The Enantiomer-selective Metabolism of Hexabromocyclododecanes (HBCDs) Enantiomers by Human HepG2 cells

Abstract Although hepatic metabolism of hexabromocyclododecanes (HBCDs) played critical roles in the selective bioaccumulation of HBCDs in humans, the hepatic metabolism patterns of its enantiomers remained ambiguous. Aiming to elucidate the mechanism on hepatic metabolism of hexabromocyclododecanes (HBCDs) enantiomers, the enantiomers ((+)-α-HBCD, (−)-α-HBCD, (+)-γ-HBCD, and (−)-γ-HBCD), the diastereoisomers (α-, β-, and γ-HBCDs) and the mixed of α- and γ-HBCDs were incubated with human HepG2 cell under different exposure levels in the present study. The clearance percentages ranked as γ-HBCD enantiomers > β-HBCD enantiomers > α-HBCD enantiomers at the same exposure levels. The clearance percentages of (+)- and (−)-α-HBCDs increased when cells were exposed to racemic α-HBCD and the mixture of racemic α- and γ-HBCDs (p