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Kanna
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Order:	Caryophyllales
Family:	Aizoaceae
Genus:	Mesembryanthemum
Species:	M. tortuosum
Binomial name
Mesembryanthemum tortuosum L.[1]
Synonyms[1]
Mesembryanthemum aridum Moench Mesembryanthemum concavum Haw. Phyllobolus tortuosus (L.) Bittrich Sceletium boreale L.Bolus Sceletium compactum L.Bolus Sceletium concavum (Haw.) Schwantes Sceletium framesii L.Bolus Sceletium gracile L.Bolus Sceletium joubertii L.Bolus Sceletium namaquense L.Bolus Sceletium ovatum L.Bolus Sceletium tortuosum (L.) N.E.Br. Sceletium tugwelliae L.Bolus

Mesembryanthemum tortuosum (many synonyms, including Sceletium tortuosum) is a succulent plant in the family Aizoaceae native to the Cape Provinces of South Africa.^[1] It is known as the Namaqua skeletonfig, kanna, channa, kougoed (kauwgoed/ 'kougoed', prepared from 'fermenting' M. tortuosum^[2])—which literally means, 'chew(able) things' or 'something to chew'.

Eight species related to M. tortuosum have also been placed in the genus Sceletium: M. crassicaule, M. emarcidum, M. exalatum, M. expansum, M. archeri (S. rigidum), M. ladismithiense (S. strictum), M. tortuosum and M. varians.^[3]

It has been used by South African pastoralists and hunter-gatherers for thousands of years. The first written account of its use dates to 1662, recorded by Jan van Riebeeck. The dried plant was chewed with the saliva swallowed, but it has also been prepared in various forms, including gel caps, teas, tinctures, snuff, and smoked. In traditional medicine, it is primarily used to alleviate stress, depression, pain, and hunger.

M. tortuosum contains around 1–1.5% total alkaloids, with mesembrine being one of its major alkaloids. The plant can be grown from seeds or propagated from cuttings, with cultivation practices similar to those of cacti like Echinopsis. It thrives in temperatures above 16 °C (61 °F) and does not tolerate frost. It is found in 50 subpopulations across the Cape provinces of South Africa and is classified as least concern in the Red List of South African Plants, although it is facing population decline due to harvesting for uses in traditional medicine.

The plant has been used by South African pastoralists and hunter-gatherers as a mood-altering substance from prehistoric times.^[4] The first known written account of the plant's use was in 1662 by Jan van Riebeeck. The traditionally prepared dried plant was often chewed and the saliva swallowed, but it has also been made into gel caps, teas and tinctures.^[5] It has also been used as a snuff and smoked.^[6]

M. tortuosum is in traditional medicine to reduce stress and depression, relieve pain and alleviate hunger.^{[6][better source needed]}

It has been studied to alleviate excessive nocturnal barking in dogs, or meowing in cats.^[4]

M. tortuosum can be grown from seeds and be propagated from cuttings. Its cultivation and care are similar to cactaceae like Echinopsis. The optimal temperature is at least 16°C and it does not tolerate frost.^[7]

M. tortuosum contains about 1–1.5% total alkaloids.^[6] A standardised ethanolic extract of dried M. tortuosum had an IC₅₀ for SERT of 4.3 μg/ml and for PDE4 inhibition of 8.5 μg/ml.^[3]

Mesembrine is a major alkaloid present in M. tortuosum.^[8] There is about 0.3% mesembrine in the roots and 0.86% in the leaves, stems, and flowers of the plant.^[6]

Traditional and contemporary methods of preparation serve to reduce levels of potentially harmful oxalates found in M. tortuosum.^[6] An analysis indicated levels of 3.6–5.1% oxalate, which falls within the median range for crop plants, just like spinach or kale.^[6]

M. tortuosum is found in 50 subpopulations in the Cape provinces from Namaqualand to Montagu and Aberdeen; in karroid habitat.^[9]

M. tortuosum is listed as least concern in the Red List of South African Plants, though it is facing a slow decline in population numbers due to harvesting for medicinal use.^[9]

• 
  Flower
• 
  Being sold commercially in Cape Town, South Africa. It is ground into a brown powder and ingested orally.
• 
  Seedling

• Ethnomedicine
• Psychoactive plants
• San healing practices

• Monograph on Sceletium tortuosum
• The past, present and possible future of kanna Video. Talk of Nigel Gericke at Ethnopharmacologic Search for Psychoactive Drugs. 2017.

• van Wyk, Ben-Erik; van Oudtshoorn, Bosch; Gericke, Nigel (2009). Medicinal Plants of South Africa (2nd ed.). Pretoria, South Africa: Briza Publications. p. 200. ISBN 978-1-875093-37-3.