Enantioselective metabolism and cytotoxicity of the chiral herbicide ethofumesate in rat and chicken hepatocytes

We investigated the metabolic kinetics and toxicity of ethofumesate (ETO) in rat and chicken hepatocytes using a chiral high-performance liquid chromatographic (HPLC) method. The metabolic of ETO in rat hepatocytes was enantioselective, whereas it was not in chicken hepatocytes. The T_1/2 of (−)-ETO was about two times longer than that of (+)-ETO after the rat hepatocytes had been incubated with 20 μM rac-ETO. There was no chiral conversion or transformation during their incubation with the hepatocytes. Toxicity differences were observed between the two enantiomers of ETO, reflected in their EC₅₀ values in rat and chicken hepatocytes. The stereoselective cytotoxicity of the two enantiomers was opposite in rat and chicken hepatocytes. We have developed a method of studying the toxicokinetics and cytotoxicity of chiral agrochemicals in hepatocytes isolated from mammals (rats) and chicken. The data presented here allow a more thorough understanding of this pesticide and should be useful in its full environmental assessment.