Herbicidal activity and differential metabolism of lactofen in rat and loach on an enantiomeric level

• Published in: Environmental science and pollution research international Vol. 29; no. 19; pp. 28307 - 28316
• Main Authors: Wang, Fang, Gao, Jing, Li, Peize, Jiang, Shanxue, Wu, Junxue, Yao, Zhiliang
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2022; Springer Nature B.V
• Subjects: Animals; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Earth and Environmental Science; Ecotoxicology; Enantiomers; Environment; Environmental behavior; Environmental Chemistry; Environmental Health; Environmental science; Halogenated Diphenyl Ethers - metabolism; Herbicides; Liver; Metabolic pathways; Metabolism; Metabolites; Microsomes; Microsomes, Liver - metabolism; Rats; Research Article; Rodents; Stereoisomerism; Waste Water Technology; Water Management; Water Pollution Control; Weeds; Enantioselectivity; Metabolites; Lactofen; Herbicidal activity; Metabolic pathways; Liver microsomes; Responsible Editor: Ludek Blaha
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-021-17986-2

Enantioselectivity of chiral compounds is receiving growing concern. Lactofen, a chiral herbicide widely used in field crops and vegetables to control broadleaf weeds, is still sold as racemate. In this work, the herbicidal activity and metabolism behavior of lactofen were investigated on an enantiomeric level. Two common broadleaf weeds ( Eclipta prostrata L . and Portulaca oleracea L .) were used to evaluate the herbicidal activity of rac-/R- and S-lactofen, and their metabolism behavior in loach and rat liver microsomes was explored. Higher herbicidal activity of S-lactofen was observed, with the 20d-EC 50 values being 1.9–3.4 times lower than R-lactofen. Both loach and rat liver microsomes had ability to metabolize rac-lactofen, with half-lives of 1.93 and 1.28 h, respectively. Enantioselective metabolism behaviors were observed in loach and rat liver microsomes and the direction of enantioselectivity were different. R-lactofen was preferentially metabolized in loach liver microsome, while S-lactofen was preferentially metabolized in rat liver microsome. No interconversion of R- and S-lactofen was found. Besides, the main metabolic pathways of R- and S-lactofen were found to be significantly different. R-lactofen was metabolized to R-desethyl lactofen in both loach and rat liver microsomes without further metabolism. However, S-lactofen was metabolized to both S-desethyl lactofen and acifluorfene in rat liver microsome, which was mainly metabolized to acifluorfene in loach liver microsome. This study indicated enantioselectivity and metabolites should be taken into consideration when overall evaluating the environmental behavior of lactofen. Graphical abstract