Evidence for the Formation of F₃-Isoprostanes during Peroxidation of Eicosapentaenoic Acid

Author： Nourooz-Zadeh J. Halliwell B. änggård E.E.

Publisher： Elsevier

ISSN： 0006-291X

Source： Biochemical and Biophysical Research Communications, Vol.236, Iss.2, 1997-07, pp. : 467-472

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

8-Epi PGF_2, a potent vasocontrictor, is a specific product of non-enzymatic peroxidation of arachidonic acid. It seems likely that similar products could arise from other polyunsaturated fatty acids (PUFAs) and might be useful biomarkers of their peroxidationin vivo.This was investigated using eicosapentaenoic acid (EPA). EPA liposomes (1 mg/ ml PBS) were exposed at 37 °C to either 2,2′-azobis-(2-amidinopropane) dichloride (AAPH) or copper ions at final concentrations of 1 mM and 10 μM, respectively. Sample processing involved solid-phase extraction on a C₁₈- followed by an NH₂cartridge. After conversion to pentafluorobenzyl ester/trimethylsilyl derivatives, F₃-isoprostanes were analysed by negative ion-chemical ionisation mass spectrometry (GC-MS/NICI) using tetradeuterated PGF_2(PGF₂-d₄) as the internal standard. Quantitative analysis was carried out by selected ion monitoring of the carboxylated anion [M-180]^-at m/z 567 and 573 for the PGF₃-like compounds and PGF₂-d₄, respectively. EPA oxidised by AAPH or by copper ions gave rise to a family of F₃-isoprostanes with 8-epi PGF_3as a minor product. Formation of F₃-isoprostanes correlated well with other indices of lipid peroxidation (hydroperoxides and thiobarbituric acid reactive substances). The possibility of analysing specific lipid peroxidation products from individual fatty acids should facilitate nutritional and biomedical studies.