The Synthesis And Anti Influenza Activity Study Of Multivalent Oseltamivir Conjugates

Influenza is an acute,fast-spreading respiratory disease that poses a huge threat to global health and a huge economic burden.Hemagglutinin(HA)and neuraminidase(NA)present on the surface of virus particles are two important proteins for virus infection of host cells,in which HA binds to terminal sialic acid residues of host cell surface glycoproteins and glycolipids,promotes cell entry and fusion,while NA cleaves sialic acid residues,mainly catalyzing the α-glycosidic bond of sialic acid(SA)residues at the terminal end of the host cell,which in turn releases progeny virus after assembly in the infected host cell,promoting infection spread.Zanamivir(ZA)and Oseltamivir(OS),two sialic acid(SA)analogs,are first-line NA inhibitor drugs for the treatment of influenza.However,due to the high mutation rate,a large number of drug-resistant strains have emerged.Several approaches have been employed to address influenza virus resistance: one strategy is to chemically modify the structure of existing OS;another parallel approach to the development of effective inhibitors is to introduce "cluster effects".It is proposed that the antiviral activity of drug-resistant strains can be significantly enhanced through multivalent effects.In this project,oseltamivir was used as raw material for structural modification,and the natural protein(bovine serum albumin,BSA)existing in plasma and polymaleic anhydride with more linking sites were selected as the construction of our sugar macromolecule The scaffolds,synthesized a set of oseltamivir protein conjugates and oseltamivir polymaleic anhydride conjugates.Multiple NA-resistant oseltamivirs linked to protein conjugates via a copper-free catalyzed "click" reaction and an aminolysis reaction enabled the successful coupling of oseltamivir monomers and polymers,which mimicked HA and NA natural receptors,thereby enhancing binding affinity.Characterization was performed using matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF-MS)to determine the number of oseltamivir conjugated on the surface of BSA,and the number of oseltamivir conjugated was calculated by gel permeation chromatography(GPC)assay.The neuraminidase inhibition experiments at the enzyme level and the cellular level show that both OS-BSA and OS-PM can enhance the affinity of OS and NA through the multivalent effect,which is comparable to the marketed drug zanamivir,and both have good effects.Antiviral activity.The results of cytopathic effect experiment(CPE)showed that the two multivalent conjugates could maintain normal cell morphology at 20 μM and effectively inhibit influenza virus.Dynamic light dispersion experiments(DLS)and virus capture experiments also fully demonstrated that these two multivalent conjugates can aggregate influenza virus in the aqueous phase and have the ability to capture influenza virus,both of which confirmed the multivalent The conjugates greatly improved the antiviral ability.