Stopped-Flow Investigation of Antioxidant Activity of Tocopherols

• Kazuo Mukai

  Department of Chemistry, Faculty of Science, Ehime University

• Yoshiko Watanabe

  Department of Chemistry, Faculty of Science, Ehime University

• Yuichi Uemoto

  Department of Chemistry, Faculty of Science, Ehime University

• Kazuhiko Ishizu

  Department of Chemistry, Faculty of Science, Ehime University

抄録

It was observed by ESR measurement that the oxidation of α-, β-, γ-, and δ-tocopherols (vitamin E) with a stable phenoxyl radical in benzene immediately gives corresponding tocopheroxyl radicals. The rates of reaction of α-, β-, γ-, and δ-tocopherols with the stable phenoxyl radical in ethanol solution have been determined spectrophotometrically using stopped-flow technique, as a model reaction of tocopherols with unstable free radicals (ROO·, RO·, and HO·) in biological systems. The second-order rate constants obtained are (5.12±0.36)×103 (α-Toc), (2.24±0.04)×103 (β-Toc), (2.42±0.16)×103 (γ-Toc), and (0.51±0.01)×103 (δ-Toc), M−1 s−1 in ethanol at 25.0 °C. The relative rates agree well with those obtained from studies of the reactivities of tocopherols toward poly(styrylperoxyl) and galvinoxyl radicals by O2 consumption and by ESR method, respectively. The results suggest that the relative reactivities, that is, relative antioxidant activities of tocopherols do not depend on the kinds of unstable free radicals reacted.

収録刊行物

• Bulletin of the Chemical Society of Japan

  Bulletin of the Chemical Society of Japan 59 (10), 3113-3116, 1986-10-01

  Oxford University Press (OUP)

キーワード

• General Chemistry

詳細情報

• CRID: 1360846644032756480
• NII論文ID: 130001983214
• DOI: 10.1246/bcsj.59.3113
• ISSN: 13480634
• ISSN: 00092673
• Web Site: https://academic.oup.com/bcsj/article-pdf/59/10/3113/55722014/bcsj.59.3113.pdf
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