(A–C) Real-time PCR analysis of the expression of iNOS (A), MCP-1 (B) and IL-1β (C) in WT and PXR−/− mouse hepatocytes that were pre-treated with vehicle, PCN, carapin, santonin, or isokobusone (10 μM each) for 24 h before treatment with LPS (20 μg/ml) for 6 h. Results were normalized to cyclophilin mRNA levels and expressed as fold change over controls. *, P < 0.05, vs LPS alone treatment groups in WT mice; # P < 0.05, vs LPS alone treatment groups in PXR KO mice. N = 3 for each group.