Epoxyphomalin A and B, prenylated polyketides with potent cytotoxicity from the marine-derived fungus Phoma sp.

Chemical investigation of a strain of the marine-derived fungus Phoma sp. has led to the discovery of epoxyphomalin A (1) and B (2), two new prenylated polyketides with unusual structural features. Epoxyphomalin A (1) showed superior cytotoxicity at nanomolar concentrations toward 12 of a panel of 36 human tumor cell lines. In COMPARE analyses, the observed cytotoxic selectivity pattern of 1 did not correlate with those of reference anticancer agents with known mechanisms of action.