alpha-Tocopherol Attenuates the Triglyceride- and Cholesterol-Lowering Effects of Rice Bran Tocotrienol in Rats Fed a Western Diet

作者：Shibata Akira; Kawakami Yuki; Kimura Toshiyuki; Miyazawa Teruo; Nakagawa Kiyotaka^*

来源：Journal of Agricultural and Food Chemistry, 2016, 64(26): 5361-5366.

DOI：10.1021/acs.jafc.6b02228

• cholesterol
• F344 rat
• tocopherol
• tocotrienol
• triglyceride

Previous studies demonstrated the ability of tocotrienol (T3) to lower levels of lipids, including cholesterol (Cho) and triglycerides (TG). Although a-tocopherol (alpha-Toc) reportedly inhibits the hypocholesterolemic effect of T3, there is no information about whether alpha-Toc influences the TG-lowering effect of T3 in vivo. In this study, we investigated the influence of alpha-Toc on the antihyperlipidemic effects (Cho- and TG-lowering) of rice bran tocotrienols (RBT3) in F344 rats fed a western diet. alpha-Toc attenuated both the Cho- and TG-lowering effects of RBT3 in vivo, whereas alpha-Toc alone exhibited no hypolipidemic effects. RBT3-induced Cpt-1a and Cyp7a1 gene expression was reduced by alpha-Toc. Furthermore, coadministration of alpha-Toc decreased liver and adipose tissue concentrations of tocotrienols in F344 rats. These results indicate that alpha-Toc has almost no antihyperlipidemic effect in vivo, but abrogates the antihyperlipidemic effect of RBT3 by reducing tissue concentrations of tocotrienols and regulating expression of genes involved in lipid metabolism. Understanding the underlying mechanism of the beneficial effects of T3 on lipid metabolism and the interaction with alpha-Toc will be important for developing T3-based therapeutics.

• 出版日期2016-7-6