Antimicrobial and studies of the triterpenoids of Dichapetalum albidum.

Here we report a new polyhydroxylated triterpene, 2β,6β,21α-trihydroxyfriedelan-3-one () isolated from the root and stem bark of A. Chev (Dichapetalaceae), along with six known triterpenoids (-, , , ), sitosterol-3β--D-glucopyranoside (), a dipeptide (), and a tyramine derivative of coumaric acid (). Friedelan-3-one () showed an antimicrobial activity (IC) of 11.40 μg/mL against , while friedelan-3α-ol () gave an IC of 13.07 μg/mL against with ampicillin reference standard of 19.52 μg/mL and 0.30 μg/mL respectively. 3β-Acetyl tormentic acid () showed an IC of 12.50 μg/mL against and sitosterol-3β--d-glucopyranoside () showed an IC of 5.06 μg/mL against with respective reference standards of IC 5.02 μg/mL for suramin and IC 0.27 μg/mL for amphotericin B. Molecular docking of the isolated compounds on the enzyme glucose-6-phosphate dehydrogenase (G6PDH) suggested 3β-acetyl tormentic acid () and sitosterol-3β--D-glucopyranoside ( as plausible inhibitors of the enzyme in accordance with the experimental biological results observed.