title: Antioxidant properties and free radical-scavenging reactivity of a family of hydroxynaphthalenones and dihydroxyanthracenones.
abstract: This study was undertaken to investigate the free radical-scavenging and antioxidant activities of various structurally related hydroquinones including hydroxynaphthalenones and dihydroxyanthracenones. Electron spin resonance spectroscopy and spin trapping techniques were used to evaluate the ability of hydroquinones to scavenge hydroxyl, diphenylpicrylhydrazyl, and galvinoxyl radicals. In addition, the oxygen radical absorbing capacity assay using fluorescein (ORAC-FL) was used to obtain the relative antioxidant capacity of these radicals. The rate constants of the first H atom abstraction by 2,2-diphenyl-2-picrylhydrazyl (k(2)), were obtained under pseudo-first-order conditions. The free radical-scavenging activities and k(2) values discriminate well between hydroxynaphthalenones and dihydroxyanthracenones, showing that the latter have better antioxidant properties. The aforementioned experimental data agree with quantum-chemical results demonstrating the relevance of intramolecular H bonding to radical-scavenging activities.
authors.affiliation: Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile.
authors.forename: Jorge
authors.initials: J
authors.lastname: Rodríguez
authors.forename: Claudio
authors.initials: C
authors.lastname: Olea-Azar
authors.forename: Cristina
authors.initials: C
authors.lastname: Cavieres
authors.forename: Ester
authors.initials: E
authors.lastname: Norambuena
authors.forename: Tomás
authors.initials: T
authors.lastname: Delgado-Castro
authors.forename: Jorge
authors.initials: J
authors.lastname: Soto-Delgado
authors.forename: Ramiro
authors.initials: R
authors.lastname: Araya-Maturana
mesh_terms: D000818:Animals; D000873:Anthracenes / Q000737:chemistry* / Q000494:pharmacology; D000975:Antioxidants / Q000737:chemistry* / Q000494:pharmacology; D045744:Cell Line, Tumor; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D016166:Free Radical Scavengers / Q000737:chemistry* / Q000494:pharmacology; D006860:Hydrogen Bonding; D007700:Kinetics; D051379:Mice; D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry* / Q000494:pharmacology; D010100:Oxygen / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000737:chemistry / Q000378:metabolism; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000873:Anthracenes; D000975:Antioxidants; D016166:Free Radical Scavengers; D009281:Naphthalenes; D017382:Reactive Oxygen Species; D010100:Oxygen