Reidispongiolide A and B, two new potent cytotoxic macrolides from the New Caledonian spongeReidispongia coerulea

Two new 26-membered macrolides, reidispongiolide A (I) and B (II), were isolated from the New Caledonian marine sponge R. coerulea and their structures elucidated. They are related to sphinxolides previously isolated from an unknown nudibranch and later from the sponge Neosiphonia superstes. I and II co-occur with sphinxolide B and D. These macrolides exhibited potent cytotoxicity against various human carcinoma cells.