Fig. 7: Hyp13 does not activate PXR.

Induction of PXR activity by hyperforin and its derivate in HepG2 cells (A). HepG2 cells were co-transfected with plasmids expressing GAL4-responsive UAS-driven firefly luciferase, human PXR-LBD fused to GAL4-DBD, and Renilla luciferase. The transfected cells were exposed to 10 µM of positive controls rifampicin and SR12813 or different concentrations of hyperforin and its derivate. After 24 h, cell lysates were assayed for firefly and Renilla luciferase activity. Firefly luciferase activity was normalized against Renilla luciferase activity and fold induction relative to the solvent control (SC 0.5% DMSO) was calculated. Data are presented as means ± SD of three independent experiments performed with six replicates each. B Gene expression analysis of CYP3A4. Differentiated HepaRG cells were exposed to hyperforin and its derivate as well 10 µM Rifampicin (PC) for 24 h. Total mRNA was isolated and transcribed into cDNA and subsequently mRNA expression of CYP3A4 was analyzed by real-time qPCR. For relative quantification, Ct values were normalized to reference genes (ACTB and GAPDH) according to the ΔΔCT method. Log2 fold changes of 2^−ΔΔCT values were calculated and mRNA levels were expressed in relation to the solvent control (SC 0.5% DMSO). Data are presented as means ± SD of two to three independent experiments.