title: The rapid oxidative degradation of a phosphatidylcholine bearing an oxidatively modified acyl chain with a 2,4-dienal terminal.
abstract: Phosphatidylcholines (PCs) having an acyl chain with a 2,4-dienal terminal are expected to be important bioactive compounds formed during lipid peroxidation in vivo. However, they have not been isolated from biological tissues. Here we used electrospray mass spectroscopy to investigate whether a high autoxidative instability may contribute to the difficulty in detecting one such compound, 13-oxo-9,11-tridecadienoyl PC (OTDA-PC, 1). Although we found that pure, synthetic OTDA-PC was very stable, OTDA-PC formed during the decomposition of a PC bearing the 13-hydroperoxide of alpha-linolenic acid (PC-LNA-OOH, 2) was readily converted (i) anaerobically to its corresponding acid PC, 13-carboxy-9,11-tridecadienoyl PC, 3; (ii) aerobically to other bioactive aldehyde (or acid) PC species that have been detected in atherosclerotic tissues. We attribute the high oxidative instability of OTDA-PC to a high vulnerability of its carbonyl hydrogen [H-C(=O)R] to abstraction by lipid-derived radicals, and propose mechanisms for its conversion to the other oxidised PC species (vide supra).
authors.affiliation: Department of Bioresources Chemistry, Faculty of Agriculture, Okayama University, Tsushimanaka, Okayama 700-8530, Japan.
authors.forename: Arnold N
authors.initials: AN
authors.lastname: Onyango
authors.forename: Shuhei
authors.initials: S
authors.lastname: Nakajima
authors.forename: Takao
authors.initials: T
authors.lastname: Kaneko
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Matsuo
authors.forename: Naomichi
authors.initials: N
authors.lastname: Baba
mesh_terms: D000332:Aerobiosis; D000447:Aldehydes / Q000737:chemistry; D000466:Alkadienes / Q000737:chemistry*; D000693:Anaerobiosis; D005231:Fatty Acids, Unsaturated / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D015227:Lipid Peroxidation; D008081:Liposomes / Q000737:chemistry*; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010713:Phosphatidylcholines / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D017962:alpha-Linolenic Acid / Q000737:chemistry
chemical_list: D000447:Aldehydes; D000466:Alkadienes; D005231:Fatty Acids, Unsaturated; D005609:Free Radicals; D008081:Liposomes; D010713:Phosphatidylcholines; D017962:alpha-Linolenic Acid