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Chiral polychlorinated biphenyls: absorption, metabolism and excretion—a review
Journal article   Peer reviewed

Chiral polychlorinated biphenyls: absorption, metabolism and excretion—a review

Izabela Kania-Korwel and Hans-Joachim Lehmler
Environmental science and pollution research international, Vol.23(3), pp.2042-2057
02/2016
DOI: 10.1007/s11356-015-4150-2
PMCID: PMC4527964
PMID: 25651810

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Abstract

Seventy eight out of the 209 possible polychlorinated biphenyl (PCB) congeners are chiral, 19 of which exist under ambient conditions as stable rotational isomers that are non-superimposable mirror images of each other. These congeners (C-PCBs) represent up to 6 % by weight of technical PCB mixtures and undergo considerable atropisomeric enrichment in wildlife, laboratory animals, and humans. The objective of this review is to summarize our current knowledge of the processes involved in the absorption, metabolism, and excretion of C-PCBs and their metabolites in laboratory animals and humans. C-PCBs are absorbed and excreted by passive diffusion, a process that, like other physicochemical processes, is inherently not atropselective. In mammals, metabolism by cytochrome P450 (P450) enzymes represents a major route of elimination for many C-PCBs. In vitro studies demonstrate that C-PCBs with a 2,3,6-trichlorosubstitution pattern in one phenyl ring are readily oxidized to hydroxylated PCB metabolites (HO-PCBs) by P450 enzymes, such as rat CYP2B1, human CYP2B6, and dog CYP2B11. The oxidation of C-PCBs is atropselective, thus resulting in a species- and congener-dependent atropisomeric enrichment of C-PCBs and their metabolites. This atropisomeric enrichment of C-PCBs and their metabolites likely plays a poorly understood role in the atropselective toxicity of C-PCBs and, therefore, warrants further investigation.
Environmental Chemistry Environmental Health Environment, general Enantioselective Ecotoxicology Cytochrome P450 enzyme Chirality Biotransformation Environment Oxidation Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution Atmospheric Protection/Air Quality Control/Air Pollution Synthesis Core

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