728) ( Fig. 4B), indicating that PYC has an antiviral effect and acts synergistically with PEG-IFN in chimeric mice with humanized livers infected with HCV. A ROS assay was used to assess the ability of PYC to

act as a free radical scavenger. Fluorescence intensity was measured for each sample. Total ROS production was significantly JAK inhibitor decreased by PYC in the HCV replicon cell line in a dose-dependent manner (Fig. 5). Treatment with PYC at 40 μg/mL reduced ROS to levels comparable to cells cured of the HCV replicon by IFN treatment (Blight et al., 2002), suggesting that PYC may scavenge ROS in HCV replicon cell lines. Oxidative stress has been identified as a key mechanism of HCV-induced pathogenesis (de Mochel et al., 2010, Ke and Chen, 2012, Quarato et al., 2013 and Tardif et al., 2005). Moreover, several studies have reported a correlation between oxidative stress and IFN treatment response, and have observed that oxidative stress was reduced to normal levels after viral eradication (Levent et al., 2006 and Serejo et al., 2003). These data provide a firm theoretical basis for investigation of antioxidants as therapeutics. PYC is a mixture of various chemical groups and exhibits radical-scavenging antioxidant, anti-inflammatory, and antiviral activities (Maimoona et al., 2011). In addition, PYC protects biomolecules such as proteins against oxidative damage (Voss et al., 2006). To our knowledge, this is the first

report to demonstrate a direct antiviral effect of PYC against HCV. Sirolimus cost Our results show that PYC inhibits HCV replication in HCV replicon cell lines and JFH-1 without

cytotoxicity. Moreover, this result is in line with a recent report, based on data obtained from 5723 subjects that showed side effect incidence rates of 2.4% and 0.19% in patients and healthy subjects, respectively (American Cell Penetrating Peptide Botanical Council, 2010). The study also found PYC to be nontoxic at doses of 20–100 mg/day for extended periods (months) and 100–300 mg for shorter periods (American Botanical Council, 2010). Treatments of replicon and JFH-1 cell lines using combinations of PYC with RBV, IFN, and telaprevir showed that co-administration of these compounds increased HCV antiviral activity. In addition, we found that PYC suppressed HCV replication in telaprevir-resistant replicon cells and may improve the response to protease inhibitors. In this report, we found that procyanidins, oligomeric compounds formed from catechin and epicatechin, but not taxifolin, inhibited HCV replication at doses between 15 and 60 μg/mL and had a synergistic effect with IFN treatment without cytotoxicity. Moreover, procyanidin B1 extracted from Cinnamomum cassia cortex suppresses hepatitis C virus replication ( Li et al., 2010). Other studies have also shown that epicatechin, catechin-derived compounds, and caffeic acid phenethyl ester inhibit HCV replication and attenuate the inflammation induced by the virus ( Khachatoorian et al., 2012, Lin et al., 2013 and Shen et al., 2013).