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

<p>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 of <i>Commiphora pedunculata</i>. 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-resistant <i>entrococci</i> (VRE), <i>Escherichia coli, Staphylococcus aureus</i> and <i>Candida albicans</i>. 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 against <i>Shigella dysentriae, Bacillus cereus</i> and <i>S. aureus</i> while the minimum bactericidal concentration was as low as 50 μg/mL against <i>Pseudomonas aeruginosa,</i> VRE and <i>C. albicans</i>. This is the first report of the isolation of the compound.</p>