以齐墩果酸为先导物的流感病毒进入抑制剂研究

Due to the high mutation rate of gene replication of RNA viruses including influenza, traditional antiviral drugs lose their activities rapidly. However, the upstream of virus replication - virus entry the cell, involving the interaction of virus and host cells (low mutation rate), provides an efficient approach to reduce mutations of RNA viruses. Our previously study found that oleanolic acid exhibited anti-influenza entry activity. In this project, we will design and synthesize oleanolic acid derivatives bearing amino acid, neamine, oligosaccharide, sulfonamide etc. groups to investigate the structure activity relationship (SAR) of these compounds which can inhibit highly pathogenic influenza virus and develop the pharmacophore structure conserved in pentacyclic triterpene with high activity and low side effect. Next, we will adopt the biotin-label technology, HA assay to analyze the effect of active compounds on virus-cell interaction, and other experiments in the field of molecular biology to discover the molecular mechanism of anti-influenza activity of such compounds. This study will provide new clues for developing highly efficient and low toxicity anti-influenza agents, be helpful to understand the mechanism of antiviral activity of natural products, and also valuable for identification novel drug targets to develop novel antiviral drugs for influenza infection treatment and prevention.

流感病毒因其基因的高突变率，导致它对传统的抗病毒药物较易产生耐药性。而针对病毒进入阶段研发的药物，由于涉及到病毒与宿主细胞（低突变率）的相互作用，因此是延缓病毒产生耐药性的有效途径之一。本研究基于前期发现的能够抑制流感病毒进入细胞的齐墩果酸为基础，设计合成以氨基酸、新霉胺、寡糖、磺胺等功能片段修饰的齐墩果酸衍生物，借助高致病性流感病毒感染模型，系统地研究该类化合物抑制流感病毒进入细胞的构效关系，以期发现活性好、副作用低、成药性强的候选药物；并利用生物素标记活性成分、病毒血凝素与细胞融合实验等现代生物学方法揭示齐墩果酸及其衍生物抗流感病毒作用的分子机制。本研究对研制高效、低毒的抗流感病毒药物，阐明天然产物抗病毒的作用机理及新药靶点的发现均具有重要意义。

流感病毒因其基因的高突变率，导致它对传统的抗病毒药物较易产生耐药性。而针对病毒进入阶段研发的药物，由于涉及到病毒与宿主细胞（低突变率）的相互作用，因此是延缓病毒产生耐药性的有效途径之一。本项目建立了安全、可靠的抗流感药物细胞水平的筛选平台，通过检测流感病毒株A/WSN/33/2009(H1N1)引起MDCK细胞的病变程度，来反映化合物抗流感病毒作用的强弱。以前期研究为基础，对设计合成的多个系列齐墩果酸（OA）28位羧基修饰的化合物进行了抗流感病毒活性评价，总结了构效关系，并对活性较好的化合物抗流感病毒的广谱性进行评价，发现部分化合物对A/Victoria/361/2011(H3N2)，B/Yamagata/16/88(BY)，B/Sichuan/531/2018(BV)，B/Massachusetts/2/2012(BV)等多个亚型的毒株均具有显著的抑制作用，甚至强于奥司他韦。在此基础上，综合运用血凝抑制、表面等离子共振及分子对接等实验，对齐墩果酸衍生物抗流感病毒的作用机制进行了研究，进一步确证了这类化合物的作用靶点为流感病毒的血凝素蛋白（HA）。本研究不仅发现了数个活性较强且毒性较低的具有抗流感病毒进入活性的化合物，为五环三萜抗流感病毒药物的研究提供了基础，同时对阐明这类天然产物抗流感病毒的作用机理及新药靶点的发现具有一定意义。.本项目发表相关研究论文4篇，其中在本领域权威刊物European Journal of Medicinal Chemistry，Bioorganic & Medicinal Chemistry各发表论文一篇，申请国内发明专利4项。