title: Chlorination by-products of bisphenol A enhanced retinoid X receptor disrupting effects.
abstract: There is increasing evidence of activities of chlorinated by-products of bisphenol A (BPA) on retinoic acid system. Their agonistic and antagonistic activities to human retinoid X receptor (RXR) were assessed by a two-hybrid yeast assay. Aqueous solutions of 1mg/L BPA were chlorinated by sodium hypochlorite (NaClO). It showed that chlorination of BPA increased RXRβ antagonistic activity, while no agonistic activity was detected, showing chlorine might act as a toxic potentiator rather than a toxic deactivator in RXRβ disrupting effects. BPA and its byproducts including 2,2',6,6'-tetrachlorobisphenol A (TCBPA) and 2,4,6-trichlorophenol (TCP) were quantitatively determined by gas chromatography/mass spectrometry (GC/MS). BPA rapidly degraded. With the increasing of ICC and reaction time, concentration of formed TCBPA increased initially then decreased, while concentration of formed TCP increased stably. Using the toxic equivalent (TEQ) approach, the main contributors should be mono-, di- and tri- chlorobisphenol A at initial chlorine concentration (ICC) of 1mg/L. At ICC of 2 and 5mg/L, the main contributors were TCBPA and TCP, being 57.7%-70.7% and 45.3%-59.4%. Molecular docking showed BPA chlorination by-products might have the same mode of action with BPA, forming hydrogen bond and pi-pi interaction with their OH group or hydrophobic ring.
authors: Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China.
authors: Na
authors: N
authors: Li
authors: Shanghai Municipal Water Resource Development and Utilization National Engineering Center Co., Ltd., Shanghai 200082, China.
authors: Weiwei
authors: W
authors: Jiang
authors: Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China. Electronic address: mamei@rcees.ac.cn.
authors: Mei
authors: M
authors: Ma
authors: Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China.
authors: Donghong
authors: D
authors: Wang
authors: Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China. Electronic address: wangzj@rcees.ac.cn.
authors: Zijian
authors: Z
authors: Wang
mesh_terms: D001559:Benzhydryl Compounds / Q000737:chemistry*; D004203:Disinfection; D052244:Endocrine Disruptors / Q000737:chemistry*; D054879:Halogenation; D006801:Humans; D062105:Molecular Docking Simulation; D010636:Phenols / Q000737:chemistry*; D049230:Retinoid X Receptor beta / Q000819:agonists* / Q000037:antagonists & inhibitors*; D012973:Sodium Hypochlorite; D020798:Two-Hybrid System Techniques; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D052244:Endocrine Disruptors; D010636:Phenols; D049230:Retinoid X Receptor beta; D012973:Sodium Hypochlorite; C006780:bisphenol A; D000098826:Bisphenol A Compounds
keywords: Bisphenol A; Chlorinated byproducts; Molecular docking; Retinoid X receptor; TEQ