鼓槌石斛素衍生物的合成及抗胆碱酯酶活性评价

Synthesis and biological evaluation of chrysotoxine derivatives as cholinesterase inhibitors

目的:合成一系列鼓槌石斛素(chrysotoxine,CTX)环取代衍生物,并对其进行胆碱酯酶抑制活性评价。方法:以丁香醛为原料,以Wittig反应为关键步骤,通过乙酰基保护等7步反应合成天然联苄类化合物CTX,并在此基础上通过醚键或酯键合成环取代的CTX衍生物,采用改良Ellman法考察它们对胆碱酯酶的抑制活性,并通过分子对接模拟配体-蛋白作用方式。结果:共合成10个环取代CTX衍生物,结构经1H核磁共振(1H-NMR)、13C核磁共振(13C-NMR)和电喷雾电离质谱(ESI-MS)确证,体外对乙酰胆碱酯酶和丁酰胆碱酯酶表现出不同程度的抑制活性。对氯苯甲酸取代的CTX衍生物CTX-2的选择性最强,对乙酰胆碱酯酶的IC50为(11.05±1.12)μmol·L^(-1),选择性指数(SI)为7.26。分子对接结果显示CTX-2以"N型"构象与乙酰胆碱酯酶疏水口袋结合,键能为-10.2 kcal·mol^(-1)。结论:CTX-2具有胆碱酯酶抑制活性,有望进一步研究用于阿尔茨海默病的治疗。

Objective:To synthesize a series of ring-substituted chrysotoxine(CTX)derivatives and evaluate their cholinesterase inhibitory activities.Methods:CTX was totally synthesized by a 7-step reaction,in which syringaldehyde was used as the raw material and the Wittig reaction was taken as the key step.Based on the lead compound CTX,10 novel ring-substituted CTX derivatives were synthesized and their inhibitory activities against cholinesterase were investigated by Ellman method.Besides,the ligand-protein interaction mode between acetylcholinesterase and one of CTX derivatives with the best inhibition activities was simulated by molecular docking software AutoDock vina.Results:Ten ring-substituted CTX derivatives were synthesized and their structures were confirmed by 1H-NMR,13C-NMR and ESI-MS.The activity assay showed that all of the CTX derivatives possessed mild-to-moderate inhibitory activity against acetylcholinesterase and butyrylcholinesterase.Among them,CTX-2 had the strongest selectivity,of which the IC50 for acetylcholinesterase was(11.05±1.12)μmol·L^(-1) and the selectivity index(SI)was 7.26.Molecular docking result showed that CTX-2 binded to the acetylcholinesterase hydrophobic pocket in the"N-type"conformation and the bond energy was-10.2 kcal·mol^(-1).Conclusion:CTX-2 has good cholinesterase inhibitory activity,which suggested CTX-2 has the potential to be developed for the treatment of Alzheimer’s disease.