ビタミンEの抗酸化反応の機構

概要

論文の詳細を見る
A kinetic and ab initio study of the antioxidant effect of vitamin E derivatives (tocopherols) has been carried out. The second-order rate constants, k_s, for the reaction of tocopherols with a substituted phenoxyl radical in ethanol were measured with a stopped-flow spectrophotometer. k_s increases as the total electron-donating capacity of the alkyl substituents on the aromatic ring of tocopherol increases. A substantial deuterium kinetic isotope effect on k_s is observed. The first ionization energies (I. P. ) of tocopherols were calculated with the ab initio method. A plot of log k_s vs. I. P. is found to be linear. From these results, it is considered that both of the charge transfer and the proton tunneling play important roles in the antioxidant reaction of tocopherol. The transition state in this reaction has the property of the charge-transfer intermediate. The proton tunneling takes place below the transition state.
日本ビタミン学会の論文
1991-09-25