Similarities in the lipid class profiles of oils from Atlantic and Pacific dogfish livers

Ether lipids

The naturally occurring 1-O-alkyl-sn-glycerols and their methoxylated congeners, 1-O-(2'-methoxyalkyl)-sn-glycerols, are biologically active compounds, ubiquitously found in nature as diacyl glyceryl ether lipids and phosphoether lipids. The chief objective of this article is to provide a comprehensive and up to date review on such ether lipids. The occurrence and distribution of these compounds in nature are extensively reviewed, their chemical structure and molecular variety, their biosynthesis and chemical synthesis and, finally, their various biological effects are described and discussed. An unprecedented biosynthesis of the 2'-methoxylated alkylglycerols is proposed. The first synthesis of enantiopure (Z)-(2'R)-1-O-(2'-methoxyhexadec-4'-enyl)-sn-glycerol, the most prevalent 2'-methoxylated type alkylglycerol present in cartilaginous fish, is described. It was accomplished by a highly convergent five step process.

Variation in lipid classes and fatty acid composition of salmon shark (Lamna ditropis) liver with season and gender

The influence of season and gender on lipid content, lipid classes, and fatty acid compositions was assessed in livers of salmon shark (Lamna ditropis), caught in the Pacific Ocean. No significant difference in the hepatosomatic index was noted with season, though the lipid content was significantly higher (P<0.05) in winter. Triacylglycerol (TAG) was identified as the predominant lipid class (78.5-82.0%), followed by sterol esters (5.7-9.1%) and hydrocarbons (3.4-5.4%). No significant differences were observed in TAG composition with respect to the season or gender. However, diacylglyceryl ether contents were significantly higher (P<0.05) in winter (3.8-5.3%) than those obtained in summer (1.3-1.1%). Polyunsaturated fatty acids constituted the major fatty acid class of salmon shark total liver lipid and docosahexaenoic acid (C22:6n-3) (22.7-28.4%) was the most abundant fatty acid which was significantly lower (P<0.05) in winter. These results suggested that lipid characteristics of salmon shark liver were influenced by season, but not by gender.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of cod liver oil and the effect of analyte/matrix concentration on signal intensities

Cod liver oil (CLO) is known to contain a complex mixture of triacylglycerols (TAGs) in which the component fatty acids include: myristic (C(14:0), M), C(14:1) (M(1)), palmitic (C(16:0), P), palmitoleic (C(16:1), P(1)), stearic (C(18:0), S), oleic (C(18:1), O), linoleic (C(18:2), L), arachidic (C(20:0), A), C(20:1) (A(1)), eicosapentaenoic (EPA, C(20:5), A(5)), docosanoic (C(22:0), D), docosaenoic (C(22:1), D(1)), and docosahexaenoic (DHA, C(22:6), D(6)). Because of the presence of EPA and DHA in cod liver oil, it has been used for several generations as a nutritional supplement, and recommended for the relief of various physiological ailments including arthritis, depression, and high blood pressure. Consequently, it was of interest to develop a sample preparation protocol that would enable rapid screening of such a chemically complex and nutritionally useful oil. Thus, we have analyzed two commercial brands of cod liver oil by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). There was no significant difference between the mass spectral profile of the two CLO brands. alpha-Cyano-4-hydroxycinnamic acid, dissolved in acetonitrile/tetrahydrofuran, was used as the matrix. MALDI-TOFMS produced only sodiated triacylyglycerol molecules [M + Na](+). Based on the sodiated TAGs, 64 TAG assignments were made, and these include MM(1)L, MML, MMO and MMS, M(1)P(1)L MP(1)L, P(1)P(1)P, PPP, P(1)P(1)Ln, P(1)PLn, PPL, PPO, P(1)LnLn, PLnLN, PLLn, PLL, POL, POO, P(1)A(6)Ln, P(1)A(5)Ln, P(1)A(5)L, PA(5)L PA(5)O, PP(1)D(6), OOL, OOO, SOO, SSS, P(1)LnD(6), PLnD(6), PLD(6), POD(6) (or P(1)A(5)A(1)), PA(5)A(1), OLA, OLA(1), SLA(1), SOA(1), SSA, LA(5)A(5) (or P(1)A(5)D(6)), OA(5)A(5) (or PA(5)D(6)), SA(5)A(5), LnA(1)A(5), OOD(6), SOD(6), SSD(6), LA(1)D(6), OA(1)D(6), OA(5)D(6), SA(5)D(6), SA(5)D(5), D(6)A(1)O, D(6)A(1)S, D(1)A(1)O, DA(1)O, D(1)D(6)O, and DD(6)O. The sample preparation method developed in this study could be used for the routine screening of oils that contain similar types of polyunsaturated TAGs.