Analysis of the Different Metabolic Phenotypes of Metalaxyl Enantiomers in Adolescent Rat by Using 1H NMR Based Urinary Metabolomics.

Over 30% of commercial pesticides are racemic mixtures. Nowadays, the environmental safety of chiral pesticides has received more and more attention. Metalaxyl is a broad-spectrum fungicide with systemic function, which has a chiral carbon. Although its fungicidal activity almost entirely originates from the R-enantiomer, the enantioselective toxicity of metalaxyl in animals and human beings are not yet clear. In this study, the urinary metabolomics approach was applied to analyze the changes in metabolic phenotypes in adolescent rats by using nuclear magnetic resonance (NMR). In the urinary metabolomics results, the metabolic profiles of the different enantiomers were distinguishable, and the characteristic metabolites were different. Both in the exposure of R/S-enantiomers, the disturbed metabolic pathways in common were butanoate metabolism, valine, leucine and isoleucine biosynthesis, alanine, aspartate and glutamate metabolism, and glutamine and glutamate metabolism. These pathways were closely involved in gut microbiota. In addition to the disturbed metabolic pathways common to both, three metabolic pathways were abnormal in the exposure of S-metalaxyl, including aminoacyl-tRNA biosynthesis, arginine biosynthesis, and citrate cycle. These disturbed metabolic pathways could cause genetic diseases and affect the liver function. These results indicate that a specific insight into the effects of different metalaxyl enantiomers on metabolic disturbance. Our work could allow us to well understand the health risk assessments of metalaxyl enantiomers, especially at the metabolic level.