Isolation and assessment of the in vitro anti-tumor activity of smenothiazole A and B, chlorinated thiazole-containing peptide/polyketides from the Caribbean sponge, Smenospongia aurea.

The study of the secondary metabolites contained in the organic extract of Caribbean sponge Smenospongia aurea led to the isolation of smenothiazole A (3) and B (4), hybrid peptide/polyketide compounds. Assays performed using four solid tumor cell lines showed that smenothiazoles exert a potent cytotoxic activity at nanomolar levels, with selectivity over ovarian cancer cells and a pro-apoptotic mechanism.