Saponin inhibits HCV propagation.

<p>(A) Saponin inhibits HCV protein expression in a dose-dependent manner. Huh7.5 cells infected with either HCV Jc1 or mock for 4 h were incubated with the selected amounts of saponin (2.5, 5, 10, and 20 µg/ml) for 24 h. Cells were harvested and then equal amounts of cell lysates were immunoblotted with anti-NS3 and NS5A antibodies, respectively. β-actin was used as a loading control for the same amount of cell lysates. (B) Relative viral protein levels in HCV-infected cells treated with the indicated dosage of saponin were normalized by β-actin. (C) Huh7.5 cells were infected with Jc1 for 4 h and then treated with the indicated amounts of saponin. At 24 h postinfection, intracellular HCV RNAs were analyzed by qRT-PCR using a primer targeting HCV 5′UTR-core. (D) Relative HCV infectivity was determined by focus-forming units (FFU) as we reported previously <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039366#pone.0039366-Lim1" target="_blank">[16]</a>. Error bars indicate the standard deviation. * indicates statistical significance (p<0.05) and ** indicates p<0.01 versus control.