The Study Of Scutcllaria Baicalensis Georgi Water Extraction Anti-RSV In Vitro

OBJECTIVE:In order to find the new drug for respiratory syncytial virus (RSV)infection treatment,we study effect and mechenism of anti-respiratory syncytial virus of the water extraction of Scutcllaria Baicalensis Georg.METHODS:We decoct the Chinese medicine Scutcllaria Baicalensis Georgi by adding water,then drainaging and filtering it under the negative pressure before we collect the filtrate.We concentrate the medicial solution and make it into Scutcllaria Baicalensis Georgi water extractiong using the method of vacuum evaporation.The cytotoxicity of Scutcllaria Baicalensis Georgi water extraction was tested by 3-(4,5-dimethylthiazole-2-yl)2, 5-diphenyl tetrazolium bromide)MTT assay and visual assessment using the method of cell culture in vitro.Antiviral activity of the Scutcllaria Baicalensis Georgi water extraction was tested by the method of cell culture using ribavirin as positive control.The median effective concentration(50%effective concentration,EC₅₀)of the Scutcllaria Baicalensis Georgi water extraction was tested by the plaque reduction method.Using the CPE inhibition assay,the cytopathic effect of the drugs in the time-course and the cytopathic effect of the drugs in the inhibition assay for virus absorption and penetration was tested,and the direct effect of it on RSV was also be determined.All date were analysed by software spss 13.0.RESULTS:The median cytotoxicity concentration(50%cytotoxicity concentration,CC₅₀)of Scutcllaria Baicalensis Georgi was 16.26 mg/ml and 16.32 mg/ml by visual assessment and MTT assay respectively.The median effective concentration(50%effective concentration,EC₅₀)of the extraction of Scutcllaria Baicalensis Georgi was 2.43mg/ml by the plaque reduction method.The media cytotoxicity concentration(50%cytotoxicity concentration,CC₅₀)of ribavirin was 0.42 mg/ml by visual assessment and it was 0.44 mg/ml by MTT assay.The median effective concentration (50%effective concentration,EC₅₀)of the extraction of ribavirin was 35.66μg/ml by the plaque reduction method.There was a dose-dependent response of Scutcllaria Baicalensis Georgi and ribavirin in inhibiting RSV, Both Scutcllaria Baicatensis Georgi water extraction and ribavirin can inhibit RSV adhesion to the cells(P＜0.01),they can also inhibit RSV penetrating into the cells(P＜0.05).In assaying its effect on virual growth, it showed obvious effect of inhibition on RSV when ribavirin was added at 2,4,6 hours and 8 hours after RSV infection(P＜0.01),but Scutcllaria Baicalensis Georgi had no effect of inhibition on RSV when it was added at 2,4,6 hours and 8 hours after RSV infection.Ribavirin displayed direct inhibition on RSV,but Scutcllaria Baicalensis Georgi did not show direct inhibition on RSV.CONCLUSIONS:1.Scutcllaria Baicalensis Georgi showed potent inhibition on RSV in vitro.There was a dose-dependent response of Scutcllaria Baicalensis Georgi in inhibiting RSV.2.Scutcllaria Baicalensis Georgi had antiviral effect when it was added at early stage of RSV infection,but it had no effect of inhibition on RSV when it added at middle and advanced stage of RSV infection.3.Scutcllaria Baicalensis Georgi water extraction could inhibit RSV adhesion to the cells,it also could inhibit RSV penetrating into the cells.