Kinetic Study of the α-Tocopherol-Regeneration Reaction of Ubiquinol-10 : Notable Effect of the Alkali and Alkaline Earth Metal Salts on the Reaction Rates

• Ouchi Aya

  Department of Chemistry, Faculty of Science, Ehime University

• Oi Masanori

  Department of Chemistry, Faculty of Science, Ehime University

• Nagaoka Shin-ichi

  Department of Chemistry, Faculty of Science, Ehime University

• Mukai Kazuo

  Department of Chemistry, Faculty of Science, Ehime University

Bibliographic Information

Other Title

• ユビキノールによるビタミンEの再生反応に及ぼす金属塩の効果とメカニズム
• ユビキノール ニ ヨル ビタミン E ノ サイセイ ハンノウ ニ オヨボス キンゾクエン ノ コウカ ト メカニズム

Abstract

A kinetic study of regeneration reaction of α-tocopherol (α-TocH) by ubiquinol-10 has been performed in the presence of alkali and alkaline earth metal salts in methanol and acetonitrile solutions. Notable effects of metal cations on the UV-Vis absorption spectrum of α-tocopheroxyl (α-Toc・) radical were observed in aprotic acetonitrile solution, suggesting a complex formation between α-Toc・ and metal cations. On the other hand, effects of metal cations were negligible in protic methanol, suggesting that the complex formation between α-Toc・ and metal cations is hindered by the hydrogen bond between α-Toc・ and methanol molecules. The second-order rate constants (k_r) for the reaction of α-Toc・ with ubiquinol-10 increased and decreased notably with increasing concentrations of metal salts in methanol and acetonitrile, respectively. The difference in the reaction mechanism in methanol and acetonitrile was discussed based on the results obtained. High concentrations of alkali and alkaline earth metal salts coexist with α-TocH and ubiquinol-10 in plasma, blood and many tissues, suggesting the contribution of the metal salts to the above regeneration reaction in biological systems.

Journal

• VITAMINS

  VITAMINS 86 (5-6), 293-302, 2012

  THE VITAMIN SOCIETY OF JAPAN

Keywords

• Vitamin E
• ubiquinol
• regeneration reaction
• reaction mechanism
• antioxidant activity

Details

• CRID: 1390282680677114752
• NII Article ID: 110009471131
• NII Article ID: 10031086226
• NII Book ID: AN00207833
• DOI: 10.20632/vso.86.5-6_293
• ISSN: 2424080X
• ISSN: 0006386X
• NDL BIB ID: 023854122
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I023854122
• Web Site: https://search.jamas.or.jp/link/ui/2012342108
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed