Figure 3.

Plaque reduction assay to verify the antiviral activity of Californian natural and blanched skin almond extracts: Vero cells were infected with HSV-1 (F) and incubated for 1 h at 37 °C. After the incubation time, the inoculum was removed, and the monolayers were overlaid with Dulbecco’s Modified Eagle’s Medium containing 0.8% methylcellulose in the presence of NS and BS extracts at different concentrations (0.4 mg/mL, 0.2 mg/mL and 0.1 mg/mL). The plates were incubated at 37 °C and 5% CO₂ for three days, and the plaques were visualized by staining cells with crystal violet. The DMSO was used in the HSV-1 control. Results are the mean ± SD of triplicate experiments and asterisks (** and ***) indicate significant changes of p-value less than 0.01 and 0.001, respectively. In (a,b), the plaque reduction assay was performed following NS and BS almond extracts treatment, respectively; (c) shows the plaque morphological change due to NS treatment 0.4 mg/mL vs. 0.2 mg/mL. No reduction was observed at 0.1 mg/mL.