Berries as a potential anti-influenza factor - A review

Influenza is a highly dangerous disease, as it is connected with a risk of complications and in extreme cases - also death. Treatment based on virustatic drugs is not always effective, as mutations lead to the development of drug-resistant viruses. A relatively efficacious protection against influenza is provided by vaccinations; however, they are not very popular due to the common distrust in their efficacy and concerns over their supposed adverse effects. Phytotherapy uses several raw materials which may be applied in the prevention and treatment of influenza. Plant origin materials of particular interest include berry fruits containing considerable amounts of bioactive compounds. The multifaceted health-promoting action of berry fruits is connected first of all with the presence of polyphenols. Antiviral activity against influenza viruses results from the presence of anthocyanins and other classes of flavonoids, proanthocyanidins and phenolic acids. An important group of compounds other than polyphenols, which may be readily used in influenza infections comprises polysaccharides. Research indicates that components of berry fruits may inhibit replication of the virus both directly and indirectly, e.g. by blocking surface glycoproteins of influenza virus and stimulating the immune system of the organism. In consequence to their properties berry fruits are raw materials of potential use in the prevention and treatment of influenza.