyl ether whereasA. flavus produced aflatoxins B1 and B2. Ochratoxin A, sterigmatocystin, citrinin and T-2 toxin were produced byA. ochraceus, A. versicolor, P. citrinum andF. oxysporum, respectively. The presence of such toxigenic fungi associated with qat leaves is considered to be a threat to public health.
105. Hattab, Faiez N and {Angmar-Månsson}, Birgit, Fluoride Content in Khat (Catha Edulis) Chewing Leaves, Archives of Oral Biology, vol. 45, no. 3, pp. 253--255, March 2000. doi: 10.1016/S0003-9969(99)00133-8. Abstract
     Khat (qat) leaves are chewed for their psychostimulative effects; there is an unconfirmed suggestion that they contain a high concentration of fluoride (F). Khat samples from Yemen were suspended in deionized water, spun, and the supernatants exposed to a chelator that decomplexes F, which was assayed with an F−-electrode coupled to an ion analyser. F released into whole saliva after chewing khat for 15~min and from khat suspended in stimulated whole saliva for 1.5~h in vitro was measured also. Total F in dried khat leaves and their ash was assayed by the acid-hexamethyldisiloxane microdiffusion method. All methods demonstrated negligible amounts of F in or from khat leaves ({$<$}0.02~μg F/ml leached into water or saliva; 0.06~μg F/ml in saliva after chewing; 0.93~μg total F/g in dried leaf; 2.07~μg total F/g in ash).
106. Ripani, L. and Schiavone, S. and Garofano, L., GC/MS Identification of Catha Edulis Stimulant-Active Principles, Forensic Science International, vol. 78, no. 1, pp. 39--46, March 1996. doi: 10.1016/0379-0738(95)01855-7. Abstract
     The chemical composition of Khat (Catha edulis Forsk. Celastraceae) was discovered in recent years by a study undertaken at the United Nations Narcotics Laboratory in Geneva. Considering two phenylpropylamines to be the main compounds responsible for the stimulant activity of the plant, we propose a rapid and efficient method for the extraction and determination of cathinone, cathine and norephedrine.
107. Mathys, Karoline and Brenneisen, Rudolf, HPLC and TLC Profiles of Phenylalkylamines of Khat (Catha Edulis Forsk.) Confiscated in Switzerland, Pharmaceutica Acta Helvetiae, vol. 68, no. 2, pp. 121--128, September 1993. doi: 10.1016/0031-6865(93)90014-W. Abstract
     Khat, the leaves of Catha edulis Forsk., is widely used as a “natural amphetamine” in East Africa and the Arab Peninsula. In recent years, air-transported khat appeared on local khat markets in Europe (e.g. France, Italy, Great Britain). Due to increasing seizures of khat imported by ethnic communities and emigrants the psychoactive drug has been banned in 1992 by the Swiss Health Authorities. The demand for monitoring the psychotropic potential of the illicit drug made it necessary to establish specific, sensitive and rapid methods for the determination of the alkaloids, mainly the psychoactive principle S-(−)-cathinone. The S-(−)-cathinone concentration measured by high-performance liquid chromatography with photodiode array detection (HPLC-DAD) and alternatively by instrumental thin-layer chromatography (TLC) varied between 2182 and 4506 μg/g dried material. It is typical for khat originating from Kenya and demonstrates its high psychoactivity. The S,S-(+)-norpseudoephedrine and R,S-(−)-norephedrine content ranged from 2114 to 4094 and 192 to 1345 μg/g, respectively.
108. Lehmann, T. and Geisshüsler, S. and Brenneisen, R., Rapid TLC Identification Test for Khat (Catha Edulis), Forensic Science International, vol. 45, no. 1, pp. 47--51, March 1990. doi: 10.1016/0379-0738(90)90220-S. Abstract
     A rapid and sensitive method for identification of Catha edulis (khat) basing on a simple extraction and TLC separation is described. The test is specific for the main khatamines cathinone and norpseudoephedrine.
109. Crombie, L. and Crombie, W. M. L. and Whiting, D. A., Chapter 4 Alkaloids of Khat (Catha Edulis), vol. 39, pp. 139--164, January 1990. doi: 10.1016/S0099-9598(08)60166-2. Abstract
     This chapter discusses the chemistry of the khat alkaloids that mainly concerns two groups, the phenylalkylamines and the complex polyesters of polyhydroxylated dihydroagarofurans. Cathinone is the major active component and in some samples of khat accounts for up to 70\% of the phenylalkylamine bases. Cathinone shows amphetamine, a strong potency in stimulating the central nervous system (CNS) and exhibits a similar mechanism of action. Cathinone base is fairly stable in dilute solution in non-hydroxylic, and nonpolar media. There are quantitative differences in alkaloid content between samples of fresh and dried plant material and between samples of differing ages, but there appeared to be no gross differences between the number and types of alkaloid.
110. Rizk, A. M. [عبد الفتاح محمد رزق and Mobarak, Z. M. and {El-Shihi}, T., Constituents of Catha Edulis (Alkaloids, Triterpenoids and Related Substances and Saponins), 1989. url: http://qspace.qu.edu.qa/handle/10576/9983. Abstract
     The study of the alkaloids of khat samples from Egypt and Yemen revealed qualitative and quantitative differences. Cathine and the dimer of cathinone occured in both samples, while norephedine was detected only in Yemen samples. Investigation of certain other constituents viz. triterpenes, sterols, fatty alcohols, hydrocarbons, fatty acids and saponins resulted in the isolation and identification of several components
111. Geisshüsler, S. and Brenneisen, R., The Content of Psychoactive Phenylpropyl and Phenylpentenyl Khatamines in Catha Edulis Forsk. of Different Origin, Journal of Ethnopharmacology, vol. 19, no. 3, pp. 269--277, May 1987. doi: 10.1016/0378-8741(87)90004-3. Abstract
     Khat, the leaves of Catha edulis Forsk. (Celastraceae), is widely used as a stimulant in East Africa and the Arab Peninsula. Samples from the most important markets of Ethiopia, Kenya, North Yemen and Madagascar were analysed with high-performance liquid chromatography (HPLC) concerning their khatamine content (phenylpropyl and phenylpentenylamines). The variability of khatamines depending on origin, type and quality is discussed. In many samples a good correlation between the amount of cathinone, the main CNS-active compound, and quality estimation (price) of dealers and consumers was found.
