CYSTUS052, a polyphenol rich plant extract, exerts potent anti-influenza virus activity in cell culture by blocking viral attachment to host cells

Infections with influenza A viruses still pose a major threat to humans and several animal species. The occurrence of highly pathogenic influenza viruses of H5N1 subtype capable to infect and kill humans highlights the urgent need for new efficient anti-viral drugs. Here we demonstrate that a polyphenol rich plant extract, CYSTUS052 from the Mediterranean plant Cistus incanus exerts a potent anti-influenza virus activity in cells infected with various influenza viruses including those of the H5N1 type [1]. CYSTUS052 did not exhibit apparent harming effects on cell viability, metabolism or proliferation [2]. Furthermore, viruses did not develop resistance to CYSTUS052 upon consecutive passaging. Mechanistically, the protective effect appears to be due to a binding of the CYSTUS052-ingredients to the virus surface, preventing virus-binding to cellular receptors. Thus, local application of CYSTUS052 to the respiratory tract may be a promising approach to prevent influenza virus infection.

References: 1. Droebner, K. et al. (2007) Antiviral Res. 76: 1–10.

2. Ehrhardt, C. et al. (2007) Antiviral Res. 76: 38–47.