Simultaneous Determination of α-, γ-Tocopherol and Their Quinones in Rats Plasma and Tissues Using Reversed-phase High-performance Liquid Chromatography

抄録

We established a method to determine simultaneously α-and γ-tocopherol (-Toc) and their quinones (α-TQ and p-γ-TQ) in biological samples by reverse-phase high-performance liquid chromatography (HPLC). Tocs had a shorter retention time than TOs, and α-forms had a shorter retention times than γ-forms. Four peaks of Tocs and TQs were completely separated by this method. Subsequently, we investigated the distribution of α-, γ-Toc and To in rat tissues and the excretion of Tocs and Tos in rat bile by the above HPLC method. Rats deficient in vitamin E were divided into two groups, γ-Toc group and α+ γ-Toc group, and tissues were collected at 6 and 24 h after intravenous administration of Tocs. Also, bile collection was started immediately and performed at 3 h intervals during 24 h after intravenous administration. The concentration of α-and γ-Toc and their quinones in plasma, tissues and bile were determined by this method. γ-Toc concentration in the liver of α+ γ-Toc group was higher than that of γ-Toc group. However, p-γ-TQ in the liver was not significantly different between α+γ-Toc group and γ-Toc group. Also, both α-TO and p-γ-TQ were present in very low concentrations in all tissues. Therefore, we suggested that the distribution of γ-Toc is affected by a-Toc present in vivo, but the oxidative production of p-γ-TQ from γ-Toc is not affected.