Analysis of possible genotoxicity of the herbicide flurochloridone and its commercial formulations: Endo III and Fpg alkaline comet assays in Chinese hamster ovary (CHO-K1) cells

Abstract

Cytotoxic and genotoxic effects of flurochloridone (FLC) and its formulations Twin Pack Gold® and Rainbow® were evaluated in CHO-K1 cells. Using the alkaline single-cell gel electrophoresis (SCGE) assay, we observed that FLC (15 μg/ml), Twin Pack Gold® or Rainbow® induced primary DNA damage, increasing the frequency of damaged nucleoids. Vitamin E pretreatment did not modify the effect. Decreased cell viability was observed only in Twin Pack Gold®-treated cultures and was significantly ameliorated by vitamin E. Post-treatment of herbicide-damaged CHO-K1 cells with the enzymes Endo III or Fpg did not increase FLC-, Twin Pack Gold®-, or Rainbow®-induced DNA damage. These results demonstrate that neither FLC nor FLC-based formulations induce DNA damage through hydroxyl radical or lipid alkoxyl radical production, and that the induced DNA lesions were not related to oxidative damage at the purine/pyrimidine level. Our observations strongly suggest that the cytotoxic effects observed after Twin Pack Gold® exposure are due to the excipients contained within the technical formulation rather than FLC itself.