A novel antimicrobial flavonoid from the stem bark of Commiphora pedunculata (Kotschy & Peyr.) Engl.

A new flavonoid, 2-(3,5-dihydroxy-4-methoxy-phenyl)-3,5-dihydroxy-8,8-dimethyl-2,3-dihydro-8H-pyrano[3,2]chromen-4-one, together with previously reported epicatechin was isolated from the ethyl acetate soluble fraction of the methanol extract of the stem bark ofCommiphora pedunculata. The structures of these compounds were elucidated based on extensive analysis of their spectral data, including 1 and 2D NMR. The compounds were active against 9 out of 12 tested microorganisms including a resistant strain; vancomycin-resistantentrococci(VRE),Escherichia coli, Staphylococcus aureusandCandida albicans. The zones of inhibition ranged between 22 and 34 mm against the microorganisms. The minimum inhibitory concentration was as low as 6.25 μg/mL againstShigella dysentriae, Bacillus cereusandS. aureuswhile the minimum bactericidal concentration was as low as 50 μg/mL againstPseudomonas aeruginosa,VRE andC. albicans. This is the first report of the isolation of the compound. [ABSTRACT FROM PUBLISHER]