Novel coumarin derivatives bearing N-benzyl pyridinium moiety: potent and dual binding site acetylcholinesterase inhibitors.

PubMed

Alipour, Masoumeh; Khoobi, Mehdi; Foroumadi, Alireza; Nadri, Hamid; Moradi, Alireza; Sakhteman, Amirhossein; Ghandi, Mehdi; Shafiee, Abbas

2012-12-15

A novel series of coumarin derivatives linked to benzyl pyridinium group were synthesized and biologically evaluated as inhibitors of both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The enzyme inhibitory activity of synthesized compounds was measured using colorimetric Ellman's method. It was revealed that compounds 3e, 3h, 3l, 3r and 3s have shown higher activity compared with donepezil hydrochloride as standard drug. Most of the compounds in these series had nanomolar range IC(50) in which compound 3r (IC(50) = 0.11 nM) was the most active compound against acetylcholinesterase enzyme. Copyright © 2012 Elsevier Ltd. All rights reserved.

Old and new acetylcholinesterase inhibitors for Alzheimer's disease.

PubMed

Galimberti, Daniela; Scarpini, Elio

2016-10-01

To date, pharmacological treatment of Alzheimer's disease (AD) includes Acetylcholinesterase Inhibitors (AChEIs) for mild-to-moderate AD, and memantine for moderate-to-severe AD. AChEIs reversibly inhibit acetylcholinesterase (AChE), thus increasing the availability of acetylcholine in cholinergic synapses, enhancing cholinergic transmission. These drugs provide symptomatic short-term benefits, without clearly counteracting the progression of the disease. On the wake of successful clinical trials which lead to the marketing of AChEIs donepezil, rivastigmine and galantamine, many compounds with AChEI properties have been developed and tested mainly in Phase I-II clinical trials in the last twenty years. Here, we review clinical trials initiated and interrupted, and those ongoing so far. Despite many clinical trials with novel AChEIs have been carried out after the registration of those currently used to treat mild to moderate AD, none so far has been successful in a Phase III trial and marketed. Alzheimer's disease is a complex multifactorial disorder, therefore therapy should likely address not only the cholinergic system but also additional neurotransmitters. Moreover, such treatments should be started in very mild phases of the disease, and preventive strategies addressed in elderly people.

Distribution of intravenously administered acetylcholinesterase inhibitor and acetylcholinesterase activity in the adrenal gland: 11C-donepezil PET study in the normal rat.

PubMed

Watabe, Tadashi; Naka, Sadahiro; Ikeda, Hayato; Horitsugi, Genki; Kanai, Yasukazu; Isohashi, Kayako; Ishibashi, Mana; Kato, Hiroki; Shimosegawa, Eku; Watabe, Hiroshi; Hatazawa, Jun

2014-01-01

Acetylcholinesterase (AChE) inhibitors have been used for patients with Alzheimer's disease. However, its pharmacokinetics in non-target organs other than the brain has not been clarified yet. The purpose of this study was to evaluate the relationship between the whole-body distribution of intravenously administered (11)C-Donepezil (DNP) and the AChE activity in the normal rat, with special focus on the adrenal glands. The distribution of (11)C-DNP was investigated by PET/CT in 6 normal male Wistar rats (8 weeks old, body weight  = 220 ± 8.9 g). A 30-min dynamic scan was started simultaneously with an intravenous bolus injection of (11)C-DNP (45.0 ± 10.7 MBq). The whole-body distribution of the (11)C-DNP PET was evaluated based on the Vt (total distribution volume) by Logan-plot analysis. A fluorometric assay was performed to quantify the AChE activity in homogenized tissue solutions of the major organs. The PET analysis using Vt showed that the adrenal glands had the 2nd highest level of (11)C-DNP in the body (following the liver) (13.33 ± 1.08 and 19.43 ± 1.29 ml/cm(3), respectively), indicating that the distribution of (11)C-DNP was the highest in the adrenal glands, except for that in the excretory organs. The AChE activity was the third highest in the adrenal glands (following the small intestine and the stomach) (24.9 ± 1.6, 83.1 ± 3.0, and 38.5 ± 8.1 mU/mg, respectively), indicating high activity of AChE in the adrenal glands. We demonstrated the whole-body distribution of (11)C-DNP by PET and the AChE activity in the major organs by fluorometric assay in the normal rat. High accumulation of (11)C-DNP was observed in the adrenal glands, which suggested the risk of enhanced cholinergic synaptic transmission by the use of AChE inhibitors.

Pharmacological characterization of RS-1259, an orally active dual inhibitor of acetylcholinesterase and serotonin transporter, in rodents: possible treatment of Alzheimer's disease.

PubMed

Abe, Yasuyuki; Aoyagi, Atsushi; Hara, Takao; Abe, Kazumi; Yamazaki, Reina; Kumagae, Yoshihiro; Naruto, Shunji; Koyama, Kazuo; Marumoto, Shinji; Tago, Keiko; Toda, Narihiro; Takami, Kazuko; Yamada, Naho; Ori, Mayuko; Kogen, Hiroshi; Kaneko, Tsugio

2003-09-01

A dual inhibitor of acetylcholinesterase (AChE) and serotonin transporter (SERT), RS-1259 (4-[1S)-methylamino-3-(4-nitrophenoxy)]propylphenyl N,N-dimethylcarbamate (fumaric acid)(1/2)salt), was newly synthesized. RS-1259 simultaneously inhibited AChE and SERT in the brain following an oral administration in mice and rats. Actual simultaneous elevation of extracellular levels of 5-HT and ACh in the rat hippocampus was confirmed by microdialysis. The compound was as effective as SERT inhibitors such as fluoxetine and fluvoxamine in a 5-hydroxytryptophan-enhancing test in mice. Spatial memory deficits in the two-platform task of a water maze in aged rats were ameliorated by RS-1259 as well as donepezil. Both RS-1259 and donepezil increased the awake episodes in the daytime electroencephalogram of rats. Although RS-1259 was weaker than donepezil in enhancing central cholinergic transmission, as observed by ACh elevation in the hippocampus and memory enhancement in aged rats, the efficacy of RS-1259 on the consciousness level, which reflects the whole activity in the brain, was almost the same as that of donepezil. These results suggest that both cholinergic and serotonergic systems are involved in maintaining brain arousal and that a dual inhibitor of AChE and SERT may be useful for the treatment of cognitive disorders associated with reduced brain activity such as in Alzheimer's disease.

Acquisition and reinstatement of ethanol-induced conditioned place preference in rats: Effects of the cholinesterase inhibitors donepezil and rivastigmine.

PubMed

Gawel, Kinga; Labuz, Krzysztof; Gibula-Bruzda, Ewa; Jenda, Malgorzata; Marszalek-Grabska, Marta; Silberring, Jerzy; Kotlinska, Jolanta H

2016-07-01

The present study examined the influence of the cholinesterase inhibitors donepezil (a selective inhibitor of acetylcholinesterase) and rivastigmine (also an inhibitor of butyrylcholinesterase) on the acquisition and reinstatement of ethanol-induced conditioned place preference (CPP) in rats. Before the CPP procedure, animals received a single injection of ethanol (0.5 g/kg, 10% w/v, intraperitoneally [i.p.]) for 15 days. The ethanol-induced CPP (biased method) was developed by four injections of ethanol (0.5 g/kg, 10% w/v, i.p.) every second day. Control rats received saline instead of ethanol. Donepezil (0.5, 1 or 3 mg/kg, i.p.) or rivastigmine (0.03, 0.5 or 1 mg/kg, i.p.) were administered before ethanol during conditioning or before the reinstatement of ethanol-induced CPP. The cholinesterase inhibitors were equally effective in increasing (dose dependently) the acquisition of ethanol-induced CPP. Furthermore, priming injections of both inhibitors reinstated (cross-reinstatement) the ethanol-induced CPP with similar efficacy. These effects of both cholinesterase inhibitors were reversed by mecamylamine (3 mg/kg, i.p.), a nicotinic acetylcholine receptor antagonist, but not by scopolamine (0.5 mg/kg, i.p.), a muscarinic acetylcholine receptor antagonist. Thus, our results show that the cholinergic system is involved in the reinforcing properties of ethanol, and nicotinic acetylcholine receptors play an important role in the relapse to ethanol-seeking behaviour. © The Author(s) 2016.

Effect of Donepezil, Tacrine, Galantamine and Rivastigmine on Acetylcholinesterase Inhibition in Dugesia tigrina.

PubMed

Bezerra da Silva, Cristiane; Pott, Arnildo; Elifio-Esposito, Selene; Dalarmi, Luciane; Fialho do Nascimento, Kátia; Moura Burci, Ligia; de Oliveira, Maislian; de Fátima Gaspari Dias, Josiane; Warumby Zanin, Sandra Maria; Gomes Miguel, Obdulio; Dallarmi Miguel, Marilis

2016-01-11

Dugesia tigrina is a non-parasitic platyhelminth, which has been recently utilized in pharmacological models, regarding the nervous system, as it presents a wide sensitivity to drugs. Our trials aimed to propose a model for an in vivo screening of substances with inhibitory activity of the enzyme acetylcholinesterase. Trials were performed with four drugs commercialized in Brazil: donepezil, tacrine, galantamine and rivastigmine, utilized in the control of Alzheimer's disease, to inhibit the activity of acetylcholinesterase. We tested five concentrations of the drugs, with an exposure of 24 h, and the mortality and the inhibition of acetylcholinesterase planarian seizure-like activity (pSLA) and planarian locomotor velocity (pLMV) were measured. Galantamine showed high anticholinesterasic activity when compared to the other drugs, with a reduction of 0.05 μmol·min(-1) and 63% of convulsant activity, presenting screw-like movement and hypokinesia, with pLMV of 65 crossed lines during 5 min. Our results showed for the first time the anticholinesterasic and convulsant effect, in addition to the decrease in locomotion induced by those drugs in a model of invertebrates. The experimental model proposed is simple and low cost and could be utilized in the screening of substances with anticholinesterasic action.

