title: Antioxidant activity of ubiquinol in solution and phosphatidylcholine liposome.
abstract: The antioxidant activities of ubiquinol and ubiquinone were measured in the free radical-mediated oxidations of methyl linoleate in solution and phosphatidylcholine liposomes in aqueous dispersion. Ubiquinol-10 suppressed the oxidation of methyl linoleate in hexane, although its reactivity toward peroxyl radical was about 10 times less than that of alpha-tocopherol. Ubiquinone-10, on the contrary, did not show any antioxidant activity. On the other hand, ubiquinol-10 inhibited the oxidation of phosphatidylcholine liposomal membranes as efficiently as alpha-tocopherol. When both ubiquinol-10 and alpha-tocopherol were present, ubiquinol-10 decreased first and alpha-tocopherol decreased after all ubiquinol-10 was consumed in both solution and liposomes. These results and electron spin resonance (ESR) study suggest that ubiquinol-10 regenerates alpha-tocopherol by reducing alpha-tocopheroxyl radical.
authors.affiliation: Department of Reaction Chemistry, Faculty of Engineering, University of Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: E
authors.initials: E
authors.lastname: Komuro
authors.forename: E
authors.initials: E
authors.lastname: Niki
mesh_terms: D000818:Animals; D000975:Antioxidants; D005609:Free Radicals; D008041:Linoleic Acids / Q000378:metabolism; D015227:Lipid Peroxidation; D008081:Liposomes / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism*; D012996:Solutions; D014451:Ubiquinone / Q000378:metabolism* / Q000031:analogs & derivatives; D014810:Vitamin E / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D008041:Linoleic Acids; D008081:Liposomes; D010713:Phosphatidylcholines; D012996:Solutions; D014451:Ubiquinone; D014810:Vitamin E; C005575:methyl linoleate; C026663:ubiquinol-10