On the isolation of the new fatty acid 6,11-eicosadienoic (20∶2) and related 6,11-dienoic acids from the spongeEuryspongia rosea

The phospholipid fatty acids from the spongeEuryspongia rosea were studied revealing the presence of the new 6,11-eicosadienoic (20∶2) acid and the rare 6,11-octadecadienoic acid (18∶2). The isolation of these 6,11-dienoic acids reveals the presence of new biosynthetic possibilities in sponges and suggests the presence of an active Δ6 desaturase inE. rosea. Other acids isolated fromE. rosea include 12-eicosenoic (20∶1) and 17-tetracosenoic acid (24∶1). The major phospholipids encountered in the sponge were phosphatidylethanolamine (PE), phosphatidylserine (PS), and phosphatidylcholine (PC).