Inhibition of influenza virus protein synthesis by a plant preparation from Geranium sanguineum L.

A polyphenolic complex (PC) with antiviral properties has been isolated from the Bulgarian medicinal plant Geranium sanguineum L. A study was undertaken to investigate the effect of PC on virus-specific protein synthesis in influenza virus-infected cells. The expression of viral glycoproteins on the surface of chick embryo fibroblasts infected with virus A/FPV, strain Rostock (H7N1) was suppressed. Virus protein synthesis was selectively inhibited as shown by SDS polyacrylamide gel electrophoresis of 35S-methionine-labelled proteins and proteins immunoprecipitated with monoclonal antibodies. The inhibitory effect was dose-dependent and better pronounced when PC was applied after virus infection. Two variants of influenza virus FPV/Rostock with reduced drug susceptibility were selected. PC affected to a lesser extent the synthesis of viral proteins in cells infected with the variants as compared to the sensitive parental virus.