Isolation and characterization of novel 2-hydroxy fatty acids from the phospholipids of the sponge Smenospongia aurea.

The Caribbean sponge Smenospongia aurea revealed the presence of six novel branched alpha-hydroxy fatty acids: 2-hydroxy-17-methyloctadecanoic acid, 2-hydroxy-21-methyldocosanoic acid, 2-hydroxy-22-methyltricosanoic acid, and 2-hydroxy-22-methyltetracosanoic acid, 2-hydroxy-24-methylpentacosanoic acid, and 2-hydroxy-23-methylpentacosanoic acid. These novel alpha-hydroxy fatty acids were associated with phosphatidylethanolamine. The sponges Aplysina lacunosa and Aplysina fistularis also contained considerable amounts of alpha-hydroxy fatty acids, the very long-chain 5,9,23-tricontatrienoic acid (30:3), and phytanic acid. The sterol composition of the three sponges was also studied. It indicated that A. lacunosa and A. fistularis contained large amounts of aplysterol and verongulasterol, while S. aurea did not show any of these sterols. The results are discussed in terms of the taxonomy of the species.