New derivatives of 5,10-dihydro-11H-dibenzo[b,e][1,4]diazepine-11-ones with anticholinergic activity

Starting from 2-aminobenzoic acid and correspondingly substituted 2-chloronitrobenzenes, 5-substituted-aminoacyl-5,10-dihydro-11H-dibenzo[b,e][1,4]diazepin -11- one derivatives with a differently high activity on ulcers were prepared. 8-Chloro-5,10-dihydro-5-[bis(2-hydroxyethyl)a-minoacetyl]-11H- dibenzo[b,e][1,4]diazepin-11-one hydrochloride (AWD 26-06) was selected for further clinical evaluation.     

Inactivation of cholinesterase induced by chlorpromazine cation radicals

To clarify the mechanism of the side effect of chlorpromazine, we examined the inactivation of cholinesterase induced by chlorpromazine. Cholinesterase was inactivated and its activity was lost in rat serum during interaction of chlorpromazine with horseradish peroxidase and H2O2. When chlorpromazine was oxidized by horseradish peroxidase and H2O2, the reaction solution colored pink and the visible absorption spectrum was consistent with the absorption spectrum of the chlorpromazine cation radical (CPZ*+). Adding cholinesterase immediately decreased the pink color of CPZ*+, indicating that CPZ*+ directly attacked cholinesterase to cause loss of the enzyme activity. Tryptophan residues in cholinesterase sharply decreased during the interaction of cholinesterase with horseradish peroxidase and H2O2. Presumably, loss of tryptophan residues changed the conformation of the cholinesterase protein and then the activity of the enzyme was lost. Other phenothiazine derivatives, including promethazine, triflupromazine, trifluoperazine, trimeprazine, thioridazine and perphenazine, also inactivated cholinesterase during the oxidation by horseradish peroxidase and H2O2. These results suggest that phenothiazine cation radicals participate in toxicological signs caused by the drugs.     

Design,synthesis and cholinesterase inhibitory evaluation study of fluorescent <Emphasis Type="Italic">N</Emphasis>-benzylpiperidine-4-one derivatives

Some N-benzylpiperidine-4-one derivatives were synthesized via one-pot three-component protocols in excellent yields, and were evaluated for their potential cholinesterase inhibition. The mono-substituted derivatives except 4b showed butyrylcholinesterase selective, while unsubstituted and di-substituted derivatives showed acetylcholinesterase selective inhibitions. It is interesting to note that all the mono-substituted derivatives showing butyrylcholinesterase inhibitory activity were more potent than galanthamine. Compound 4c bearing ortho-methoxy group showed the most potent, mixed-mode inhibitory activity on both acetylcholinesterase and butyrylcholinesterase with IC₅₀ 5.67 and 0.87?μM, respectively. Molecular docking revealed that compound 4c had hydrophobic interactions and hydrogen bonding at the catalytic triad and choline binding sites of the enzymes. In conclusion, this simple and cheaper synthesis method yielded derivatives with good cholinesterase inhibition and favorable photophysical properties.     

Anticholinesterase activity and structure activity relationships of a new series of hemicholinium-3 analogs

Piperidine derivatives of hemicholinium-3 were synthesized and included the following spacing groups between the bis-cationic heads: trans,trans-bicyclohexyl, phenanthrene, naphthalene and biphenyl. Anticholinesterase activity was determined using rat striatal synaptosomal cholinesterase, bovine erythrocyte acetylcholinesterase and horse serum butyrylcholinesterase. Hemicholinium-3 has little anticholinesterase activity but when the choline moiety of hemicholinium-3 is replaced with selected heterocyclic amine ring systems active inhibitors can be obtained. Results in this communication identify several quaternary amines which are equipotent with physostigmine for inhibition of cholinesterase. Several tertiary amines were also found to be active. Optimal anticholinesterase activity of these piperidine derivatives appear to be related to the necessity of 14 A interatomic distance between the cationic heads as well as C = O substitution in the phenylethyl spacing moiety. Reduction of C = O to secondary alcohol or CH2 results in decreased activity. The anticholinesterase activity is not only related to internitrogen distance and C = O substitution but also structural planarity and positional isomerism of the quaternary cationic head.     

