Novel Hepatitis C virus Protease Inhibitors: 2,4,6-Trihydroxy,3-Nitro-Benzamide Derivatives

This study evaluated the inhibitory effects of 2,4,6-trihydroxy,3-nitro-benzamide (THNB) derivatives against hepatitis C virus (HCV) protease and other human serine proteases. The inhibitory efficacy was tested with a reversed-phase HPLC assay system using a NS3-NS4A fusion protein as the HCV protease and a synthetic peptide substrate that mimics the NS5A-5B junction. Twelve THNB derivatives showed more than 50% inhibition at 100 μg mL -1 . The most potent derivative was RD3-4082, with 50% inhibition at a concentration of 2.3 μg mL -1 ; this concentration was lower than those of other protease inhibitors reported previously. The most selective derivative was RD2-4039, with 50% inhibition at a concentration of 32.8 μg mL -1 , a lower concentration than those against other serine proteases (chymotrypsin, trypsin, plasmin and elastase). These results suggest that the RD2-4039 skeleton is an important structure for inhibitory activity against the HCV protease NS3-NS4A.