Anti-influenza Mechanism Study Of Sialic Acid And Oleanolic Acid-Polymaleic Acid Conjugate

Influenza virus is a pathogen that causes severe respiratory disease.Influenza virus are divided into four subtypes,type A,B,C and D,the tetramer neuraminidase(NA)and trimer hemagglutinin(HA)which in the surface of influenza virus can be used as targets for the study of novel anti-influenza drugs.In this paper,the antiviral activity and mechanism of the prepared sialic acid-polymaleic acid conjugates was studied,NA inhibition assay(NAI)showed that IC50 value reached nanomolar level.The inhibition of virus-induced cytologic effects by sialic acid-polymaleic acid conjugate was studied at the cellular level,and the EC50 value reached nanomolar level.In order to study the mode of drug action,surface plasmon resonance experiment(SPR)、time of addition assay、hemagglutination inhibition assay(HAI),anti-adhesion experiment and virus capture assay showed that the conjugates could not only bind with virus NA and inhibit the enzyme activity,but also synergistically inhibit the early stages of influenza virus infection by capturing and aggregating them,thus sialic acid-polymaleic acid conjugates could significantly improve the antiviral effect.Inspired by the early and late stages of influenza virus infection were inhibited by sialic acid-polymaleic acid.On this basis,the antiviral activity of the synthesized oleanolic acid-polymaleic acid was evaluated and the mechanism of action was studied.HAI results showed that the Ki was 200 nM,meanwhile the EC50 was about 229 nM.In order to further determine the action of oleanolic acid-polymaleic acid conjugate on influenza virus,we conducted the SPR、NAI time of addition assay and virus capature assay,the results showed that it could not only have a good inhibitory effect by targeting HA,but also inhibited the release stage of virus infection.This inhibitory effect was not caused by binding with NA,instead of capturing the virus,so that the aggregation of progeny virus could not be released to achieve the inhibitory effect.The anti-influenza activity of sialic acid-polymaleic acid and oleanolic acid-polymaleic acid was systematically studied,it is further confirmed that their mechanism is to synergistic inhibit the early and late stages of influenza virus life cycle,production of these macromolecules will contribute to the development of novel polyvalent antiviral agents and virion-adsorbent material for the control and prevention of influenza.