New cytotoxic coumarins and prenylated benzophenone derivatives from the bark of Ochrocarpos punctatus from the Madagascar rainforest.

Bioassay-guided fractionation of a CH2Cl2-MeOH extract of the bark of Ochrocarpos punctatus resulted in the isolation of seven new coumarins, ochrocarpins A-G (1-7), three new benzophenone derivatives, ochrocarpinones A-C (8-10), and five known coumarins, mammea A/AC cyclo F (11), mammea A/AD cyclo D (12), mammea A/AB cyclo F (13), mammea A/AA cyclo F (14), mammea A/AB cyclo D (15), and 15,16-dihydro-16-hydroperoxyplukenetione (16). The structures of compounds 1-10 were established on the basis of extensive 1D and 2D NMR spectroscopic data interpretation. All compounds exhibited cytotoxicity against the A2780 ovarian cancer cell line.