112. González, Antonio G. and López, Isabel and Ferro, Esteban A. and Ravelo, Angel G. and Gutiérrez, Javier and Aguilar, Marcelino A., Taxonomy and Chemotaxonomy of Some Species of Celastraceae, Biochemical Systematics and Ecology, vol. 14, no. 5, pp. 479--480, October 1986. doi: 10.1016/0305-1978(86)90005-0. Abstract
     β-Amyrin, iguesterin, celastrol, pristimerin, tingenone, salaspermic acid, 3β,29-dihydroxy-glutin-5-ene and myricadiol are found in the root extract of Maytenus umbellata. Its chemical composition is thus similar to that of the other Macaronesian endemic, Maytenus canariensis Loes and also to the East African Catha edulis Forsk.
113. Crombie, Leslie and Toplis, Dane and Whiting, Donald A. and Rozsá, Zsuzsanna and Hohmann, Judit and Szendrei, Kalman, New Macrolide Sesquiterpene Alkaloids of Catha Edulis: Examples Containing a Novel Dilactone Bridge, Journal of the Chemical Society, Perkin Transactions 1, no. INVALID\_SCITE\_VALUE, pp. 531--534, January 1986. doi: 10.1039/P19860000531. Abstract
     The constitutions of three new sesquiterpene alkaloids, cathedulin-K19 (1)(C54H58N2O23, M 1 102), cathedulin-K17 (6)(C59H62N2O23, M 1 166), and cathedulin-K20 (8)(C59H62N2O23, M 1 166), obtained in small quantities from stems and leaves of Catha edulis(khat), have been demonstrated by spectroscopic examination. Alkaloids K17 and K19 contain a novel diester bridge derived from (Z)-4-(3-carboxy-2-pyridyl)-2-methylbut-3-enoic acid.
114. {Al-Meshal}, Ibrahim A. and Nasir, Mohammad and {El-Feraly}, Farouk S., (-)-N-Formylnorephedrine from Catha Edulis, Phytochemistry, vol. 25, no. 9, pp. 2241--2242, January 1986. doi: 10.1016/0031-9422(86)80102-9. Abstract
     The alkaloidal fraction of Catha edulis yielded upon repeated chromatography (-)-N-formylnorephedrine whose 1HNMR and 13CNMR spectra suggested the presence of cisoid (major) and transoid forms (minor). The identity of the isolated compound was established by comparison with the major product obtained by formylating (-)-norephedrine; the minor product was found to be (-)-N,O-diformylnorephedrine.
115. Brenneisen, Rudolf and Geisshülser, Stefan and Schorno, Xaver, Merucathine, A New Phenylalkylamine from Catha Edulis, Planta Medica, vol. 50, no. 6, pp. 531--531, December 1984. doi: 10.1055/s-2007-969796. Abstract
     Thieme E-Books \& E-Journals
116. Guantai, Anastasia N., Catha Edulis, (Vahl) Forsk, (Miraa): Occurrence, Active Constituents And Pharmacological Activity., 1982. url: http://erepository.uonbi.ac.ke/handle/11295/56790. Abstract
     The Catha edulis material used in this research, unless otherwise stated was obtained as required from River Road, Nairobi between 7.00 a.m. and 9.00. a.m when the material is in its freshest condition. Usually the material had been transported from Meru, approximately 260 Kilometres from Nairobi less than 20 hours before then. Samples of Catha material, weighing 25 grammes were extracted by refluxing with 75 percent ethylalcohol followed by solvent-solvent extraction at PH-5-6 (to remove neutrals and acids) and PH9 (to recover basic substances) using chloroform. The final basic residue was taken up in chloroform and used in subsequent analysis • The best solvent systems for thin 1ayer chromatography (T.l.C) were found to be Ethyl acetate: Nethanol: Ammonia (17:2:1) and Cyclohexane: Chloroform: Diethylamine (5:4:1). Thin layer , Chromatographic plates were coated with silica gel. After development of plotes, cathinone, DNE were viewed under short and long ultraviolet light using uv chromatoview and subsequently sprayed with 0.3\% ninhydrin. Cathinone was easily detected under short (UV) light but d-norpseudoephadrine (DNE) was more sensitive to ninhydrin spray reagent than UV light. Samples of Catha edulis plant used for investigating the relative distribution were obtained from Runyenjes (Embu) and Kangeta (Meru) and were preserved in dry ice until analysed two days later. Results obtained with thin layer chromatographic (TLC) and Gas liquid chromatographic (GLC) analysis of samples obtained from two different geographical localities indicated that there is no significant difference in the chemical constituents of Catha material from the two localities DNE was present in all parts of the plant examined except the root. However the concentrations of ONE in the different plant parts varied, with the highest concentration being in the young growing shoots and young leaves and the lowest concentration in the old branches and stem. Cathinone was more restricted than ONE, with high concentrations occurring in the young growing shoots, lesser amounts in the growing branch lets and none in any other plant part. This finding suggests that cathinone is possibly formed first and then converted to the more stable DNE. Individual preference for the freshest and youngest Catha shoots, is well recognized, However in absence of a reliable method for quantitative estimation of cathinone and DNE it is difficult to explain this observation on the basis of relative concentrations of the active constituents in the plant. Results obtained in the present work however show that cathinone and DNE were still present in large amounts in Catha material dried at room Gonditions (20-230c) over a period of 7-10 days. This suggests that t h e po tancv of the Catha material sold in the market (usually wrapped in moist green banana Ieaves) is unlikely to change significantly over a period of even 3-4 days, a suggestion corroborated by some indigenous people who chew Catha material. It therefore appears that the preference for fresh Catha material is based on tenderness palatability and colour appeal rather than on potency. Salts of cathinone and DNE were found to be stable to when dissolved in methanol, dilute ethanol Dr dilute hydrochloric acid. When the salt solutions were kept at ordinary room conditions (20-230c) in colour less glass containers for one month, TLC analysis revealed some degradation. This degradation was even faster with the basic residue from Catha material dissolved in chloroform. Analysis revealed that some cathinone was converted to DNE and one other unindentified substance. No cathinone was detectable in the d-norpseudoephedrine solution which had sparingly changed to another unindentified substance. Cathinone and DNE stored at temperatures below 1oc in solid form, in acidic, basic or neutral solutions or in untreated plant material showed a high degree of stability. Preliminary observations made on whole animals (mice, average weight 25 gms) injected with SO-2oomg/kg cathinone or DNE intraperitonially revealed that these two