Anti-influenza virus activity of propolis in vitro and its efficacy against influenza infection in mice

Background:

Propolis has been used worldwide as a dietary supplement to maintain and improve human health. We examined whether ethanol extracts of Brazilian propolis exhibit antiviral activity against influenza virus in vitro and in vivo.

Methods：

Among 13 ethanol extracts screened in a plaque reduction assay, four showed anti-influenza virusactivity. The anti-influenza efficiacy of the four extracts was further examined in a murine influenza virus infection model. The mice were infected intranasally with influenza virus. and the four extracts were orally administered at 10 mg/kg three times daily for seven successive days after infection．

Results：

In this infection model, only one extract, AF-08, was significantly effective at 10 mg/kg inreducing the body weight loss of infected mice. The doses of 2 and 10 mg/kg were also effective in prolonging the survival times of infected mice significantly but 0.4 mg/kg was not The anti-influenza efficacy of AF-08 at 10 mg/kg was confirmed in a dose-dependent manner in maice.
AF-08 at 10mg/kg significantly reduced virus yields in the bronchoalveolar lavage fluids of lungs in infected mice as compared with the control．The reduction of virus yields by AF-08 at 10 mg/kg significantly corresponded to those induced by oseltamivir at 1 mg/kg twice daily from day 1 to day 4 after infection.

Conclusion：

The Brazilian propolis AF-08 was indicated to possess anti-influenza virus activity and to amelio-rate influenza symptoms AF-08 may be a possible candidate for an anti-influenza dietary supplement for humans．