Design,synthesis and the evaluation of cholinesterase inhibition and blood-brain permeability of daidzein derivatives or analogs

In the present study, a series of derivatives and analogs of daidzein were designed and synthesized to investigate cholinesterase inhibition and blood–brain barrier permeability. The enzyme assay showed that most of the compounds containing a tertiary amine group exhibit moderate cholinesterase inhibition, 7-hydroxychromone derivatives (absence of B ring of daidzein scaffold) only have a weaker bioactivity, while those compounds without the tertiary amine group have no bioactivity. Among them compound 15a (4’-N,N-dimethylaminoethoxy-7-methoxyisoflavone) appeared the best inhibitory activity (IC₅₀: 2.14 ± 0.31 μmol/L) and higher selectivity for AChE over BuChE (Ratio: 7.07). It was selected for the further investigation by UPLC-MS/MS. The results show that C_Brain/Serum of compound 15a in mice was more than 2.87 within 240 min. This discovery may provide worthy information for the future development of central nervous drugs including but not limited to cholinesterase inhibitors.     

Synthesis and acetylcholinesterase and butyrylcholinesterase inhibitory activities of 7-alkoxyl substituted indolizinoquinoline-5,12-dione derivatives

A series of novel 7‐alkoxyl substituted indolizinoquinoline‐5,12‐dione derivatives were synthesized. The cholinesterase inhibition assays indicated that most synthesized compounds exhibited good activity for acetylcholinesterase (AChE) and high selectivity index of AChE over butyrylcholinesterase (BuChE). Compound 12b exhibited the most potent AChE inhibitory activity with an IC₅₀ value of 0.068 µM and the highest selectivity index of 144. Kinetic study of AChE indicated that a mixed type of inhibition pattern existed for these indolizinoquinoline‐5,12‐dione derivatives. Molecular docking study indicated that compound 12b could bind to both the catalytically active site and the peripheral anionic site of AChE.     

Comparison of inhibitory activities of donepezil and other cholinesterase inhibitors on acetylcholinesterase and butyrylcholinesterase in vitro

This study was designed to compare the in vitro inhibitory effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) of donepezil and some other cholinesterase (ChE) inhibitors which have been developed for the treatment of Alzheimer's disease. The carbamate derivatives physostigmine and rivastigmine needed preincubation to exhibit appropriate anti-ChE activity. The maximum ChE inhibition by physostigmine developed within 30-60 min, while the inhibitory effect of rivastigmine on AChE and BuChE activities reached its peak after 48 and 6 h, respectively. The order of inhibitory potency (IC50) towards AChE activity under optimal assay conditions for each ChE inhibitor was: physostigmine (0.67 nM) > rivastigmine (4.3 nM) > donepezil (6.7 nM) > TAK-147 (12 nM) > tacrine (77 nM) > ipidacrine (270 nM). The benzylpiperidine derivatives donepezil and TAK-147 showed high selectivity for AChE over BuChE. The carbamate derivatives showed moderate selectivity, while the 4-aminopyridine derivatives tacrine and ipidacrine showed no selectivity. The inhibitory potency of these ChE inhibitors towards AChE activity may illustrate their potential in vivo activity.     

