title: Effect of α-tocopherol on the hemin-catalyzed decomposition of 1-palmitoyl-2-linoleoyl-3-sn-phosphatidylcholine 13-hydroperoxide in micelles and liposomes.
abstract: The secondary process of lipid peroxidation produces some toxic aldehydes. Since this process takes place via free radical reaction in lipophilic circumstances, α-tocopherol would suppress the formation of such aldehydes by trapping free-radical intermediates. This study reports the effect of α-tocopherol on the hemin-catalyzed decomposition of 1-palmitoyl-2-linoleoyl-3-sn-phosphatidylcholine 13-hydroperoxide (PLPC-OOH) in micelles and liposomes. PLPC-OOH and α-tocopherol were reacted with hemin in micelles, and the reaction products were characterized to be 1-palmitoyl-2-(α-tocopheroxy-12,13-epoxyoctadecenoyl)-3-sn-phosphatidylcholines (T-epoxyPLPC) and known compounds, 1-palmitoyl-2-[(8a-dioxy-α-tocopherone)-12,13-epoxyoctadecenoyl]-3-sn-phosphatidylcholines (TOO-epoxyPLPC) and α-tocopherol dimer. The hemin-catalyzed decomposition of PLPC-OOH in micelles produced hexanal as one of secondary aldehydic products. α-Tocopherol suppressed the formation of hexanal, and α-tocopherylquinone, α-tocopherol dimer, TOO-epoxyPLPC, and T-epoxyPLPC were detected during the reaction. In liposomes, α-tocopherol could partially suppress the formation of hexanal, and the main products were TOO-epoxyPLPC and α-tocopherol dimer. The results indicate that α-tocopherol may suppress the formation of hexanal by trapping the epoxyperoxyl and epoxyalkyl radicals derived from PLPC-OOH.
authors.affiliation: Department of Applied Life Science, Graduate School of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan. Electronic address: yamautir@gifu-u.ac.jp.
authors.forename: Ryo
authors.initials: R
authors.lastname: Yamauchi
authors.affiliation: Department of Applied Life Science, Graduate School of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan.
authors.forename: Siori
authors.initials: S
authors.lastname: Watanabe
authors.affiliation: Department of Applied Life Science, Graduate School of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan. Electronic address: anittasm@gmail.com.
authors.forename: Ana S
authors.initials: AS
authors.lastname: Martín
authors.affiliation: Department of Applied Life Science, Graduate School of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan. Electronic address: isatoshi@gifu-u.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Iwamoto
mesh_terms: D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D056148:Chromatography, Reverse-Phase; D006427:Hemin / Q000737:chemistry*; D008054:Lipid Peroxides / Q000032:analysis / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D010713:Phosphatidylcholines / Q000737:chemistry; D024502:alpha-Tocopherol / Q000737:chemistry*
chemical_list: D008054:Lipid Peroxides; D008081:Liposomes; D008823:Micelles; D010713:Phosphatidylcholines; C055402:1-palmitoyl-2-linoleoylphosphatidylcholine; D006427:Hemin; D024502:alpha-Tocopherol; C028694:1-palmitoyl-2-oleoylphosphatidylcholine
keywords: Free radical; Hemin; Hexanal; Lipid peroxidation; Phosphatidylcholine hydroperoxide; α-Tocopherol