<unk>  is a naturally occurring psychoactive substance found in plants in the family Apocynaceae such as Tabernanthe<unk> ga, Voacanga africana, and Tabernaemontana undulata. It is a psychedelic with dissociative properties. Preliminary research indicates that it may help counter drug addiction. Its use has been associated with serious side effects and death. Between the years 1990 and 2008, a total of 19 fatalities temporally associated with the ingestion of<unk>  were reported, from which six subjects died of acute heart failure or cardiopulmonary arrest. The total number of subjects who have used it without major side effects during this period remains unknown. It is used as an alternative medicine treatment for drug addiction in some countries. Its prohibition in other countries has slowed scientific research.<unk>  is also used to facilitate psychological introspection and spiritual exploration. Various derivatives of<unk>  designed to lack psychedelic properties (such as 18-MC) are under clinical trials which have shown them to be neither psychedelic nor psychoactive and to have acceptable safety profiles in humans. The psychoactivity of the root bark of the<unk> ga tree (Tabernanthe<unk> ga), from which<unk>  is extracted, was first discovered by the Pygmy tribes of Central Africa, who passed the knowledge to the Bwiti tribe of Gabon. French explorers in turn learned of it from the Bwiti tribe and brought<unk>  back to Europe in 1899–1900, where it was subsequently marketed in France as a stimulant under the trade name Lambarène.<unk> -containing preparations are used for medicinal and ritual purposes within African spiritual traditions of the Bwiti, who claim to have learned it from the Pygmy peoples. Although<unk> 's anti-addictive properties were first widely promoted in 1962 by Howard Lotsof, its Western medical use predates that by at least a century. Additionally, the U.S. Central Intelligence Agency (CIA) studied the effects of<unk>  in the 1950s.<unk>  is an indole alkaloid that is obtained either by extraction from the<unk> ga plant or by semi-synthesis from the precursor compound voacangine, another plant alkaloid. The total synthesis of<unk>  was described in 1956. Structural elucidation by X-ray crystallography was completed in 1960.
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