Novel N‐allyl/propargyl tetrahydroquinolines: Synthesis via Three‐component Cationic Imino Diels–Alder Reaction,Binding Prediction,and Evaluation as Cholinesterase Inhibitors

New N‐allyl/propargyl 4‐substituted 1,2,3,4‐tetrahydroquinolines derivatives were efficiently synthesized using acid‐catalyzed three components cationic imino Diels–Alder reaction (70–95%). All compounds were tested in vitro as dual acetylcholinesterase and butyryl‐cholinesterase inhibitors and their potential binding modes, and affinity, were predicted by molecular docking and binding free energy calculations (∆G) respectively. The compound 4af (IC₅₀ = 72 μm ) presented the most effective inhibition against acetylcholinesterase despite its poor selectivity (SI = 2), while the best inhibitory activity on butyryl‐cholinesterase was exhibited by compound 4ae (IC₅₀ = 25.58 μm ) with considerable selectivity (SI = 0.15). Molecular docking studies indicated that the most active compounds fit in the reported acetylcholinesterase and butyryl‐cholinesterase active sites. Moreover, our computational data indicated a high correlation between the calculated ∆G and the experimental activity values in both targets.     

Design, synthesis and biological evaluation of new 2-benzoxazolinone derivatives as potential cholinesterase inhibitors for therapy of alzheimer's disease

Currently acetylcholinesterase inhibitor (AChEI) therapy is one of the most frequently used methods in the treatment of Alzheimer's disease; tacrine, donepezil, rivastygmine and galantamine are applied in different stages of AD. In the present study, we propose a new series of 2-benzoxazolinone derivatives as potential cholinesterase inhibitors. These compounds were synthesized by condensation of 6-chloro acetyl-2-benzoxa zolinone with the corresponding amine and evaluated as acetylcholinesterase inhibitors using the colorimetric Ellman's method. Selectivity and the IC50 values were determined for the received derivatives. All tested compounds exhibited the inhibitory activity towards acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Compound 3e showed stronger activity than the standard tacrine, and compound 3a showed activity similar to that of tacrine for AChE. Compounds 3a, 3b, 3c, and 3e showed stronger activity than the standard donepezil towards the inhibition of BChE, and the compound 3e showed stronger activity than donepezil towards AChE.     

2型糖尿病患者血清胆碱酯酶活性变化分析(附155例报告)

目的 探讨2型糖尿病患者血清胆碱酯酶的活性变化及临床应用价值.方法 选择本所门诊155例2型糖尿病患者为观察组,同期203例健康人为正常对照组,采用全自动生化分析仪检测血清胆碱酯酶活性.结果 观察组较对照组血清胆碱酯酶活性明显增高(P<0.05).结论 测定血清胆碱酯酶活性可作为2型糖尿病患者一项辅助检测指标.     

Automated Instrument Analysis of Cholinesterase Activity in Tissues From Carbamate-Treated Animals: A Cautionary Note

Summary: When using a spectrophotometric method to measure cholinesterase activity in carbamate-treated tissues, precautions must be taken to limit the reactivation of the inhibited cholinesterase. Many testing laboratories use automated instruments to measure cholinesterase activity, instruments that usually employ a spectrophotometric method. To date, there has been no systematic investigation of the validity of the cholinesterase data obtained from carbamate-treated tissues using these automated instruments. The purpose of this study was to compare the cholinesterase data obtained using an automated analyzer with those obtained using a radiometric assay (i.e., the optimal method for unstable inhibitors). Using both an automated analyzer and the radiometric method, cholinesterase activity was measured in whole blood and brain tissue taken from rats treated with various dosages of carbaryl. Reactivation occurred when using the automated instrument. In the brain tissue, cholinesterase activity of the treated tissues was as much as 16% higher with the automated method than with the radiometric method. In the whole blood, there was an 18-26% reactivation using the automated method. Further detailed analyses indicate that this reactivation is not due to the initial dilution required of the tissue sample for automated analysis. The results indicate that the length of the preincubation may be a major factor that encourages the reactivation of the cholinesterase activity; however, even when the preincubation period is minimized, reactivation still occurs.     

