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.
