Context: Given that Pinus massoniana Lamb (Pinaceae) bark extract (PMBE) is a safe and non-toxic flavonoid found abundantly in nature, it was considered a promising novel candidate agent in the treatment of virus infection.
Object: Experiments were conducted to assay the antiviral character of PMBE against Hepatitis C virus (HCV).
Materials and methods: Assay of PMBE cytotoxicity, HCV replication, infectious HCV production, and its potential influence on the pathways for IFN-ISRE and NS3 protease were conducted.
Results: HCV replication was suppressed when the concentration of PMBE raised greater than 5 μg/mL and its EC50 was 9.58 μg/mL. In the 10 μg/mL group, HCV replication was suppressed for 48 h. When the concentration increased to 40 μg/mL, HCV replication was significantly suppressed (luciferase activity was only 10% at 96 h). PMBE could inhibit HCV virus production efficiently (PMBE group was 5 FFU). Cell viability was affected by 40 μg/mL of PMBE. The F/R ratio ranged from 98% to 101%. The rate of OD450 ranged from 96% to 102%. NS3 catalytic activity ranged from 5% (40 μg/mL PMBE) to 45% (5 μg/mL PMBE). Even when used in a low amount (5 μg/mL), NS3 catalytic activity was significantly inhibited (p < 0.01).
Conclusions: The results suggest that PMBE is effective for use in the stabilization of HCV replication and active liver inflammation.
Keywords: IFN-ISRE; NS3 catalytic activity; PMBE cytoxicity; replicon.