Epigallocatechin gallate markedly enhances formation of 8-oxo-7,8-dihydro-2′-deoxyguanosine in the reaction of 2′-deoxyguanosine with hypochlorous acid

Toshinori Suzuki, Toshiki Nakano, Mitsuharu Masuda, Hiroshi Ohshima

    Research output: Contribution to journalArticlepeer-review

    13 Citations (Scopus)

    Abstract

    A tea polyphenol, (-)-epigallocatechin gallate (EGCG), which can scavenge a variety of reactive oxygen species, enhances the yield of 8-oxo-7,8-dihydro- 2′-deoxyguanosine (8-oxo-dG) up to 20-fold in the reaction of 2′-deoxyguanosine with hypochlorous acid (HOCl), compared with the reaction without EGCG. Certain concentrations of EGCG inhibited HOCl-mediated oxidation of 2′-deoxyguanosine to 8-oxo-dG to a limited extent, but efficiently inhibited further oxidation of 8-oxo-dG to spiroiminodihydantoin nucleoside, resulting in the accumulation of 8-oxo-dG in the reaction mixture. Conversely, EGCG inhibited dose-dependently an increase in 8-oxo-dG levels in calf thymus DNA incubated with HOCl. However, addition of HOCl to the DNA preoxidized with an oxidant-generating system (CuCl2, ascorbate, H2O2), led to the extensive loss of 8-oxo-dG due to its further oxidation. EGCG effectively inhibited this HOCl-mediated loss of 8-oxo-dG in the oxidized DNA, resulting in an apparent increase in 8-oxo-dG levels in the oxidized DNA, compared with the levels found without EGCG. The conversion of 8-oxo-dG into other oxidized lesions will inevitably affect recognition by DNA repair enzymes as well as the rates of mutations and DNA synthesis. Thus, our results suggest that as a biomarker of oxidative DNA damage, not only 8-oxo-dG but also the products of its further oxidation should be analyzed.

    Original languageEnglish
    Pages (from-to)1087-1093
    Number of pages7
    JournalFree Radical Biology and Medicine
    Volume36
    Issue number9
    DOIs
    Publication statusPublished - 2004 May 1

    Keywords

    • (-)-epigallocatechin gallate
    • 2′-Deoxyguanosine
    • 2′-deoxyguanosine
    • 8-Oxo-7,8-dihydro-2′-deoxyguanosine
    • 8-oxo-dG
    • EGCG
    • Epigallocatechin gallate
    • Free radicals
    • Hypochlorous acid
    • Spiroiminodihydantoin
    • Spiroiminodihydantoin nucleoside
    • dG
    • dS

    ASJC Scopus subject areas

    • Biochemistry
    • Physiology (medical)

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