Multibranched polyunsaturated and very-long-chain fatty acids of freshwater Israeli sponges.

Very-long-chain and multibranched polyunsaturated fatty acids of three freshwater sponges, Ephydatia syriaca, Nudospongilla sp., and Cortispongilla barroisi, were studied by silver TLC, GC-MS, UV, IR, HRMS, and NMR methods. One hundred and eighty-five conventional fatty acids were identified by GC-MS, out of which five were new multibranched polyunsaturated fatty acids. The freshwater sponges belonging to the family Spongillidae (class Demospongia) were shown to contain novel di-, tri-, and tetramethyl substituted dienoic, tetraenoic, and hexaenoic fatty acids. The compounds gave positive results in a brine shrimp toxicity assay.