白骨壤果实中抗血管性痴呆苯乙醇苷类化合物的定向发现及其调控Keap1-Nrf2-ARE信号通路研究

Vascular dementia (VD) refers to a kind of cognitive dysfunction syndrome induced by cerebrovascular diseases. Vascular dementia accounts for 68.5% of the prevalence according to current data from Chinese government reports. Along with the coming of aged society, the treatments of vascular dementia have increasingly become urgent, which are not only a serious social problem, but an important medical problem as well. The fruits of Avicennia marina are used as a folk food and herbal medicine in Beihai city, Guangxi province. In our previous study, we have discovered the fruits of A. marina are rich of characteristic phenylethyl glycosides. The fruits were collected, extracted and fractionated to yield five active parts (P1-P5) which contain phenylethyl glycosides and have protective effects potent on cognitive impairment induced by chronic cerebral hypoperfusion. The pyramidal neurons in the CA1 region of hippocampus in five parts group were tightly ranked in order, and the neurons were clear and moderate in size comparing with vehicle group. Initial searching for bioactive metabolites from Part 1 has led to the isolation of six phenylethyl glycosides (of which 3 compounds are new) showing protective effects potent on cognitive impairment induced by chronic cerebral hypoperfusion. In order to obtain highly efficient and specific anti-VD drugs with independent intellectual property, this project plans to systematically investigate the active anti-VD phenylethyl glycosides from the fruit of A. marina. The contents include: 1) targeted isolating phenylethyl glycosides from the Part 2 to Part 5 by HPLC-DAD(UV)-MS and various modern chromatography techniques; 2) determining the structures of phenylethyl glycosides by MS, 1D and 2D NMR, CD, ORD and chemical methods; 3) examining the activity of the isolated compounds based on the Morris water maze and Hematoxylin-Eosin (HE) staining and analyzing the Structure-Activity-Relationship (SAR) of phenylethyl glycosides; 4) studying the mode-of-action of lead compounds through activating Keap1-Nrf2-ARE signaling pathway in rats. The current research would provide fundamentally new phenylethyl glycosides as lead compound for treatment of vascular dementia.

血管性痴呆患病率占我国所有痴呆症的首位，随着老龄化社会的来临，血管性痴呆的防治已经成为急需解决的医学和社会问题。在前期研究中，我们对广西红树白骨壤果实的提取物进行了成分分离和活性筛选，发现5个富含苯乙醇苷类化合物的活性部位（P1-P5）能改善血管性痴呆大鼠认知能力并减少大鼠海马CA1区神经元细胞损伤，进一步从P1部位中分离到6个苯乙醇苷类单体化合物能显著改善血管性痴呆大鼠的认知能力。本项目拟运用HPLC-DAD(UV)-MS方法从P2-P5部位定向追踪分离苯乙醇苷类特征活性成分，运用现代波谱技术和化学手段鉴定单体化合物的结构，系统评价苯乙醇苷类化合物改善血管性痴呆大鼠的认知和对大鼠海马CA1区神经元细胞的保护能力，分析系列化合物的构效关系，并深入研究其对Keap1-Nrf2-ARE信号通路的影响，筛选出结构新颖、活性显著的苯乙醇苷类先导化合物，为研制治疗血管性痴呆的创新药物提供物质基础。

白骨壤为马鞭草科海榄雌属真红树植物，白骨壤果实为绿色，略呈浑圆心形，表面附有白色稀疏短柔毛，由于外形酷似绿色钱币，俗称“榄钱”。白骨壤果实醇提物经过模型小鼠口服验证属于无毒物质。白骨壤果实醇提物能够提升血管性痴呆大鼠学习记忆能力，增强氧化应激。高纯度苯乙醇苷类化合物能够改善血管性痴呆大鼠认知能力和保护大鼠海马CA1区神经细胞。通过定向追踪分离白骨壤果实醇提物中苯乙醇苷类化合物，共分离鉴定到31个苯乙醇苷类化合物，其中新化合物4个，测试活性和探讨构效关系，发现新化合物Marinoid J具有最好活性。Marinoid J能够提高模型大鼠脑部SOD、GSH-Px酶活力，减少有害物质MDA和NO的含量，呈现剂量正相关。Marinoid J能够调控氨基酸运输、血管发育等功能加速VD大鼠的神经修复，下调促凋亡蛋白PKC、PKCδ和活性氧生成途径蛋白RIP1、COX3等，间接或直接抑制VD大鼠脑部的神经细胞凋亡和活性氧增加，作用机制中涉及TRP、阿尔茨海默症、帕金森病等多条信号通路。项目组共发表标注基金号且直接相关论文7篇，其中SCI论文收录2篇。获得授权国家发明专利4件。主编出版著作1部。2人晋升正高职称，1人晋升副高职称，培养博士后1名，硕士研究生2名。