Figure 2.

 Effect of San‐Huang‐Xie‐Xin‐Tang (SHXT)‐frC on hepatitis C virus (HCV)‐induced cyclooxygenase‐2 (COX‐2) gene promoter, protein expression and activity in HCV replicon cells. (a) Dose‐dependent reduction in COX‐2 promoter activity by SHXT‐frC. The pCOX‐2‐Luc‐transfected Ava5 cells were treated with indicated concentrations of SHXT‐frC and (+)‐catechin for 3 days. Subsequently, cell lysates were subjected to luminescence detection using the Steady‐Glo Luciferase Assay kit (Promega). The luciferase activity in the pCOX‐2‐Luc‐transfected Huh‐7 cells without drugs treatment served as the basal control of induced COX‐2 promoter activity, which was defined as 1. [□, SHXT‐frC; , (+)‐catechin] (b) Dose‐dependent reduction in COX‐2 expression by SHXT‐frC. Ava5 cells were incubated for 3 days with indicated concentrations of (i) SHXT‐frC and (ii) (+)‐catechin. Cell lysates were subjected to Western blotting with anti‐COX2 and anti‐GAPDH (a loading control) antibodies. (c) Dose‐dependent reduction in prostaglandin E2 (PGE₂) production by SHXT‐frC. After 3 days of treatment, the intercellular PGE₂ levels were assayed with the Biotrak PGE₂ enzyme immunoassay system (Amersham). ‘Mock’ indicates a treatment of 0.1% dimethylsulphoxide. Each value represents the mean ± SD from triplicate experiments. The * symbol represents statistical significance of P‐value ≤0.05. The ** symbol represents statistical significance of P‐value ≤0.01.