NEW DELTA(5,9)-FATTY-ACIDS IN THE PHOSPHOLIPIDS OF THE SEA-ANEMONE STOICNACTIS-HELIANTHUS

The diunsaturated fatty acids 5,9-heneicosadienoic acid, 5,9-docosadie noic acid and 5,9-tricosadienoic acid, the brominated fatty acids 6-br omo-5,9-heneicosadienoic acid and 6-bromo-5,9-docosadienoic acid, and the polyunsaturated fatty acids 5,9,13-eicosatrienoic acid and 5,9,13- docosatrienoic acid, were identified for the first time in nature in t he phospholipids (mainly phosphatidylethanolamine and phosphatidylseri ne) of the anemone Stoichactis helianthus. Structural elucidation was accomplished by means of mass spectrometry and chemical transformation s such as pyrrolidide and dimethyldisulfide derivatization. Other Delt a(5,9) fatty acids such as 5,9-hexadecadienoic acid, 5,9-octadecadieno ic acid, and 5,9-eicosadienoic acid were also identified in the anemon e. Our results indicate that Delta(5,9) phospholipid fatty acids are n ot unique to sponges, as previously recognized, but can be found in ot her marine invertebrates such as an anemone. 24-Methylated sterols pre dominated in the sterol composition of the anemone investigated.