丁酰胆碱酯酶活性与急性心肌梗死患者预后的关系研究

目的 研究丁酰胆碱酯酶活性以及急性心肌梗死患者预后之间的关系.方法 将2012年1月至2017年1月本院收治的300例急性心肌梗死病例选为研究对象,依据丁酰胆碱酯酶活性差异分为低丁酰胆碱酯酶活性患者(A组,n=160)与高丁酰胆碱酯酶活性患者(B组,n=140).比较2组预后及各项临床指标.结果 2组吸烟史、性别组成、高血压、Killip分级以及HDL水平比较差异无统计学意义(P＞0.05);A组年龄、血清肌酸酐、死亡率明显高于B组,且BMI、丁酰胆碱酯酶活性、收缩压、舒张压、血糖、LDL、甘油三酯、总胆固醇及LVEF明显低于B组(P＜0.05).丁酰胆碱酯酶活性与年龄、血清肌酸酐呈负相关性,而与BMI、收缩压、舒张压、血糖、LDL、甘油三酯、总胆固醇及LVEF呈正相关性(P＜0.05).死亡率升高独立影响因素主要为丁酰胆碱酯酶活性降低、LVEF减小.结论 急性心肌梗死预后与丁酰胆碱酯酶活性存在相关性,患者死亡率升高主要独立因素包括丁酰胆碱酯酶活性,其测定可为患者治疗及预后提供一定指导.     

Multitargeted C9-substituted ester and ether derivatives of berberrubine for Alzheimer's disease: Design,synthesis, biological evaluation,metabolic stability,and pharmacokinetics

Berberrubine is a naturally occurring isoquinoline alkaloid and a bioactive metabolite of berberine. Berberine exhibits a wide range of pharmacological activities, including cholinesterase inhibition. The cholinesterase inhibitors provide symptomatic treatment for Alzheimer's disease; however, multitarget-directed ligands have the potential as disease-modifying therapeutics. Herein, we prepared a series of C9-substituted berberrubine derivatives intending to discover dual cholinesterase and beta-site amyloid-precursor protein cleaving enzyme 1 (BACE-1) inhibitors. Most synthesized derivatives possessed balanced dual inhibition (AChE and BChE) activity in the submicromolar range and a moderate inhibition against BACE-1. Two most active ester derivatives, 12a and 11d , display inhibition of AChE, BChE, and BACE-1. The 3-methoxybenzoyl ester derivative, 12a , inhibits electric eel acetylcholinesterase (EeAChE), equine serum butyrylcholinesterase (eqBChE), and human hBACE-1 with IC₅₀ values of 0.5, 4.3, and 11.9 μM, respectively and excellent BBB permeability (P_e = 8 × 10⁻⁶ cm/s). The ester derivative 12a is metabolically unstable; however, its ether analog 13 is stable in HLM and exhibits inhibition of AChE, BChE, and BACE-1 with IC₅₀ values of 0.44, 3.8, and 17.9 μM, respectively. The ether analog also inhibits self-aggregation of Aβ and crosses BBB (P_e = 7.3 × 10⁻⁶ cm/s). Administration of 13 at 5 mg/kg (iv) in Wistar rats showed excellent plasma exposure with AUC_0−∞ of 28,834 ng min/ml. In conclusion, the multitargeted berberrubine ether derivative 13 is CNS permeable and has good ADME properties.     

Synthesis and anticholinesterase activity of fumaramide derivatives

A series of fumaramide derivatives were synthesized from substituted benzanilines and their cholinesterase inhibitory activity was assayed according to Ellman’s method using galanthamine-HBr as the reference compound. Most of the fumaramide compounds showed inhibitory activity of both cholinesterase enzymes. Compounds 29 (IC₅₀ = 0.14 μM) and 30 (IC₅₀ = 16.50 μM) were found to be the most active inhibitors on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes, respectively. Molecular docking studies were performed with Surflex-Dock programme to provide the possible interactions between compounds and enzymes. A Lineweaver–Burk plot and molecular modelling studies showed that fumaramide compounds targeted both the catalytic anionic site and the peripheral anionic site of AChE. It was revealed that the nature of α,β-unsaturated 1,4-diketone moiety in fumaramide compounds brought about useful and efficient modification especially on AChE inhibition.     

