No abstract

The stem bark of Ancistrocarpus densispinosus Oliv. exhibited triterpenoids, including the rare fernane-type, fern-9(11)-ene-2α,2β-diol (1) a possible chemotaxonomically distinct biomolecule for the genus. Other triterpenoids that were isolated from this plant include the ursane-type ursolic acid (2) and corosolic acid (3), friedelane-type friedelin (4) and canophyllol (5), lupane-type lupeol (6), betulin (7), betulinic acid (8) and hennadiol (9), oleanoic acid (10), maslinic acid (11) and taraxerol (12), and three sterols stigmasterol, stigmasterol-3-O-β-D-glucopyranoside and sitosterol. This is the first report of the chemistry of a plant of the Ancistrocarpus species. The structures of the compounds were elucidated based on their NMR spectroscopy, IR and MS techniques and by comparisons of their experimental data with those reported in the literature. The twelve triterpenoids 1-12 were found to be inactive against five bacterial strains Escherochia coli, Bacillus subtilis, Pseudomonas agarici, Micrococcus luteus and Staphylococcus warneri; inactive against KB-3-1 cervix carcinoma cancer cell line and inactive as antioxidants in the DPPH assay.