substances caused central nervous system (CNS) stimulation characterized by hyperactivity, restlessness, hyperresponsiveness, irritability, increased depth and rate of respiration, convulsion (shaking head and body and jumping). This was followed by muscle incordination, respiratory depression (characterised by gasping for air), loss of .righting reflex and for doses equal to or above 200 mg/kg, the animals died within 20-30 minutes. Death could result from circulatory depression and/or respiratory depression. Results obtained from the anaesthetised rat blood pressure showed that cathinone at all concentrations employed caused a sustained fall in blood pressure that lasted even for 3 hours with animals usually dying in the end. DNE on the other hand caused a rise in blood pressure with the first dose, but a second dose always gave \textasciitilde{} fall in blood pressure. This' could be due to cumulation of the drug a point supported by the slow metabolism and excretion of DNE or due to vasodilator effect of DNE as reported in literature. Ephedrine, the prototype of the indirectly acting phenylalkylamines on the same dose range as DNE caused rise in blood pressure and repeated doses gave rise to development of tachyphylaxis. In the anaesthetised rat cathinone and DNE have a different mechanism of action to that of the structural analogue ephedrine. On the isolated rabbit heart cathinone and DNE caused continous depression of the heart at all concentrations employed (10 -2M-lo -7\textasciitilde ) with little or no change in chronotropic response. There was no tachyplylaxis evident after repeated dosage. Pretreatment of the rabbit heart with atropine (3xlO-4M) did not antagonise the carciodepressant effect of cathinone and DNE indicating that the\textasciitilde 2ffect might not be mediated through release of acetylcholine. Pretreatment of the rabbits with reserpine lmg/rabbit for 3 consecutive days and consequent use of the respective isolated hearts did not alter the response of the isolated heart to cathinone and d-norpseudoephedrine. This is an indication that the drugs have no adranerqi cally mediated mechanism and may be generally depressing the contractile mechanisms in contrasv with ephedrine that potrays chololinergic and adrenergic effects that are governed by dose. Using isolated rabbit aortic strip, a vascular smooth muscle, it was shown that cathinone and d-norpseudoephedrine appreciably antagonised the potassium (K+) induced contractions of the preparation, but ephedrine enhanced the potassium induced contractions. Evidence from literature shows that K+ induced contractions of the rabbit aortic strip is due to transmembrane influx of calcium ions. This partly explains the cardiodepression and hypotension obtained with cathinone and DNE. Results obtained using isolated guinea pig ileum stimulated with barium ions (8a2+) and ONE antagonised the (2xlO-3) re.veale.d that cathinone 8a2+ induced contractions. Cathinone, DNE and ephedrine have a relaxant effect on the electrically stimulated innervated rabbit intestine, the blocked by pretreatment with adrenergic neurone blocker, guanethidine O.lmg/ml bath concentration. Acetylcholine however caused contraction of the smooth muscle in presence of guanethidine, cathinone or ONE indicating that the cholinergic receptors were not affect ed , Preliminary results on whole animals suggested that death of the animals could be due to respiratory depression an effect that could be mediated through the neuromuscular junction, or through paralysis of the nerve or direct depression of the diaphragm muscle. Results obtained with the phrenic-nerve diaphragm preparation showed that cathinone, DNE and ephedrine caused a continous 'depression of the contractile response of the preparation. This blocakade was enhanced in magnitude by lignocaine and d-tubocurarine. The neuromuscular facilitatory action of physostigmine was also blocked by DNE, cathinone and ephedrine. When tested on the directly stimulated diaphragm muscle, cathinone, DNE and ephedrine caused a depression of the contractile response of the muscle. Results obtained with the guinea pig wheal and the frog sciatic nerve preparations, showed that cathinone, DNE and ephedrine had some local anesthetic:activity. Throughout this research work, no adrenergic or cholinergic mediated actions of cathinone or DNE have been indicated. A direct action is implicated. This direct action is thought to be a generalised depression of the contractile tissue, an action usually associated with local anaesthetics and calcium antagonists. In this work cathinone and DNE have been shown to possess some local anaesthetic activity and some calcium antagonistic action. It is therefore possible that the pharmacological actions of these compounds are due to these two properties. Metabolic studies, using urine collected from 4 human volunteers who had ingested 15mg cathinone each, revealed that cathinone is metabolised to DNE and excreted in urine. No cathinone could be detected in the urine collected 15 hours after ingestion while DNE could be detected even after 46 hours. Analysis of urine collected from human volunteers who had taken 15mg DNE showed that DNE is excreated unchanged and no cathinone could be detected at all. Similar metabolic results were obtained in rabbits fed on cathinone and DNE
117. Baxter, Robert L. and Crombie, Leslie and Simmonds, Derek J. and Whiting, Donald A. and Braenden, Olav J. and Szendrei, Kalman, Alkaloids of Catha Edulis(Khat). Part 1. Isolation and Characterisation of Eleven New Alkaloids with Sesquiterpene Cores (Cathedulins); Identification of the Quinone–Methide Root Pigments, Journal of the Chemical Society, Perkin Transactions 1, pp. 2965--2971, January 1979. doi: 10.1039/P19790002965. Abstract
     Extraction of fresh and dried specimens of Catha edulis(khat) originating from Ethiopia, Kenya, and the Yemen, has led to the isolation of eleven new celastraceous alkaloids having molecular weight of ca. 600—ca. 1 200 and a sesquiterpene core. They fall into three groups: (a) cathedulins E2 and E1, esters of a pentahydroxydihydroagarofuran; (b) cathedulins K1 (Y1), K2, K6, and K15, esters of euonyminol a nonahydroxyagarofuran, containing one dilactone bridge; and (c) cathedulins E3(K11), E4, E5, E6, and K12, more complex esters of euonyminol containing two dilactone bridges.Apart from norpseudoephedrine (cathine) and the corresponding ketone (cathinone) and a related pyrazine, khat contains steroids and triterpenes including, in the root-bark, a range of triterpenoid quinonemethides characteristic of the Celastraceae.
