Skip Navigation

Publication Detail

Title: Identification of three novel natural product compounds that activate PXR and CAR and inhibit inflammation.

Authors: Kittayaruksakul, Suticha; Zhao, Wenchen; Xu, Meishu; Ren, Songrong; Lu, Jing; Wang, Ju; Downes, Michael; Evans, Ronald M; Venkataramanan, Raman; Chatsudthipong, Varanuj; Xie, Wen

Published In Pharm Res, (2013 Sep)

Abstract: PURPOSE: To investigate the effects of three natural product compounds, carapin, santonin and isokobusone, on the activity of pregnane X receptor (PXR) and constitutive androstane receptor (CAR) in induction of drug-metabolizing enzymes and inhibition of inflammation. METHODS: The monkey kidney-derived fibroblast (CV-1) cells and human embryonic kidney HEK293 cells were used for transient transfection and luciferase reporter gene assays. Human primary hepatocytes and primary hepatocytes from wild type, PXR-/-, and hPXR transgenic mice were used to study the induction of drug-metabolizing enzymes and the implication of these compounds in inflammation. RESULTS: Carapin, santonin and isokobusone activated both PXR and CAR in transient transfection and luciferase reporter gene assays. Mutagenesis studies showed that two amino acid residues, Phe305 of the rodent PXR and Leu308 of the human PXR, are critical for the recognition of these compounds by PXR. Importantly, the activation of PXR and CAR by these compounds induced the expression of drug-metabolizing enzymes in primary human and mouse hepatocytes. Furthermore, activation of PXR by these compounds inhibited the expression of inflammatory mediators in response to lipopolysaccharide (LPS). The effects of these natural compounds on drug metabolism and inflammation were abolished in PXR-/- hepatocytes. CONCLUSIONS: Our results show that carapin, santonin and isokobusone activate PXR and CAR and induce drug-metabolizing enzymes. In addition, these compounds inhibited the expression of inflammatory mediators in response to LPS through the activation of PXR.

PubMed ID: 23896737 Exiting the NIEHS site

MeSH Terms: Animals; Anti-Inflammatory Agents/isolation & purification; Anti-Inflammatory Agents/pharmacology*; Aryl Hydrocarbon Hydroxylases/genetics; Aryl Hydrocarbon Hydroxylases/metabolism; Benzopyrans/pharmacology*; Biological Products/isolation & purification; Biological Products/pharmacology*; Cell Line; Cells, Cultured; Constitutive Androstane Receptor; Cyclooctanes/pharmacology*; Cytochrome P-450 CYP2B6; Cytochrome P-450 CYP3A/genetics; Cytochrome P-450 CYP3A/metabolism; Cytochrome P450 Family 2; Gene Deletion; Gene Expression Regulation/drug effects; HEK293 Cells; Haplorhini; Hepatocytes/drug effects; Hepatocytes/metabolism; Humans; Inflammation/drug therapy; Inflammation/genetics; Inflammation/immunology; Inflammation/metabolism; Lipopolysaccharides/immunology; Mice; Mice, Transgenic; Pharmaceutical Preparations/metabolism; Plants, Medicinal/chemistry; Polycyclic Compounds/pharmacology*; Pregnane X Receptor; Receptors, Cytoplasmic and Nuclear/metabolism*; Receptors, Steroid/genetics; Receptors, Steroid/metabolism*; Santonin/pharmacology*; Steroid Hydroxylases/genetics; Steroid Hydroxylases/metabolism

Back
to Top