Donepezil in the Treatment of ADHD-Like Symptoms in Youths with Pervasive Developmental Disorder: A Case Series

ERIC Educational Resources Information Center

Doyle, Robert L.; Frazier, Jean; Spencer, Thomas J.; Geller, Daniel; Biederman, Joseph; Wilens, Timothy

2006-01-01

Background: Recent studies reported ADHD-like symptoms and cognitive deficits in pervasive developmental disorder (PDD). Because work in dementia documents improvement in executive function deficits with the acetylcholinesterase inhibitor donepezil, the authors reason that similar benefits could be obtained in PDD. Method: The authors describe…

Cholinesterase inhibitors, donepezil and rivastigmine, attenuate spatial memory and cognitive flexibility impairment induced by acute ethanol in the Barnes maze task in rats.

PubMed

Gawel, Kinga; Labuz, Krzysztof; Gibula-Bruzda, Ewa; Jenda, Malgorzata; Marszalek-Grabska, Marta; Filarowska, Joanna; Silberring, Jerzy; Kotlinska, Jolanta H

2016-10-01

Central cholinergic dysfunction contributes to acute spatial memory deficits produced by ethanol administration. Donepezil and rivastigmine elevate acetylcholine levels in the synaptic cleft through the inhibition of cholinesterases-enzymes involved in acetylcholine degradation. The aim of our study was to reveal whether donepezil (acetylcholinesterase inhibitor) and rivastigmine (also butyrylcholinesterase inhibitor) attenuate spatial memory impairment as induced by acute ethanol administration in the Barnes maze task (primary latency and number of errors in finding the escape box) in rats. Additionally, we compared the influence of these drugs on ethanol-disturbed memory. In the first experiment, the dose of ethanol (1.75 g/kg, i.p.) was selected that impaired spatial memory, but did not induce motor impairment. Next, we studied the influence of donepezil (1 and 3 mg/kg, i.p.), as well as rivastigmine (0.5 and 1 mg/kg, i.p.), given either before the probe trial or the reversal learning on ethanol-induced memory impairment. Our study demonstrated that these drugs, when given before the probe trial, were equally effective in attenuating ethanol-induced impairment in both test situations, whereas rivastigmine, at both doses (0.5 and 1 mg/kg, i.p.), and donepezil only at a higher dose (3 mg/kg, i.p.) given prior the reversal learning, attenuated the ethanol-induced impairment in cognitive flexibility. Thus, rivastigmine appears to exert more beneficial effect than donepezil in reversing ethanol-induced cognitive impairments-probably due to its wider spectrum of activity. In conclusion, the ethanol-induced spatial memory impairment may be attenuated by pharmacological manipulation of central cholinergic neurotransmission.

Multi-Target Directed Donepezil-Like Ligands for Alzheimer's Disease

PubMed Central

Unzeta, Mercedes; Esteban, Gerard; Bolea, Irene; Fogel, Wieslawa A.; Ramsay, Rona R.; Youdim, Moussa B. H.; Tipton, Keith F.; Marco-Contelles, José

2016-01-01

HIGHLIGHTS ASS234 is a MTDL compound containing a moiety from Donepezil and the propargyl group from the PF 9601N, a potent and selective MAO B inhibitor. This compound is the most advanced anti-Alzheimer agent for preclinical studies identified in our laboratory.Derived from ASS234 both multipotent donepezil-indolyl (MTDL-1) and donepezil-pyridyl hybrids (MTDL-2) were designed and evaluated as inhibitors of AChE/BuChE and both MAO isoforms. MTDL-2 showed more high affinity toward the four enzymes than MTDL-1.MTDL-3 and MTDL-4, were designed containing the N-benzylpiperidinium moiety from Donepezil, a metal- chelating 8-hydroxyquinoline group and linked to a N-propargyl core and they were pharmacologically evaluated.The presence of the cyano group in MTDL-3, enhanced binding to AChE, BuChE and MAO A. It showed antioxidant behavior and it was able to strongly complex Cu(II), Zn(II) and Fe(III).MTDL-4 showed higher affinity toward AChE, BuChE.MTDL-3 exhibited good brain penetration capacity (ADMET) and less toxicity than Donepezil. Memory deficits in scopolamine-lesioned animals were restored by MTDL-3.MTDL-3 particularly emerged as a ligand showing remarkable potential benefits for its use in AD therapy. Alzheimer's disease (AD), the most common form of adult onset dementia, is an age-related neurodegenerative disorder characterized by progressive memory loss, decline in language skills, and other cognitive impairments. Although its etiology is not completely known, several factors including deficits of acetylcholine, β-amyloid deposits, τ-protein phosphorylation, oxidative stress, and neuroinflammation are considered to play significant roles in the pathophysiology of this disease. For a long time, AD patients have been treated with acetylcholinesterase inhibitors such as donepezil (Aricept®) but with limited therapeutic success. This might be due to the complex multifactorial nature of AD, a fact that has prompted the design of new Multi-Target-Directed Ligands

[Effects of the association of sulbutiamine with an acetylcholinesterase inhibitor in early stage and moderate Alzheimer disease].

PubMed

Ollat, H; Laurent, B; Bakchine, S; Michel, B-F; Touchon, J; Dubois, B

2007-01-01

The efficacy of the inhibitors of acetylcholinesterase in Alzheimer's Disease (AD) is moderated and some patients do not respond to these treatments. Sulbutiamine potentializes cholinergic and glutamatergic transmissions, mainly in hippocampus and prefrontal cortex. This multicentric, randomized and double-blind trial evaluates the effects of the association of sulbutiamine to an anticholinesterasic drug in cognitive functions in patients with AD at an early stage (episodic memory, working memory, executive functions, attention). Patients had first donepezil (D) or sulbutiamine (S) during three months. During this period, only attention improved in both groups. During the three following months, a placebo (P) in patients D and donepezil in patients S were added. Compared to entry results, episodic memory decreased in group D + P but improved in group S + D. At the same time the improvement of attention persisted in both groups. Daylife activities only improved in group S + D. In conclusion sulbutiamine can be an adjuvant to treatment in early stage and moderate AD by anticholinesterasic drugs.

Tacrine-based dual binding site acetylcholinesterase inhibitors as potential disease-modifying anti-Alzheimer drug candidates.

PubMed

Camps, Pelayo; Formosa, Xavier; Galdeano, Carles; Gómez, Tània; Muñoz-Torrero, Diego; Ramírez, Lorena; Viayna, Elisabet; Gómez, Elena; Isambert, Nicolás; Lavilla, Rodolfo; Badia, Albert; Clos, M Victòria; Bartolini, Manuela; Mancini, Francesca; Andrisano, Vincenza; Bidon-Chanal, Axel; Huertas, Oscar; Dafni, Thomai; Luque, F Javier

2010-09-06

Two novel families of dual binding site acetylcholinesterase (AChE) inhibitors have been developed, consisting of a tacrine or 6-chlorotacrine unit as the active site interacting moiety, either the 5,6-dimethoxy-2-[(4-piperidinyl)methyl]-1-indanone fragment of donepezil (or the indane derivative thereof) or a 5-phenylpyrano[3,2-c]quinoline system, reminiscent to the tryciclic core of propidium, as the peripheral site interacting unit, and a linker of suitable length as to allow the simultaneous binding at both sites. These hybrid compounds are all potent and selective inhibitors of human AChE, and more interestingly, are able to interfere in vitro both formation and aggregation of the beta-amyloid peptide, the latter effects endowing these compounds with the potential to modify Alzheimer's disease progression. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Progressive cholinergic decline in Alzheimer's Disease: consideration for treatment with donepezil 23 mg in patients with moderate to severe symptomatology.

PubMed

Sabbagh, Marwan; Cummings, Jeffrey

2011-02-07

Of the estimated 5.3 million people with Alzheimer's disease in the United States, more than half would be classified as having moderate or severe disease. Alzheimer's disease is a progressive disorder with the moderate to severe stages generally characterized by significant cognitive, functional, and behavioral dysfunction. Unsurprisingly, these advanced stages are often the most challenging for both patients and their caregivers/families. Symptomatic treatments for moderate to severe Alzheimer's disease are approved in the United States and include the acetylcholinesterase inhibitor donepezil and the glutamate receptor antagonist memantine. Progressive symptomatic decline is nevertheless inevitable even with the available therapies, and therefore additional treatment options are urgently needed for this segment of the Alzheimer's disease population. An immediate-release formulation of donepezil has been available at an approved dose of 5-10 mg/d for the past decade. Recently, the United States Food and Drug Administration approved a higher-dose (23 mg/d) donepezil formulation, which provides more gradual systemic absorption, a longer time to maximum concentration (8 hours) versus the immediate-release formulation (3 hours), and higher daily concentrations. Herein, we review (1) the scientific data on the importance of cholinergic deficits in Alzheimer's disease treatment strategies, (2) the rationale for the use of higher-dose acetylcholinesterase inhibitors in patients with advanced disease, and (3) recent clinical evidence supporting the use of higher-dose donepezil in patients with moderate to severe Alzheimer's disease.

The effect of donepezil on the cognitive ability early in the course of recovery from traumatic brain injury.

