Novel antibacterial triterpenoid from Combretum padoides [Combretaceae]

Abstract

The dichloromethane extract of C. padoides leaves was subjected to antibacterial activity guided fractionation against Staphylococcus aureus to afford a new oleanene-type triterpenoid glycoside identified as 1α,23β-dihydroxy-12-oleanen-29-oic-acid-23β-O-α-4- acetylrhamnopyranoside (1) together with two known compounds 1,22-dihydroxy-12-oleanen-30-oic acid (2) and 24-ethylcholesta-7,22,25-trien-O- β-D-glucopyranoside (3) on the basis of 1D NMR, 2D NMR and ESI-MS analysis. Compounds 1 and 2 had a reasonable antibacterial activity [MIC of 0.031 and 0.063 mg/ml] against S. aureus and Escherichia coli. All compounds were non-cytotoxic. The results indicate that pentacyclic triterpenes from C. padoides have some antibacterial activity with no cytotoxic activity. ©ARKAT USA, Inc.