Inhibitory Effects of Cordyceps militaris( Bombyx mori )Extract against Respiratory Syncytial Virus

[ Objective] This study aimed to investigate the inhibitory effects of 95%, 70% ethanol extracts and water extract of Cordyceps militaris （Bombyx mori）, on cells infected with respiratory syncytial virus （RSV）. [Method] Human embryonic kidney cells （HEK293, RSV virus-sensitive cells） were infected with respiratory syncytial virus and incubated with tissue cell culture method, to analyze the inhibitory effects of different extracts of Cordyceps militaris （Bombyx mori） on proliferation of RSV-infected cells by cytopathic effect （CPE） observation and tetrazolium salt reduction assay （ MTF method）. [ Result] Different extracts of Cordyceps militaris （Bombyx mori） were non-toxic to HEK293 cells. CPE occurred successively in various sample groups after 48 h, and the degree of CPE was reduced gradually with the increasing concentration. To be specific, 95 % ethanol extract （100 μg/ml）, 70% ethanol extract （100, 25 μg/ml） and water extract （100, 25 μg/ml） of Cordyceps militaris （BombTx mori） exhibited inhibitory effects against RSV subtype A; 70% ethanol extract （100, 25 μg/ml） and water extract （100, 25 μg/ml） of Cordyceps militaris （Bombyx mori） exhibited inhibitory effects against RSV subtype B; the effects of water extract （100 μg/ml） of Cordyceps militaris （Bombyx mori） on RSV subtypes A and B were similar to positive control group. However, different extracts of Cordyceps militaris （Bombyx mot/） with low concentrations （6.25, 1.56 μg/ml） exhibited no inhibitory effects against respiratory syncytial virus. [ Conclusion ] Cordyceps militaris （Bombyx mori） exhibited significant inhibitory effects against syncytial virus, and the inhibitory effects were related to the water soluble components.