PubMed

Campbell, Kelsey A; Kennedy, Richard E; Brunner, Robert C; Hollis, Sean D; Lumsden, Ross A; Novack, Thomas A

2018-05-08

To investigate the effect of donepezil on cognitive ability in patients who have sustained a traumatic brain injury (TBI). We hypothesized that donepezil, an acetylcholinesterase inhibitor, would enhance cognitive recovery beyond that of usual care in an acute rehabilitation facility. This retrospective, longitudinal analysis included 55 patients who were non-randomly prescribed donepezil during acute care and compared them to 74 patients who received usual rehabilitation treatment. All 129 patients completed neuropsychological assessment at two time points. Donepezil was increased from 5 to 10 mg 7-10 days after initiation and maintained until follow-up cognitive assessment. Primary cognitive abilities of interest included processing speed, attention and memory. Cognitive and functional abilities were assessed by a standard neuropsychological battery for TBI. Propensity scores were used to adjust for differences between groups. Mixed effect model analysis showed no significant differences between treatment and control groups on all neuropsychological subtests over time. Acute administration of donepezil did not significantly improve measures of cognitive or functional ability beyond that of treatment as usual in patients with moderate-to-severe TBI.

Novel Triazole-Quinoline Derivatives as Selective Dual Binding Site Acetylcholinesterase Inhibitors.

PubMed

Mantoani, Susimaire P; Chierrito, Talita P C; Vilela, Adriana F L; Cardoso, Carmen L; Martínez, Ana; Carvalho, Ivone

2016-02-05

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder worldwide. Currently, the only strategy for palliative treatment of AD is to inhibit acetylcholinesterase (AChE) in order to increase the concentration of acetylcholine in the synaptic cleft. Evidence indicates that AChE also interacts with the β-amyloid (Aβ) protein, acting as a chaperone and increasing the number and neurotoxicity of Aβ fibrils. It is known that AChE has two binding sites: the peripheral site, responsible for the interactions with Aβ, and the catalytic site, related with acetylcholine hydrolysis. In this work, we reported the synthesis and biological evaluation of a library of new tacrine-donepezil hybrids, as a potential dual binding site AChE inhibitor, containing a triazole-quinoline system. The synthesis of hybrids was performed in four steps using the click chemistry strategy. These compounds were evaluated as hAChE and hBChE inhibitors, and some derivatives showed IC50 values in the micro-molar range and were remarkably selective towards hAChE. Kinetic assays and molecular modeling studies confirm that these compounds block both catalytic and peripheral AChE sites. These results are quite interesting since the triazole-quinoline system is a new structural scaffold for AChE inhibitors. Furthermore, the synthetic approach is very efficient for the preparation of target compounds, allowing a further fruitful new chemical library optimization.

Reversal of Acetylcholinesterase Inhibitor Toxicity In Vivo by Inhibitors of Choline Transport.

DTIC Science & Technology

1983-10-31

the increased interaction of acetylcholine with the receptor resulting from the inhibition of the enzyme acetylcholinesterase. . Acetylcholinesterase...competitive inhibitors of acetylcholine at the enzyme receptor. The second category, "reversible" cholinesterase inhibitors, form covalent bonds with the...method of Ellman et al. (46) was used to determine the acetyicholinesterase activity in mouse brain homogenates. Briefly, the enzyme activity was

Donepezil

MedlinePlus

... ability to think, learn, communicate and handle daily activities). Donepezil is in a class of medications called cholinesterase inhibitors. It improves mental function (such as memory, attention, ...

Exposure to acetylcholinesterase inhibitors alters the physiology and motor function of honeybees.

PubMed

Williamson, Sally M; Moffat, Christopher; Gomersall, Martha A E; Saranzewa, Nastja; Connolly, Christopher N; Wright, Geraldine A

2013-01-01

Cholinergic signaling is fundamental to neuromuscular function in most organisms. Sub-lethal doses of neurotoxic pesticides that target cholinergic signaling can alter the behavior of insects in subtle ways; their influence on non-target organisms may not be readily apparent in simple mortality studies. Beneficial arthropods such as honeybees perform sophisticated behavioral sequences during foraging that, if influenced by pesticides, could impair foraging success and reduce colony health. Here, we investigate the behavioral effects on honeybees of exposure to a selection of pesticides that target cholinergic signaling by inhibiting acetylcholinesterase (AChE). To examine how continued exposure to AChE inhibitors affected motor function, we fed adult foraging worker honeybees sub-lethal concentrations of these compounds in sucrose solution for 24 h. Using an assay for locomotion in bees, we scored walking, stopped, grooming, and upside down behavior continuously for 15 min. At a 10 nM concentration, all the AChE inhibitors caused similar effects on behavior, notably increased grooming activity and changes in the frequency of bouts of behavior such as head grooming. Coumaphos caused dose-dependent effects on locomotion as well as grooming behavior, and a 1 μM concentration of coumaphos induced symptoms of malaise such as abdomen grooming and defecation. Biochemical assays confirmed that the four compounds we assayed (coumaphos, aldicarb, chlorpyrifos, and donepezil) or their metabolites acted as AChE inhibitors in bees. Furthermore, we show that transcript expression levels of two honeybee AChE inhibitors were selectively upregulated in the brain and in gut tissues in response to AChE inhibitor exposure. The results of our study imply that the effects of pesticides that rely on this mode of action have subtle yet profound effects on physiological effects on behavior that could lead to reduced survival.

Exposure to Acetylcholinesterase Inhibitors Alters the Physiology and Motor Function of Honeybees

PubMed Central

Williamson, Sally M.; Moffat, Christopher; Gomersall, Martha A. E.; Saranzewa, Nastja; Connolly, Christopher N.; Wright, Geraldine A.

2013-01-01

Cholinergic signaling is fundamental to neuromuscular function in most organisms. Sub-lethal doses of neurotoxic pesticides that target cholinergic signaling can alter the behavior of insects in subtle ways; their influence on non-target organisms may not be readily apparent in simple mortality studies. Beneficial arthropods such as honeybees perform sophisticated behavioral sequences during foraging that, if influenced by pesticides, could impair foraging success and reduce colony health. Here, we investigate the behavioral effects on honeybees of exposure to a selection of pesticides that target cholinergic signaling by inhibiting acetylcholinesterase (AChE). To examine how continued exposure to AChE inhibitors affected motor function, we fed adult foraging worker honeybees sub-lethal concentrations of these compounds in sucrose solution for 24 h. Using an assay for locomotion in bees, we scored walking, stopped, grooming, and upside down behavior continuously for 15 min. At a 10 nM concentration, all the AChE inhibitors caused similar effects on behavior, notably increased grooming activity and changes in the frequency of bouts of behavior such as head grooming. Coumaphos caused dose-dependent effects on locomotion as well as grooming behavior, and a 1 μM concentration of coumaphos induced symptoms of malaise such as abdomen grooming and defecation. Biochemical assays confirmed that the four compounds we assayed (coumaphos, aldicarb, chlorpyrifos, and donepezil) or their metabolites acted as AChE inhibitors in bees. Furthermore, we show that transcript expression levels of two honeybee AChE inhibitors were selectively upregulated in the brain and in gut tissues in response to AChE inhibitor exposure. The results of our study imply that the effects of pesticides that rely on this mode of action have subtle yet profound effects on physiological effects on behavior that could lead to reduced survival. PMID:23386834

Repeated administration of an acetylcholinesterase inhibitor attenuates nicotine taking in rats and smoking behavior in human smokers

PubMed Central

Ashare, R L; Kimmey, B A; Rupprecht, L E; Bowers, M E; Hayes, M R; Schmidt, H D

2016-01-01

Tobacco smoking remains the leading cause of preventable death worldwide and current smoking cessation medications have limited efficacy. Thus, there is a clear need for translational research focused on identifying novel pharmacotherapies for nicotine addiction. Our previous studies demonstrated that acute administration of an acetylcholinesterase inhibitor (AChEI) attenuates nicotine taking and seeking in rats and suggest that AChEIs could be repurposed for smoking cessation. Here, we expand upon these findings with experiments designed to determine the effects of repeated AChEI administration on voluntary nicotine taking in rats as well as smoking behavior in human smokers. Rats were trained to self-administer intravenous infusions of nicotine (0.03 mg kg−1 per 0.59 ml) on a fixed-ratio-5 schedule of reinforcement. Once rats maintained stable nicotine taking, galantamine or donepezil was administered before 10 consecutive daily nicotine self-administration sessions. Repeated administration of 5.0 mg kg−1 galantamine and 3.0 mg kg−1 donepezil attenuated nicotine self-administration in rats. These effects were reinforcer-specific and not due to adverse malaise-like effects of drug treatment as repeated galantamine and donepezil administration had no effects on sucrose self-administration, ad libitum food intake and pica. The effects of repeated galantamine (versus placebo) on cigarette smoking were also tested in human treatment-seeking smokers. Two weeks of daily galantamine treatment (8.0 mg (week 1) and 16.0 mg (week 2)) significantly reduced smoking rate as well as smoking satisfaction and reward compared with placebo. This translational study indicates that repeated AChEI administration reduces nicotine reinforcement in rats and smoking behavior in humans at doses not associated with tolerance and/or adverse effects. PMID:26784967

