Antiviral Effect of Korean Red Ginseng Extract and Ginsenosides on Murine Norovirus and Feline Calicivirus as Surrogates for Human Norovirus

Korean red ginseng has been studied various biological activities such as immune, anti-oxidative, anti-microbial, and anticancer activities but antiviral mechanism needs further studies. In this study, we aimed to examine the antiviral effects of Korea red ginseng extract and ginsenosides on norovirus surrogate, including murine norovirus (MNV) and feline calicivirus (FCV). We evaluated the pre-, co-, and post-treatment effects of Korean red ginseng (KRG), ginsenosides $Rb_1$ and $Rg_1$. To measure the antiviral effect and cytotoxicity of KRG extract, and ginsenosides $Rb_1$ and $Rg_1$, we treated Crandell-Reese Feline Kidney for FCV or RAW264.7 cells for MNV with concentrations of 0, 5, 6.7, 10, 20 ug/mL total saponin. There was cytotoxic effect in the highest concentration 20 ug/mL of KRG extract so this concentration was excluded in this study. The FCV titer was significantly reduced to 0.23-0.83 $log_{10}$ 50% tissue culture infectious dose ($TCID_{50}$)/mL in groups pre-treated with red ginseng extract or ginsenosides. The titer of MNV was significantly reduced to 0.37-1.48 $log_{10}$ $TCID_{50}$/mL in groups pre-treated with red ginseng extract or ginsenosides. However, there was no observed antiviral effect in groups co-treated or post-treated with KRG and its constituents. Our data suggest that KRG extract has an antiviral effect against norovirus surrogates. The antiviral mechanisms of KRG and ginsenosides should be addressed in future studies.