Phenolic acids from malt are efficient acetylcholinesterase and butyrylcholinesterase inhibitors

Anticholinesterase activities of mashes produced using wheat (‘Wheat Pale’) or barley malts (‘Pilsner’, ‘Pale Ale’, ‘Munich Light’, ‘Carahell’ or ‘Carared’) were studied by spectrophotometric method. The highest inhibition of acetylcholinesterase and butyrylcholinesterase was observed at 52 °C and/or 64 °C, followed by a decrease or stabilization of the activity at 72 °C. Changes in the total phenolics content in the test mashes were correlated with changes in the acetylcholinesterase and/or butyrylcholinesterase activities. Phenolic acids were singled out from phenolic compounds for more detailed studies owing to their simplicity and structural similarity to well‐known cholinesterase inhibitors. The main phenolic acids in the test malts were ferulic, gallic, p‐coumaric and vanillic acids followed by chlorogenic, caffeic, syringic, p‐OH‐benzoic, sinapic and protocatechuic acids. The anticholinesterase activities of the phenolic acids were studied using model standard solutions at concentrations similar to the maximal content of these compounds in the test mashes. Among the phenolic acids, p‐coumaric acid had the largest share in the anticholinesterase activity, even though it was present in the test mashes at a significantly lower concentration (~0.38 mm L^?1) than ferulic acid (~1.00 mm L^?1). Sinapic acid and p‐OH‐benzoic acid (0.03 and 0.01 mm L^?1, respectively) were equally efficient inhibitors as ferulic acid at ~1.00 mm L^?1. This preliminary study should be extended to other phenolic compounds from malt (wort) in the near future. Copyright © 2012 The Institute of Brewing & Distilling     

基于MnO2纳米片类氧化酶特性的有机磷农药荧光分析方法建立

利用MnO2纳米片类氧化酶特性并结合有机磷农药的酶抑制原理,构建一种快速、简便、高灵敏有机磷农药荧光分析方法。通过测定反应体系荧光强度前后的变化,可以检测样品中有机磷农药的含量。通过优化酶浓度、底物浓度和反应时间,发现乙酰胆碱酯酶浓度为9.375 U/L,底物浓度为10 mmol/L,反应时间为11 min时,该荧光分析方法检测性能最佳,对氧磷的动态检测范围为1.56～200 ng/mL,检出限达到0.5 ng/mL（RSN=3）,运用该方法测定标准添加的自来水、卷心菜、燕麦样品的回收率在83.4%～105.9%之间,表明该方法具有很高的灵敏度与准确性,为快速高灵敏测定有机磷农药提供一种新的可能。     

传感器法检测甲萘威残留的研究

利用固定化的乙酰胆碱酯酶(AChE)制作了一种可用于农药残留检测的快捷灵敏的传感器,并探讨了AChE的固定化技术。酶固定化实验确定:固定化载体为孔径0.45μm硝酸纤维素膜、保护剂牛血清白蛋白(BSA)浓度为1.0%、交联剂戊二醛浓度为5.0%时,固定化酶传感器具有较高的灵敏度和稳定性。用氨基甲酸酯类农药甲奈威为抑制剂,与GC法(GB14877-94)进行对比,当喷洒量为10.0mg.L-1时,GC法测定的结果为9.03mg.L-1,生物传感器法测定的结果为6.56mg.L-1,可以满足对甲萘威农药残留的快速检测要求。     

有机磷农药对乙酰胆碱酯酶活性的联合抑制作用

为研究二元有机磷农药对乙酰胆碱酯酶活性的影响，分别测定了21种有机磷农药对乙酰胆碱酯酶的半抑制浓度IC50在此基础上用等毒法测定了二元有机磷农药对乙酰胆碱酯酶的缺合抑制作用。结果表明有机磷农药对乙酰胆碱酯酶的联合抑制作用主要表现为协同作用与相加作用，拮抗作用较少发生。量子化学参数分析表明具有相似电子效应的二元混合有机磷农药对乙酰胆碱酯酶的抑制主要表现为协同作用，而电子效应相差较大的二元混合有机磷农药对乙酰胆碱酯酶的抑制主要表现为拮抗作用。     

