Figure 1.

Papaya pulp extract exerts antiviral activity against African and Asian strains of ZIKV in A549 cells. (a) A549 cells were incubated with two-fold serial dilutions (125–4000 µg/mL) of pineapple juice, mango or papaya pulp extracts for 48 h. Cell viability was assessed through the MTT assay. Results are means ± standard deviation (SD) of four independent experiments and are expressed as relative value compared to non-treated cells. (b) A549 cells were infected with ZIKV^GFP at MOI (Multiplicity of Infection) of 2 PFU/cell in the presence of pineapple juice, mango or papaya pulps at 2000 µg/mL. Flow cytometric analysis of GFP fluorescence was performed 24 h post-infection. The results shown are means ± SD of three independent experiments and are expressed as relative value compared to untreated infected cells. (c) A549 cells were infected with ZIKV^GFP at MOI of 2 PFU/cell and continuously incubated with different concentrations (125–2000 µg/mL) of papaya pulp extract. Flow cytometric analysis of GFP fluorescence was performed 24 h post-infection. The results shown are means ± SD of three independent experiments and are expressed as relative value compared to untreated infected cells. (d) A549 cells were infected with ZIKV-PF13 at MOI of 2 PFU/cell and continuously incubated with different concentrations of papaya pulp extract (31–2000 µg/mL). ZIKV progeny production was quantified by the plaque-forming assay. Data represent the means ± SD from four independent experiments. Statistical analyses were performed using a one-way analysis of variance (ANOVA) and Dunnett’s test for multiple comparisons (*** p < 0.001, **** p < 0.0001; n.s. = not significant).