118. Baxter, Robert L. and Crombie, Leslie and Simmonds, Derek J. and Whiting, Donald A., Alkaloids of Catha Edulis. Part 2. Constitution of Cathedulins E2 and E8, Polyesters of a New Sesquiterpene Pentaol, Journal of the Chemical Society, Perkin Transactions 1, no. INVALID\_SCITE\_VALUE, pp. 2972--2975, January 1979. doi: 10.1039/P19790002972. Abstract
     Cathedulin E2 yields on ethanolysis a new 1-eq, 2-ax, 8-ax, 9-ax, 15-pentahydroxylated agarofuran, as deduced from 1H, 13C, and nuclear Overhauser n.m.r. Data, together with cyclic carbonate formation. Ethyl acetate, benzoate, and nicotinate in the molar ratio 2 : 1 : 2 are also produced. Graded alcoholysis (methanolic triethylamine, 5°C) gives an 8-denicotinoyl derivative identical with cathedulin E8 from Catha edulis, whilst at 25 °C the 8,15-bis(denicotinyl) derivative is produced. Aqueous-methanolic sodium hydrogencarbonate further strips the 1- and 2-acetate residues leaving only the 9-benzoate ester. The placing of these ester residues is deduced from a study of the spectral changes caused by graded hydrolysis, thus leading to complete structural proposals for cathedulin E2 and E8.
119. Baxter, Robert L. and Crombie, W. Mary L. and Crombie, Leslie and Simmonds, Derek J. and Whiting, Donald A. and Szendrei, Kalman, Alkaloids of Catha Edulis. Part 4. Structures of Cathedulins E3, E4, E5, E6, and K12. Novel Sesquiterpene Alkaloids with Mono- and Bismacrolide Bridges, Journal of the Chemical Society, Perkin Transactions 1, no. INVALID\_SCITE\_VALUE, pp. 2982--2989, January 1979. doi: 10.1039/P19790002982. Abstract
     Alcoholysis and reduction shows that cathedulin E3, C54H60N2O23, is made up of a euonyminol core (3)(octaacetate), together with four acetates, a hydroxyisobutyrate, and evoninate (1) and cathate residues. The latter, a novel residue, is shown to be (4). By study of 1H and 13C n.m.r. data for the intact alkaloid and its hydrogenolysis and partial methanolysis produces, E3 is formulated as (12). Cathedulin E4, converted into E3 by acetylation, is (13). Corresponding to both alkaloids is a minor series in which one acetate is replaced by a benzoate residue.Cathedulin E6, C57H62N2O22, formulated as (17), is also based on a euonyminol core but gives, on methanolysis, dimethyl evoninate, methyl benzoate, methyl nicotinate, and trimethyl gallate; a 2-acetoxyisobutyrate and a further acetate residue are also present. Alkaloid E6 bears to E5 (16) the same relationship as does E4 to E3. The minor alkaloid cathedulin K12, C54H62N2O23, has the structure (18), similar to E3 but with the cathate span reductively cleaved : this suggests a biosynthetic connection.
120. Crombie, Leslie and Crombie, W. Mary L. and Whiting, Donald A. and Szendrei, Kalman, Alkaloids of Catha Edulis. Part 3. Structures of Cathedulins K1, K2, K6, and K15; New Macrolide-Bridged Polyesters of Euonyminol, Journal of the Chemical Society, Perkin Transactions 1, no. INVALID\_SCITE\_VALUE, pp. 2976--2981, January 1979. doi: 10.1039/P19790002976. Abstract
     It is shown by mass spectral and 1H and 13C n.m.r. methods, together with ethanolysis, that the structure of the polyester alkaloid cathedulin K2 (C40H51NO19) is compiled from euonyminol (1), one evoninic acid residue (cf. 2), five acetic acid residues, and one 2-hydroxyisobutyric acid residue. Some of the ester residues can be positioned on the basis of spectral information. The remainder are assigned as a result of a study of the products formed when cathedulin K2 is treated under controlled conditions with methanolic diethylamine. Four compounds were isolated, C28H37NO13(5), C34H45NO16(6), C36N47NO17(7), and C38H49NO18(8), the structures being assigned spectrally. This leads to the formulation of cathedulin K2 as (4). Using this information, together with further spectral data and information from models, cathedulin K1 (C42H53NO20), K6 (C38H49NO18), and K15 (C36H47NO17) are allocated structures (9), (10), and (11) respectively.
121. Crombie, Leslie and Crombie, W. Mary L. and Whiting, Donald A. and Branenden, Olav J. and Szendrei, Kalman, Structures of Cathedulin Alkaloids from Catha Edulis(Khat) of Kenyan and Ethiopian Origin, Journal of the Chemical Society, Chemical Communications, no. 3, pp. 107--108, January 1978. doi: 10.1039/C39780000107. Abstract
     The structures of cathedulins K-1, K-2, K-6, K-12, and K-15, isolated from Kenyan khat, are formulated as (4), (3), (5), (8), and (6) respectively; cathedulin E-3 (Ethiopian khat) is formulated as (7) and E-4, E-5, and E-6 can be treated similarly.
122. Baxter, Robert L. and Crombie, Leslie and Simmonds, Derek J. and Whiting, Donald A., Structures of Cathedulin-2 and Cathedulin-8, New Sesquiterpene Alkaloids from Catha Edulis, Journal of the Chemical Society, Chemical Communications, no. 12, pp. 465--466, January 1976. doi: 10.1039/C39760000465. Abstract
     The structures of cathedulin-2 and -8, alkaloids from C. edulis, are shown to be (1) and (2) respectively.
123. Baxter, Robert L. and Crombie, Leslie and Simmonds, Derek J. and Whiting, Donald A., Extractives of Catha Edulis(Khat): Occurrence of Celastraceaeous Alkaloids Having Mono- and Bis-Macrolide Bridges, Journal of the Chemical Society, Chemical Communications, no. 12, pp. 463--465, January 1976. doi: 10.1039/C39760000463. Abstract
     Six purified alkaloids have been isolated from C. edulis: four have mol. wts {$>$} 1100, two (cathedulin-5 and -6) being mono-macrolide-bridged and two (cathedulin-3 and -4) bis-macrolide-bridged derivatives of euonyminol.
124. Cais, M. and Ginsburg, D. and Mandelbaum, A. and Smith, Roger M., Constituents of Catha Edulis: Isolation and Structure of Cathidine D, Tetrahedron, vol. 31, no. 21, pp. 2727--2731, January 1975. doi: 10.1016/0040-4020(75)80339-5. Abstract
     Work which has recently appeared on the structures of Celastraceae alkaloids in addition to physical and chemical evidence adduced with respect to cathidine D permits formulation of structure 7a or 7b for this component of Catha edulis.
