catechin-gallate and Liver-Neoplasms

The constitutive androstane receptor (CAR) is known as a xeno-sensor that regulates genes involved in xenobiotic excretion and energy metabolism. This study tested a variety of polyphenols for their ability to modulate CAR activity. HepG2 cells were transfected with a CAR expression plasmid and a reporter plasmid containing the human CYP2B6 regulatory region and then treated with flavonoids, catechins, and other bioactive polyphenols. Luciferase assays revealed that baicalein (5,6,7-OH flavone) was a potent activator of both human and mouse CAR. Catechin gallates also activated human and mouse CAR. Wild-type and CAR knockout mice were treated with baicalein and chrysin (5,7-OH flavone), and their liver mRNA was analyzed by real-time polymerase chain reaction (PCR). A significant increase in cyp2b10 mRNA content was observed only in wild-type mice fed chrysin. These results suggest that dietary flavonoids regulate CAR activity and thereby accelerate both detoxification and energy metabolism.

Topics: Androstanes; Animals; Aryl Hydrocarbon Hydroxylases; Carcinoma, Hepatocellular; Catechin; Cell Line, Tumor; Constitutive Androstane Receptor; Cytochrome P450 Family 2; Diet; Flavonoids; Genes, Reporter; Humans; Liver; Liver Neoplasms; Luciferases; Mice; Mice, Knockout; Polymerase Chain Reaction; Receptors, Cytoplasmic and Nuclear; RNA, Messenger; Steroid Hydroxylases