Plant Resources of Tropical Africa

Tabernanthe iboga belongs to the family Apocynaceae and is a shrub up to 4 m tall with small fragrant flowers and yellowish to red berries. It is distributed in Central Africa, from Cameroon east to eastern DR Congo and south to Angola.

The root bark is very important in the initiation ceremonies of the Bwiti tradition in Gabon, and is mainly used as a hallucinogenic. In the 1980s iboga became popular in the United States and Europe as a non-addictive interrupter of drug dependency, but soon thereafter it was classified as a hallucinogen in the United States, where it is therefore illegal to buy, sell, or possess it without a licence. Its possession is also prohibited in several countries in Europe. There has been renewed interest in iboga since the late 1990s.

The active compounds in the root bark, stem bark, leaves and seeds are indole alkaloids, with ibogaine being the most important one. There is no consensus yet on how ibogaine works precisely, but it is known to inhibit the re-uptake of the neurotransmitter serotonin, which can cause hallucinations. Research on animals and humans reveal that ibogaine is converted in the liver to noribogaine, which fills opiate receptors, thus eliminating withdrawal symptoms. Ibogaine also stimulates nicotinic receptors in the cerebellum, which contributes to modulating the dopamine reward circuit. At high doses though, ibogaine is toxic as it destroys neurons in the cerebellum.

Tabernanthe iboga has considerable socio-economic importance in Gabon because of its role in the Bwiti tradition, and outside Gabon because the root bark or purified ibogaine is used in Europe and America in treating addictions to drugs, alcohol and smoking. Apart from the need to investigate whether ibogaine really does suppress the craving for drugs, its toxic side-effects need to be elucidated. Tabernanthe iboga is not yet threatened in its natural environment, but as most plants are harvested from the wild, and whole plants are uprooted, it may become endangered in the near future when demand remains high. More research on cultivation practices and methods of propagation of superior plant types is warranted.