Amazonian ethnobotany and the search for new drugs.

Tropical rain forests offer enormous prospects for the discovery of new drugs for use in Western medicine. The Amazon supports 80,000 species of higher plants and a diverse Indian population. Focusing attention on those plants used as medicines by indigenous peoples is the most efficient way of identifying the plants that contain bioactive compounds. There is an urgent need for more ethnobotanists and ethnopharmacologists to be trained to document as much information as possible before it and the plants are lost through destruction of the rain forest and acculturation of the indigenous peoples. Ethnobotanical studies have identified plants documented by early travellers; these include Paullinia yoco and Ilex guayusa which are used as stimulants and have been shown to be rich in caffeine. Studies of the hallucinogen prepared from Banisterioposis caapi have shown that the native people know which plants to add to the mixture to lengthen and intensify the intoxication produced by the beta-carboline alkaloids in the plant. Three major snuffs are used in the Amazonia; the plants from which they are derived have been identified. One of the snuffs also has antifungal and curare-like activities; chemical analysis on the active principles has not been done. Several plants are considered as prime candidates for scientific study as sources of useful chemicals for medicine or industry. These include some used to prepare teas or other infusions for treatment of various symptoms of senile dementia.