Combined effect of selected antiviral substances of natural and synthetic origin. II. Anti-influenza activity of a combination of a polyphenolic complex isolated from Geranium sanguineum L. and rimantadine in vivo.

The synergistic effect shown by the combination of a natural product, polyphenolic complex (PC) isolated from Geranium sanguineum L., and rimantadine (R) in vitro and in ovo [7], encouraged us to continue these studies by in vivo testing. A marked protective effect in experimental influenza virus A (H3N2) infection in mice was found when PC was applied nasally (i.n.) (1.0 mg/kg) only once 6 h before infection in combination with R applied orally in concentration 10.5 and 2.5 mg/kg 2h before and 2.24 and 48 h after viral inoculation (PI = 72.55%, 55% and 57.8% respectively).