Screening Of Traditional Chinese Medicine Monomer Compounds With Inhibition Of Influenza Neuraminidase Activity Based On Computer-aided Design

Influenza is an acute respiratory infection caused by the influenza virus.It poses a serious threat to human health every year and a huge burden on the world economy.Current research on influenza is mainly focused on the development of broad-spectrum influenza vaccines and anti-influenza drugs.Anti-influenza drugs have been an important and effective way to treat the influenza.In recent years,however,influenza virus resistance has increased,and drug-resistant influenza virus strains have been able to spread throughout the world.This has made resolving influenza virus resistance become the focus and hot spot for research on anti-influenza virus drugs.Traditional Chinese medicine has a long history of anti-influenza and has accumulated a large number of effective anti-influenza medicines and herbal complexes.Traditional Chinese medicine has a different anti-influenza mechanism than western medicine.Traditional Chinese medicine and traditional Chinese medicine compounds can often act on multiple targets in the process of influenza virus replication,and many traditional Chinese medicines can treat influenza by regulating the body's immunity.This makes it possible to use traditional Chinese medicine to solve the influenza virus resistance.At the same time,in view of the fact that NA plays an important role in the entire replication process of influenza virus,and Chinese medicine can effectively treat the influenza.These suggest that we may find components that inhibits NA in traditional Chinese medicine.However,the current research on traditional Chinese medicine and traditional Chinese medicine compound mainly focuses on the effect of anti-influenza,and there are few studies on its anti-influenza mechanism and components that exert anti-influenza effect.In II addition,the anti-influenza efficacy of traditional Chinese medicine and Chinese herbal compound has to be improved compared with western medicine such as oseltamivir etc..Drug Combination is an effective means to solve the emergence of drug resistance,reduce the amount dose of drugs,improve clinical efficacy and reduce drug side effects.Based on the above considerations,the main idea of this dissertation is to screen influenza virus neuraminidase inhibitors from the compounds of traditional Chinese medicines,in order to reduce the neuraminidase resistance and improve the efficacy of traditional Chinese medicine monomer compounds by combining with oseltamivir.In this paper,the following two parts are mainly studied:1.Screening NAI from a monomer compounds library of exterior-releasing,heat-clearing,and detoxicating traditional Chinese medicine and analysis of its interaction with NAFirst,three-dimensional crystal structures of two classical influenza A virus NA types(N1,N2)were retrieved from a protein database.All of the 3D structures of the NA proteins were de-watered,dehemated,etc.by Discovery Studio 2.5 software for future experiments.In the Chinese TCMs in Taiwan,a total of 59 kinds of herbal medicines for exterior-releasing,heat-clearing,and detoxicating were searched.A total of 2,981 monomer components of these traditional Chinese medicines for detoxification and detoxification were searched through the TCMs database,and their three-dimensional conformations were downloaded to form a library of small molecule compounds.Finally,using the Auto Dock4.2 software,N1,N2 as the target,respectively,the small molecular database for virtual screening.Candidate compounds were obtained by sequencing by binding energy for subsequent enzymatic experiments.The substrate fluorescence assay was used to examine the inhibitory activities of candidate Chinese herbal compounds on N1 and N2.The IC50 values of inhibition of N1 and N2 by various candidate Chinese medicine monomer compounds were obtained through experiments.Among them,5 kinds of Chinese herbal medicines were obtained.The compounds exhibited better inhibition effects on N1 and N2 with IC50 values less than 200 ?M.The docking of Chinese medicine monomer compound 1 and Chinese medicine monomer compound 2 to N1 and N2 were performed by Auto Dock4.2 software.The interaction between Chinese medicine monomer compound 1 and Chinese medicine monomer compound 2 and NA was analyzed.The results showed that the interaction between Chinese medicine monomer compound 1 and Chinese medicine monomer compound 2 and NA included hydrogen bonds,hydrophobic interactions,and electrostatic interactions.2.The inhibitory effect and mechanism of Chinese medicine monomer compound 1 and Chinese medicine monomer compound 2 combined with oseltamivir on NAThe combination of two or more drugs can solve the problem of influenza virus resistance,and it can improve the clinical efficacy of anti-influenza drugs and reduce the side effects of drugs.Therefore,the combined effect of Chinese medicine monomer compound 1 and Chinese medicine monomer compound 2combined with oseltamivir on the inhibitory effect of NA was studied by combination therapy and the effect of the combination of the two drugs was analyzed with the combination software Calcu Syn2.0.The experimental results showed that the CI values of the combination of Chinese medicine monomer compound 1 and oseltamivir on N1 and N2 were all less than 1,indicating that the combination of the two drugs showed a synergistic effect on the inhibition of N1 and N2.Combinations of Chinese medicine monomer compound 2and oseltamivir also showed synergistic effects on inhibition of N1,but the combination of both drugs showed antagonistic effects on inhibition of N2.In addition,the dose-reduction index(DRI)values for the combination of these two drugs with oseltamivir were all greater than 1,indicating the dose of both drugs was reduced,and this will help reduce the toxic side effects of drugs.The crystal structure of NA(N1,N2)combined with oseltamivir was found in the protein database,and then the Myricetin was docked with N1 and N2 combined with oseltamivir using Auto Dock4.2 software,and the interactions between the three was analyzed.Molecular docking results showed that the combination of Chinese medicine monomer compound 1 and oseltamivir increased the hydrogen bonding interaction with NA,which may be the reason for the synergistic effect of the combination of the two on the inhibition of NA.Through this study,two kinds of traditional Chinese medicine monomer compounds,Chinese medicine monomer compound 1 and Chinese medicine monomer compound 2,with good inhibitory effects on N1 and N2 were screened out.It was confirmed that the combination of Chinese medicine monomer compound 1 and western medicine oseltamivir exhibited a synergistic effect on the inhibition of NA,and could reduce the dose of each drug,reduce the toxic and side effects of the drug,and improve the curative effect.This study describes the effect and mechanism of TCM from the perspective of the synergistic effect of the combination of traditional Chinese medicine monomer compounds and Western medicine on the key enzyme NA of influenza virus,and provides a theoretical basis for the clinical application of integrated Chinese and Western medicine in the treatment of influenza.