Molecular species composition of glycerophospholipids from white matter of human brain.

The molecular species composition of the major glycerophospholipids from white matter of human brain were determined by high-performance liquid chromatography of the 3,5-dinitrobenzoyl derivatives of the corresponding diradylglycerols. In phosphatidylcholine (PC) and phosphatidylserine (PS), molecular species containing only saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) comprised 85.7 and 82.4% of the respective totals, with 18:0/18:1 predominant in PS and 16:0/18:1 in PC. These molecular species were also abundant in phosphatidylethanolamine (PE), but in this phospholipid species containing polyunsaturated fatty acids (PUFA), largely 18:0/22:6n-3 and 18:0/20:4n-6, accounted for over half the total; 18:1/18:1 was also abundant in PE. In contrast, 1-O-alk-1'-enyl-2-acyl sn-glycero-3-phosphoethanolamine (GPE) had much more SFA- and MUFA-containing species, predominantly 16:0a/18:1, 18:0a/18:1 and 18:1a/18:1, with low amounts of species containing 20:4n-6 and 22:6n-3. In alkenylacyl GPE, 22:4n-6 was the major PUFA and 16:0a/22:4n-6 and 18:1a/22:4n-6 the main PUFA-containing species. There was six times more 22:6n-3, twice as much 20:4n-6 and half the amount of 22:4n-6 in PE as compared to alkenylacyl GPE.