First report of compounds from an Ancistrocarpus species: Triterpenoids from A. densispinosus Oliv. (Malvaceae).

The stem bark of Ancistrocarpus densispinosus Oliv. exhibited triterpenoids, including the rare fernane-type, fern-9(11)-ene-2α,3β-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. This is the first report of the chemistry of a plant of the Ancistrocarpus . The structures of the compounds were elucidated based on their NMR, IR and MS techniques and by comparisons of their experimental data with those reported. The twelve triterpenoids 1 - 12 were found to be inactive against five bacterial strains Escherichia 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.