title: Superoxide anion scavenging capacity measured by a polarographic method. Comparison with a colourimetric method.
abstract: A polarographic method to assess the scavenging capacity of a molecule for O2-. is proposed. This method is based on the fact that O2-. is not detected by the Clark electrode and that a scavenger competes with spontaneous dismutation of O2-. So, the reduction of O2 into O2-. and the decomposition of H2O2 by catalase, releasing O2, show a biphasic kinetic. Various kinetic parameters can be used to calculate the nmol of O2-. scavenged and also supply data on the reaction mechanisms (oxidation or reduction of O2-.) involved in scavenging. This method presents several other advantages: scavenging capacity can be assayed without added indicators which themselves behave as scavengers (as demonstrated for NBT), the presence of scavengers which interfere with the O2-. generating system (xanthine-xanthine oxidase) does not invalidate the measurements made.
authors.affiliation: Institut de Physiologie, Toulouse, France.
authors.forename: N
authors.initials: N
authors.lastname: Darmon
authors.forename: Y
authors.initials: Y
authors.lastname: Fernandez
authors.forename: A
authors.initials: A
authors.lastname: Periquet
authors.forename: S
authors.initials: S
authors.lastname: Mitjavila
mesh_terms: D000838:Anions / Q000494:pharmacology; D003124:Colorimetry; D003574:Cytochrome c Group / Q000737:chemistry; D016166:Free Radical Scavengers; D006861:Hydrogen Peroxide / Q000737:chemistry; D007700:Kinetics; D009580:Nitroblue Tetrazolium; D010084:Oxidation-Reduction; D011048:Polarography; D015203:Reproducibility of Results; D013481:Superoxides / Q000494:pharmacology*; D019820:Xanthine; D014969:Xanthine Oxidase; D014970:Xanthines
chemical_list: D000838:Anions; D003574:Cytochrome c Group; D016166:Free Radical Scavengers; D014970:Xanthines; D013481:Superoxides; D019820:Xanthine; D009580:Nitroblue Tetrazolium; D006861:Hydrogen Peroxide; D014969:Xanthine Oxidase