I A Khan1, A M Clark, J D McChesney. 1. National Center for Development of Natural Products, School of Pharmacy, University of Mississippi 38677, USA.
Abstract
PURPOSE: In a continuation of our search for novel antifungal compounds from higher plants, the standard extract of the bark of Pithecellobium racemosum was found to have good activity against important AIDS-related opportunistic yeasts. METHODS: The extract was subjected to bioguided fractionation using silica gel column chromatography which led to purification of triterpene glycosides. The structures of these compounds were determined by a combination of spectroscopic (IR, NMR, HRMS) and chemical methods. RESULTS: Compound 1 is a new glycoside, 3-O[alpha-L-arabinopyranosyl (1-2)][alpha-L arabinopyranosyl (1-6)]2-acetoamido-2-deoxy-beta-D-glucopyranosyl oleanolic acid and Compound 2 was identified as the known compound 3-O-[alpha-L-arabinopyranosyl (1-2)]alpha-L-arabinopyranosyl (1-6)] 2-acetamido-2-deoxy-beta-D-glucopyranosyl echinocystic acid. CONCLUSIONS: Compound 1 is a new glycoside, 3-O-[alpha-L-arabinopyranosyl (1-2)]alpha-L-arabinopyranosyl (1-6)]-2-acetoamido-2-deoxy-beta-D-glucopyranosyl oleanolic acid and exhibits moderate antifungal activity against T. mentogrophytes, C. albicans and S. cerevisiae with MIC values of 6.25, 12.5 and 12.5 micrograms/ml respectively.
PURPOSE: In a continuation of our search for novel antifungal compounds from higher plants, the standard extract of the bark of Pithecellobium racemosum was found to have good activity against important AIDS-related opportunistic yeasts. METHODS: The extract was subjected to bioguided fractionation using silica gel column chromatography which led to purification of triterpene glycosides. The structures of these compounds were determined by a combination of spectroscopic (IR, NMR, HRMS) and chemical methods. RESULTS: Compound 1 is a new glycoside, 3-O[alpha-L-arabinopyranosyl (1-2)][alpha-L arabinopyranosyl (1-6)]2-acetoamido-2-deoxy-beta-D-glucopyranosyl oleanolic acid and Compound 2 was identified as the known compound 3-O-[alpha-L-arabinopyranosyl (1-2)]alpha-L-arabinopyranosyl (1-6)] 2-acetamido-2-deoxy-beta-D-glucopyranosyl echinocystic acid. CONCLUSIONS: Compound 1 is a new glycoside, 3-O-[alpha-L-arabinopyranosyl (1-2)]alpha-L-arabinopyranosyl (1-6)]-2-acetoamido-2-deoxy-beta-D-glucopyranosyl oleanolic acid and exhibits moderate antifungal activity against T. mentogrophytes, C. albicans and S. cerevisiae with MIC values of 6.25, 12.5 and 12.5 micrograms/ml respectively.