Donepezil in Alzheimer’s disease: From conventional trials to pharmacogenetics

PubMed Central

Cacabelos, Ramón

2007-01-01

Donepezil is the leading compound for the treatment of Alzheimer’s disease (AD) in more than 50 countries. As compared with other conventional acetylcholinesterase inhibitors (AChEIs), donepezil is a highly selective and reversible piperidine derivative with AChEI activity that exhibits the best pharmacological profile in terms of cognitive improvement, responders rate (40%–58%), dropout cases (5%–13%), and side-effects (6%–13%) in AD. Although donepezil represents a non cost-effective treatment, most studies convey that this drug can provide a modest benefit on cognition, behavior, and activities of the daily living in both moderate and severe AD, contributing to slow down disease progression and, to a lesser exetnt, to delay institutionalization. Patients with vascular dementia might also benefit from donepezil in a similar fashion to AD patients. Some potential effects of donepezil on the AD brain, leading to reduced cortico-hippocampal atrophy, include the following: AChE inhibition, enhancement of cholinergic neurotransmission and putative modulation of other neurotransmitter systems, protection against glutamate-induced excitotoxicity, activation of neurotrophic mechanisms, promotion of non-amyloidodgenic pathways for APP processing, and indirect effects on cerebrovascular function improving brain perfusion. Recent studies demonstrate that the therapeutic response in AD is genotype-specific. Donepezil is metabolized via CYP-related enzymes, especially CYP2D6, CYP3A4, and CYP1A2. Approximately, 15%–20% of the AD population may exhibit an abnormal metabolism of AChEIs; about 50% of this population cluster would show an ultrarapid metabolism, requiring higher doses of AChEIs to reach a therapeutic threshold, whereas the other 50% of the cluster would exhibit a poor metabolism, displaying potential adverse events at low doses. In AD patients treated with a multifactorial therapy, including donepezil, the best responders are the CYP2D6-related extensive

Methodological improvements in quantifying cognitive change in clinical trials: an example with single-dose administration of donepezil.

PubMed

Pietrzak, R H; Maruff, P; Snyder, P J

2009-03-01

Change in cognitive function in response to a pharmacologic challenge can be observed with greater sensitivity by employing cognitive tests with optimal psychometric properties and a statistical approach that more accurately accounts for individual variability in performance. To demonstrate this approach we examined the cognitive effects of a single acute dose administration of an acetylcholinesterase inhibitor, donepezil, in healthy older adults and in older adults with mild Alzheimer's disease (AD). Placebo-controlled crossover study with three separate testing days: baseline, placebo, and donepezil, with assessments at baseline, and 1-, 2-, 3-, 6-, and 8-hrs post-dosing on each day. Early phase I clinical trial. 15 healthy older adults; 14 older adults with mild Alzheimer's disease. Single acute dose of 5mg donepezil. Performance on the Groton Maze Learning Test (GMLT), a computerized neuropsychological measure of spatial working memory and error monitoring. A single acute dose of donepezil improved GMLT performance in healthy older adults (effect size: 0.83 at 6 hrs post-dosing) and older adults with mild AD (effect size: 0.58 at 3 hrs post-dosing). The GMLT detected cognitive improvement following a single, acute dose administration of donepezil in healthy older adults and older adults with mild AD. The choice of cognitive tests designed for repeated administration, as well as an analytic approach that emphasizes individual-level change in cognitive function, provides a sensitive approach to detecting central nervous system drug penetration and activity of cognitive-enhancing agents.

Multipotent cholinesterase/monoamine oxidase inhibitors for the treatment of Alzheimer's disease: design, synthesis, biochemical evaluation, ADMET, molecular modeling, and QSAR analysis of novel donepezil-pyridyl hybrids.

PubMed

Bautista-Aguilera, Oscar M; Esteban, Gerard; Chioua, Mourad; Nikolic, Katarina; Agbaba, Danica; Moraleda, Ignacio; Iriepa, Isabel; Soriano, Elena; Samadi, Abdelouahid; Unzeta, Mercedes; Marco-Contelles, José

2014-01-01

The design, synthesis, and biochemical evaluation of donepezil-pyridyl hybrids (DPHs) as multipotent cholinesterase (ChE) and monoamine oxidase (MAO) inhibitors for the potential treatment of Alzheimer's disease (AD) is reported. The 3D-quantitative structure-activity relationship study was used to define 3D-pharmacophores for inhibition of MAO A/B, acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) enzymes and to design DPHs as novel multi-target drug candidates with potential impact in the therapy of AD. DPH14 (Electrophorus electricus AChE [EeAChE]: half maximal inhibitory concentration [IC50] =1.1±0.3 nM; equine butyrylcholinesterase [eqBuChE]: IC50 =600±80 nM) was 318-fold more potent for the inhibition of AChE, and 1.3-fold less potent for the inhibition of BuChE than the reference compound ASS234. DPH14 is a potent human recombinant BuChE (hBuChE) inhibitor, in the same range as DPH12 or DPH16, but 13.1-fold less potent than DPH15 for the inhibition of human recombinant AChE (hAChE). Compared with donepezil, DPH14 is almost equipotent for the inhibition of hAChE, and 8.8-fold more potent for hBuChE. Concerning human monoamine oxidase (hMAO) A inhibition, only DPH9 and 5 proved active, compound DPH9 being the most potent (IC50 [MAO A] =5,700±2,100 nM). For hMAO B, only DPHs 13 and 14 were moderate inhibitors, and compound DPH14 was the most potent (IC50 [MAO B] =3,950±940 nM). Molecular modeling of inhibitor DPH14 within EeAChE showed a binding mode with an extended conformation, interacting simultaneously with both catalytic and peripheral sites of EeAChE thanks to a linker of appropriate length. Absortion, distribution, metabolism, excretion and toxicity analysis showed that structures lacking phenyl-substituent show better druglikeness profiles; in particular, DPHs13-15 showed the most suitable absortion, distribution, metabolism, excretion and toxicity properties. Novel donepezil-pyridyl hybrid DPH14 is a potent, moderately selective h

Effects of donepezil on verbal memory after semantic processing in healthy older adults.

PubMed

FitzGerald, David B; Crucian, Gregory P; Mielke, Jeannine B; Shenal, Brian V; Burks, David; Womack, Kyle B; Ghacibeh, Georges; Drago, Valeria; Foster, Paul S; Valenstein, Edward; Heilman, Kenneth M

2008-06-01

To learn if acetylcholinesterase inhibitors alter verbal recall by improving semantic encoding in a double-blind randomized placebo-controlled trial. Cholinergic supplementation has been shown to improve delayed recall in adults with Alzheimer disease. With functional magnetic resonance imaging, elderly adults, when compared with younger participants, have reduced cortical activation with semantic processing. There have been no studies investigating the effects of cholinergic supplementation on semantic encoding in healthy elderly adults. Twenty elderly participants (mean age 71.5, SD+/-5.2) were recruited. All underwent memory testing before and after receiving donepezil (5 mg, n=11 or 10 mg, n=1) or placebo (n=8) for 6 weeks. Memory was tested using a Levels of Processing task, where a series of words are presented serially. Subjects were either asked to count consonants in a word (superficially process) or decide if the word was "pleasant" or "unpleasant" (semantically process). After 6 weeks of donepezil or placebo treatment, immediate and delayed recall of superficially and semantically processed words was compared with baseline performance. Immediate and delayed recall of superficially processed words did not show significant changes in either treatment group. With semantic processing, both immediate and delayed recall performance improved in the donepezil group. Our results suggest that when using semantic encoding, older normal subjects may be aided by anticholinesterase treatment. However, this treatment does not improve recall of superficially encoded words.

6-Methyluracil derivatives as acetylcholinesterase inhibitors for treatment of Alzheimer's disease.

PubMed

Zueva, I V; Semenov, V E; Mukhamedyarov, M A; Lushchekina, S V; Kharlamova, A D; Petukhova, E O; Mikhailov, A S; Podyachev, S N; Saifina, L F; Petrov, K A; Minnekhanova, O A; Zobov, V V; Nikolsky, E E; Masson, P; Reznik, V S

2015-01-01

Alzheimer's disease (AD) is the major age-related progressive neurodegenerative disorder. The brain of AD patients suffers from loss of cholinergic neurons and decreased number of synapses [1]. AD is caused by an imbalance between Aβ production and clearance, resulting in increased amount of Aβ in various forms [2]. Reduction of Aβ production and increasing clearance of Aβ pathogenic forms are key targets in the development of potential therapeutic agents for AD treatment. Unfortunately, only nosotropic approaches for treatment of AD are currently effective in humans. These approaches mainly focus on the inhibition of brain acetyl-cholinesterase (AChE) to increase lifetime of cerebral acetylcholine [3]. It is important to emphasize that AChE itself promotes the formation of Aβ fibrils in vitro and Aβ plaques in the cerebral cortex of transgenic mouse models of AD [4]. This property of AChE results from interaction between Aβ and the peripheral anionic site of the enzyme (PAS) [5]. Dual binding site inhibitors of both catalytic active site (CAS) and PAS can simultaneously improve cognition and slow down the rate of Aβ-induced neural degeneration. Unfortunately, the assortment of AChE PAS ligands is still extremely limited. To study putative advantages of AChE non-charged PAS inhibitors based on 6-methyluracil derivatives for the treatment of Alzheimer's disease. In vitro studies. Concentration of drug producing 50% of AChE/BuChE activity inhibition (IC50) was measured using the method of Ellman et al. [6]. Toxicological experiments were performed using IP injection of the different compounds in mice. LD50, dose (in mg/kg) causing lethal effects in 50% of animals was taken as a criterion of toxicity [7]. The ability of compound to block in vitro AChE-induced Aβ1-40 aggregation was studied using a thioflavin T (ThT) fluorescent probe [8].In vivo biological assays. For in vivo blood-brain barrier permeation assay brains were removed 30 min after IP injection

Synthesis, docking and acetylcholinesterase inhibitory assessment of 2-(2-(4-Benzylpiperazin-1-yl)ethyl)isoindoline-1,3-dione derivatives with potential anti-Alzheimer effects

