Study On The Activity Of Oseltamivir Carboxylate Derivatives Against N2 Avian Influenza Virus

Avian influenza?AI?is an acute,highly contagious and fatal zoonotic infectious disease caused by A avian influenza virus?AIV?.Neuraminidase is one of the major surface protein of avian influenza virus,playing an important role in replication and transmission of avian influenza virus.Therefore,it is one of the hot research directions in design of anti avian influenza virus inhibitors with neuraminidase as target at present.So far,the listed neuraminidase inhibitors are zanamivir,oseltamivir and preamivir.Studies have shown that avian influenza viruses have varying degrees of resistance to existing drugs.Therefore,the development of anti avian influenza drugs based on new targets and new structures is imminent.In 2013,Gao Fu academician research group in the analysis of N2-type neuraminidase structure,found that high concentrations of oseltamiviric carboxylate can induce rigid closure of the N2 type 150-loop open.This topic attempts to use the interaction of ligand with N2 to induce 150-loop opening,thus setting the direction for the design of high activity NA inhibitors.This thesis mainly consists of three parts.First,based on the protein structure of neuraminidase,19 kinds of target compounds?Lu17A1 Lu17A19?were designed by introducing groups such as arylmethyl,thienylmethyl,acyl and sulfonyl groups on the oxalic acid C-5 amino group.Second,the target compound was tested for anti-H5N2 activity on CEF cells.The inhibitory activity of the target compound was compared according to the IC₅₀ value of each compound.The experimental results show that Lu17A16,Lu17A17,Lu17A18,Lu17A7,Lu17A19 inhibitory activity is poor,Lu17A9,Lu17A10,Lu17A11,Lu17A13 inhibitory a ctivity is good,other compounds showed moderate inhibitory activity.In order to show that the target compound is indeed acting on N2 neuraminidase,the best activity of the target compound?Lu17A9?was selected to evaluate the neuraminidase activity.The results show that the target compound represented by Lu17A9 does act on N2 and can be used as N2 neuraminidase inhibitors.Thirdly,five compounds?Lu17A7,Lu17A9,Lu17A10,Lu17A11,Lu17A13?with good inhibitory activity were screened to detect their anti-H9N2 activity on chicken embryos.The chick embryo allantoic fluid was collected for hemagglutination test and fluorescent quantitative PCR detection,and the HA and CP values were obtained respectively.The results showed that the compounds corresponding to HA and CP had the same inhibitory a ctivity,which was consistent with the inhibitory activity against H5N2 in cells.The results of the above experimental results show that the structural characteristics of the compound have a certain effect on its inhibitory activity.Conclusions are as follows.First,the alkaline retention and introduction of hydrophobic substituents on C-5 amino of oseltamivir carboxylic are beneficial to increase the inhibitory activity of the compounds.The introduction of arylmethyl and thienylmethyl is beneficial to increase the inhibitory activity of the compounds.But the introduction of acyl groups and sulfonyl groups is not conducive to the increase of the inhibitory activity.Second,the relative position,the number and the size of substituents on the aryl group,and the presence of heteroatoms also have a certain effect on the inhibitory activity of the compounds.The presence of para-substituents on the aryl groups of the substituents is better than that of the meta-substituents.The activity is lower when there is a larger volume substituent or two excess substituents on the aryl group.The presence of heteroatom on aryl group of arylmethyl is relatively good.