Assessment of in vitro and in vivo anti-influenza activity of propolis from karadeniz region

Propolis is a resinous substance obtained from enrichment of substances which are collected from different plants by bees, and has been reported to be effective in preventing and/or treat some sort of infections. In the present study, this view was challenged in vitro and vivo using influenza virus cell and host infection model. Influenza is an acute, contagious disease of the respiratory system, occurs in the form of epidemics affecting a wide range of ages from young children to elder people. There are a few of reports about the effects of propolis against influenza viruses. In this study we investigated in vitro and in vivo the anti-influenza effects of ethanolic and aqueous extracts of propolis collected from the north-eastern Black Sea Region. Our findings were that propolis prepared in ethanol or water had no direct anti- influenza effects in assay conditions where the virus was left to grow in susceptible cells in the presence of propolis extracts. However, it was shown that aqueous extract of propolis given to mice at 10mg/kg concentrations for 7 days prior to and during the first 6-7 days of the infection with live virus was protective in some respects. First finding was that aqueous extract was better in decreasing the virus titer in nasal washes of Balb/c mice at day four of non-lethal infection with influenza virus. Secondly, it was shown that aqueous extract of propolis was also protective against a sub-lethal challenge of mice with live influenza virus. As such that while only 3 of 11 mice survived in control group there were 8 mice surviving sub-lethal live influenza virus challenge suggestion some protective attributes to propolis. Our findings suggest that further studies are warranted to support our observations.