基于多靶点策略的氧化异阿朴菲衍生物的设计合成与抗阿尔茨海默病活性研究

Currently, drugs approved for Alzheimer's disease (AD) treatment are mainly acetylcholinesterase (AChE) inhibitors and NMDA antagonists. As single-target anti-AD drugs, both of them can only be employed to alleviate the symptoms of AD. Complete recovery seems impossible. Because of AD sharing multi-factorial pathogenic mechanism, much attention has been paid to the multi-target therapy and lots of multi-target agents were designed and synthesized. Oxoisoaporphine alkaloids were isolated from the rhizome of Menispermum dauricum DC. (Menispermaceae) which occurred widely in the People's Republic of China. The rhizomes of the plant were used in traditional Chinese medicine as an analgesic and antipyretic. We recently reported that synthetic derivatives of oxoisoaporphine alkaloids exhibited high acetylcholinesterase inhibitory activity and significant in vitro inhibitory activity toward the AChE-induced and self-induced β-amyloid (Aβ) aggregation. In the project, oxoisoaporphine alkaloids were chosen as lead compounds. Structural modification was carried out on several sites of 1-azabenzanthone (parent compound of oxoisoaporphine alkaloids) by dual-active sites hypothesis and the "multi-target-directed ligand" design strategy. Activities of anti-cholinesterase, β-amyloid antiaggregation, inhibition of β-secretase, antioxidant, anti-inflammatory and blood-brain barrier permeability for synthetical compounds will be tested. Acute toxicity and neuroprotection of new synthetical derivatives on Aβ42 transgenic drosophila model will also be evaluated. Structure activity relationship for above activities will be summarized. Finally the project will develop promising anti-Alzheimer drug candidates.

临床上用于治疗阿尔茨海默症(AD)的药物多属于针对单靶标的化合物，这类化合物可缓解AD 症状，但未能从根本上改善疾病状态或终止疾病的进程。因为AD 的发病机制很复杂，存在着多种假说。所以，针对AD多机制、多因素特点的多靶点治疗策略便成了AD治疗药物研发的热点和趋势。氧化异阿朴菲是一类从中药蝙蝠葛根茎中提取的具有抗炎和退热功能的生物碱，前期研究表明其衍生物同时具有抑制胆碱酯酶和Aβ聚集的活性。本项目以氧化异阿朴菲为先导，依据双中心和一药多靶理论的设计思想，在氧化异阿朴菲生物碱母环的多个位置进行结构改造。并对合成的衍生物的抗胆碱酯酶活性，抑制Aβ淀粉样蛋白聚集和β分泌酶活性，抗氧化活性，抗炎活性，血脑屏障透过能力和毒性进行系统评价；然后利用Aβ42转基因果蝇模型评价合成化合物的神经保护作用。最后总结出该类化合物产生上述生物活性的构效关系并且筛选出具有较高应用前景的抗AD候选化合物。

通过各种取代苯乙胺和取代邻苯二甲酸酐合成氧化异阿朴生物碱母环（1-氮杂苯并蒽酮）。在1-氮杂苯并蒽酮的6，8，9和11位等多个位点进行结构改造，通过亚甲基桥、烷胺基或烷酰胺基桥将一些抗氧化基团或抗炎基团与氧化异阿朴菲生物碱连接，并通过改变连接桥的长度，连接基团的结构，设计合成出71种基于氧化异阿朴菲的双分子衍生物。利用多功能酶标仪、CD光谱、紫外和荧光光谱等现代光学仪器设备系统评价合成的衍生物的抑制胆碱酯酶（包括AChE和BuChE），抑制Aβ聚集（包括Aβ的自聚集和AChE诱导的Aβ聚集）和抗氧化性能。利用小鼠小胶质细胞（BV-2）和巨噬细胞（RAW264.7）作为炎症模型研究化合物的体外抗炎活性。选用改进的平行人工膜透过率测试来评价和预测合成的化合物的血脑屏障透过能力。利用SH-SY5Y人神经母细胞瘤细胞评价合成衍生物的毒性和体外神经保护作用。利用果蝇对合成的氧化异阿朴菲衍生物进行体内毒性试验。通过Aβ42在果蝇神经系统表达的转基因果蝇模型评价合成的衍生物的体内神经保护作用。