125. Sissi, H. I. El and Alla, M. F. Abd, Polyphenoligs of the Leaves of Cathaedu Li S (Part I), Planta Medica, vol. 14, no. 1, pp. 76--83, February 1966. doi: 10.1055/s-0028-1100030. Abstract
     Thieme E-Books \& E-Journals
126. RISTIC, S and THOMAS, A, [On the constituents of Catha edulis. I], Archiv der Pharmazie und Berichte der Deutschen Pharmazeutischen Gesellschaft, vol. 295/67, pp. 524--525, July 1962. doi: 10.1002/ardp.19622950709.
127. Rücker, G. and Kroger, H. and Schikarski, M. and Qédan, S., Über Die Alkaloide Aus Catha Edulis, Planta Medica, vol. 24, no. 5, pp. 61--65, 1973. doi: 10.1055/s-0028-1099470. Abstract
     Thieme E-Books \& E-Journals
128. Algabr, Methaq and {Al-Hajj}, Nabil and {Al-Wadhaf}, Hussein and Aissaoui, Hanane and Hammoud, Leila and Mekkiou, Ratiba and Benayache, Samir and Benayache, Fadila, A Comparative Study of Metabolic Content of Three Generations of Catha Edulis Species, Journal of Natural Products and Biomedical Research, vol. 1, no. 3, pp. 68--70, 2015. Abstract
     The remarkable and big widespread of Catha trees, especially in Yemen, due to the increasing demand and its chewers preferences for its leaves refreshing effect similar to drugs effect. Chewing khat leaves represent an old social habit and traditional culture in Africa and Yemen. In spite of several studies that have focused on different sites of this plant (historical, botanicals, and chemical). This study reveals the secondary metabolic contents similarities and differences, in particular, flavonoids for three different generations of this plant (2, 28, and 50 years), hence knowing microbiological effects of some extracts.
129. Atlabachew, Minaleshewa and Chandravan, Bhagwan Singh and Redi, Mesfin, Profile of Major, Minor and Toxic Metals in Soil and Khat (Catha Edulis Forsk) Cultivars in Ethiopia, Trends in Applied Sciences Research, vol. 6, no. 7, pp. 640--655, July 2011. doi: 10.3923/tasr.2011.640.655.
130. Lee, Marsha M., The Identification of Cathinone in Khat (Catha Edulis): A Time Study, Journal of Forensic Sciences, vol. 40, no. 1, pp. 13773J, January 1995. doi: 10.1520/JFS13773J.
131. Rashed, Khaled, Phytochemical and Biological Activities of Khat (Catha Edulis Forsk): A Review, South Asian Journal of Agricultural Sciences, vol. 1, no. 2, pp. 14--16, 2021. url: https://www.agrijournal.org/archives/2021.v1.i2.A.12. Abstract
     Catha edulis Forsk (Celastraceae)], is an ancient plant associated with psychological, health and socioeconomic issues on humans. Khat (the flower of paradise) is a plant vastly used on the African continent. Many different compounds are found in khat including alkaloids, terpenoids, flavonoids, sterols, glycosides, tannins, amino acids, vitamins and minerals. The phenylalkylamines and the cathedulins are the major alkaloids which are structurally related to amphetamine. The major effects of khat include those on the gastro-intestinal system and on the nervous system. Constipation, urine retention and acute cardiovascular effects may be regarded as autonomic (peripheral) nervous system effects; increased alertness, dependence, tolerance and psychiatric symptoms as effects on the central nervous system. The main toxic effects include increased blood pressure, tachycardia, insomnia, anorexia, constipation, general malaise, irritability, migraine and impaired sexual potency in men.
132. Mn, Algabr and Ha, Al-Wadhaf, Analysis of the Essential Oil of Catha Edulis Leaves from Yemen, International Journal of Applied Research in Natural Products, vol. 7, no. 2, pp. 21--24, 2014. url: https://www.researchgate.net/publication/284263241_Analysis_of_the_essential_oil_of_Catha_edulis_leaves_from_Yemen. Abstract
     The essential oil obtained by hydrodistillation from dried aerial parts of Catha edulis (Celastraceae) growing in Yemen and some East Africa countries, was analyzed by gas chromatography-flame ionization detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC-MS). The main constituents of the essential oil were carvotanacetone (84.41\%), trans pulegol (2.16\%), trans para menthan-2-one (1.29\%), 2,5-dimethoxy-p-cymene (1.89\%). The Other constituents are mainly non oxygenated monoterpenes.
133. Njagi, Ngari Vindesio and Hashim, Nadir and Abdallah, Merenga, Levels Of Natural Radionuclides in Khat (Catha Edulis) Leaves and Soils In Selected Areas In Embu County, Kenya, International Journal of Engineerings and Applied Physics, vol. 2, no. 3, pp. 566--579, September 2022. url: https://ijeap.org/ijeap/article/view/103. Abstract
     Over the past years, khat (Catha edulis) has been the major cash crop grown in some parts of the Eastern side of Kenya.The leaves from this plant are chewed for their stimulating effect. However, some studies have reported detrimental effects on the users of khat. This research established the level of human exposure due to radiation by natural sources in the khat growing areas of Embu County by measuring the specific activities of 238U, 232Th and 40K, estimate the dose rate absorbed and obtain the hazard indices due to these radionuclides. A total of 30 samples were collected from different areas distributed throughout Embu County, 15 for khat and 15 for soil samples. The samples were then prepared and analyzed using the Thallium activated Sodium Iodide Detector (NaI (Tl). Mean activities for khat leaves were obtained as 875.8±11 Bq/kg, 10.1±1 Bq/kg and 51.1±4 Bq/kg for 40K, 238U and 232Th respectively. The activities of soil in the same region were obtained as 344±12 Bq/kg, 22±11 Bq/kg and 33±5 Bq/kg for 40K, 238U and 232Th respectively. The mean absorbed dose rates obtained for soil was 44±0 nGyh-1 while the average Annual Effective Dose (AED) for ingested radionuclides for khat was 0.45±0.19 mSv/y. Average values of soil hazard indices for soil 0.26, 0.32, 0.70 and 0.76 for external index (Hex), internal index (Hin), gamma index (γ) and Excess Lifetime Cancer Risk (ELCR) respectively. All the indices in this work were within the safe limit.
