Neutral glycerolipids

Monoacylglycerols and diacylglycerols. The early GC/MS methods of analysis of MGs and DGs utilized TMS ethers, which were unstable and could 

Triacylglycerols. The effectiveness of GC/EI/MS for the structural characterization of natural TG was demonstrated by using TG separated by GLC on packed and open tubular columns (Nakeham and Frew, 1982). The GC/ EI/MS combination provided a great deal of compositional information with a quadrupole MS, even without the production of molecular ions. 

Spanos et al. (1995) employed direct probe desorption chemical ionization to examine the bovine milk fat TG fractions collected by reversed-phase HPLC. MS/MS analyses were obtained by CID of selected [M -h 1] ions followed by linked scanning at constant magnetic field strength/electrostatic analyser voltage BIE), where the magnetic field B) was scanned at a constant ratio to the electrostatic analyser voltage .) Helium was used as the CID gas. 

Duffin, Henion and Shieh (1991) introduced an ES/MS/MS method for MGs, DGs and TGs based on the analysis of the [M -h NH4] ions produced in an ion spray (pneumatically-assisted ES) source. Samples were dissolved in a solution of chloroform/methanol, 70 30 vol./vol., which was modified by 

Byrdwell and Emken (1995) and Neff and Byrdwell (1995) have described the application of atmospheric pressure chemical ionization (APCI)/MS to the qualitative analysis of simple homogeneous (mono-acid) TGs and genetically modified soybean oils separated by reversed-phase HPLC. The mass spectra obtained were relatively simple and consisted primarily of DG ions, [M — RCOO] or [DG] , and protonated molecular ions, [M + 1]. The degree of unsaturation was the primary factor in determining the amount of DG ions compared with TG ions formed. DG fragments were the base peaks in spectra of TGs containing less than three or four sites of unsaturation. Mass spectra of TGs with three or four sites of unsaturation contained 

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Finally, to underscore further redundancy as a hallmark of 2-AG inactivation pathways, strong evidence also exists for the direct esterification of this compound into neutral glycerolipids and phospholipids (Di Marzo et al. 1999a). The relevance of these pathways, which were already known when 2-AG was considered a mere intermediate in glyc-erol(phospho)lipid metabolism, to the regulation of the cannabinergic signal still need to be assessed. 

Kuksis, A. 1994. GLC and HPLC of neutral glycerolipids, in Lipid Chromatographic Analysis, Shibamoto, T., Ed., Marcel Decker, New York, Chapter 5. 

The term lipids in this entry is restricted to esters and amides of the long-chain aliphatic monocarboxylic acids, the fatty acids, and to their biosynthetically or functionally related compounds. The most abundant lipids are the esters of fatty acids with glycerol (1,2,3-trihydroxypropane), denoted as glycerolipids. Lipids are classified according to the number of hydrolytic products per mole. Simple (or neutral) lipids release two types of products (e.g., fatty acids and glycerol). 

Recently Liu and Weller [84] have reviewed the arachidonic acid metabolism in filarial parasites and other helminths. Arachidonic acid (AA) is a 20 carbon polyunsaturated fatty acid derived from dietary fatty acids. In human tissues, AA is usually present in the esterified form such as glycerolipids, phospholipids and neutral lipids. The free AA, released by phospholipases, undergoes various enzymatic oxygenations to form local mediators such as prostaglandins and leukotrienes, which are collectively known as eicosanoids (Chart 9). These eicosanoids are associated with platelet aggregation, vasodilation, leukocyte inflammatory and immune functions and cellular adhesion [85]. 

Cell suspension cultures of cacao (Th. cacao) readily incorporated [l- C]acetate into both neutral and ionic glycerolipids [57]. After 24 h of incubation, around 18% and 45% of labeled acetate were incorporated into triacylglycerols and polar lipids, respectively. The incorporation of radioactive... 

Glycerolipidic metabolism in olive tree is affected by the calcium chloride action. It exerces an inhibitory effect on the phospholipids biosynthesis enz3mies and particularly on CDP-choline and CDF-ethanolamine phosphotransferases (5,6). Phospholipids acylation reactions are widely dropped in favour of neutral lipids at increasing CaCl2 levels (6). 

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