In vitro anti-influenza virus (H1N1) activity of eleven species of Korean medicinal mushrooms

Abstract

Abstract Background: Oseltamivir is the most commonly used antiviral drug for the treatment and prevention of influenza. However, there are growing concerns about its use due to the risk of psychiatric side effects. Methods: Eleven species of edible medicinal mushrooms (Pleurotus ostreatus, Phallus rubrovolvata, Phallus luteus, Morchella esculenta, Grifola frondosa, Sarcodon imbricatus, Tricholoma bakamatsutake, Pachyma hoelen, Sparassis latifolia, Amanita caesareoides, and Marasmius siccus) were collected from forests in Korea to evaluate their anti-influenza A properties. After collection, the identification of each mushroom type was verified with internal transcribed spacer (ITS) gene sequencing using fungal-specific primers. Extracts were prepared by heating dried mushroom powder at 100℃ for 2 h. The cytotoxicity of the extracts was evaluated by MTT assay. The anti-influenza A properties of each extract were evaluated using the ASTM E1052-11 protocol, which is the international standardized approach. Results: The efficacy of the mushroom extracts against influenza A was evaluated using hot mushroom extract solutions, each of which had a concentration of 10 g powdered mushroom per liter of hot water. This ratio was selected as all of the mushrooms had little cytotoxic effect at this concentration. The influenza virus reduction titer of Pleurotus ostreatus was 5.519, with a virus removal efficacy of 99.999%. This was the highest antiviral efficacy among the 11 mushroom species. The virus inhibition titers of Phallus rubrovolvata and P. luteus were 4.477 and 2.247, respectively. Their virus inhibition efficacies were 99.997% and 99.433%, respectively. The efficacy of M. esculenta was 90.303%. The antiviral effects of Grifola% that of G. frondosawas 78.788%, and that of S. imbricatuswas 75.758%. The virus suppression efficacy of Tricholoma bakamatsutake and Pachyma hoelen were 66.667% and 63.636%, respectively. The extract solutions of the remaining three species (Sparassis latifolia, Amanita caesareoides, and Marasmius siccus) all showed a virus reduction efficacy of 60%. Conclusions: This study demonstrates the potential of mushroom extracts for medicinal use as antiviral treatments for influenza A infections.