Tocopheronolactoneの生理活性について(第1報)

抄録

Mechanism of antioxidation of tocopheronolactone, isolated as the quinonoid metabolic product of α-tocopherol, was examined. Tocopheronolactone was as effective as α-tocopherol in inhibiting the increase of TBA value during the in vitro incubation of α-tocopherol-deficient mouse liver homogenate, but the production of peroxide from unsaturated fatty acids irradiated with ultraviolet ray was not depressed by the sole addition of tocopheronolactone. Reduced tocopheronolactone depressed TBA value during the irradiation of unsaturated fatty acid with ultraviolet ray and reacted with the stable free radical α, α-diphenyl-β-picrylhydrazyl, but tocopheronolactone was not active. Reduced tocopheronolactone was oxidized to tocopheronolactone by free radical products of heme-catalyzed decomposition of cumene hydroperoxide. Tocopheronloactone in cytoplasm was reduced in 9000×g supernatant fraction but not in mitochondria, so that mitochondrial peroxidation was not inhibited by tocopheronolactone itself. Antioxidativeeffect of tocopheronolactone seems to appear after the biochemical reduction of the tocopheronolactone in vivo, followed by the reaction with free radicals and peroxides.