title: Reactions of superoxide ion with tocopherol and its model compounds: correlation between the physiological activities of tocopherols and the concentration of chromanoxyl-type radicals.
abstract: Reactions of tocopherol model compounds with superoxide ion (02-) were investigated. 6-Hydroxy-2,2,5,7,8-pentamethylchroman (alpha-model), 6-hydroxy-2,2,5,7-tetramethylchroman and 6-hydroxy-2,2,5,8-tetramethylchroman (beta-model) were oxidized by O2- to yield chromanoxyl radicals which gave ESR spectra, but the radical species were not obtained from 6-hydroxy-2,2,7,8-tetramethylchroman (gamma-model) and 6-hydroxy-2,2-dimethylchroman, both of which do not have a methyl substituent at the C-5 position. ESR studies of the reactions of O2- with tocopherols or their model compounds indicate that the radical concentrations from tocopherol models correlate with the physiological activities of the tocopherols.
mesh_terms: D000838:Anions; D002839:Chromans; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D010084:Oxidation-Reduction; D013481:Superoxides; D014810:Vitamin E / Q000502:physiology*
chemical_list: D000838:Anions; D002839:Chromans; D005609:Free Radicals; D013481:Superoxides; D014810:Vitamin E; C042764:6-hydroxy-2,2,5,7-tetramethylchroman; C042765:6-hydroxy-2,2-dimethylchroman; C029141:2,2,5,7,8-pentamethyl-1-hydroxychroman