PXR- and CAR-mediated herbal effect on human diseases

• Nuclear receptor PXR and CAR regulate a number of genes encoding drug metabolizing enzymes and transporters.
• Increasing herbal extract and their active components have been identified as PXR and/or CAR ligands.
• PXR and CAR are involved in the herbal effect against multiple human diseases.
• Pharmacological targeting of PXR/CAR with herbal compounds may be an effective therapeutic strategy against human diseases.

The pregnane X receptor (PXR) and constitutive androstane receptor (CAR) are two members of the nuclear receptor superfamily that regulate a broad range of genes involved in drug metabolism and transport. A variety of naturally occurring compounds present in herbal medicines were identified as ligands of PXR and CAR. Recently, accumulative evidences have revealed the PXR- and CAR-mediated herbal effect against multiple human diseases, including inflammatory bowel disease (IBD), cholestatic liver disease, and jaundice. The current review summarized the recent progress in identifying the expanding libraries of herbal medicine as ligands for PXR and CAR. Moreover, the potential for herbal medicines as promising therapeutic agents which were mainly regulated through PXR/CAR signaling pathways was also discussed. The discovery of herbal medicines as modulators of PXR and CAR, and their PXR- and CAR-mediated effect on human diseases will provide a basis for rational drug design, and eventually be explored as a novel therapeutic approach against human diseases. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie.