Stereoselective in vitro metabolism of cyproconazole in rat liver microsomes and identification of major metabolites. (February 2021)

• Record Type: Journal Article
• Authors: He, Rujian; Fan, Jun; Chen, Ran; Guo, Dong; Zhao, Mengjiu; Zhang, Zhifeng; Liang, Chuying; Chen, Ming; Song, Haiyan; Zhang, Weiguang
• Is Part Of: Chemosphere. Volume 264(2021)Part 2
• Publication Date: 2021-02
• Subjects: Cyproconazole -- Stereoselective metabolism in vitro -- Rat liver microsomes -- Molecular docking -- Metabolic reaction; CPZ cyproconazole -- CYPs Cytochrome P450 -- EF enantiomeric fraction -- LODs limits of detection -- LOQs limits of quantification -- NADPH β-nicotinamide adenine dinucleotide phosphate -- RSD relative standard deviation; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.128495
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The vast usage of agrochemicals enhances food security globally but may pose challenge to understand the risk assessment to non-target organisms and human beings, and liver microsomes are responsible for metabolism of these agrochemicals in vivo . In this study, stereoselective metabolism of chiral triazole fungicide cyproconazole in rat liver microsomes has been investigated through chiral LC-MS/MS technique. The half-lives of four cyproconazole stereoisomers were different ranging from 95 to 187 min, and (2 S, 3 R )-cyproconazole preferentially metabolized in rat liver microsomes. In addition, the results from metabolism kinetic study indicated that rat liver microsomes showed the stronger potency to deplete (2 S, 3 R )-cyproconazole than the others. Then, homology modeling and molecular docking results revealed that the docking energy between (2 S, 3 R )−cyproconazole and the cytochrome P450 CYP3A1 (−7.46 kcal⋅mol −1 ) was higher than the others, meaning that (2 S, 3 R )−cyproconazole exhibited the strongest binding ability to this enzyme. Moreover, two main metabolites of cyproconazole coming from hydroxylation and dehydration were observed, and possible metabolic reactions of cyproconazole in rat liver microsomes were identified through using an LCQ ion trap mass spectrometer. This kind of systematic metabolic investigation of cyproconazole at chiral level would provide valuable information for ecological and human health risk assessment of chiral pesticides. Graphical abstract: Image 1 Highlights: Stereoselective metabolism of cyproconazole was found in rat liver microsomes. (2 S, 3 R )-cyproconazole is preferentially metabolized in rat liver microsomes. Docking energy supported enantiospecific binding of cyproconazole with CYP3A1. Two main metabolites of cyproconazole were identified by LC-MS spectrometry.