乙酰胆碱酯酶抑制剂虚拟筛选方法研究

在虚拟筛选过程中，虚拟筛选策略和方法是获取结果的基础，但需要通过实验数据来检验。获得虚拟筛选合理的限制因素，将为大规模虚拟筛选提供方法依据。通过建立乙酰胆碱酯酶抑制剂的活性检测方法，检测了4000多个化合物的生物活性，并发现了34个活性较高的化合物，同时将设计的6个不同的虚拟筛选方法分别用于2个乙酰胆碱醋酶抑制剂虚拟筛选模型。将所预测的可能活性化合物及两模型共有的可能活性化合物分别与实验所得的活性化合物对照，综合分析讨论虚拟筛选乙酰胆碱酯酶抑制剂的重要因素和进一步富集活性化合物的方法，为大规模的虚拟筛选乙酰胆碱醋酶抑制剂提供可靠依据，并为其他基于蛋白酶结构的虚拟筛选提供参考。     

检测有机磷农药电流型胆碱酯酶传感器的研究进展

综述了检测有机磷农药电流型胆碱酯酶传感器的研究概况,对胆碱酯酶的固定化技术,工作电极的种类以及电化学修饰进行了探讨,并就其发展前景进行了展望。     

乙酰胆碱酯酶生物传感器法测定蔬菜水果中有机磷农药残留

研究一种快速简便测定蔬菜水果中有机磷农药残留的方法。利用乙酰胆碱酯酶生物传感器技术,以苹果、黄瓜为样品,采用标准加入法进行分析,测定蔬菜水果中有机磷农药残留。实验结果表明,该方法回收率在96.45%～100.12%,相对标准偏差为2.76%～3.09%,对马拉硫磷和甲基对硫磷的检出限分别为4.80×10-11、2.93×10-10mol/L。     

鲫鱼肝脏AChE的提取及有机磷农药对AChE的抑制效应研究

本研究利用淡水鲫鱼肝脏为主要原材料提取乙酰胆碱酯酶(acetylcholinesterase,AChE),并设计正交试验确定了鲫鱼肝脏中乙酰胆碱酯酶的最佳提取条件:通过酶抑制法衡量敌敌畏、辛硫磷、三唑磷、乐果等四种不同种类有机磷农药对粗酶液的抑制作用;将鱼肝和鱼脑中乙酰胆碱酯酶活性及蛋白含量的进行对比研究。研究结果表明:提取液pH值、提取液种类以及原料与提取液的质量体积比对酶液的活性影响显著;被测四种有机磷农药中,敌敌畏对AChE活性抑制作用最强。鱼脑的AChE比酶活是肝脏的AChE比酶活的3～7倍。     

海洋真菌抗老年痴呆相关活性成分的筛选与追踪研究

本文作者对44株海洋真菌的抗老年痴呆相关活性成分进行了筛选与追踪。采用DTNB法和DPPH自由基清除法分别评价其提取物抑制乙酰胆碱酯酶(AChE)和抗氧化活性,采用生物自显影和专一性显色剂分析活性物质多样性及结构类型,采用高分辨液质联用分析代表性菌株的活性代谢产物。发现共计32株菌在不同培养基中的发酵产物,显示了显著的双重活性,它们来自不同真菌类群。生物自显影显示它们可产生多样化活性成分,化学显色显示其活性成分可能为生物碱等含氮化合物、酚类及其他结构类型的天然产物。通过液质联用分析,发现一株真菌中分子式为C_(16)H_(13)NO_2的代谢产物具有较强抑制AChE活性。本研究表明海洋真菌是多样化抗老年痴呆活性物质的重要来源,为活性物质的后续分离鉴定奠定了基础。     

Structural Modifications on Chalcone Framework for Developing New Class of Cholinesterase Inhibitors

Due to the multifaceted pharmacological activities of chalcones, these scaffolds have been considered one of the most privileged frameworks in the drug discovery process. Structurally, chalcones are α, β-unsaturated carbonyl functionalities with two aryl or heteroaryl units. Amongst the numerous pharmacological activities explored for chalcone derivatives, the development of novel chalcone analogs for the treatment of Alzheimer’s disease (AD) is among the research topics of most interest. Chalcones possess numerous advantages, such as smaller molecular size, opportunities for further structural modification thereby altering the physicochemical properties, cost-effectiveness, and convenient synthetic methodology. The present review highlights the recent evidence of chalcones as a privileged structure in AD drug development processes. Different classes of chalcone-derived analogs are summarized for the easy understanding of the previously reported analogs as well as the importance of certain functionalities in exhibiting cholinesterase inhibition. In this way, this review will shed light on the medicinal chemistry fraternity for the design and development of novel promising chalcone candidates for the treatment of AD.