Comparison of in vitro toxicity in HepG2 cells: Toxicological role of Tebuconazole-tert-butyl-hydroxy in exposure to the fungicide Tebuconazole

Abstract

Fungicides are often used prophylactically, to control fungal diseases. Although fungicides have been designed to control pests/fungi, they frequently share molecular targets with non-target species, including humans. Tebuconazole, a fungicide belonging to the class of triazoles, is widely employed, has moderate to high persistence in soil, and can be found in different environmental levels. This fungicide is metabolized to the main hydroxy-derived metabolite, Tebuconazole-tert-butyl-hydroxy (or hydroxytebuconazole). This study aims to unveil the action mechanism of Tebuconazole and the role played by its metabolite, Tebuconazole-tert-butyl-hydroxy (5-(4-Chlorophenyl)-2,2-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)-1,3-pentanediol), within the expected spectrum of toxicity. In silico and in vitro analyses (MTT assay, cell cycle evaluation, annexin/PI assay, ROS accumulation assay, and mitochondrial membrane potential determination) were performed in HepG2 cells for 24 h and 48 h. Although in silico analysis suggested that both Tebuconazole and Tebuconazole-tert-butyl-hydroxy are potentially hepatotoxic, only Tebuconazole affected the tested cell line. Reduced MTT metabolism, and decreased mitochondrial membrane potential were the main findings. In conclusion, the action mechanism of Tebuconazole may be related to mitochondrial dysfunction. However, the findings of this study pointed out that Tebuconazole-tert-butyl-hydroxy does not play an important role in Tebuconazol toxicity. The study has generated new data that will help to understand how fungicides behave in the environment.