NEW BRANCHED-CHAIN FATTY-ACIDS FROM THE SENEGALESE GORGONIAN LEPTOGORGIA-PICCOLA (WHITE AND YELLOW MORPHS)

Fatty acids from total lipids of the gorgonian Leptogorgia piccola (wh ite and yellow morphs), collected from the same area at two different periods with regard to the average water temperature, were studied. Mo re than fifty fatty acids were identified as methyl esters and N-acyl pyrrolidides by gas chromatography and gas chromatography/mass spectro metry. Three new, branched-chain unsaturated fatty acids were identifi ed in addition to the unusual 7-methyl-6-hexadecenoic acid, namely 10- methyl-6-hexadecenoic, 7,9-dimethyl-6-hexadecenoic, and 10-methyl-6,9- heptadecadienoic acids. Also 6,9-heptadecadienoic acid was identified. The fatty acid patterns of specimens harvested in colder waters were quite different from those harvested in warmer waters in that the form er contained high amounts of methylene-interrupted polyunsaturated aci ds, including tetracosapolyenoic acids, especially 6,9,12,15,18-24:5 ( up to 15.8% of the total acid mixture) and 6,9,12,15,18,21-24:6 (up to 5.3%). Arachidonic acid was, nevertheless, a major component in all t he fatty acid mixtures studied (13.6-20.5%). Based on gas chromatograp hy/fourier transform infrared experiments, the double bonds were assig ned the (Z) configuration. Several fatty aldehydes and their dimethyl acetals were also detected, of which the most abundant was octadecanal .