基于NO抑制的三烯霉素A衍生物的设计、合成及神经保护活性作用研究

Neurodegenerative diseases are seriously threatening health of the people in the elderly. With the ageing population and increased cases of neurodegenerative diseases, there is a crucial need for the development of new strategies capable to prevent, delay the onset or treat brain dysfunction and associated cognitive decline. Oxidative stress and neuroinflammatory has recently been read as a common key element of pathogenic mechanisms of central nervous system diseases. The inhibition of NO, which is an important way against oxidative stress and neuroinflammatory for cells, and the pathways triggering its release are emerging as an important research focus in the search for strategies to prevent, halt or cure neurodegenerative diseases. Our previous studies have firstly proved that trienomycin A can inhibit NO and showed moderate neuroprotection activity in BV-2 cells. In this project we try to design and synthesize several series of derivatives with trienomycin A as the lead compound based on NO inhibition and evaluate their neuroprotective activities through the cell survival using BV-2 and PC12 cells as model. Furthermore, the action mechanisms of trienomycin A derivatives will be explored by biology techniques such as western blotting analysis and real-time reverse transcription-PCR (RT-PCR) to investigate the key targets and signaling pathways like iNOS, Nrf-2/HO-1 signaling pathways and so on. This project is expected to find 1-2 new lead compounds with improved neuroprotective activities, which provide pharmacy and pharmacology basis for developing novel candidate drugs targeted on the treatment of neurodegenerative diseases.

神经退行性疾病严重威胁着老年人的健康，随着人口老龄化的加剧，迫切需要有效的治疗策略出现。神经炎症及氧化应激是神经退行性疾病发生的重要途径，已成为神经退行性疾病研究的热点。课题组前期研究首次发现天然活性物质三烯霉素A对NO有着优异的抑制活性，具有良好的神经保护活性，基于此基础，本项目对三烯霉素A进行结构修饰和优化，以小胶质细胞BV-2和神经细胞PC12为模型，在NO抑制活性以及存活率分析的基础上对该类衍生物进行神经保护活性的筛选；以D-半乳糖所致的AD模型小鼠对活性优秀的化合物进行体内活性评价；最后通过蛋白质印迹法、RT-PCR等技术手段来初步探讨活性化合物作用的相关蛋白和信号通路（iNOS、Nrf-2/HO-1信号通路等）。期望发现1-2个有效的先导化合物，为发现新颖的治疗神经退行性疾病活性物质提供药学和药理学依据。

安莎霉素类天然产物往往表现出优异的抑制活性，具有良好的神经保护活性。其中以具有共轭多烯结构的三烯霉素A为代表。山东大学沈月毛课题组利用基因敲除的手段分离得到了三烯霉素的同系物-ansatrienol K，该天然产物与三烯霉素相比，具有独特的共轭二烯结构，本项目主要围绕其开展了合成研究及活性评估。其中利用钯催化的偶联反应实现了三取代苯环衍生物的高效构建；对其结构中具有的Z-三取代双键的构建采用了多种策略，包括Wittig烯基化反应、金属催化的硅氢化和锡氢化反应，最终利用Still-Gennari反应实现了构建，并利用Sakurai烯丙基化反应完成了相应片段的制备；同时利用Co2(CO)8介导的插羰反应和Julia-Kocienski烯基化反应实现了beta-羰基酸小片段的制备；两片段最后经过酰胺缩合和RCM反应实现了ansatrienol K的首次全合成。对其中间体及天然产物进行了活性测试，但未找到有明显NO抑制活性的化合物；本项目第二部分基于上述工作基础进行了拓展，其中针对沈月毛课题组分离的aminoansamycin D展开了合成探索，以三取代苯环衍生物为中间体，通过与手性小片段连接，拿到了关环反应的前体，但是利用RCM关环未获成功；另一方面，利用有机催化的[2+2]环加成反应实现了1,3-顺式二醇的高效构建，并应用于降血脂药物阿托伐他丁的合成，该药物分子的新工艺已经申请专利保护；同时利用分子内形式[3+2]环加成完成了具有潜在神经营养活性天然产物Codonopiloneolignanin A的全合成。