The Effect Of Extract From Radix Isatidis On Influenza Virus FM1 Strain In Vitro And Vivo

Background: Influenza is a very common disease caused by influenza virus and isknown to be associated with respiratory tract. The prevalence of the disorder is veryhigh and it can spread among general population very fast. Hence, the research onnovel medicince has come to be more and more important. Some well-used medicineat current such as the admantane, virazole, appears to have obvious side effect. Thestudy on Chinese herb medicine and its complex prescription, theretbre, is gainingmuch advantage. The present study aiming to find new medicine for influenza, is toinvestigate the effect of extract from Radix Isatidis AA and A, on fighting againstinfluenza virus FM1 and on building up the immune system of ICR mice as well.Method: This is an observational study of the antiviral effects of AA and A, whichare extracted from Radix Isatidis in two different ways. The antiviral effects of extractfrom Radix Isatidis on influenza virus FM1 strain were observed by means of embryochicken and in vitro. In embryo chicken: The preparations are mixed with the virus invitro for 1 hour before being injected into embryo chicken. After cultivated for 3 daysin 35℃, the allantonic fluid from embryo chicken is collected and its hemagglutintiter was measured. In ICR mice aspect: we examined the performance of themedicine from three different functions: (1) anti-virus function: The 70 mice aresorted into 7 similar groups with 10 mice for each. In the first three days, themedicine were administered to them entogastrically at a dosage of 0.4mL/each. Thenevery group except for the medicine control group was challenged by the virusintranasally. This procedure is carried on for eight days and the mortality of the mice was recorded in entire 14 days. (2) Anti-inflammatory function: the procedure is thesame as administering the medicine and challenging virus mentioned above, and themice were sacrificed at the 9th day and their lungs were kept for pathologicalexamination. (3)Immunologic function: After having been infected virus and givenmedicine until the 9th day, the mice were sacrificed and the spleen were taken, thespleen T and B lymphocyte transformation experiments were therefore carried out.Several cytokines of the sera from the mice,like TNF-α,IFN-γ,IL-2,were alsosurveyed by ELISA.Results: (1) The extract of Radix Isatidis is able to inactivate the influenza virusFMI strain in embryo chicken. (2) The mortality of ICR mice has been reduced,meanwhile, their pathological change has been improved, and the immunologicalcells have been multiplied due to the presence of the Radix Isatidis extract. Comparedwith those from the virus control groups, the IFN-γand IL-2 level in the serum of thegroups treated with the medicine increased and the TNF-α, in constract, decreased.Conclusion: Radix Isatidis extract AA and A have antiviral effects on influenza virusFM1 strain in vitro and in vivo. They improve the immune system of ICR mice tosome extents. However the effects of Radix Isatidis extract AA and A has showed nodifference significantly between each other.