Assessment of DNA damage, cytotoxicity, and apoptosis in human hepatoma (HepG2) cells after flurochloridone herbicide exposure

In vitro effects of flurochloridone (FLC) and its formulations Twin Pack Gold® [25% active ingredient (a.i.)] and Rainbow® (25% a.i.) were evaluated in HepG2 cells. Whereas cytokinesis-blocked micronucleus cytome (CBMN-cyt) and single-cell gel electrophoresis (SCGE) assays were employed for genotoxicity, MTT, neutral red, and apoptosis detections were used for cytotoxicity evaluation. Activities were tested within the concentration range of 0.25-15 μg/ml FLC. Results demonstrated that neither FLC nor Rainbow® was able to induce MNs. On the other hand, 5 μg/ml Twin Pack Gold® only increased MN frequency. Furthermore, 10 and 15 μg/ml of both formulations resulted in cellular cytotoxicity demonstrated by alterations in the nuclear division index and cellular death. A marked increase in the genetic damage index was observed after treatment with all compounds. SCGE assay appeared to be more sensitive bioassay for detecting primary DNA strand breaks at lower concentrations of FLC than did MN. Our results reveal that FLC and its two formulations trigger apoptosis on HepG2 cells. The results represent the first experimental evidence of the in vitro apoptogenic role exerted on mammalian cells by FLC and the FLC-based formulations Rainbow® and Twin Pack Gold®, at least on HepG2 cells.