Catha edulis (Vahl) Forssk. ex Endl. - Celastraceae - khat, Arabian tea, Khat, Katstrauch, Arabischer Tee

Evergreen shrub, up to 3m tall, native to South Arabia (Yemen), East Africa to South Africa, also cultivated; leaves opposite, toothed, oblanceolate; flowers small (3-5mm in diam.), white, in axillary cymes; calyx 5-lobed, petals 5, stamens 5; ovary 3-celled with 3 styles and 2 ovules in each cell; fruit a 3-celled loculicidally dehiscent capsule; seed with white aril at base.
http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=250084159
https://npgsweb.ars-grin.gov/gringlobal/taxonomydetail.aspx?id=9606

„Cathinone produced increases in blood pressure and in heart rate, and these changes were concomitant with the presence of cathinone in blood plasma… The physical and mental changes that the subjects reported during the experiment indicated that cathinone has in humans euphorigenic and psychostimulant effects… These observations support the assumption that cathinone is the constituent mainly responsible for the effects of khat, and they show that this alkaloid has also in humans amphetamine-like effects.“
[Amphetamine‐like effects in humans of the khat alkaloid cathinone., Brenneisen, R., Fisch, H.U., Koelbing, U., Geisshusler, S., Kalix, P., British journal of clinical pharmacology, 30(6), 1990, 825-828] http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2125.1990.tb05447.x/pdf

„The mucosa of the oral cavity is considered to be the first absorption segment, where the major proportion of the alkaloids [cathinone, cathine and norephedrine] is absorbed (mean ± SD 59 ± 21% for cathinone and 84 ± 6% for cathine). The extraction of the alkaloids from the leaves by chewing was very effective with only 9.1 ± 4.2% remaining as a residue. Cathinone was eliminated from the central compartment with a mean half-life of 1.5 ± 0.8 h. The half-life of cathine was 5.2 ± 3.4 h. The metabolism of cathinone to norephedrine had a substantial influence on its plasma concentration profile. Psychophysical functions were essentially unaffected by the chewing of khat… The pharmacokinetics of khat alkaloids in humans explain why chewing is the preferred form of khat ingestion. Subjects absorbed a mean dose of 45 mg of cathinone, and did not suffer any severe adverse reactions.“
[Pharmacokinetics of cathinone, cathine and norephedrine after the chewing of khat leaves., Toennes, S.W., Harder, S., Schramm, M., Niess, C., Kauert, G.F., British journal of clinical pharmacology, 56(1), 2003, 125-130] http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2125.2003.01834.x/full

Literature surveys and clinical diagnostic studies revealed an association of long-term chewing of catha edulis leaves with the prevalence of psychiatric morbidity, several peripheral effects like increases in blood pressure and increased incidence of acute coronary vasospasms and myocardial infarct. „Catha edulis also accounts for a number of gastrointestinal tract problems, oesophagitis, gastritis and delay intestinal absorption, as well as the development of oral keratotic white lesions at the site of chewing.“
[Al-Habori, M. (2005). The potential adverse effects of habitual use of Catha edulis (khat).]

„Khat chewing is a practice that dates back thousands of years in the Horn of Africa and the Arabian Peninsula where the khat plant is widely cultivated and known by a variety of names, including qaat and jaad in Somalia, and chat in Ethiopia. The chewing of khat leaves releases chemicals structurally related to amphetamines, which give the chewer a mild high that some say is comparable to drinking strong coffee.“
[Khat Chewing in Yemen: Turning over a New Leaf: Khat Chewing Is on the Rise in Yemen, Raising Concerns about the Health and Social Consequences., Al-Mugahed, L., Bulletin of the World Health Organization, 86(10), 2008, 741]

Catha edulis (Vahl) Endl. as Catha forsskalii A. Rich.; Richard,A., Tentamen florae Abyssinicae, Atlas, t.30 (1851) [A.C.Vauthier]
http://plantgenera.org/species.php?id_species=212907