Figure 5.

Inhibition of viral entry by DGFW. Human foreskin fibroblast (HFF3) cells were cultured in 96-well plates. Cytoprotection was then measured by crystal violet staining of the attached cells on the plates. A Pueraria lobata extract at 3.125 mg/mL served as a positive control. (A) Dose dependence of DGFW inhibition of EV71 attachment. Increasing concentrations of DGFW were added to cells infected with EV71 and incubated for 3 h on ice. The cells were washed with DPBS and replaced with E2, warmed to 37 °C and incubated for 72 h. Cytoprotection was then determined. (B) Dose dependence of DGFW inhibition of EV71 penetration. HFF3 cells were chilled on ice for 1 h, followed by preadsorption of EV71 for 3 h on ice. Increasing concentrations of DGFW were then added, warmed to 37 °C and incubated for 1 h to allow the virus to enter the cells. The monolayers were treated with alkaline PBS (pH 11) to inactivate extracellular virus and were incubated at 37 °C for 72 h. Cytoprotection was then determined. This is a representative result from three independent experiments.