(L.) N.E. Brown
Sceletium tortuosum is a succulent herb commonly found in South Africa, which is also known as Kanna, Channa, Kougoed (Kauwgoed/ 'kougoed', prepared from 'fermenting' S. tortuosum) - which literally means, 'chew(able) things' or 'something to chew'. The plant has been used by South African pastoralists and hunter-gatherers as a mood-altering substance from prehistoric times. The first known written account of the plant's use was in 1662 by Jan van Riebeeck. The traditionally prepared dried Sceletium was often chewed and the saliva swallowed, but it has also been made into gel caps, teas and tinctures. It has also been used as a snuff and smoked.
It is possible that Sceletium may cause elevated mood and decreases anxiety, stress and tension. Intoxicating doses can be euphoric but the plant is not hallucinogenic, contrary to some literature on the subject, and no adverse effects have been documented.[medical citation needed] According to some anecdotal reports kanna may potentiate the euphoriant effects of cannabis.
The alkaloids contained in S. tortuosum believed to possess psychoactivity include: mesembrine, mesembrenone, mesembrenol and tortuosamine. Mesembrine is a major alkaloid present in Sceletium tortuosum and serves as a selective serotonin reuptake inhibitor (SSRI) with less prominent inhibitory effects on phosphodiesterase 4 (PDE4). Mesembrenone on the other hand serves as a more balanced serotonin reuptake inhibitor and PDE4 inhibitor. A standardised ethanolic extract of dried S. tortuosum had a IC50 for PDE4 inhibition of 8.5μg/ml and for SERT of 4.3μg/ml.
S. tortuosum contains about 1–1.5% total alkaloids. There is about 0.3% mesembrine in the leaves and 0.86% in the leaves, stems, and flowers of the plant.
Little is known about the interactions of S. tortuosum, although it should not be combined with other SSRIs, MAOIs, or cardiac medications. Headache in conjunction with alcohol have been noted with kanna use. Some reports suggest a synergy with cannabis. A 90 day toxicological safety study showed that S. tortuosum is non-toxic and well-tolerated in rats. The maximum doses used in this rat study were the equivalent of 420mg/day in an average-sized human. This combined with the long history of traditional human use suggests that S. tortuosum is non-toxic and relatively safe for human consumption.
- "SCELETIUM TORTUOSUM HERBA" (pdf). South African National Biodiversity Institute.
- Smith, M. T.; Field C. R.; Crouch N. R.; Hirst, M. (1998). "The Distribution of Mesembrine Alkaloids in Selected Taxa of the Mesembryanthemaceae and their Modification in the Sceletium Derived 'Kougoed'". Pharmaceutical Biology 36 (3): 173–179. doi:10.1076/phbi.188.8.131.5250.
- Gericke, N.; Viljoen, A. M. (2008). "Sceletium--A Review Update". Journal of Ethnopharmacology 119 (3): 653–663. doi:10.1016/j.jep.2008.07.043. PMID 18761074.
- Smith, M. T.; Crouch, N. R.; Gericke, N.; Hirst, M. (1996). "Psychoactive Constituents of the Genus Sceletium N.E.Br. and other Mesembryanthemaceae: A Review". Journal of Ethnopharmacology 50 (3): 119–130. doi:10.1016/0378-8741(95)01342-3. PMID 8691846.
- Harvey, A. L.; Young, L. C.; Viljoen, A. M.; Gericke, N. P. (2011). "Pharmacological Actions of the South African Medicinal and Functional Food Plant Sceletium tortuosum and its Principal Alkaloids". Journal of Ethnopharmacology 137 (3): 1124–1129. doi:10.1016/j.jep.2011.07.035. PMID 21798331.
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