Influenza, a respiratory disease caused by influenza viruses, is still a worldwide threat with a high potential to cause a pandemic. Beside vaccination, only two classes of drugs are available for antiviral treatment against the pathogen. Cystus052, a plant extract from a special variety of Cistus incanus that is rich in polymeric polyphenols, exhibits antiviral activity against a broad range of pathogenic influenza viruses.
On a molecular basis Cystus052 acts by unspecific binding to the surface of the virus particle, thereby preventing viral attachment to cells. Scientists has demonstrated antiviral action of Cystus052 against all influenza viruses tested so far including subtypes H1N1, H5N1, H3N2 and H7N7. Because of the broad and unspecific action Cystus052 also is active in vitro against the novel H1N1 swine influenza viruses that have emerged in Mexico. Moreover, antiviral action has already been shown for human viruses of the same subtype (H1N1).
Cystus052 may have several advantages with regard to its use as an antiviral agent. First, the plant extract has been applied for centuries in traditional medicine without reports of adverse effects or allergic reactions. This apparent lack of side effects would even allow long-term prophylactic use. Furthermore, a broad and unspecific anti-pathogen action as shown for Cystus052 prevents emergence of viral resistance and the compound may also be active against opportunistic bacterial infections.
• Rainer H. Bubenzer, Berlin (November 2009).
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