Identification of novel nonmethylene‐interrupted fatty acids, 7E,13E‐20∶2, 7E,13E,17Z‐20∶3, 9E,15E,19Z‐22∶3, and 4Z,9E,15E,19Z‐22∶4, in ophiuroidea (Brittle star) lipids

Abstract

Fatty acids of Ophiuroidea (brittle star) Ophiura sarsi have been investigated by gas-liquid chromatography (GLC). About 2-13% of four unidentified fatty acids were found in total fatty acids from a sample caught at a depth of 1,100 m. Structural analyses were undertaken after partial hydrogenation of their concentrates with hydrazine hydrate and subsequent isolation of the monoenoate products by argentation thin-layer chromatography. The structures of the unidentified fatty acids were determined as 7E,13E-eicosadienoic (20:2), 7E,13E,17Z-eicosatrienoic (20:3), 9E,15E,19Z-docosatrienoic (22:3), and 4Z,9E,15E,19Z-docosatetraenoic (22:4) acids by gas chromatography-mass spectrometry of dimethyl disulfide adducts and GLC of the monoenoates on a polar column. These fatty acids belong to a family of nonmethylene-interrupted (NMI) polyunsaturated fatty acids frequently observed in marine invertebrates and conifer seeds. As far as the authors know, however, these NMI fatty acid types with mixed geometry of ethylenic bonds have not been reported previously.

Distribution of Novel Nonmethylene-Interrupted Fatty Acids over Neutral and Polar Lipids of Ophiuroidea (Brittle Star).

“…No detection of 24:6n-3 in fatty acids from the Holothuroidea lipids suggested that 24:6n-3 in Ophiuroidea did not originate from their diets. The novel NMI fatty acids have not been observed in Ophiuroidea at a significant level except for one sample caught at a depth of 1,100 m in Toyama Bay, and therefore the NMI fatty acids or their precursors seemed to be related to diets (4). In the present study, these NMI fatty acids were revealed to be concentrated in NL (mainly triacylglycerols) and seem to be less important for function and structure.…”

“…Ophiuroidea Ophiura sarsi was caught at a depth of 1,100 m in Toyama Bay, the Sea of Japan (37 15'N, 137 35'E) on March 18, 1999, and was the same as that reported previously (4). Total lipids (TL) were extracted from whole bodies by the method of Bligh and Dyer (6).…”

“…Peak area percentages were obtained with a Shimadzu C-R6A integrator. Peaks of the NMI fatty acids were identif ied by comparison of the equivalent chain lengths described in the recent paper (4 .6%, respectively. The present sample showed higher proportions of NL and triacylglycerols in particular than those reported.…”

Marine natural products

“…492 Four novel nonmethyleneinterrupted polyunsaturated fatty acid derivatives 787-790 were identified in extracts of the brittle star Ophiura sarsi. 493 Hedathiosulfonic acids A 791 and B 792 were isolated as acute toxicity-exhibiting constituents of the deep-sea urchin Echinocardium cordatum. 494 A triterpene glycoside patagonicoside A 793, bearing a novel aglycon moiety, was reported from the sea cucumber Psolus patagonicus.…”

Sulfated and Sulfur-Containing Steroids and Their Pharmacological Profile

“…Thus, compound ( 57 ) was isolated from the starfish Tremaster novaecaledonia [ 84 ] and from Aphelasterias japonica [ 85 ]. Brittle stars that are echinoderms and belong to the class Ophiuroidea produce many active metabolites including plasmalogen lipids, fatty acids, and steroids [ 86 , 87 , 88 , 89 , 90 , 91 ]. Sulfated stanols are widely distributed in various representatives in more than 30 species of Ophiuroidea [ 2 , 15 , 16 , 17 ].…”