Cytotoxic Xanthones from Psorospermum molluscum from the Madagascar Rain Forest

摘要

Two new cytotoxic xanthones were isolated from extracts of the Madagascar rain forest plant Psorospermum cf. molluscum using bioassay guided fractionation with the Escherichia coli SOS chromotest. The structures of the new dihydrofuranoxanthones, designated 3′,4′-deoxy-4′-chloropsoroxanthin-(3′,5′-diol) (>1) and psoroxanthin (>4), were determined on the basis of 2D-NMR, MS and UV spectroscopic data, and are structurally related to the psorospermins, a known class of plant antitumor agents. A new hydroxyprenylated xanthone (>5) is also described. Xanthones (>1) and (>4) showed selective in vitro cytotoxicity against ABAE cells (bovine endothelial cell line).