Fatty acids from the Okhotsk sea sponge Forcepia uschakowi

Abstract

The fatty-acid (FA) composition of total lipids from the Okhotsk sea marine sponge Forcepia uschakowi was studied. A total of 56 acids were identified by GC and GC-MS. The principal saturated acids were 16:0 and 18:0. The main monoene acid was , which was observed for the first time in sponge lipids. Polyunsaturated acids represented of 64.1% of the total FA of F. uschakowi. Of these, the principal ones were non-methylene-separated acids 26:2(5,9) and 26:3(5,9,19), which are typical of sponges, and bromo-acid 9).The search for new fatty acids, the elucidation of their structures and biosynthetic pathways, and the study of their properties and roles in organisms are currently of great biochemical interest. From this viewpoint, some of the most interesting subjects are representatives of the phylum Porifera. Of all marine animals, sponges have the largest variety of sterols, lipids, and fatty acids (FA) with unusual and sometimes unique structures [1]. Certain unusual sponge lipids possess biological activity [2].According to the literature, lipid and FA compositions of tropical and subtropical sponges are most studied whereas sponges from boreal regions are practically unstudied. Herein the FA composition of total lipids from the Okhotsk Sea marine sponge Forcepia uschakowi is studied for the first time.According to GC analysis, FA from total lipids of F. uschakowi contained more than 70 components. Of these, 56 components (94.8%) were identified (Table 1).Saturated FA made up 10.2% of the total FA from F. uschakowi. The principal saturated acids were 16:0 and 18:0. Saturated FA with a branched carbon skeleton made up 4.3%. These were basically acids with a methyl group in the (n-2) and (n-3) position. Saturated C 15-20 FA of i/ai-structure were observed previously in many sponges and other organisms [3]. It is commonly thought that such acids are of bacterial origin [4]. Saturated FA of isoprenoid structure were observed in small quantities in lipids of F. uschakowi. It is known that acids of isoprene structure are formed by degradation of phytol, which in turn is produced by destruction of chlorophyll [5]. It was shown earlier that isoprene acids in sponges occurred in plasma membranes [6].Monoene FA of linear structure totalled 13.3% of total FA in F. uschakowi. Of these, the principal ones were 16:1(9), 18:1(11), and 22:1(15). Two different monoene FA with one branch in the middle of the chain were observed in the studied sponge. These were 7-Me-16:1(6) (1.6%) and 15-Me-24:1(14) (6.1%). Acid 7-Me-16:1(6) was observed earlier in sponges Trikentnon loeve and Pseudaxinella af. lunaecharta [7] whereas acid 15-Me-24:1(14) was found for the first time in sponge lipids and is probably synthesized in F. uschakowi by elongation of 7-Me-16:1(6).Mass spectra of the pyrrolidide of 15-Me-24:1(14) contained a molecular ion [M] ·+ with m/z 433. A gap of 12 amu occurred between ions of C-13 (m/z 266) and C-14 (m/z 278) fragments. The peak for the C-15 ion (m/z 292) was almost completely absent (0.1%), i.e., a gap of 28 amu oc...

Metabolites of the marine sponge Suberites cf. aurantiacus

“…The fraction of total lipids was extracted by CHCl 3 :MeOH (2:1) [22] from the lyophilized specimen (2 g). Fatty-acid methyl esters were prepared as described above [23] and purified by preparative TLC on Sorbfil (Russia) plates using benzene. Fatty-acid pyrrolidides for MS analysis were prepared as before [24] and purified by preparative TLC using EtOAc.…”

“…Fatty-acid pyrrolidides for MS analysis were prepared as before [24] and purified by preparative TLC using EtOAc. Fattyacid methyl esters and the corresponding pyrrolidides were identified by comparison of their GC and MS properties with those reported [23].…”