134. Krizevski, Raz, Comparative Functional Genomics of Ephedrine Alkaloids: Biosynthesis in Catha Edulis and Ephedra Sinica, 2012. url: https://cris.bgu.ac.il/en/studentTheses/comparative-functional-genomics-of-ephedrine-alkaloids-biosynthes. Abstract
     Khat Catha edulis (Celastraceae) is an angiosperm whose leaves are traditionally chewed as a stimulant in the Middle East and Eastern Africa. Ephedra sinica Stapf (Ephedraceae) is a gymnosperm widely used in Chinese medicine (Chinese name: Ma Huang). The main active constituents of both plants are the unique taxonomically restricted adrenergic agonists phenylpropylamino alkaloids, also known as ephedrine alkaloids: (S)-cathinone, (1R,2S)-norephedrine, (1S,2S)-norpseudoephedrine (cathine), (1R,2S)-ephedrine, (1S,2S)-pseudoephedrine, (1R,2S)-N-methylephedrine and (1S,2S)N-methylpseudoephedrine. In general, ephedrine alkaloids mimic the action of adrenaline, both by direct agonist activity as well as by indirect release of norepinephrine via a carrier-mediated exchange mechanism resulting in the release of endogenous cathecholamines from the post-ganglionic sympathetic fibers. Ephedrine alkaloids are highly valuable pharmaceuticals and are often used in Western medicine to treat nasal congestion, bronchial asthma, allergies, acute asthma attacks, rhinitis, sinusitis, and rhinopharyngitis, as well as being widely used during anesthesia. Very little is known about the mechanisms by which plants biosynthesize these compounds. In this work, the biosynthesis of ephedrine alkaloids in the two plants was characterized. A targeted pathway-oriented metabolomic analysis demonstrated that both plants apparently utilize a similar biosynthetic pathway for ephedrine alkaloids biosynthesis. GC–MS analysis of freshly picked young E. sinica stems and C. edulis leaves enabled the detection of 1-phenylpropane-1,2-dione and (S)-cathinone, the first two putatively committed biosynthetic precursors to the ephedrine alkaloids. These metabolites are only present in young tissues and not in mature tissues or roots. Feeding experiments also supported the hypothesis that 1-phenylpropane-1,2-dione and (S)-cathinone are the first two putatively committed biosynthetic precursors of the pathway. A marked diversity in the ephedrine alkaloids content and stereochemical composition in 16 different E. sinica accessions growing under the same environmental conditions was revealed, indicating genetic control of these traits. The accessions can be classified into two groups, according to the stereochemistry of the products accumulated: a group that displayed only 1R stereoisomers, and a group that displayed both 1S and 1R stereoisomers. Predicted key biochemical reactions in the ephedrine alkaloids pathway were assayed in cell-free extracts derived from khat young-leaves. Cell-free protein extracts derived from young C. edulis and E. sinic 5 stems catalyzed the formation of (R)-phenylacetylcarbinol and (S)phenylacetylcarbinol, in a manner similar to the reaction catalyzed by acetolactate synthase (ALS) in E. coli. This reaction utilized benzaldehyde and pyruvate as substrates and required the presence of thiamine pyrophosphate and magnesium. This cell-free protein extract fraction probably consists of a mixture of proteins containing several different enzymes capable of accepting benzaldehyde and pyruvate as substrates. Several other products, including the precursor for ephedrine alkaloids 1phenylpropane-1,2-dione as well as trans-cinnamaldehyde, the main aroma compound of cinnamon, for which a biosynthesis was previously unknown along with (R)phenylpropane 1-one 2-ol and (S)-phenylpropane 1-one 2-ol were formed by this reaction. A comparative functional genomics platform was established to facilitate the study of the biochemical and molecular factors that direct the accumulation of ephedrine alkaloids in plants. Several sequences of genes putatively involved in ephedrine alkaloids biosynthesis were identified. Data mining designed to target thiamine pyrophosphate dependent enzymes from the acetolactate synthase (ALS) family led to the functional expression of a promising candidate gene for the enzyme catalyzing the formation of phenylacetylcarbinol (PAC) isomers. This novel gene, unexpectedly, exclusively produced trans-cinnamaldehyde from benzaldehyde and pyruvate. trans-Cinnamaldehyde is present at low levels in C. edulis stems. In addition, (S)-cathinone reductase activities were detected in young E. sinica stems and C. edulis leaves capable of reducing (S)-cathinone to (1R,2S)-norephedrine and (1S,2S)-norpseudoephedrine in the presence of NADH. The proportion of the diastereoisomers formed varied according to the E. sinica accession tested and was higher in accessions O, A, M, K, H, F, G and J. A (1R,2S)-norephedrine Nmethyltransferase, capable of converting (1R,2S)-norephedrine to (1R,2S)-ephedrine in the presence of S-adenosylmethionine (SAM), was also detected in E. sinica stems. This multidisciplinary functional genomics platform will contribute to our understanding of the key enzymatic steps and the regulation of this understudied biosynthetic pathway.
135. Dawson, B. A. and Black, D. B. and Lavoie, A. and LeBelle, M. J., Nuclear Magnetic Resonance Identification of the Phenylalkylamine Alkaloids of Khat Using a Chiral Solvating Agent, Journal of Forensic Sciences, vol. 39, no. 4, pp. 13681J, July 1994. doi: 10.1520/JFS13681J.
136. Ye, Shuang and Hu, Jin and Liu, Zilong and Liang, Man, Progress and Research Trends on Catha Edulis (Vahl) Endl. (Catha Edulis): A Review and Bibliometric Analysis, Frontiers in Pharmacology, vol. 12, pp. 705376, November 2021. doi: 10.3389/fphar.2021.705376. Abstract
     Catha edulis (Vahl) Endl., known as Catha edulis or Khat is a traditional and regional plant for chewing, smoking and drinking, that has posed a worldwide public health problem due to its recent emerging abused consumption. In the face of the massive use of Catha edulis, we reviewed related publications to analyze the progress and research trends through bibliometric methods. After screening, a total of 514 scientific publications published from 1997 to 2020 were included by systematic retrieval from the Web of Science (WoS) database. According to further scientometric analysis, the annual number of publications output kept rising in most of the years. Ethiopia and the United States of America (USA) have been devoting significant contributions to the field. Though the research emphasis had been the chemical composition and pharmacological and toxicological effects for several years, the hot spots were transferred; the mechanism investigations of Catha edulis have been the focus in recent years, which might be continued in the future. Furthermore, co-operations of multi-disciplinary researchers are needed to minimize abuse harms and maximize the medicinal benefits of Catha edulis to human beings.
