Pausinystalia johimbe

Pausinystalia johimbe, (Rubiaceae), common name Yohimbe, is a plant species native to western and central Africa (Nigeria, Cabinda, Cameroon, Congo-Brazzaville, Gabon, Equatorial Guinea).^[1] Extracts from yohimbe have been used in traditional medicine in West Africa as an aphrodisiac and have been marketed in developed countries as dietary supplements.^[2][3]

The active ingredient in the extract, yohimbine, is a veterinary drug used to stimulate recovery from sedation in certain animals. Although proposed as a potential treatment for erectile dysfunction in humans, there are cautions about its safety or effectiveness.^[2][3] Yohimbine is banned in manufactured human products in numerous countries.

Description

Yohimbe is one of five Pausinystalia evergreen species growing in West and Central Africa in lowland forests. The tree grows about 30m tall, with a straight bole that is rarely larger that 50-60 cm in diameter. The bark is grey to reddish-brown, with longitudinal fissures, easy to peel and bitter-tasting. The inner bark is pinkish and fibrous. The sapwood is yellowish and the heartwood is ochre-yellow; the wood is fine-grained and relatively dense and moderately hard. The leaves grow in groups of three, with short (about 2 cm) stems. The blades are oval-shaped, 11-47 cm long and 5 - 17 cm wide. ^[4]

The demand for yohimbe bark has led to over-exploitation, with possibility of long-term threat to sustainability of the species. Cameroon is the biggest exporter.^[4]

Uses

The wood and bark are used for firewood and construction. Bark, the most commercially important product, is used in extractions to make tinctures for traditional medicine and dietary supplements.^[4]

Traditional medicine

Extracts from the bark of yohimbe are used in West Africa as a general tonic and as an aphrodisiac.^[2][3][4]

Dietary supplements

Yohimbe bark and extract are widely used in manufactured dietary supplements.^[2][3] However, the bark and extracts are banned from use in food and dietary supplements in many countries, including Great Britain, Ireland, Belgium, the Netherlands, Australia, New Zealand, Denmark, the Czech Republic, and Canada.^[3]

The primary alkaloid in the extract, yohimbine, is a veterinary drug used to reverse sedation in dogs, elk or deer.^[3][5] In addition to yohimbine, yohimbe extract contains other alkaloids with undefined properties, adding to concern about its safety.^[2] Among other alkaloids is corynanthine, an alpha-1 adrenergic receptor blocker and raubasine.^[3][6]

The levels of yohimbine present in yohimbe bark and manufactured supplements are highly variable.^[2][3]

Safety

Yohimbe bark extract and yohimbine specifically have been declared as insufficiently characterized and possibly unsafe to consume by the European Union and US National Institutes of Health.^[2][3]

References