Natural product and medicinal chemistry

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We propose to continue our successful bio-prospecting approach jointly with the Arnason group. (1) In particular we plan to investigate up to seven previously uninvestigated Costa Rican tree species with reputed anti-cancer activity. We have already collected leaves, wood and bark of two species and will begin bio-assay guided isolation shortly. (2) We have identified the very active anti-herpes/anti-biotic component found in the ethyl extracts of algae harvested on the shores of Ungava Bay in Northern Quebec as a glycolipid built from galactose, glycerol and ?-linolenic acid. We propose to synthesize and evaluate a small family of the metabolically more stable C-glycoside analogs. (3) We will also isolate and determine the structure of a very active anti-epileptic extract isolated from a Piperaceae species collected in Belize after discussion with traditional healers. The semi-purified extract has activity comparable to that of the currently used anti-epileptic drug in Canada using the GABA-T bio-assay. Assuming that the structure is not overly complex we will initiate studies towards its synthesis and the synthesis of analogs. (4) We will also continue our studies of the rare Costa Rican tree Ruptilliocarpon caracolito to probe for additional components that may shed light on the biosynthesis of the highly unusual spiro CD-ring triterpenoids that we have previously isolated from the bark of this species.