137. Kiunga, Josphat K. and Lukhoba, Catherine W. and Dossaji, Saifuddin F. and Yenesew, Abiy, A Survey Of Traditional Medicinal Uses Of Catha Edulis (Celastraceae) In Meru And Eembu Counties Of Kenya., 2016. url: http://erepository.uonbi.ac.ke/handle/11295/107095. Abstract
     Catha edulis (qat) is an evergreen tree or shrub whose young leaves and stems are widely chewed in Eastern Africa. The aim of the present study was to document ethnomedicinal value of Catha edulis as used traditionally by the Ameru and Aembu communities of Kenya. The study was conducted between the months of September (2014) and February (2015), and involved 42 key informants (32 males and 10 females) aged between 45 and 84 years. Snowball and purposeful sampling techniques were used in the selection of key respondents. A semi-structured questionnaire was administered to collect ethnomedicinal data using faceto-face interviews and discussions with key respondents. Eleven traditional varieties based on information from key informants were identified and described. Out of these, 5 were from Embu County while 6 were from Meru County. Plant samples were collected and deposited at the University of Nairobi herbarium as voucher specimens. A total of 13 ethnomedicinal uses of qat were documented. Of these, 62\% were reported only in Meru County while 15\% were reported only in Embu County. The remaining (23\%) were reported in both Meru and Embu counties. The major parts of the plant reported to have medicinal value were leaves. Young stems and roots had scanty medicinal value. Chewing fresh material was identified as the major method of crude drug preparation, although in some cases such as in the treatment of diarrhea, gonorrhea and toothache, boiling of fresh material was reported. The main mode of administration of drug is oral and there was no precise dosage reported for any given ailment. The present study indicates that there is a rich knowledge of ethnomedicinal uses of qat particularly in Meru which forms groundwork for further efficacious study of the plant as that may provide a lead to the discovery of novel bioactive therapeutic agents. In addition, the traditional varieties of C. edulis identified by some morphological characters of taxonomic importance provide a vital clue of possible existence of infraspecific taxa of C. edulis which, to date, has no documented infraspecific taxa.
138. Patel, Nilesh B., Chapter Eleven - “Natural Amphetamine” Khat: A Cultural Tradition or a Drug of Abuse?, vol. 120, pp. 235--255, January 2015. doi: 10.1016/bs.irn.2015.02.006. Abstract
     Khat, Catha edulis Forsk, is among the most widely used plant-based psychoactive substance in the world. Grown in Eastern Africa, Horn of Africa, and southwestern part of the Arabian Peninsula, its fresh young leaves and twigs are used daily by over 20 million people for the psychostimulatory effects it produces in the user, a practice deeply rooted in the history, tradition, and culture of the indigenous population. Once hardly known outside the regions where it is grown and used, khat use has now spread to other countries. This review will cover the, phytochemistry, pharmacokinetics of the active ingredients—cathinone, cathine, norephedrine, neurochemistry, effects on cognitive and executive functions as well as its ability to produce dependency in the user. Whether it is an innocuous cultural practice or a drug of abuse is debatable as the preclinical and clinical data needed to arrive at an authoritative conclusion is lacking.
139. Zyoud, Sa’ed H., Bibliometric Analysis on Global Catha Edulis (Khat) Research Production during the Period of 1952–2014, Globalization and Health, vol. 11, no. 1, pp. 39, September 2015. doi: 10.1186/s12992-015-0124-x. Abstract
     Publication of scientific articles related to khat (Catha edulis) in peer-reviewed journals is considered a measure of research productivity. The principal objectives of this study were to quantify the research contribution related to khat at the global level, as well as to determine its relative growth rate, collaborative measures taken, productivity at the institutional level, and the most prolific journals publishing on the topic.
140. Klein, Axel, Framing the Chew: Narratives of Development, Drugs and Danger with Regard to Khat (Catha Edulis), pp. 131--147, 2014. doi: 10.1007/978-3-642-40957-8_7. Abstract
     Khat has become increasingly subject to legal regulation in European and North American countries, even though there is very little consumption among mainstream populations. The regulation of khat has been introduced for the “protection” of migrant populations, and is sometimes even demanded by anti-khat campaigners. The unintended consequence of these bans, once introduced, is that migrant populations are targeted by law enforcement. This has not helped these groups’ social integration nor promoted public health. What has not been considered in the discussion is the effect on khat farmers. Khat has been an engine of development for parts of Kenya and Ethiopia. It has also provided an opportunity for capital accumulation in Somaliland. It is a major source of revenue across the region. The positions of all stakeholders must be considered when defining the regulatory context, as well as the dimension of community cohesion and the potential for development.
141. Birhanu, Zewdu, Traditional Use of Medicinal Plants By the Ethnic Groups of Gondar Zuria District, North-Western Ethiopia, Journal of Natural Remedies, vol. 13, pp. 8, 2013. Abstract
     The aim of the study was to document information on medicinal plants and to describe the traditional health care practices of Gondar Zuria district, North-west Ethiopia. Field trip was made in each village of the district to collect ethnomedicinal information from the traditional healers by using semi-structured questionnaire and field observation. Forty-two plant species representing forty-one genera and thirty-one families were encountered during the study. Results of the study were analysed using two quantitative tools: informant consensus factor for the analysis of general use of medicinal plants and fidelity level for calculating the most frequently occurring diseases for the categories with the highest informant consensus factor. The result of the informant consensus factor showed that the general health category had the greatest agreement followed by the respiratory, malarial, and gastrointestinal categories. The present study has documented curious ethno medicinal facts on the plant therapies currently utilised in Gondar Zuriadistrict. Evaluation of the pharmacological activity for the promising medicinal plant is suggested.
142. Thomas, Sophie and Williams, Tim, Khat (Catha Edulis): A Systematic Review of Evidence and Literature Pertaining to Its Harms to UK Users and Society, Drug Science, Policy and Law, vol. 1, pp. 2050324513498332, January 2013. doi: 10.1177/2050324513498332. Abstract
     The use of khat (Catha edulis) has been associated with a large number of physiological and societal harms, leading to calls for it to be controlled in the UK. The evidence of these harms is often equivocal, limited by confounding factors, or entirely anecdotal: high-powered, quality-controlled studies are lacking. Regardless, the body of relevant literature indicates that the once socially-regulated use of khat has been eroded. Some individuals have developed excessive consumption patterns, either using khat daily or in binge-sessions, though daily consumption is not necessarily problematic per se. The majority of users seem to use khat in moderation, where the associated harms appear low. For excessive users, harms associated with khat are greater, particularly relating to mental health. Social harms also seem to be largely related to excessive khat use rather than khat use itself. Even in cases of excessive khat use, however, causal relationships between chewing and harms have not been described. More research is required to establish the role of khat in liver disease, coronary problems, cancers of the digestive tract and incidents of domestic violence. Studies should consider the likeliness that certain users are more vulnerable to developing patterns of excessive khat use due to an interwoven set of factors such as social health determinants and pre- and post-migration experiences.
