The value of central-African traditional medicine for lead finding : some case studies

Abstract Ethnoparmaological relevance: One of the possible methodologies for the discovery of novel drugs is the screening of selected plant extracts for a broad array of pharmacological activities. Materials and Methods: The selection based on enthnomedicinal uses, combined with a follow-up of existing literature on the plants’ chemotaxonomic properties, would seem to be the most cost-effective strategy for finding active plant extracts. A bioassay-guided fractionation of the active extracts should subsequently lead to the isolation and identification of the active lead constituent(s). Results and Discussion : Taking into account the enormous number and the amazing structural diversity of the currently known plant constituents, one might hope that promising model compounds with new structures and/or novel mechanisms of action might be found. In order, however, to optimize such a natural product drug discovery methodology, dereplication and selectivity of activity should be included in the screening system. Dereplication by which known compounds can rapidly be identified from a partially purified mixture prevents a research group from wasting resources by rediscovering known compounds. The use of single-target specific bioassays such as tests on isolated enzymes or on receptor-binding, or multiple target functional bioassays on isolated organs or intact cells must allow at an early stage to isolate compounds with specific pharmacological properties. Conclusions : In this publication, several examples of bioassay-guided isolation and identification of pharmacologically active lead compounds from plants used in Central-African traditional medicine by our research group will be presented and discussed.