Figure 6.

Fermented ginseng extract sample A had antiviral activity against influenza virus in vitro. (A) Microneutralization assay. Different strains of viruses (100 TCID₅₀ H1N1, 120 TCID₅₀ H3N2, and 200 TCID₅₀ H5N1) were incubated with 10 mg/mL of F.G.A or F.G.B for 1 h at 37 °C and added to MDCK cells (1 × 10⁵) for 18 h cultures. ELISA was done using primary antibody (Anti-NP) and secondary antibody (IgG-HRP) to determine percentage of growth based on control virus infection without ginseng samples. TCID₅₀: Tissue culture infectious dose. (B) Plaque assay in MDCK cells. The H1N1 and F.G.A or F.G.B mixture incubated with MDCK cells monolayer for 30 min, then covered with 1.5% agarose to culture for 3–5 days to determine percentage of control plaques. (C) Effects of fermented ginseng samples treatment prior to infection on viral growth in plaques. The mixture of H1N1 California/A/2009 and 10 mg/mL of F.G.A or F.G.B was incubated for 0, 5, 10, and 20 min at 37 °C. (D) Effects of fermented ginseng samples treatment postinfection on viral growth in plaques. MDCK monolayers were first infected with H1N1 or H5N1 virus and incubated for 1 h at 37 °C. After washing away the virus, 10 mg/mL of F.G.A or F.G.B were added to virus-infected MDCK monolayers for 3 h or 6 h. (E,F) ELISA for F.G.A-treated viral plates. The 96-wells were coated with H1N1 or H5N1 inactivated virus overnight, then incubated with 10 mg of F.G.A or nonfermented ginseng for 1 h at 37 °C. The primary Anti-H1 HA and Anti-H5 HA and secondary goat anti-mouse IgG were used for ELISA test. (G) 8000 TCID₅₀ of rgH5N1 virus was incubated with different concentration of F.G.A or F.G.B for 30 min, and neuraminidase activity was determined. (H) Cell viability test. 2 mL of EMEM medium (with 5 mg and 10 mg/mL of F.G.A) was incubated with MDCK monolayer for 6 h. Medium–ginseng mixture was removed, and cell viability was counted by trypan blue method. *, **, *** symbols indicate statistical significance, p < 0.05, p< 0.01 and p < 0.001 between the comparing groups. ‘ns’ indicates no significance.