The Anti-H3N2 Swine Influenza Virus Effect And Mechanism Of Sophora’s Main Ingredients In Vitro

Swine Influenza(SI), caused by Swine Influenza Virus(SIV), is an acute, feverous, highly contagious respiratory disease. It is a commonly-occurring illness in large-scale pig farm with high morbidity and low mortality. SIV can make co-infection in pigs with other respiratory pathogens, leading to a sharp increase in the mortality, which usually bring huge economic loss to the pig industry. Pig is common susceptible host of swine flu, flu and avian flu. The influenza virus is easy to produce a new one by gene recombination in pig’s body. Meanwhile, SIV can not only infect pigs, but also infect other animals. Therefore, the study of SIV has an important meaning to veterinary infectious diseases and a more profound meaning to public health. The use of vaccine and antiviral medicine is often useless because of the variety of SIV serotype, the mutability of virus and the drug resistance, and there is no specific medicine for swine flu. So, the study of anti-SIV crude medicine and its active ingredients is imminent.Objective: The purpose of this study is to discuss the anti-H3N2 SIV effect of Sophora flavescens Ait’s main components on cell level. The results will provide a basis for further research on the mechanism of anti-flu, provide a scientific reference for clinical medication, and lay the foundation for the development of new anti-virus drugs.Methods: Traditional techniques of organic solvent extraction, water decoction and alcohol sedimentation were used to extract alkaloid, flavonoid, saponins and polysaccharide. Ribavirin was used as the positive control drug. MDCK cells were used as the acting cell system of SIV. CPE observation and MTT method were used to estimate MDCK cells’ state, so as to compare the anti-H3N2 SIV effect of alkaloid, flavonoid, saponins and polysaccharide. Then the inhibition mechanism was initially discussed through 4 different drug-delivery ways.Results: High dosage of alkaloid, flavonoid, saponins and polysaccharide can all affect the growth of MDCK cells, and the maximum safe concentration was from 6.9 μg/ml to 1.5138 mg/ml. Saponins had the highest maximum safe concentration. The study on the anti-H3N2 SIV effect of four components in vitro shows that the components can all significantly inhibit H3N2 sub-type SIV, and results of alkaloid and polysaccharide were better than ribavirin’s. In addition, ⑴Four components can all resist SIV’s adsorption, and saponins was more effective than ribavirin; ⑵Four components can all interfere virus’ replication, and alkaloid was more effective; ⑶All components had an inhibit-effect on virus as being added into cell culture with SIV at the same time, and saponins was more effective than ribavirin; ⑷Four components can all directly kill SIV in vitro, among which alkaloid was more effective. The minimum concentration of the four ingredients was from 0.1078 μg/ml to 19.2 μg/ml. Flavonoid had the lowest minimum concentration. The therapeutic index of the four ingredients was from 32 to 128, and saponins’ was the highest. In addition, alkaloids, flavonoid, saponins and polysaccharide were all dose dependent when added into cell culture with SIV at the same time.Conclusion: Alkaloids, flavonoid, saponins and polysaccharide of Sophora flavescens Ait all had anti-H3N2 SIV effect in vitro. Saponins had the strongest action on resisting virus’ adsorption and combination. Alkaloid had the strongest action on interfering virus’ replication and directly killing SIV.