title: LC/ESR/MS study of spin trapped carbon-centred radicals formed from in vitro lipoxygenase-catalysed peroxidation of gamma-linolenic acid.
abstract: Gamma-linolenic acid (GLA) has been reported as a potential anti-cancer and anti-inflammatory agent and has received substantial attention in cancer care research. One of the many proposed mechanisms for GLA biological activity is free radical-mediated lipid peroxidation. However, no direct evidence has been obtained for the formation of GLA-derived radicals. In this study, a combination of LC/ESR and LC/MS was used with alpha-[4-pyridyl-1-oxide]-N-tert-butyl nitrone (POBN) to profile the carbon-centred radicals that are generated in lipoxygenase-catalysed GLA peroxidation. A total of four classes of GLA-derived radicals were characterized including GLA-alkyl, epoxyallylic, dihydroxyallylic radicals and a variety of carbon-centred radicals stemming from the beta-scissions of GLA-alkoxyl radicals. By means of an internal standard in LC/MS, one also quantified each radical adduct in all its redox forms, including an ESR-active form and two ESR-silent forms. The results provided a good starting point for ongoing research in defining the possible biological effects of radicals generated from GLA peroxidation.
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, Nursing, and Allied Sciences, North Dakota State University, Fargo, ND 58105, USA.
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Yu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Shan
authors.forename: Kunyi
authors.initials: K
authors.lastname: Ni
authors.forename: Steven Y
authors.initials: SY
authors.lastname: Qian
mesh_terms: D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002853:Chromatography, Liquid / Q000379:methods; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D005609:Free Radicals; D006801:Humans; D015227:Lipid Peroxidation; D008084:Lipoxygenase / Q000378:metabolism*; D013058:Mass Spectrometry / Q000379:methods; D008956:Models, Chemical; D010084:Oxidation-Reduction; D013113:Spin Labels; D019097:Spin Trapping; D017965:gamma-Linolenic Acid / Q000378:metabolism*
chemical_list: D005609:Free Radicals; D013113:Spin Labels; D002244:Carbon; D017965:gamma-Linolenic Acid; D008084:Lipoxygenase