title: Antioxidant capacity of foods for scavenging reactive oxidants and inhibition of plasma lipid oxidation induced by multiple oxidants.
abstract: Unregulated oxidation of biological molecules induced by multiple oxidants has been implicated in the pathogenesis of various diseases. Consequently, the effects of antioxidants contained in foods, beverages and supplements on the maintenance of health and prevention of diseases have attracted much attention of the public as well as scientists. However, recent human studies have shown inconsistent results and failed to demonstrate the beneficial effects of antioxidants. The mechanisms and dynamics of antioxidant action and assessment of antioxidant capacity have been the subject of extensive studies and arguments. In the present article, the antioxidant capacity has been reviewed focusing on two main issues: the capacity of antioxidants to scavenge multiple reactive oxidants and to inhibit plasma lipid oxidation induced by different biological oxidants. It is emphasized that the capacity of antioxidants to scavenge reactive oxidants does not always correlate linearly with the capacity to inhibit lipid oxidation and that it is necessary to specify the oxidant to assess the efficacy of antioxidants, since multiple oxidants contribute to oxidative damage in vivo and the effects of antioxidants depend on the nature of oxidants. A convenient and rapid method using a microplate reader is discussed for assessing the antioxidant capacity against plasma lipid oxidation induced by multiple oxidants including peroxyl radicals, peroxynitrite, hypochlorite, 15-lipoxygenase, and singlet oxygen.
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
authors.forename: Etsuo
authors.initials: E
authors.lastname: Niki
mesh_terms: D000975:Antioxidants / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D001093:Arachidonate 15-Lipoxygenase / Q000378:metabolism; D001628:Beverages; D019587:Dietary Supplements; D005502:Food; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005609:Free Radicals; D006801:Humans; D007700:Kinetics; D050356:Lipid Metabolism / Q000187:drug effects; D015227:Lipid Peroxidation / Q000187:drug effects; D008055:Lipids / Q000097:blood*; D008670:Metals / Q000737:chemistry; D016877:Oxidants / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects*; D010545:Peroxides / Q000378:metabolism; D030421:Peroxynitrous Acid / Q000378:metabolism; D026082:Singlet Oxygen / Q000378:metabolism
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D005609:Free Radicals; D008055:Lipids; D008670:Metals; D016877:Oxidants; D010545:Peroxides; D030421:Peroxynitrous Acid; D026082:Singlet Oxygen; C049375:perhydroxyl radical; D001093:Arachidonate 15-Lipoxygenase