Impact of propolis and/ or chitosan nanoparticles on H1N1 influenza A virus: In vitro study

The H1N1 influenza A virus is the leading cause of seasonal flu outbreaks in humans. Even if there are vaccines for it, it still causes devastating outbreaks and a lot of money to lose. This study aimed to investigate the antiviral efficacy of chitosan nanoparticles and/or propolis against the H1N1 virus. Nanoparticles were synthesized and characterized by transmission electron microscope (TEM). Cytotoxicity was assessed using the MTT assay on Vero cells, and antiviral efficacy was evaluated by calculating the median tissue culture infectious dose (TCID 50 ). Chitosan nanoparticles, with average diameters of 100–200 nm were successfully integrated with propolis extract forming rounded aggregates with average diameters ranging between 200 and 300 nm. Remarkably, cytotoxic concentrations against Vero cells for chitosan nanoparticles, propolis extract, and a combination of the two were 277.40 ± 14.94, 238.60 ± 12.25, and 440.10 ± 18.17 μg/mL, respectively. These concentrations indicate high cell viability (>90 %) at doses of 50, 50, and 100 μg/mL, respectively. To evaluate their antiviral effectiveness, the TCID 50 ratios of viral suspensions treated with propolis extract and/or chitosan nanoparticles were compared to those of untreated controls. The results showed that the antiviral activity against the H1N1 influenza A virus improved as the concentration of propolis alone or in the mixture increased, whereas chitosan nanoparticles alone did not exhibit antiviral properties. The findings shed light on the possible uses of propolis and chitosan as antiviral drugs against the H1N1 influenza A virus, which are novel, safe, and effective.