Oxidation of α-tocopherol in micelles and liposomes by the hydroxyl, perhydroxyl, and superoxide free radicals

Kenji Fukuzawa*, Janusz M. Gebicki

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

143 Citations (Scopus)

Abstract

Rates of oxidation of α-tocopherol by the hydroxyl- and superoxide free radicals were measured. The radicals were produced in known yields by radiolysis of aqueous solutions with gamma rays. Two main systems were used to dissolve the tocopherol; micelles, made up from charged and uncharged amphiphiles, and membranes made from dimyristyl phosphatidylcholine which could be charged by addition of stearyl amine or dicetyl phosphate. The HO. radicals were efficient oxidants of α-tocopherol in all systems, with up to 83% of radicals generated in micelle and 32% in membrane suspensions initiating the oxidation. The HO2 ̇ radical was an even more effective oxidant, but when most of it was in the O form at neutral or alkaline pH, the oxidation rates became low. Tocopherol held in positively charged micelles or membranes was oxidized at a higher rate by the O than in uncharged or negative particles. Possible biological significance of these results is discussed.

Original languageEnglish
Pages (from-to)242-251
Number of pages10
JournalArchives of Biochemistry and Biophysics
Volume226
Issue number1
DOIs
Publication statusPublished - 1 Oct 1983

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