Understanding the endocrine disruption of chiral pesticides:The enantioselectivity in estrogenic activity of synthetic pyrethroids

Synthetic pyrethroids(SPs) ,a family of chiral insecticides consisting of multiple stereoismers,have been regarded as estrogenic endocrine-disrupting chemicals(EDCs) .In this study,we applied the yeast two-hybrid and molecular docking(MD) assay to assess the enantioselective estrogenic activities of three commonly used SPs,bifenthrin(cis-BF) ,permethrin(PM) and fenvalerate(Fen) .The β-galactosidase analyses indicated that all of the testing pyrethroids displayed significant(p<0.05) enantioselectivity.The results showed that the estrogenic potential of cis-BF was mainly attributed to 1S-cis-BF.Neither PM nor Fen showed estrogenic effects.However,two stereoisomers of PM possessed estrogenic potential activities.αR-2R-Fen and αS-2S-Fen also induced the β-galactosidase activity.The inability to initiate the reporter gene expression by the racemic chemicals may be due to the low ratios of these isomers or the antagonism among them.The strong hydrophobic interaction and the hydrogen bond between positive estrogenic isomers and ERα support our biological testing results.This research demonstrated that the enantioselective estrogenic activity of chiral SPs was due to selective binding between their isomers and the ERαreceptor.The data suggests that enantioselectivity of these chiral pesticides is significant to their estrogenic activities.