Detection of Radical Species in Mixtures of Some Retinoids with Hematin by Using the ESR Spin-Trapping Technique

Abstract

Radical species were detected in mixtures of some retinoids with hematin by using the ESR spin-trapping technique. The rates of radical formation were approximately proportÌonal to the oxygen consumptÌon during the incubation of the retinoids with hematin. HPLC analyses of the incubation mixtures of the retinoids with hematin showed that 5, 6-epoxides of the retinoids were formed. The amounts of the epoxides formed were proportional to both oxygen consumption and the amounts of radicals formed. These results suggest that the 5, 6-epoxidations proceed via radical intermediates.