Oxidation of Sesamol Dimer by Active Species produced in the Interaction of Peroxide and Hemoglobin

Abstract

Sesamol dimer (I) was converted into the quinone (II) having an absorption maximum at 550 nm by treatment with hydrogen peroxide, linoleic acid hydroperoxide or tert-butyl hydroperoxide in the presence of hemoglobin. The order of the color-forming activity was linoleic acid hydroperoxide»hydrogen peroxide>tert-butyl hydroperoxide. Methemoglobin was much more effecive than oxyhemoglobin for coloration. Hydrogen peroxide and methemoglobin produced a complex which generated singlet oxygen and hydroxyl radical, the latter being effective for coloration of I. The reaction of linoleic acid hydroperoxide with methemoglobin produced a complex which generated peroxy free radical and then the keto acid and singlet oxygen ; the peroxy free radical was found to be the active species for oxidation of I. Sesamol dimer (I) may be useful for chromogenic assay of hydroxyl and peroxy free radicals.