Cytotoxicity of benalaxyl,metalaxyl, and triadimefon on Chinese hamster ovary cells

The cytotoxicity of the fungicides benalaxyl, metalaxyl, and triadimefon was evaluated in vitro using the Chinese hamster ovary (CHO-K1) cell line. The midpoint cytotoxicity values of neutral red (NR) incorporation (NRI₅₀), total cellular protein content (TCP₅₀), and the methyl tetrazolium assay (MTT₅₀) were estimated. Benalaxyl was the most cytotoxic fungicide, followed by metalaxyl and triadimefon. Fetal calf serum (10%) caused a reduction in benalaxyl, metalaxyl, and triadimefon cytotoxicity by factors of 1.8, 1.3, and 1.3. The effects of sublethal concentrations (NRI₂₅) of the three fungicides on the glutathione redox cycle components glutathione S-transferase, glutathione reductase, glutathione peroxidase, and total glutathione content were studied. The ameliorative effects of extracellular glutathione (1 mmol L^?1), vitamin C (70 µmol L^?1), and vitamin E (30 µmol L^?1) were also investigated. The three antioxidants led to significant effects on the glutathione redox cycle components.