Development And Molecular Mechanism Investigation Of Natural Compounds With Antiviral Activity Against Influenza A Virus And Enterovirus71

The infectious diseases could lead to a wide range of regular or non-regular epidemic, and resulting in serious threat to human health. Recently, Influenza A Virus (IAV) and Enterovirus71(EV71) are two of the most popular epidemic viruses, particularly in the Asia-Pacific region. They break out more and more and more frequently with wider effect area each time. All of above necessitate effective treatments against them. In our study, new antiviral candidates were screened from natural medicinal compounds utilizing the cellular model of IAV and EV71infection. Furthermore, we demonstrated the underlying molecular mechanism of these screened compounds.As is well known, Highly Pathogenic Avian Influenza (HPAI) virus infection is known for to the initiation of severe pandemics epidemics, and its multivariate genetic mutation and drug resistance. Therefore, it is important to find new effective antiviral drugs against HPAI viruses. In this study, more than three hundreds of pure Traditional Chinese Medicinal Compounds (TCMC) were screened in MDCK cell line as a drug screening model against the HPAI H5N1virus with MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. Among these compounds, berberine (BR) and usnic acid (UA) stood out, not only for their significant antiviral activity, but also for their capability to improve the viability of host cells. Further studies demonstrated that BR and UA could inhibit virus replication by Hemagglutination Inhibition (HI) assay and Immunofluorescence assay. Then, we proved their inhibitory effect against the accumulation of influenza complementary RNA (cRNA) and messenger RNA (mRNA) using quantitative real-time PCR analysis. Subsequently, a mammalian two-hybrid analysis was carried out to verify the remarkable effect of BR on blocking the interaction between nucleoprotein (NP) and viral polymerase proteins polymerase basic protein2(PB2). All of above findings justified that BR and UA could serve as good candidates for anti-influenza medicine in future clinical trials.On the other hand, as a major public health issue across the Asia-Pacific region and even beyond, EV71could cause hand-foot-mouth disease, which happens mostly on children. Severe EV71infections could cause neurological complications, shock and associated with a high mortality rate. However, till now, the pathogenic mechanism of EV71has not been fully understood. Moreover, there is no specialized drug for the prevention and treatment of EV71. Hence, it is necessary and urgent to develop new therapies and drugs for its treatment. In our study, over two hundreds compounds obtained from Chinese medicinal plants were screened in vitro to examine their inhibitory effects against Enterovirus71(EV71). We found that Matrine, Ganodenic acid L13A and Ganodenic acid L13B have significant antiviral efficiency compared to other agents. Additionally, we identified that they could enhance the viability of cells during our experiments. Further studies demonstrated that the screened compounds are able to block the uncoating of EV71by computer modeling and molecular docking calculations.In conclusion, our study provides a collection of good candidates for the prevention and treatment of the two mentioned epidemics. Furthermore, our experimental and theoretical analysis offers more sound support for clinical treatments again the two viruses.