ISOLATION OF KAURENOIC ACID AND PREPARATION OF SOME SEMI-SYNTHETIC DERIVATIVES IN THE SEARCH FOR ANTI-LEISHMANIAL AND MOLLUSCICIDAL COMPOUNDS

Abstract

Purpose: The increasing application of natural products in pharmaceutical industry has expanded the interest in the study and search for new bioactive structures. The class of Diterpenes has a wide range of biologic activity, such as antimicrobial, antiparasitic, anti-HIV, hypotensive and anti-inflammatory, among others. Thus, the aim of this project is to obtain some semi-synthetic derivatives from the diterpene Kaurenoic Acid (KA), isolated from leaves of Mikania glomerata , and evaluate the antileishmanial and molluscicidal potencial activity of KA and the obtained derivaives. Methods: Initially, 500 g of grinded leaves of M. glomerata were subjected to a more eco-friendly washing with ethyl acetate (the original procedure uses dichloromethane), which led to the plant extract, after solvent evaporation. The extract was suspended in MeOH/H 2 O 9:1 (v/v) and washed with hexane (5 x 200 mL). This phase, after solvent evaporation was submitted to sequential chromatographic methods (VLC and CC) to purify KA. The pure KA was than submitted to reaction with MeOH and sulfuric acid at room temperature for 12 h. Results: From the leaves of M. glomerata , it was obtained 11,5 g of the extract, which yielded 400 mg of pure KA. The first chemical transformation of KA resulted on the addition of a methoxyl group in the tertiary olefinic carbon of KA, yield 85%. Conclusion: The results obtained so far indicates that we can reach a considerable number of derivatives in the next period. Therefore, several compounds can be sent to the leishmanial and molluscicidal assays.