| Resumo: |
Oxidative DNA damage results from overproduction of reactive oxygen species (ROS). Sources of ROS may be exogenous or endogenous. Hydrogen peroxide (H2O2) is a ROS that, by interacting with transition metals, such as Fe2+, produces hydroxyl radicals (HO• ) via Fenton reaction. Phytic acid (PA), also known as myo-inositol hexaphosphate (IP6), is a natural compound found in cereals, vegetables, and oilseeds. Its chemical structure provides the ability to chelate metal ions such as Fe2+ , which characterizes it as an antioxidant agent with the ability to inhibit radical (HO• ) formation by Fenton reaction. Considering the antioxidant activity of PA, this study aimed to evaluate the antigenotoxic potential of the compound against H2O2- induced oxidative damage. In vitro assays were performed using L929 murine fibroblasts. The cytotoxicity of PA and H2O2 was determined by the MTT colorimetric assay. The anticytotoxic effect of PA was also assessed by the MTT assay. Genotoxic and antigenotoxic effects of PA were evaluated by two methods, namely the alkaline comet assay and the plasmid DNA topology assay. On the basis of the results of cytotoxicity assessment, we selected the concentrations of PA (1.56, 0.156, and 0.0156 mM) and H2O2 (75 µM) that afforded cell viabilities greater than 70%. Regarding the anticytotoxic effect of PA on L929 cells, a cytoprotective effect was observed at concentrations of 0.156 and 0.0156 mM PA. The results of the antigenotoxicity test by the comet method showed that, at the three concentrations tested, PA exerted a protective effect (>75%) against oxidative DNA damage. The DNA topology assay showed that PA was not genotoxic at the tested concentrations and partially inhibited the cleavage of plasmid DNA induced by the Fenton reaction. Although further investigations are needed, such as assessment of antimutagenic activity, the current results revealed that, at the tested concentrations, PA protects DNA against cleavage induced by oxidative stress. Thus, PA is an antioxidant compound with antigenotoxic action that may be explored for disease prevention. |
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