THE NIGERIAN ZANTHOXYLUM; CHEMICAL AND BIOLOGICAL VALUES

Abstract

The Nigerian Zanthoxylum is a common component of the rain forest vegetation of Southern Nigeria, and is represented by eleven species. A few of these species occur more abundantly in the savannah and dry forest vegetation of South-western Nigeria. The eleven Zanthoxylum species demonstrate very close similarities and relationships among themselves, and are identified as trees, erect shrubs or small trees, straggling or scandent shrubs or as a forest liane. Traditional healers throughout Nigeria have used species of the Zanthoxylum for the treatment of a wide range of disorders, including toothache, urinary and venereal diseases, rheumatism and lumbago. Metabolites isolated from Zanthoxylum species so far include alkaloids, aliphatic and aromatic amides, lignans, coumarins, sterols, carbohydrate residues etc. Some of the metabolites have shown cytotoxic, molluscicidal, anticonvulsant, anti-sickling, anaesthetic, antibacterial, anti-hypertensive and anti-inflammatory properties. A common feature of most, if not all, the species studied is the wonderful capacity to produce gums and volatile oils. These vary in composition and so show different properties. In this presentation, the author has discussed the chemistry of the various species examined to date. The focus has been on the local uses and commercial importance of the species, the values of the various metabolites in medicine and their general potential in drug development.