A new polyether acid from a cold water marine sponge, a Phakellia species.

A new polyether acid, 14, 15-dihydrodinophysistoxin-1 [1], was isolated along with dinophysistoxin-1 [2] and okadaic acid [3], from an unidentified species of the sponge genus Phakellia. The structure of 1 was assigned by comparison of its 1H- and 13C-nmr and fabms spectral data to those of 2 and 3, as well as interpretation of homonuclear 2D nmr data. Compounds 1-3 showed cytotoxicity against L-1210 leukemia cells with IC50 values of 3 ng/ml. The isolation, structure determination, and biological activities of these compounds are described (1).