Gamma-tocopherol is less effective than alpha-tocopherol in preventing oxidant-induced sister chromatid exchanges in Chinese hamster V79 cells

K. A. O'Leary, J. A. Woods, N. M. O'Brien

    Research output: Contribution to journalArticle

    4 Citations (Scopus)

    Abstract

    Although alpha-tocopherol (alpha-TOC) is the most biologically active form of vitamin E and is found at high levels in plasma, gamma-tocopherol (gamma-TOC) has also been found to be a powerful antioxidant in vitro and constitutes up to 70% of the dietary intake of TOC. Low plasma levels of gamma-TOC and a high alpha-TOC:gamma-TOC ratio may be associated with coronary heart disease, suggesting that there may be a positive protective role for the gamma-form of TOC. In this study the ability of different forms of vitamin E to protect against sister chromatid exchanges (SCE) induced by either hydrogen peroxide or menadione was investigated. Chinese hamster V79 cells were pre-treated with 10 microM TOC for 24 h, and then challenged with a genotoxin. After a 24 h pre-treatment, there was a greater incorporation of gamma-TOC (319.8 +/- 66.2 ng/10(6) cells) into V79 cells compared to alpha-TOC (66.9 +/- 6.4 ng/10(6) cells). Gamma-TOC did not protect the cells against SCE induced by either hydrogen peroxide or menadione, alpha-TOC acetate was partially protective against both genotoxins, whereas alpha-TOC completely abolished the oxidant induced SCE. These results demonstrate that, despite a greater incorporation of gamma-TOC into V79 cells, alpha-TOC but not gamma-TOC was more effective at inhibiting oxidatively-induced SCE in V79 cells.
    Original languageEnglish
    Pages (from-to)917-924
    Number of pages8
    JournalFree Radical Research
    Volume35
    Issue number6
    DOIs
    Publication statusPublished - 2001

    Keywords

    • Sister chromatid exchange
    • Tocopherol
    • Menadione
    • Hydrogen peroxide

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