In-silico identification of the binding mode of synthesized adamantyl derivatives inside cholinesterase enzymes

Aim:

To investigate the binding mode of synthesized adamantly derivatives inside of cholinesterase enzymes using molecular docking simulations.

Methods:

A series of hybrid compounds containing adamantane and hydrazide moieties was designed and synthesized. Their inhibitory activities against acetylcholinesterase (AChE) and (butyrylcholinesterase) BChE were assessed in vitro. The binding mode of the compounds inside cholinesterase enzymes was investigated using Surflex-Dock package of Sybyl7.3 software.

Results:

A total of 26 adamantyl derivatives were synthesized. Among them, adamantane-1-carboxylic acid hydrazide had an almost equal inhibitory activity towards both enzymes, whereas 10 other compounds exhibited moderate inhibitory activity against BChE. The molecular docking studies demonstrated that hydrophobic interactions between the compounds and their surrounding residues in the active site played predominant roles, while hydrophilic interactions were also found. When the compounds were docked inside each enzyme, they exhibited stronger interactions with BChE over AChE, possibly due to the larger active site of BChE. The binding affinities of the compounds for BChE and AChE estimated were in agreement with the experimental data.

Conclusion:

The new adamantly derivatives selectively inhibit BChE with respect to AChE, thus making them good candidates for testing the hypothesis that BChE inhibitors would be more efficient and better tolerated than AChE inhibitors in the treatment of Alzheimer''s disease.     

Focal bicuculline increases extracellular dopamine concentration in the nucleus accumbens of freely moving rats as measured by in vivo microdialysis

Donepezil hydrochloride (donepezil: E2020: (+/-)-2-[(1-benzylpiperidin-4-yl)methyl]-5,6-dimethoxy-indan-1-one monohydrochloride)) is a centrally acting acetylcholinesterase inhibitor developed for the treatment of Alzheimer's disease. In the present study, its inhibitory effect on the activity of cholinesterase ex vivo was evaluated in the brain, plasma, erythrocytes, heart, small intestine, liver and pectoral muscle of young adult as well as aged rats, in comparison with that of tacrine (9-amino-1,2,3,4-tetrahydroacridine hydrochloride). In aged animals, cholinesterase activity in heart, small intestine and pectoral muscle was lower, whereas that in plasma and liver was higher than in young rats. Both groups showed the highest levels in the brain. Donepezil, at doses of 1.25, 2.5 and 5 mg/kg, p.o., inhibited brain, plasma, erythrocyte, liver and pectoral muscle cholinesterase activity in young rats in a dose-dependent manner but had less effect on cholinesterase activity in heart and small intestine. In aged animals, inhibition of cholinesterase activity in the brain, erythrocytes and pectoral muscle by donepezil was more potent than that in young animals. Tacrine, at doses of 5, 10 and 20 mg/kg, p.o., dose-dependently inhibited cholinesterase activity in all tissues of both young and aged animals, but most potently in heart, small intestine and liver. The inhibition of cholinesterase activity by tacrine in the brain, plasma, erythrocytes, heart and liver was more potent in aged rats than in tissues of young rats. Brain and plasma concentrations of unchanged donepezil and tacrine were measured in the same animals as used for the cholinesterase inhibition study. Brain and plasma concentrations of donepezil and tacrine were higher in aged than in young animals. It is concluded that the inhibitory effects of donepezil and tacrine on cholinesterase activity are greater in aged than in young rats, owing to differences in the tissue concentrations of these compounds between young and aged animals. It is also suggested that the effect of donepezil on cholinesterase activity is more tissue-selective than that of tacrine.     

