Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka 142432, Russia.
Postovsky Institute of Organic Synthesis, Urals Branch of Russian Academy of Sciences, Yekaterinburg 620990, Russia.
Bioorg Chem. 2019 Oct;91:103097. doi: 10.1016/j.bioorg.2019.103097. Epub 2019 Jul 3.
To search for effective and selective inhibitors of carboxylesterase (CES), a series of 3-oxo-2-tolylhydrazinylidene-4,4,4-trifluorobutanoates bearing higher or natural alcohol moieties was synthesized via pre-transesterification of ethyl trifluoroacetylacetate with alcohols to isolate transesterificated oxoesters as lithium salts, which were then subjected to azo coupling with tolyldiazonium chloride. Inhibitory activity against porcine liver CES, along with two structurally related serine hydrolases, acetylcholinesterase and butyrylcholinesterase, were investigated using enzyme kinetics and molecular docking. Kinetics studies demonstrated that the tested keto-esters are reversible and selective mixed-type CES inhibitors. Analysis of X-ray crystallographic data together with our IR and NMR spectra and QM calculations indicated that the Z-isomers were the most stable. The kinetic data were well explained by the molecular docking results of the Z-isomers, which showed specific binding of the compounds in the CES catalytic active site with carbonyl oxygen atoms in the oxyanion hole and non-specific binding outside it. Some compounds were studied as inhibitors of the main human isozymes involved in biotransformation of ester-containing drugs, hCES1 and hCES2. Esters of geraniol (3d) and adamantol (3e) proved to be highly active and selective inhibitors of hCES2, inhibiting the enzyme in the nanomolar range, whereas esters of borneol (3f) and isoborneol (3g) were more active and selective against hCES1. Computational ADMET studies revealed that all test compounds had excellent intestinal absorption, medium blood-brain barrier permeability, and low hERG liability risks. Moreover, all test compounds possessed radical-scavenging properties and low acute toxicity. Overall, the results indicate that members of this novel series of esters have the potential to be good candidates as hCES1 or hCES2 inhibitors for biomedicinal applications.
为了寻找有效的、选择性的羧酸酯酶（CES）抑制剂，我们通过先将三氟乙酰乙酸乙酯与醇类物质进行预酯交换，以分离出作为锂盐的反式酯，然后再与甲苯重氮盐酸盐进行偶联反应，合成了一系列带有较高或天然醇部分的 3-氧代-2-（对甲苯基）腙基-4,4,4-三氟丁酸酯。采用酶动力学和分子对接法，研究了这些化合物对猪肝 CES 以及两种结构相关的丝氨酸水解酶（乙酰胆碱酯酶和丁酰胆碱酯酶）的抑制活性。动力学研究表明，所测试的酮酯是可逆的、选择性的混合类型 CES 抑制剂。X 射线晶体学数据分析以及我们的 IR 和 NMR 光谱和 QM 计算表明，Z-异构体是最稳定的。分子对接结果很好地解释了动力学数据，表明化合物在 CES 催化活性位点与氧阴离子空穴中的羰基氧原子特异性结合，而在其外部则是非特异性结合。一些化合物被研究为参与含酯药物生物转化的主要人类同工酶（hCES1 和 hCES2）的抑制剂。橙花醇（3d）和金刚烷醇（3e）的酯类被证明是 hCES2 的高效且选择性抑制剂，对该酶的抑制作用在纳摩尔范围内，而龙脑醇（3f）和异龙脑醇（3g）的酯类则对 hCES1 更具活性和选择性。计算的 ADMET 研究表明，所有测试化合物都具有良好的肠道吸收、中等的血脑屏障通透性和低 hERG 致心律失常风险。此外，所有测试化合物都具有自由基清除特性和低急性毒性。总的来说，这些结果表明，该系列酯类化合物具有成为用于生物医学应用的 hCES1 或 hCES2 抑制剂的潜力。
