中国南海海岸红树真菌Xylaria sp.代谢产物在体外对乙酰胆碱酯酶活性的影响

目的:体外研究中国南海海岸红树林真菌Xylaria sp.代谢产物Xyloketal A～D对乙酰胆碱酯酶(AChE)活性的影响.方法:采用改良Ellmen法测定AChE活性,考察受试化合物在体外对AChE活性及其酶动力学特征的影响,并就这些化合物对AChE和丁酰胆碱酯酶(BuChE)的选择性进行比较.结果:xyloketal A～D在体外对AChE活性均有不同程度的抑制作用,并呈一定剂量依赖关系,IC50值分别为29.9、137.4、109.3和425.6 μmol/L.通过对AChE酶抑制动力学曲线进行分析发现,xyloketals对AChE的抑制表现为可逆非竞争性抑制.此外,对于另一种胆碱酯酶BuChE,阳性药维那克林及xyloketals均表现出一定降低作用,但相对而言xyloketals对AChE的选择性较强.结论:xlylketals在体外对AChE活性有可逆非竞争性抑制作用,表明该类化合物可能作为抗早老性痴呆(AD)药物进行开发,同时该结果亦提示,从海洋微生物代谢产物中寻找新型AChE抑制剂可能成为开发AD治疗药物中的新战略.

Effects of Metabolites of Mangrove Fungus Xylaria sp.From South China Sea Coast on the Activity of Acetylcholinesterase in Vitro

OBJECTIVE: To investigate the effects of metabolites of mangrove fungus Xylaria sp. from South China Sea Coast, xyloketal A-D, on the activity of acetylcholinesterase (AChE) in vitro. METHODS: Activity of AChE was determined by a modified method of Ellmen. The selectivity of the compounds for AChE and butyrylcholinesterase (BuChE) was also tested and compared with that of a positive control, velnacrine. The inhibitory properties of xylokets on AChE were characterized as well. RESULTS: AChE activity was inhibited by xyloketal A-D in a dose-dependent manner, their IC50 were determined to be 29.9, 137.4, 109.3 and 425.6 micromol/L, respectively. At the same time, velnacrine and all the four compounds showed inhibitory effects on BuChE in different degree, and the inhibitory activity of xyloketals on AChE was found to be reversible and noncompetitive. CONCLUSION: Xyloketal A-D can inhibit AChE as well as BuChE activity in vitro. So xyloketal A-D were likely considered as drug candidates against Alzheimer' s disease (AD) for further development.