A mathematical model for evaluating the reaction of paraoxon with human serum cholinesterase and with polymorphic forms of paraoxonase

The inhibition of cholinesterase of human serum by paraoxon can be predicted by a mathematical model which considers two competing reactions for paraoxon: one, the direct interaction with cholinesterase, and the other, enzymatic hydrolysis by paraoxonase. On the basis of the residual cholinesterase activity at various times during the incubation with paraoxon, it is possible to determine the rate constants for the reaction of paraoxon with cholinesterase (k1), and the reaction with paraoxonase (k2), the latter being directly proportional to paraoxonase activity. The percentage of initial activity remaining as residual cholinesterase depends primarily upon the paraoxonase level; it is influenced only slightly by variations in initial cholinesterase levels within the normal range. From these results, we conclude that the residual cholinesterase activity test is, in fact, an indirect measure of serum paraoxonase activity; it has the same limitations and is no more reliable a means of differentiating individual paraoxonase genotypes than measuring the level of serum paraoxonase activity directly. Our model suggests that there are conditions where paraoxonase genotype may alter the clearance of paraoxon and in turn the reaction of paraoxon with target sites. Whether similar results would be obtained in vivo is unknown. Since this model predicts the degradation of paraoxon well in vitro, it may be possible to extend the model and predict the effect of paraoxonase genotype on the clearance of paraoxon in vivo.     

Novel heterobivalent tacrine derivatives as cholinesterase inhibitors with notable selectivity toward butyrylcholinesterase

Two series of novel heterobivalent tacrine derivatives were synthesized. A trimethoxy substituted benzene was linked to the tacrine moiety by a hydrazide-based linker. The compounds were evaluated as cholinesterase inhibitors, and trimethoxybenzoic acid derivatives with 11- or 12-atom spacers were the most potent inhibitors of human acetylcholinesterase. The inhibitors showed a surprising selectivity toward human butyrylcholinesterase, where several trimethoxyphenylpropionic acid derivatives had IC(50) values less than 250 pM.     

有机磷中毒患者血胆碱酯酶活性的变化规律及临床意义

目的研究急性有机磷中毒（AOPP）患者全血及血清胆碱脂酶（ChE）活性的变化规律。方法所有51例患者入院后均给予清除毒物、应用双复磷或氯磷定、阿托品及积极的对症支持治疗。分别于治疗前、治疗后6～12、24、48、72、96、120h及出院时抽末梢血测定全血及血清ChE活性,并于同期测定37名均为健康者血ChE活性作为正常对照。结果全血、血清ChE活性在中毒患者治疗前均较正常对照组明显降低（P〈0.01）,治疗后轻度患者的全血ChE活性恢复较快,至出院时基本恢复正常;中、重度患者的全血ChE活性于治疗后24h降至最低,于48h缓慢回升,至出院时仍未恢复至正常水平;3例死亡患者全血ChE活性持续不回升。血清ChE活性值波动较大,分布较离散,恢复相对较快。结论全血ChE活性是对急情有机磷中毒进行早期诊断,判断疗效和估计预后的重要指标,在治疗上具有重要的指导意义。     

Behavioral and biochemical effects of the carbamate insecticide,MOBAM

Decreases in rat plasma, erythrocyte and brain cholinesterase levels after intraperitoneal injection of 1 to 5 mg/kg of 4-benzothienyl-N-methylcarbamate (MOBAM) were compared with decrements in both spontaneous motor activity and conditioned avoidance performance produced by this compound. Significant effects were observed with all five measured phenomena at dosages producing no obvious clinical signs. In albino rats, a dosage of 2 mg/kg significantly depressed plasma and erythrocyte cholinesterase activity, and decreased motor activity 15 min after injection but only higher dosages (3 and 5 mg/kg) significantly depressed brain cholinesterase activity and avoidance performance. In Long-Evans rats, both brain cholinesterase activity and avoidance performance were significantly reduced by the lower (2 mg/kg) dosage. The avoidance impairments observed after 3 mg/kg could be prevented by prior injection with atropine sulfate. It is suggested that both central and peripheral cholinesterase changes are important in determining the nature of the behavioral effects observed after exposure to this compound.