Antibacterial activity of naphthoquinones and triterpenoids from Euclea natalensis root bark.
Weigenand O, Hussein AA, Lall N, Meyer JJ.
Phytochemical studies of an ethanolic extract of Euclea natalensis root bark afforded two new compounds, octahydroeuclein (1) and 20(29)-lupene-3 beta-isoferulate (2), in addition to three known compounds, shinanolone (3), lupeol, and betulin. The chemical structures of 1 and 2 were determined by spectroscopic means. Shinanolone (3) showed inhibitory activity against Gram-positive bacterial strains and a drug-sensitive strain of Mycobacterium tuberculosis at a concentration of 0.1 mg/mL.