PubMed Central

2013-01-01

Background Alzheimer’s disease (AD) as neurodegenerative disorder, is the most common form of dementia accounting for about 50-60% of the overall cases of dementia among persons over 65 years of age. Low acetylcholine (ACh) concentration in hippocampus and cortex areas of the brain is one of the main reasons for this disease. In recent years, acetylcholinesterase (AChE) inhibitors like donepezil with prevention of acetylcholine hydrolysis can enhance the duration of action of acetylcholine in synaptic cleft and improve the dementia associated with Alzheimer’s disease. Results Design, synthesis and assessment of anticholinesterase activity of 2-(2-(4-Benzylpiperazin-1-yl)ethyl)isoindoline-1,3-dione derivatives showed prepared compounds can function as potential acetylcholinesterase inhibitor. Among 12 synthesized derivatives, compound 4a with ortho chlorine moiety as electron withdrawing group exhibited the highest potency in these series (IC50 = 0.91 ± 0.045 μM) compared to donepezil (IC50 = 0.14 ± 0.03 μM). The results of the enzyme inhibition test (Ellman test) showed that electron withdrawing groups like Cl, F and NO2 can render the best effect at position ortho and para of the phenyl ring. But compound 4g with methoxy group at position 3(meta) afforded a favorable potency (IC50 = 5.5 ± 0.7 μM). Furthermore, docking study confirmed a same binding mode like donepezil for compound 4a. Conclusions Synthesized compounds 4a-4l could be proposed as potential anticholinesterase agents. PMID:23758724

Efficacy of acetylcholinesterase inhibitors versus nootropics in Alzheimer's disease: a retrospective, longitudinal study.

PubMed

Tsolaki, M; Pantazi, T; Kazis, A

2001-01-01

The aim of this study was to investigate the efficacy of nootropics (piracetam, aniracetam, nimodopine and dihydroergicristine) versus acetylcholinesterase inhibitors (AChE-Is) (tacrine and donepezil) in the treatment of Alzheimer's disease. This is a retrospective study of 510 patients with Alzheimer's disease. To determine clinical efficacy of treatment, we used the mean change over time in scores for the following tests: the Mini-Mental State Examination (MMSE); the Cambridge Cognitive Examination for the Elderly; and the Functional Rating Scale for Symptoms of Dementia. In all patients and in patients with severe Alzheimer's disease (baseline MMSE < 11), no significant differences were seen in the neuropsychological test scores between the two treatment groups. In patients with moderate dementia (baseline MMSE between 11 and 20), however, there was a significantly greater deterioration, as shown on the CAMCOG scale, after 12 months' treatment for patients receiving AChE-Is compared with those receiving nootropics (-4.38 for AChE-Is group versus 1.48 for nootropics group). For patients with mild dementia (baseline MMSE score between 21 and 26), there was a significantly greater deterioration on the MMSE scale for each time-point in the nootropics group compared with the AChE-Is group. In conclusion, we did not find any strong evidence that a difference in efficacy exists between AChE-Is and nootropics in the treatment of Alzheimer's disease.

Effects of Donepezil on Cognitive Functioning in Down Syndrome.

ERIC Educational Resources Information Center

Johnson, N.; Fahey, C.; Chicoine, B.; Chong, G.; Gitelman, D.

2003-01-01

Donepezil, an acetycholinesterase inhibitor, or a placebo were given to 29 subjects with Down syndrome and no dementia. Measures of cognitive functioning and caregiver ratings indicated no improvement in any cognitive subtests (with the exception of language), behavioral scores, or caregiver ratings. Results suggest donepezil may improve language…

Detecting effects of donepezil on visual selective attention using signal detection parameters in Alzheimer's disease.

PubMed

Foldi, Nancy S; White, Richard E C; Schaefer, Lynn A

2005-05-01

Attentional function is impaired in Alzheimer's disease (AD). Moreover, attention is mediated by acetylcholine. But, despite the widespread use of acetylcholinesterase inhibitors (AChE-I) to augment available acetylcholine in AD, measures of attentional function have not been used to assess the drug response. We hypothesized that as cholinergic augmentation impacts directly on the attentional system, higher-order measures of visual selective attention would be sensitive to effects of treatment using an AChE-I (donepezil hydrochloride). We also sought to determine whether these attentional measures were more sensitive to treatment than other measures of cognitive function. Seventeen patients with AD (8 untreated, 9 treated with donepezil) were contrasted on performance of a selective cancellation task. Two signal detection parameters were used as outcome measures: decision strategy (beta, beta) and discriminability (d-prime, d'). Standard screening and cognitive domain measures of vigilance, language, memory, and executive function were also contrasted. Treated patients judged stimuli more conservatively (p = 0.29) by correctly endorsing targets and rejecting false alarms. They also discriminated targets from distractors more easily (p = 0.58). The screening and neuropsychological measures failed to differentiate the groups. Higher-order attentional measures captured the effects of donepezil treatment in small groups of patients with AD. The results suggest that cholinergic availability may directly affect the attentional system, and that these selective attention measures are sensitive markers to detect treatment response. Copyright 2005 John Wiley & Sons, Ltd.

Effect of Donepezil on Wernicke Aphasia After Bilateral Middle Cerebral Artery Infarction: Subtraction Analysis of Brain F-18 Fluorodeoxyglucose Positron Emission Tomographic Images.

PubMed

Yoon, Seo Yeon; Kim, Je-Kyung; An, Young-Sil; Kim, Yong Wook

2015-01-01

Aphasia is one of the most common neurologic deficits occurring after stroke. Although the speech-language therapy is a mainstream option for poststroke aphasia, pharmacotherapy is recently being tried to modulate different neurotransmitter systems. However, the efficacy of those treatments is still controversial. We present a case of a 53-year-old female patient with Wernicke aphasia, after the old infarction in the territory of left middle cerebral artery for 8 years and the recent infarction in the right middle cerebral artery for 4 months. On the initial evaluation, the Aphasia Quotient in Korean version of the Western Aphasia Battery was 25.6 of 100. Baseline brain F-18 fluorodeoxyglucose positron emission tomographic images demonstrated a decreased cerebral metabolism in the left temporoparietal area and right temporal lobe. Donepezil hydrochloride, a reversible acetylcholinesterase inhibitor, was orally administered 5 mg/d for 6 weeks after the initial evaluation and was increased to 10 mg/d for the following 6 weeks. After the donepezil treatment, the patient showed improvement in language function, scoring 51.0 of 100 on Aphasia Quotient. A subtraction analysis of the brain F-18 fluorodeoxyglucose positron emission tomographic images after donepezil medication demonstrated increased uptake in both middle temporal gyri, extended to the occipital area and the left cerebellum. Thus, we suggest that donepezil can be an effective therapeutic choice for the treatment of Wernicke aphasia.

Effects of Acetylcholinesterase Inhibitors on Nutritional Status in Elderly Patients with Dementia: A 6-month Follow-up Study.

PubMed

Soysal, P; Isik, A T

2016-04-01

Nutritional status is one of the factors that affects disease progression, morbidity and mortality in elderly patients with dementia. The present study aimed to evaluate the effect of acetylcholinesterase inhibitor (AchEI) therapy on nutritional status and food intake in the elderly. Newly diagnosed patients with dementia, who underwent comprehensive geriatric assessment (CGA) and were followed at regular intervals, were retrospectively evaluated. A total of 116 patients, who began to receive AchEI therapy and completed 6-month follow-up period under this treatment, were enrolled in the study. Socio-demographic characteristics and data on comorbidity, polypharmacy, cognitive function, depression, activities of daily living and nutritional status (weight, Body Mass Index (BMI), Mini Nutritional Assessment (MNA)-Short Form) were recorded. The mean age of the patients was 78.0±8.9 years. There was no significant difference between baseline and 6-month BMI, weight and MNA scores of dementia patients who received AchEI therapy (p>0.05). With regard to the relation between changes in BMI, weight and MNA on the 6th month versus baseline, and donepezil, rivastigmine and galantamine therapies, no difference was determined (p>0.05). However, no worsening in food intake was observed (kappa: 0.377). When the effects of each AchEI on food intake were compared, food intake in rivastigmine treated patients was not decreased as much as it was in galantamine or donepezil treated patients (p<0.05). AchEI therapy has no unfavorable effect on nutritional status or weight in elderly patients with different types of dementia, but it seems that food intake is better in those treated by rivastigmine patch.

Olfactory Deficits in MCI as Predictor of Improved Cognition on Donepezil

DTIC Science & Technology

2013-04-01

date. Of the 14 who were ineligible, 8 were ineligible because they were already on cholinesterate inhibitors or memantine (2 subjects were on... memantine and donepezil; 2 subjects were on memantine and rivastigmine; 1 subject was on memantine ; 3 subjects were on donepezil). 5 As noted...above, many of the subjects were not eligible for the study because they were already on chlolinesterase inhibitors or memantine , prescribed by their

The 5-HT6 receptor antagonist idalopirdine potentiates the effects of donepezil on gamma oscillations in the frontal cortex of anesthetized and awake rats without affecting sleep-wake architecture.

