The ethnobotanical approach to drug discovery: strengths and limitations.

For pharmaceuticals ranging from digitalis to vincristine the ethnobotanical approach to drug discovery has proven successful. The advent of high-throughput, mechanism-based in vitro bioassays coupled with candidate plants derived from pain-staking ethnopharmacological research has resulted in the discovery of new pharmaceuticals such as prostratin, a drug candidate for treatment of human immunodeficiency virus, as well as a variety of novel antiinflammatory compounds. Not all Western diseases are equally likely to be recognized by indigenous peoples. Gastrointestinal maladies, inflammation, skin infections and certain viral diseases are likely to be of high saliency to indigenous healers, whereas diseases such as cancer and cardiovascular illness are unlikely to be easily diagnosed by indigenous peoples. Yet indigenous remedies may indicate pharmacological activity for maladies such as schizophrenia, for which the biochemical mechanisms have yet to be discovered. Ethnopharmacological information can be used to provide three levels of resolution in the search for new drugs: (1) as a general indicator of non-specific bioactivity suitable for a panel of broad screens; (2) as an indicator of specific bioactivity suitable for particular high-resolution bioassays; (3) as an indicator of pharmacological activity for which mechanism-based bioassays have yet to be developed.