title: Does the reduced form of neopterin serve as an antioxidant?
abstract: The oxygen free radical scavenging activity of the reduced form of neopterin, 5,6,7,8-tetrahydroneopterin (NPH-4), was investigated in vitro using electron paramagnetic resonance spectroscopy. In the hypoxanthine-xanthine oxidase (HPX-XOD) reaction system, NPH-4 suppressed the production of the superoxide spin adduct, but enhanced that of the hydroxyl radical spin adduct. The hydroxyl radical spin adduct was also observed in the solution containing NPH-4 and XOD but excluding HPX. These results indicate that NPH-4 is readily oxidized to some intermediates before the reaction with oxygen free radicals and that the substance which actually serves as an antioxidant in vivo is not NPH-4 but its metabolites.
authors.affiliation: Department of Anesthesia, Kyoto University Hospital, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Mori
authors.forename: T
authors.initials: T
authors.lastname: Arai
authors.forename: K
authors.initials: K
authors.lastname: Mori
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Makino
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D001708:Biopterins / Q000031:analogs & derivatives* / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000378:metabolism; D019798:Neopterin; D010084:Oxidation-Reduction; D013481:Superoxides / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D013481:Superoxides; D001708:Biopterins; C023455:tetrahydroneopterin; D019798:Neopterin; D014969:Xanthine Oxidase