蜡梅属植物中乙酰胆碱酯酶抑制剂先导化合物的发现及构效关系研究

Alzheimer's disase (AD) is a chronic neurodegenerative disorder that results in the progressive and irreversible loss of higher brain functions, such as impaired memory, thinking and behaviour in the elderly. One of the well-established theory on the causes of AD suggests that the neurotransmitter acetylcholine levels are too low in the brains of AD patients. Current treatment approaches for this disease remain primarily symptomatic with major therapeutic strategy being based on the cholinergic hypothesis and specifically on the cholinergic inhibition. The first approved drug for the managentment of AD was tacrine. Although several acetylcholinesterase inhibitor have been developed, they are only useful for treating patients with mild to moderate AD. The development of more effective anti-AD agents is still an important area of AD-associated research. . Chimonanthus is a genus endermic to China.In the before research, we have found the cholinergic inhibition activity of the fractions isolated from Chimonanthus grammatus.So,we dicided to isolate and purify the constituents that have the ACh E inhibition activity from 3 species of the genus chimonanthus by means of column chromatography such as Si Gel,ODS, Shaphadex LH-20 guided by TLC-bioautography, the stuctures of the constituents will be elucidated on the basis of spectral analysis and chemical derivation.The AChE inhibitory activity of the pure constituents will be detected by Ellman's method.The structure-activity relationships of the pure constituents will be tested by 3D-QSAR.By means of these research works, we hope to find some AChE inhibitor leading compounds and give the evidences to chemotaxonomy of the chimonanthus.

阿尔茨海默病(AD)是一种原发性中枢神经系统退行性疾病，抗乙酰胆碱酯酶药物是AD靶向治疗的重要手段，是阿尔茨海默病新药研发的热点方向。申请者在对突托蜡梅化学成分进行系统分离纯化研究的过程中，发现其乙醇提取物及分离馏分显示较强的抗乙酰胆碱酯酶活性。本课题拟在此基础上，以薄层层析-生物自显影联用等活性检测方法为指导，采用多种分离纯化技术和GC-MS、LC-MS、HPLC-NMR联用等技术从突托蜡梅、山蜡梅和柳叶蜡梅等三种蜡梅属中定向追踪分离具抗乙酰胆碱酯酶活性的化合物；根据化合物的理化性质、波谱特征和HPLC手性表征等确定其化学结构；采用化学衍生化结构改造和体内活性检测方法探讨活性化合物抗乙酰胆碱酯酶的作用机制及构效关系，寻找结构新颖的抗乙酰胆碱酯酶化合物，为研制作用机制明确、副作用小的抗乙酰胆碱酯酶药物提供先导化合物，同时也为蜡梅属植物的科学分类提供化学分类学依据。

阿尔茨海默症 (AD)是一种中枢神经系统退行性疾病，至2014年1月全球痴呆症患者人数已达4400万，到2030年患病人数预计将达到7600万。医学上治疗AD多采用乙酰胆碱酯酶抑制剂 (AChEI)抑制AChE活性，延缓ACh水解的速度，提高突触间隙ACh的水平，从而发挥对AD的治疗作用。蜡梅属 (Chimonanthus)植物既是传统园林绿化树种，同时又是一种具有较高药用价值的传统中药材，对咳嗽、高血压等常见疾病有很好的疗效，在民间有较多应用，以蜡梅提取物为原料研制开发的药物也有上市。本项目是在体外抗乙酰胆碱酯酶活性筛选结果的指导下，采用现代分离纯化技术，分别对蜡梅属 (Chimonanthus)的三种植物蜡梅 (Chimonanthus praecox (Linn.) Link)、山蜡梅 (Chimonanthus nitens Oliv. )和突托蜡梅 (Chimonanthus grammatus M. C. Liu)的叶(花)的次生代谢产物进行了系统的分离纯化，分离、鉴定了有关化合物的结构。在此基础上，对部分化合物的作用机理进行了深入的分子水平研究。利用改良的Ellman法检测发现三种蜡梅属植物的乙酸乙酯萃取物对乙酰胆碱酯酶抑制作用最强。研究采用GC-MS 法分别从突托蜡梅、山蜡梅和蜡梅的石油醚萃取物中鉴定了33、47和54种化合物。采用硅胶柱层析、反向硅胶柱层析和葡聚糖凝胶柱层析多种柱层析方法，对突托蜡梅叶、山蜡梅和蜡梅乙醇提取物的乙酸乙酯萃取物进行了系统的分离纯化和结构鉴定研究，分离得到了20、22和15个单体化合物，包括β-谷甾醇 (β-sitosterol)；槲皮素 (quercetin)；山柰酚 (kaempferol)；异秦皮定7-羟基-6,8-二甲氧基苯并吡喃-2-酮(isofraxidin)；豆甾醇(stigmasterol)；7-羟基-6-甲氧基香豆素(scopoletin)；d-夏蜡梅碱(d-Calycanthine)；小檗碱 (Berberine)等。通过本项目的研究，比较全面的了解突托蜡梅、山蜡梅和蜡梅等蜡梅属植物的次生代谢产物产物的类型、结构和生物活性，为药用植物资源的有效开发利用提供依据，为蜡梅属植物的科学分类提供了有力的化学分类学证据。