title: Rapid assessment of singlet oxygen-induced plasma lipid oxidation and its inhibition by antioxidants with diphenyl-1-pyrenylphosphine (DPPP).
abstract: Recent studies suggesting the involvement of singlet oxygen in the pathogenesis of multiple diseases have attracted renewed attention to lipid oxidation mediated by singlet oxygen. Although the rate constants for singlet oxygen quenching by antioxidants have been measured extensively, the inhibition of lipid oxidation mediated by singlet oxygen has received relatively less attention, partly because a convenient method for measuring the rate of lipid oxidation is not available. The objective of this study was to develop a convenient method to measure plasma lipid oxidation mediated by singlet oxygen which may be applied to a rapid assessment of the antioxidant capacity to inhibit this oxidation using a conventional microplate reader. Singlet oxygen was produced from naphthalene endoperoxide, and lipid hydroperoxide production was followed by using diphenyl-1-pyrenylphosphine (DPPP). Non-fluorescent DPPP reacts stoichiometrically with lipid hydroperoxides to give highly fluorescent DPPP oxide. It was found that plasma oxidation by singlet oxygen increased the fluorescence intensity of DPPP oxide, which was suppressed by antioxidants. Fucoxanthin suppressed the oxidation more efficiently than β-carotene and α-tocopherol, while ascorbic acid and Trolox were not effective. The present method may be useful for monitoring lipid oxidation and also for rapid screening of the capacity of dietary antioxidants and natural products to inhibit lipid oxidation in a biologically relevant system.
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan.|Department of Gastrointestinal Immunology, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan.
authors.forename: Mayuko
authors.initials: M
authors.lastname: Morita
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Naito
authors.affiliation: Department of Gastrointestinal Immunology, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Yoshikawa
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan. etsuo-niki@aist.go.jp.|Health Research Institute, National Institute of Advanced Industrial Science and Technology, Takamatsu, 761-0395, Japan. etsuo-niki@aist.go.jp.
authors.forename: Etsuo
authors.initials: E
authors.lastname: Niki
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism*; D008055:Lipids / Q000097:blood* / Q000737:chemistry; D008297:Male; D008810:Mice, Inbred C57BL; D009943:Organophosphorus Compounds / Q000097:blood / Q000737:chemistry*; D010084:Oxidation-Reduction; D011721:Pyrenes / Q000097:blood / Q000737:chemistry*; D026082:Singlet Oxygen / Q000097:blood* / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D000975:Antioxidants; D008055:Lipids; D009943:Organophosphorus Compounds; D011721:Pyrenes; C066322:diphenyl-1-pyrenylphosphine; D026082:Singlet Oxygen
keywords: Antioxidant; Carotenoid; Diphenyl-1-pyrenylphosphine; Plasma lipid oxidation; Singlet oxygen