Fig. 7.

Combinations of diphyllin and oseltamivir showed enhanced antiviral effect and CPE protection. (A) Diphyllin (1000, 500 nM) and oseltamivir (1000, 500, 250 nM) were used individually or in combination in NS1-GFP virus infected MDCK cells as described in Section 2.7. Cells were harvested for NP expression analysis using Western blotting, and extracellular virus titers in supernatant were determined by an HA test. (B) Oseltamivir (25, 12.5, 6.25, 3.125 nM) was used in the absence or presence of diphyllin (250, 125 nM) in NS1-GFP virus infected MDCK cells as described in Section 2.7. An MTT assay was performed and normalized cell viability was presented. Values are mean ± SD from three replicates. Cell viability between each diphyllin cooperatively treated group and the amantadine alone treated group were compared by two-way ANOVA followed by Dunnett’s multiple comparisons test. (ns: non-significant, ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001, ^∗∗∗∗p < 0.0001).