ENHANCEMENT OF THE CHROMOSOME-DAMAGING ACTION OF ASCORBATE BY TRANSITION-METALS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 39  (10) , 4145-4151
Abstract
Freshly prepared ascorbate inhibited mitosis and induced chromosome aberrations in cultured Chinese hamster ovary cells. Cu2+ and Mn2+ (10-4 or 10-5 M) enhanced both actions. Fe2+ and Fe3+ (10-4 or 10-5 M) reduced or abolished the mitosis-inhibiting action of ascorbate. At 10-4 M, Fe(II) and Fe(III) strongly enhanced the chromosome-damaging capacity of ascorbate. Up to 100% of all examined metaphase plates had multiple chromosome exchanges or breaks. Since the cytostatic and clastogenic effect of ascorbate could be due to H2O2 formed during oxidation, the capacity of H2O2 to induce chromosome aberrations was examined. H2O2 and a H2O2: Fe2+ mixture (Fenton reagent) induced chromosome breaks and exchanges but to a lesser degree than did ascorbate: Cu2+, Mn2+, Fe2+ or Fe3+ mixtures. Whether the strong chromosome damaging capacity of ascorbate plus transition metals as seen in the in vitro test system poses a human health hazard only properly designed in vivo studies can reveal.