Anti-influenza virus activity of Chaenomeles sinensis

Aim of the studyThis investigation evaluated anti-influenza virus activity of 50% ethanol extract of the fruit of Chaenomeles sinensis KOEHNE, which is widely used as a traditional Chinese medicine to treat throat diseases.Material and MethodsType A and B influenza viruses were treated with the extract at various concentrations for 1 h at room temperature; then the plaque titers of the treated viruses were determined. The neutralizing component in the extract was partially purified using HP20 column chromatography.ResultsTreatment with the extract at concentrations greater than 5 mg/ml reduced the plaque titers of the both viruses to less than 10% of those of untreated viruses. The treatment inhibited viral hemagglutination activity, too. When the 50 mg/ml extract was added to the culture medium after inoculation of the virus, viral NS2 protein synthesis was selectively inhibited and progeny virus was not detected in the infected cell medium. Partial purification showed that the neutralizing component consisted of high molecular weight polyphenols.ConclusionHigh molecular weight polyphenols in the fruits of C. sinensis neutralizes influenza virus by inhibiting hemagglutination activity and by suppressing NS2 protein synthesis.