α-tocopherol attenuates the triglyceride- and cholesterol-lowering effects of rice bran tocotrienol in rats fed a western diet

Akira Shibata, Yuki Kawakami, Toshiyuki Kimura, Teruo Miyazawa, Kiyotaka Nakagawa

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

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

Original languageEnglish
Pages (from-to)5361-5366
Number of pages6
JournalJournal of Agricultural and Food Chemistry
Volume64
Issue number26
DOIs
Publication statusPublished - 2016 Jul 6

Keywords

  • F344 rat
  • cholesterol
  • tocopherol
  • tocotrienol
  • triglyceride

ASJC Scopus subject areas

  • Chemistry(all)
  • Agricultural and Biological Sciences(all)

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