Sceletium tortuosum

Sceletium tortuosum is a succulent plant 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 generally recognised eight Sceletium species are S. crassicaule, S. emarcidum, S. exalatum, S. expansum, S. rigidum, S. strictum, S. tortuosum and S. varians. Per Klak et al. (2007), an alternative classification for the Sceletium group is Mesembryanthemum crassicaule, M. emarcidum, M. exalatum, M. expansum, M. archeri (S. rigidum), M. ladismithiense (S. strictum), M. tortuosum and M. varians. 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. S. tortuosum is traditionally used to fight stress and depression, relieve pain and alleviate hunger. S. tortuosum has been studied to alleviate excessive nocturnal barking in dogs and excessive nocturnal meowing in cats, both diagnosed with dementia. S. tortuosum may elevate mood and decrease anxiety, stress and tension. Intoxicating doses can be euphoric but not hallucinogenic, contrary to some literature on the subject. S. tortuosum contains about 1–1.5% total alkaloids. The alkaloids contained in S. tortuosum believed to possess psychoactivity include mesembrine, mesembrenone, mesembrenol and tortuosamine. A standardised ethanolic extract of dried S. tortuosum had a IC50 for SERT of 4.3 μg/ml and for PDE4 inhibition of 8.5 μg/ml. Kanna is also reported to be an acetylcholinesterase inhibitor and cannabinoid agonist.