PubMed

Amat-Foraster, Maria; Leiser, Steven C; Herrik, Kjartan F; Richard, Nelly; Agerskov, Claus; Bundgaard, Christoffer; Bastlund, Jesper F; de Jong, Inge E M

2017-02-01

The 5-HT 6 receptor is a promising target for cognitive disorders, in particular for Alzheimer's disease (AD). The high affinity and selective 5-HT 6 receptor antagonist idalopirdine (Lu AE58054) is currently in development for mild-moderate AD as adjunct therapy to acetylcholinesterase inhibitors (AChEIs). We studied the effects of idalopirdine alone and in combination with the AChEI donepezil on cortical function using two in vivo electrophysiological methods. Neuronal network oscillations in the frontal cortex were measured during electrical stimulation of the brainstem nucleus pontis oralis (nPO) in the anesthetized rat and by an electroencephalogram (EEG) in the awake, freely moving rat. In conjunction with the EEG study, we investigated the effects of idalopirdine and donepezil on sleep-wake architecture using telemetric polysomnography. Idalopirdine (2 mg/kg i.v.) increased gamma power in the medial prefrontal cortex (mPFC) during nPO stimulation. Donepezil (0.3 and 1 mg/kg i.v.) also increased cortical gamma power and pretreatment with idalopirdine (2 mg/kg i.v.) potentiated and prolonged the effects of donepezil. Similarly, donepezil (1 and 3 mg/kg s.c.) dose-dependently increased frontal cortical gamma power in the freely moving rat and pretreatment with idalopirdine (10 mg/kg p.o.) augmented the effect of donepezil 1 mg/kg. Analysis of the sleep-wake architecture showed that donepezil (1 and 3 mg/kg s.c.) dose-dependently delayed sleep onset and decreased the time spent in both REM and non REM sleep stages. In contrast, idalopirdine (10 mg/kg p.o.) did not affect sleep-wake architecture nor the effects of donepezil. In summary, we show that idalopirdine potentiates the effects of donepezil on frontal cortical gamma oscillations, a pharmacodynamic biomarker associated with cognition, without modifying the effects of donepezil on sleep. The increased cortical excitability may contribute to the procognitive effects of idalopirdine in donepezil

Use of a novel radiometric method to assess the inhibitory effect of donepezil on acetylcholinesterase activity in minimally diluted tissue samples

PubMed Central

Kikuchi, Tatsuya; Okamura, Toshimitsu; Arai, Takuya; Obata, Takayuki; Fukushi, Kiyoshi; Irie, Toshiaki; Shiraishi, Tetsuya

2010-01-01

Background and purpose: Cholinesterase inhibitors have been widely used for the treatment of patients with dementia. Monitoring of the cholinesterase activity in the blood is used as an indicator of the effect of the cholinesterase inhibitors in the brain. The selective measurement of cholinesterase with low tissue dilution is preferred for accurate monitoring; however, the methods have not been established. Here, we investigated the effect of tissue dilution on the action of cholinesterase inhibitors using a novel radiometric method with selective substrates, N-[14C]methylpiperidin-4-yl acetate ([14C]MP4A) and (R)-N-[14C]methylpiperidin-3-yl butyrate ([14C]MP3B_R), for AChE and butyrylcholinesterase (BChE) respectively. Experimental approach: We investigated the kinetics of hydrolysis of [14C]-MP4A and [14C]-MP3B_R by cholinesterases, and evaluated the selectivity of [14C]MP4A and [14C]MP3B_R for human AChE and BChE, respectively, compared with traditional substrates. Then, IC50 values of cholinesterase inhibitors in minimally diluted and highly diluted tissues were measured with [14C]MP4A and [14C]MP3B_R. Key results: AChE and BChE activities were selectively measured as the first-order hydrolysis rates of [14C]-MP4A and [14C]MP3B_R respectively. The AChE selectivity of [14C]MP4A was an order of magnitude higher than traditional substrates used for the AChE assay. The IC50 values of specific AChE and BChE inhibitors, donepezil and ethopropazine, in 1.2-fold diluted human whole blood were much higher than those in 120-fold diluted blood. In addition, the IC50 values of donepezil in monkey brain were dramatically decreased as the tissue was diluted. Conclusions and implications: This method would effectively monitor the activity of cholinesterase inhibitors used for therapeutics, pesticides and chemical warfare agents. PMID:20401964

Butyrylcholinesterase inhibitors ameliorate cognitive dysfunction induced by amyloid-β peptide in mice

PubMed Central

Furukawa-Hibi, Yoko; Alkam, Tursun; Nitta, Atsumi; Matsuyama, Akihiro; Mizoguchi, Hiroyuki; Suzuki, Kazuhiko; Moussaoui, Saliha; Yu, Qian-Sheng; Greig, Nigel H.; Nagai, Taku; Yamada, Kiyofumi

2016-01-01

The cholinesterase inhibitor, rivastigmine, ameliorates cognitive dysfunction and is approved for the treatment of Alzheimer's disease (AD). Rivastigmine is a dual inhibitor of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE); however, the impact of BuChE inhibition on cognitive dysfunction remains to be determined. We compared the effects of a selective BuChE inhibitor, N1-phenethylnorcymserine (PEC), rivastigmine and donepezil (an AChE-selective inhibitor) on cognitive dysfunction induced by amyloid-β peptide (Aβ1–40) in mice. Five-week-old imprinting control region (ICR) mice were injected intracerebroventricularly (i.c.v.) with either Aβ1–40 or the control peptide Aβ40–1 on Day 0, and their recognition memory was analyzed by a novel object recognition test. Treatment with donepezil (1.0 mg/kg), rivastigmine (0.03, 0.1, 0.3 mg/kg) or PEC (1.0, 3.0 mg/kg) 20 min prior to, or immediately after the acquisition session (Day 4) ameliorated the Aβ1–40 induced memory impairment, indicating a beneficial effect on memory acquisition and consolidation. In contrast, none of the investigated drugs proved effective when administrated before the retention session (Day 5). Repeated daily administration of donepezil, rivastigmine or PEC, on Days 0–3 inclusively, ameliorated the cognitive dysfunction in Aβ1–40 challenged mice. Consistent with the reversal of memory impairments, donepezil, rivastigmine or PEC treatment significantly reduced Aβ1–40 induced tyrosine nitration of hippocampal proteins, a marker of oxidative damage. These results indicate that BuChE inhibition, as well as AChE inhibition, is a viable therapeutic strategy for cognitive dysfunction in AD. PMID:21820013

Synthesis and biological evaluation of potential acetylcholinesterase inhibitors based on a benzoxazine core.

PubMed

Méndez-Rojas, Claudio; Quiroz, Gabriel; Faúndez, Mario; Gallardo-Garrido, Carlos; Pessoa-Mahana, C David; Chung, Hery; Gallardo-Toledo, Eduardo; Saitz-Barría, Claudio; Araya-Maturana, Ramiro; Kogan, Marcelo J; Zúñiga-López, María C; Iturriaga-Vásquez, Patricio; Valenzuela-Gutiérrez, Carla; Pessoa-Mahana, Hernán

2018-05-01

With the purpose of expanding the structural variety of chemical compounds available as pharmacological tools for the treatment of Alzheimer's disease, we synthesized and evaluated a novel series of indole-benzoxazinones (Family I) and benzoxazine-arylpiperazine derivatives (Family II) for potential human acetylcholinesterase (hAChE) inhibitory properties. The most active compounds 7a and 7d demonstrated effective inhibitory profiles with K i values of 20.3 ± 0.9 μM and 20.2 ± 0.9 μM, respectively. Kinetic inhibition assays showed non-competitive inhibition of AChE by the tested compounds. According to our docking studies, the most active compounds from both series (Families I and II) showed a binding mode similar to donepezil and interact with the same residues. © 2018 Deutsche Pharmazeutische Gesellschaft.

Assessing the binding of cholinesterase inhibitors by docking and molecular dynamics studies.

PubMed

Ali, M Rejwan; Sadoqi, Mostafa; Møller, Simon G; Boutajangout, Allal; Mezei, Mihaly

2017-09-01

In this report we assessed by docking and molecular dynamics the binding mechanisms of three FDA-approved Alzheimer drugs, inhibitors of the enzyme acetylcholinesterase (AChE): donepezil, galantamine and rivastigmine. Dockings by the softwares Autodock-Vina, PatchDock and Plant reproduced the docked conformations of the inhibitor-enzyme complexes within 2Å of RMSD of the X-ray structure. Free-energy scores show strong affinity of the inhibitors for the enzyme binding pocket. Three independent Molecular Dynamics simulation runs indicated general stability of donepezil, galantamine and rivastigmine in their respective enzyme binding pocket (also referred to as gorge) as well as the tendency to form hydrogen bonds with the water molecules. The binding of rivastigmine in the Torpedo California AChE binding pocket is interesting as it eventually undergoes carbamylation and breaks apart according to the X-ray structure of the complex. Similarity search in the ZINC database and targeted docking on the gorge region of the AChE enzyme gave new putative inhibitor molecules with high predicted binding affinity, suitable for potential biophysical and biological assessments. Copyright © 2017 Elsevier Inc. All rights reserved.

Cholinesterase inhibitors modify the activity of intrinsic cardiac neurons.

