UNUSUAL LIPIDS IN THE CARIBBEAN SPONGES AMPHIMEDON-VIRIDIS AND DESMAPSAMMA-ANCHORATA

The phospholipid fatty acid composition of the Caribbean sponge Amphimedon viridis was studied, revealing the presence of the previously unreported substances 5,13-nonadecadienoic acid, 4-nonadecenoic acid, and 15-heneicosenoic acid. In A. virdis the very long-chain 5,3,23-nonacosatrienoic acid and 5,9,23-tricosatrienoic acid predominated in the mixture. The fatty acid composition of the sponge Desmapsamma anchorata was revised and 62 phospholipid fatty acids were characterized. The rare 8,13-octadecadienoic acid and 18-tertacosenoic acid were also characterized in the mixture. The two possible stereochemical isomers of 7-methyl-6-hexadecenoic acid, i.e., 7-methyl-6(Z)-hexadecenoic acid and the 7-methyl-6(E)-hexadecenoic acid were identified in both sponges, but D. anchorata had larger amounts. This is the first time that both stereoisomers have been identified in a sponge. The previously reported 7-methyl-8-hexadecenoic acid was not found in D. anchorata. Unprecedented aldehydes, comprising 15- and 17-docosenal, were also identified in the sponges.