143. Odenwald, Michael and Klein, Axel and Warfa, Nasir, Introduction to the Special Issue: The Changing Use and Misuse of Khat (Catha Edulis)—Tradition, Trade and Tragedy, Journal of Ethnopharmacology, vol. 132, no. 3, pp. 537--539, December 2010. doi: 10.1016/j.jep.2010.11.012. Abstract
     Within the last decade the hitherto little known psychoactive substance of khat has emerged as a regional and international issue. In the Horn of Africa khat production has spurred an economic boom, but dramatic increases in consumption have raised public health concerns. Given the complexity of the topic spanning multiple academic disciplines and fields of professional practice, the need for a systematic overview is urgent. To facilitate the exchange of information, prompt interdisciplinary research and alert international organisations and governments, the authors organised an international and interdisciplinary khat conference in 2009. This special issue of the Journal of Ethnopharmacology contains articles written by different conference speakers that present the current state of knowledge and the challenges for future research and politics.
144. Balint, Erica E. and Falkay, George and Balint, Gabor A., Khat – a Controversial Plant, Wiener klinische Wochenschrift, vol. 121, no. 19, pp. 604, October 2009. doi: 10.1007/s00508-009-1259-7. Abstract
     Khat (Catha edulis) is a shrub or tree whose leaves have been chewed for centuries by people who live in the Eastern part of Africa and the Arabian Peninsula. It has recently turned up in North America and Europe, particularly among emigrants and refugees from countries such as Somalia, Ethiopia and Yemen. Khat contains a number of chemicals, among which are two controlled substances, cathinone (Schedule I) and cathine (Schedule IV). Both chemicals are stimulant drugs with effects similar to amphetamine. Chewing the leaves makes people feel more alert and talkative, and suppresses appetite. Chewing khat leaves releases cathinone, a stimulant that produces the feeling of euphoria. When cathinone is broken down in the body, it produces chemicals including cathine and norephedrine, which have a similar structure to amphetamine and adrenaline (epinephrine). Regular khat use is associated with a rise in arterial blood pressure and pulse rate, corresponding with levels of cathinone in the plasma. Moreover, regular khat chewers have gingivitis and loose teeth, but there appears to be no convincing unusual incidence of oral cancer. Among khat users in Yemen there is, however, a higher incidence of esophageal cancer compared with gastric cancer. Long term use or abuse can cause insomnia, anorexia, gastric disorders, depression, liver damage and cardiac complications, including myocardial infarction. Manic and delusional behavior, violence, suicidal depression, hallucinations, paranoia and khat-induced psychosis have also been reported. On the basis of the scientific data it seems clear that khat use has negative consequences on the economic development of a country and on the health of the society.
145. {Al-Hebshi}, Nezar and Skaug, Nils, Khat (Catha Edulis)—an Updated Review, Addiction Biology, vol. 10, no. 4, pp. 299--307, 2005. doi: 10.1080/13556210500353020. Abstract
     The habit of chewing fresh leaves and twigs of khat (Catha edulis) for their stimulating amphetamine-like effects is highly prevalent in East Africa and southwest on the Arabic peninsula. There is an extensive literature on khat providing information about its history, botany, production, geographical distribution, chemistry and pharmacology, and exploring the social, economic, medical, psychological and oral aspects related to its use. Some of this literature dates as early as the 11th century; however, most of it appeared after the first scientific description of khat by Peter Forskal in 1775. This review provides a panorama of khat and the various aspects of its use. A non-technical description of the plant chemistry and pharmacology is included. The medical, psychological and oral aspects are emphasized, and the current knowledge about the microbiological effects of khat is also presented.
146. Varisco, Daniel Martin, On The Meaning of Chewing The Significance of Qāt (Catha Edulis)in the Yemen Arab Republic, International Journal of Middle East Studies, vol. 18, no. 1, pp. 1--13, February 1986. doi: 10.1017/S002074380003018X. Abstract
     So writers the British administrator Harold Ingrams about the chewing of leaves from the qāt tree in Yemen. Qāt is the Arabic term for Catha edulis, a species of the Celastracae cultivated in the highlands of southwestern Arabia for at least the last six centuries. The leaves of this tree are chewed as a stimulant, producing a feeling of euphoria followed by depression.
147. {Żukiewicz-Sobczak}, Wioletta and Zwoliński, Jacek and {Chmielewska-Badora}, Jolanta and Krasowska, Ewelina and Piątek, Jacek and Sobczak, Paweł and Wojtyła, Andrzej and Fornal, Emilia and Kuczumow, Andrzej and Biliński, Przemysław, Analysis of Psychoactive and Intoxicating Substances in Legal Highs, Annals of Agricultural and Environmental Medicine, vol. 19, no. 2, pp. 6, 2012. url: https://bibliotekanauki.pl/articles/51459. Abstract
     Legal highs” known also as “smarts”, “legal drugs” or “boosters” contain in their composition psychoactive substances the production, sale and possession of which are not prohibited in legislation. They are offered for sale under the cover of collectors’ items, a salt bath, aroma sticks, or plant fertilizer. Marketing was the reason for such high sales of these “highs” in Poland. The phenomenon became of concern when information became available about the first cases of tragic health consequences. Raising the awareness of youth about the level of imminent danger and serious consequences associated with the use of legal highs may be a very effective way to develop appropriate attitudes of young people, and in the light of their own health can help them take proper life decisions.
148. Bálint, Erika, Khat (Catha Edulis) a Contoversial Plant: Blessing or Curse?, June 2013. url: https://core.ac.uk/display/11980204. Abstract
     Fresh leaves of khat ( Catha edulis) are customarily chewed by the inhabitants of East Africa and Southern Arabia to attain a state of stimulation. Although the use of khat is widespread, until recently it has remained mostly confined to the regions where the plant is grown since only the fresh leaves have the potency to produce the desired effects. Considering that during the last decade(s) khat chewing became more common in the socalled western or developed countries - for example due to migration, - and given the possible abuse potential of the herb, - which is prohibited by law in several European and American countries, - knowledge of its properties may be useful.