PubMed

Darvesh, Sultan; Arora, Rakesh C; Martin, Earl; Magee, David; Hopkins, David A; Armour, J Andrew

2004-08-01

Cholinesterase inhibitors used to treat the symptoms of Alzheimer's disease (AD) inhibit both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), albeit to different degrees. Because central and peripheral neurons, including intrinsic cardiac neurons located on the surface of the mammalian heart, express both BuChE and AChE, we studied spontaneously active intrinsic cardiac neurons in the pig as a model to assess the effects of inhibition of AChE compared to BuChE. Neuroanatomical experiments showed that some porcine intrinsic cardiac neurons expressed AChE and/or BuChE. Enzyme kinetic experiments with cholinesterase inhibitors, namely, donepezil, galantamine, (+/-) huperzine A, metrifonate, rivastigmine, and tetrahydroaminoacridine, demonstrated that these compounds differentially inhibited porcine AChE and BuChE. Donepezil and (+/-) huperzine A were better reversible inhibitors of AChE, and galantamine equally inhibited both the enzymes. Tetrahydroaminoacridine was a better reversible inhibitor of BuChE. Rivastigmine caused more rapid inactivation of BuChE as compared to AChE. Neurophysiological studies showed that acetylcholine and butyrylcholine increase or decrease the spontaneous activity of the intrinsic cardiac neurons. Donepezil, galantamine, (+/-) huperzine A, and tetrahydroaminoacridine changed spontaneous neuronal activity by about 30-35 impulses per minute, while rivastigmine changed it by approximately 100 impulses per minute. It is concluded that (i) inhibition of AChE and BuChE directly affects the porcine intrinsic cardiac nervous system, (ii) the intrinsic cardiac nervous system represents a suitable model for examining the effects of cholinesterase inhibitors on mammalian neurons in vivo, and (iii) the activity of intrinsic cardiac neurons may be affected by pharmacological agents that inhibit cholinesterases.

The evaluation of prophylactic efficacy of newly developed reversible inhibitors of acetylcholinesterase in soman-poisoned mice - a comparison with commonly used pyridostigmine.

PubMed

Kassa, Jiri; Korabecny, Jan; Sepsova, Vendula; Tumova, Martina

2014-12-01

The ability of four newly developed reversible inhibitors of acetylcholinesterase (PC-37, PC-48, JaKo 39, JaKo 40) and currently available carbamate pyridostigmine to increase the resistance of mice against soman and the efficacy of antidotal treatment of soman-poisoned mice was evaluated and compared. No reversible inhibitor of acetylcholinesterase studied was able to decrease the LD50 value of soman in mice. Thus, the pharmacological pre-treatment with pyridostigmine or newly synthesized inhibitors of acetylcholinesterase was not able to significantly protect mice against soman-induced lethal acute toxicity. In addition, neither pyridostigmine nor new reversible inhibitors of acetylcholinesterase was able to increase the efficacy of antidotal treatment (the oxime HI-6 in combination with atropine) of soman-poisoned mice. These findings demonstrate that pharmacological pre-treatment of soman-poisoned mice with tested reversible inhibitors of acetylcholinesterase is not promising. © 2014 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

Does caffeine influence the anticholinesterase and antioxidant properties of donepezil? Evidence from in vitro and in vivo studies.

PubMed

Oboh, Ganiyu; Ogunsuyi, Opeyemi Babatunde; Olonisola, Oluwaseyi Emmanuel

2017-04-01

Caffeine is adjudged world's most consumed pharmacologically active food component. With reports of the potential cognitive enhancing properties of caffeine, we sought to investigate if caffeine can influence the anticholinesterase and antioxidant properties of donepezil-a selective acetylcholinesterase (AChE) inhibitor used in the management of Alzheimer's disease (AD). In vitro, we investigated the effect of donepezil (DON), caffeine (CAF) and their various combinations on the activity of AChE in rat brain homogenate, as well as determined their antioxidant properties. In vivo, two rat groups were administered single oral dose of DON (5 mg/kg) and CAF (5 mg/kg) separately, while three groups, each received 5 mg/kg DON plus either 5, 50 or 100 mg/kg CAF for three hours, after which the rats were sacrificed and brain isolated. Results show that CAF concentration dependently and synergistically increased the anticholinesterase properties of DON in vitro. Also, CAF produced a significant influence on investigated in vitro antioxidant properties of DON. Furthermore, rats administered 5 mg/kg CAF and DON produced no significant difference in AChE activity compared to rats administered DON alone. However, co-administration of either 50 or 100 mg/kg CAF with DON lead to higher AChE activity compared to both control and DON groups. In addition, DON, CAF and their various combinations augmented brain antioxidant status in treated rats. We conclude that while low caffeine consumption may improve the antioxidant properties of donepezil without having a significant influence on its anticholinesterase effect, moderate-high caffeine consumption could also improve the antioxidant properties of donepezil but reduce its anticholinesterase effect; nevertheless, a comprehensive clinical trial is essential to fully explore these possibilities in human AD condition.

Pharmacodynamic, pharmacokinetic and pharmacogenetic aspects of drugs used in the treatment of Alzheimer's disease.

PubMed

Noetzli, Muriel; Eap, Chin B

2013-04-01

With the aging population and its rapidly increasing prevalence, dementia has become an important public health concern in developed and developing countries. To date, the pharmacological treatment is symptomatic and based on the observed neurotransmitter disturbances. The four most commonly used drugs are donepezil, galantamine, rivastigmine and memantine. Donepezil, galantamine and rivastigmine are acetylcholinesterase inhibitors with different pharmacodynamic and pharmacokinetic profiles. Donepezil inhibits selectively the acetylcholinesterase and has a long elimination half-life (t(1/2)) of 70 h. Galantamine is also a selective acetylcholinesterase inhibitor, but also modulates presynaptic nicotinic receptors. It has a t(1/2) of 6-8 h. Donepezil and galantamine are mainly metabolised by cytochrome P450 (CYP) 2D6 and CYP3A4 in the liver. Rivastigmine is a so-called 'pseudo-irreversible' inhibitor of acetylcholinesterase and butyrylcholinesterase. The t(1/2) of the drug is very short (1-2 h), but the duration of action is longer as the enzymes are blocked for around 8.5 and 3.5 h, respectively. Rivastigmine is metabolised by esterases in liver and intestine. Memantine is a non-competitive low-affinity antagonist of the NMDA receptor with a t(1/2) of 70 h. Its major route of elimination is unchanged via the kidneys. Addressing the issue of inter-patient variability in treatment response might be of special importance for the vulnerable population taking anti-dementia drugs. Pharmacogenetic considerations might help to avoid multiple medication changes due to non-response and/or adverse events. Some pharmacogenetic studies conducted on donepezil and galantamine reported an influence of the CYP2D6 genotype on the pharmacokinetics of the drugs and/or on the response to treatment. Moreover, polymorphisms in genes of the cholinergic markers acetylcholinesterase, butyrylcholinesterase, choline acetyltransferase and paraoxonase were found to be associated with better

Language impairment in Alzheimer’s disease and benefits of acetylcholinesterase inhibitors

PubMed Central

Ferris, Steven H; Farlow, Martin

2013-01-01

Alzheimer’s disease is characterized by progressively worsening deficits in several cognitive domains, including language. Language impairment in Alzheimer’s disease primarily occurs because of decline in semantic and pragmatic levels of language processing. Given the centrality of language to cognitive function, a number of language-specific scales have been developed to assess language deficits throughout progression of the disease and to evaluate the effects of pharmacotherapy on language function. Trials of acetylcholinesterase inhibitors, used for the treatment of clinical symptoms of Alzheimer’s disease, have generally focused on overall cognitive effects. However, in the current report, we review data indicating specific beneficial effects of acetylcholinesterase inhibitors on language abilities in patients with Alzheimer’s disease, with a particular focus on outcomes among patients in the moderate and severe disease stages, during which communication is at risk and preservation is particularly important. PMID:23946647

A review on cholinesterase inhibitors for Alzheimer's disease.

PubMed

Anand, Preet; Singh, Baldev

2013-04-01

Alzheimer's disease (AD), a progressive neurodegenerative disorder, is characterized by the deficits in the cholinergic system and deposition of beta amyloid (Aβ) in the form of neurofibrillary tangles and amyloid plaques. Since the cholinergic system plays an important role in the regulation of learning and memory processes, it has been targetted for the design of anti-Alzheimer's drugs. Cholinesterase inhibitors enhance cholinergic transmission directly by inhibiting the enzyme acetylcholinesterase (AChE) which hydrolyses acetylcholine. Furthermore, it has been also demonstrated that both acetylcholinesterase and butrylcholinesterase (BuChE) play an important role in Aβ-aggregation during the early stages of senile plaque formation. Therefore, AChE and BuChE inhibition have been documented as critical targets for the effective management of AD by an increase in the availability of acetylcholine in the brain regions and decrease in the Aβ deposition. This review discusses the different classes of cholinesterase inhibitors including tacrine, donepezil, rivastigmine, galantamine, xanthostigmine, para-aminobenzoic acid, coumarin, flavonoid, and pyrrolo-isoxazole analogues developed for the treatment of AD.

Acetylcholinesterase inhibition reveals endogenous nicotinic modulation of glutamate inputs to CA1 stratum radiatum interneurons in hippocampal slices

PubMed Central

Alkondon, Manickavasagom; Albuquerque, Edson X.; Pereira, Edna F.R.

2013-01-01

The involvement of brain nicotinic acetylcholine receptors (nAChRs) in the neurotoxicological effects of soman, a potent acetylcholinesterase (AChE) inhibitor and a chemical warfare agent, is not clear. This is partly due to a poor understanding of the role of AChE in brain nAChR-mediated functions. To test the hypothesis that AChE inhibition builds sufficient acetylcholine (ACh) in the brain and facilitates nAChR-dependent glutamate transmission, we used whole-cell patch-clamp technique to record spontaneous glutamate excitatory postsynaptic currents (EPSCs) from CA1 stratum radiatum interneurons (SRI) in hippocampal slices. First, the frequency, amplitude and kinetics of EPSCs recorded from slices of control guinea pigs were compared to those recorded from slices of guinea pigs after a single injection of the irreversible AChE inhibitor soman (25.2 μg/kg, s.c.). Second, EPSCs were recorded from rat hippocampal slices before and after their superfusion with the reversible AChE inhibitor donepezil (100 nM). The frequency of EPSCs was significantly higher in slices taken from guinea pigs 24 h but not 7 days after the soman injection than in slices from control animals. In 52% of the rat hippocampal slices tested, bath application of donepezil increased the frequency of EPSCs. Further, exposure to donepezil increased both burst-like and large-amplitude EPSCs, and increased the proportion of short (20–100 ms) inter-event intervals. Donepezil’s effects were suppressed significantly in presence of 10 μM mecamylamine or 10 nM methyllycaconitine. These results support the concept that AChE inhibition is able to recruit nAChR-dependent glutamate transmission in the hippocampus and such a mechanism can contribute to the acute neurotoxicological actions of soman. PMID:23511125

Time Course, Behavioral Safety, and Protective Efficacy of Centrally Active Reversible Acetylcholinesterase Inhibitors in Cynomolgus Macaques.

