The long-term objective of the proposed research is to locate and identify bioactive components isolated from african flora which would be effective in the control of the major African diseases: schistosomiasis, onchocerciasis and trachoma. The current proposal will concentrate on the isolation of potential antischistosomal and molluscicidal compounds for schistosomiasis (bilharzia) control. Cooperative reserch efforts in East and West Africa between native scientists at the Kalamazoo College foreign study centers (Kenya-University of Nairobi; Liberia-Cuttington College; Sierra Leone-Njala University and Fourah Bay Colleges; Nigeria- University of Ile-Ife and University of Nigeria at Nsukka; Ghana- University of Ghana at Legion; Senegal-University of Dakar) and the principal investigator will allow for the collection of medicinal plant species by either American students on foreign study or African personnel. Identification of plants will be verified by African botanists and a species deposited in a designated herbarium. The targeted plant species to be collected are based on either folk pharmacopeia or literature sources. On-site methanol or ethanol plant extraction will occur in Africa with plant extracts being forwarded to Kalamazoo College for final systematic extraction workup. Bioactivity will be pinpointed in terrestial plants by simple in-house microbial, herbicidal and molluscicidal bioassays. The components exhibiting activity will be isolated, identified and subjected to pharmacological evaluation. Screening and bioassay work will follow accepted protocols. Separation work will utilize the application of available chromatographic techniques: GC, TLC, HPLC, GC, flash chromatography and DCC-chromatography. The latter technique will be important because known active principles of plant molluscicides are water soluble and act on the snail surface membranes. The major classes of natural products of interest include the saponins, flavonoids, alkaloids and terpenoids. Structure elucidation will utilize NMR, MS, X-ray diffraction, IR and UV spectroscopic techniques; chemical degradations and transformations. While chemical investigations are proceeding on targeted species, additional new plant species will be acquired and screened to maintain a constant extract supply.