PubMed

Hamilton, Lindsey R; Schachter, Steven C; Myers, Todd M

2017-07-01

Galantamine hydrobromide and (-)huperzine A, centrally active reversible acetylcholinesterase inhibitors, are potentially superior to the current standard, pyridostigmine bromide, as a pretreatment for organophosphorus chemical warfare nerve agent intoxication. Galantamine, huperzine, and pyridostigmine were compared for time course of acetylcholinesterase inhibition in 12 cynomolgus macaques. Although both galantamine and huperzine shared a similar time course profile for acetylcholinesterase inhibition, huperzine was 88 times more potent than galantamine. The dose for 50% acetylcholinesterase inhibition (ID 50 ) was 4.1 ug/kg for huperzine, 362 ug/kg for galantamine, and 30.9 ug/kg for pyridostigmine. In a safety assessment, galantamine, huperzine, and pyridostigmine were examined using an operant time-estimation task. Huperzine and pyridostigmine were devoid of behavioral toxicity, whereas galantamine was behaviorally toxic at doses producing peak acetylcholinesterase inhibition of about 50% and higher. Following pretreatment with galantamine, huperzine or pyridostigmine, monkeys were challenged with the median lethal dose of soman at the time of peak acetylcholinesterase inhibition and evaluated for overt signs of soman toxicity (cholinergic crisis, convulsions). Both huperzine and galantamine were equally effective at preventing overt signs of soman toxicity, but neither drug was capable of preventing soman-induced neurobehavioral disruption. In contrast, three of four pyridostigmine-pretreated animals exposed to soman exhibited convulsions and required therapy. Full functional recovery required 3-16 days. The degree of acetylcholinesterase inhibition was lower for pyridostigmine, but rates of recovery of acetylcholinesterase activity following soman challenge were comparable for all drug pretreatments. Huperzine may be the more promising centrally active reversible acetylcholinesterase inhibitor due to its greater potency and superior safety profile.

A study of donepezil in female breast cancer survivors with self-reported cognitive dysfunction 1 to 5 years following adjuvant chemotherapy.

PubMed

Lawrence, J A; Griffin, L; Balcueva, E P; Groteluschen, D L; Samuel, T A; Lesser, G J; Naughton, M J; Case, L D; Shaw, E G; Rapp, S R

2016-02-01

Some breast cancer survivors report cognitive difficulties greater than 1 year after chemotherapy. Acetylcholinesterase inhibitors (AChEI) may improve cognitive impairment. We conducted a randomized, placebo-controlled, pilot study to assess the feasibility of using the AChEI, donepezil, to improve subjective and objective measures of cognitive function in breast cancer survivors. Women who received adjuvant chemotherapy 1-5 years prior with current cognitive dysfunction symptoms were randomized to 5 mg of donepezil/day vs placebo for 6 weeks and if tolerated 10 mg/day for 18 weeks for a total of 24 weeks. A battery of validated measures of attention, memory, language, visuomotor skills, processing speed, executive function, and motor dexterity and speed was administered at baseline and at 24 and 36 weeks. Subjective cognitive function, fatigue, sleep, mood, and health-related quality of life were evaluated at baseline and at 12, 24, and 36 weeks. Sixty-two patients were enrolled, 76 % completed the study, self-reported compliance was 98 %, and toxicities were minimal. At the end of treatment, the donepezil group performed significantly better than the control group on two parameters of memory-the Hopkins Verbal Learning Test -Revised (HVLT-R) Total Recall (p = 0.033) and HVLT-R Discrimination (p = 0.036). There were no significant differences on other cognitive variables or in subjective cognitive function or quality of life. Accrual to this feasibility trial was robust, retention was good, compliance was excellent, and toxicities were minimal. Randomized clinical trials in breast cancer survivors to improve cognitive dysfunction are feasible. A phase III trial testing the efficacy of donepezil is warranted given these pilot results.

Evolution of the evidence on the effectiveness and cost-effectiveness of acetylcholinesterase inhibitors and memantine for Alzheimer's disease: systematic review and economic model.

PubMed

Hyde, Christopher; Peters, Jaime; Bond, Mary; Rogers, Gabriel; Hoyle, Martin; Anderson, Rob; Jeffreys, Mike; Davis, Sarah; Thokala, Praveen; Moxham, Tiffany

2013-01-01

in 2007 the National Institute of Health and Clinical Excellence (NICE) restricted the use of acetylcholinesterase inhibitors and memantine. we conducted a health technology assessment (HTA) of the effectiveness and cost-effectiveness of donepezil, galantamine, rivastigmine and memantine for the treatment of AD to re-consider and up-date the evidence base used to inform the 2007 NICE decision. The systematic review of effectiveness targeted randomised controlled trials. A comprehensive search, including MEDLINE, Embase and the Cochrane Library, was conducted from January 2004 to March 2010. All key review steps were done by two reviewers. Random effects meta-analysis was conducted. The cost-effectiveness was assessed using a cohort-based model with three health states: pre-institutionalised, institutionalised and dead. The perspective was NHS and Personal Social Services and the cost year 2009. confidence about the size and statistical significance of the estimates of effect of galantamine, rivastigmine and memantine improved on function and global impact in particular. Cost-effectiveness also changed. For donepezil, galantamine and rivastigmine, the incremental cost per quality-adjusted life year (QALY) in 2004 was above £50,000; in 2010 the same drugs 'dominated' best supportive care (improved clinical outcome at reduced cost). This was primarily because of changes in the modelled costs of introducing the drugs. For memantine, the cost-effectiveness also improved from a range of £37-53,000 per QALY gained to a base-case of £32,000. there has been a change in the evidence base between 2004 and 2010 consistent with the change in NICE guidance. Further evolution in cost-effectiveness estimates is possible particularly if there are changes in drug prices.

Effect of acetylcholinesterase inhibitors on post-surgical complications and mortality following a hip fracture: a cohort study

PubMed Central

Tamimi, I.; Madathil, S.A.; Kezouh, A.; Nicolau, B.; Karp, I.; Tamimi, F.

2017-01-01

There is increasing evidence suggesting that the use of acetylcholinesterase inhibitors may have beneficial effects on bone. Data on the potential post-surgical effects of these medications on orthopedic interventions are very limited. This study was designed to determine whether the use of acetylcholinesterase inhibitors is associated with a decrease in post-surgical mortality and complications in hip fracture patients with Alzheimer’s disease. To accomplish this objective, a retrospective cohort study was performed using data from the Clinical Practice Research Database, UK. The study included 532 Alzheimer’s disease patients of age 65 years and older, who sustained a hip fracture between 1998 and 2012. During the follow-up period, 34% of the patients died (n=182), 22% sustained a second hip fracture (n=118) and 5% (n=29) required reintervention. The users of acetylcholinesterase inhibitors had a 56% reduction in all-cause mortality (HR= 0.44, 95% CI 0.30-0.63) and a 41% reduction in second hip fracture incidence during a year of post-surgical follow-up (HR= 0.59, 95% CI 0.38-0.94) after adjusting for potential confounders. Our results show that acetylcholinesterase inhibitors may have the potential to reduce all-cause mortality and the risk of suffering a second hip fracture during the first year after surgery. PMID:28574413

Recent advances in acetylcholinesterase Inhibitors and Reactivators: an update on the patent literature (2012-2015).

PubMed

McHardy, Stanton F; Wang, Hua-Yu Leo; McCowen, Shelby V; Valdez, Matthew C

2017-04-01

Acetylcholinesterase (AChE) is the major enzyme that hydrolyzes acetylcholine, a key neurotransmitter for synaptic transmission, into acetic acid and choline. Mild inhibition of AChE has been shown to have therapeutic relevance in Alzheimer's disease (AD), myasthenia gravis, and glaucoma among others. In contrast, strong inhibition of AChE can lead to cholinergic poisoning. To combat this, AChE reactivators have to be developed to remove the offending AChE inhibitor, restoring acetylcholine levels to normal. Areas covered: This article covers recent advances in the development of acetylcholinesterase modulators, including both inhibitors of acetylcholinesterase for the efforts in development of new chemical entities for treatment of AD, as well as re-activators for resurrection of organophosphate bound acetylcholinesterase. Expert opinion: Over the past three years, research efforts have continued to identify novel small molecules as AChE inhibitors for both CNS and peripheral diseases. The more recent patent activity has focused on three AChE ligand design areas: derivatives of known AChE ligands, natural product based scaffolds and multifunctional ligands, all of which have produced some unique chemical matter with AChE inhibition activities in the mid picomolar to low micromolar ranges. New AChE inhibitors with polypharmacology or dual inhibitory activity have also emerged as highlighted by new AChE inhibitors with dual activity at L-type calcium channels, GSK-3, BACE1 and H3, although most only show low micromolar activity, thus further research is warranted. New small molecule reactivators of organophosphate-inhibited AChE have also been disclosed, which focused on the design of neutral ligands with improved pharmaceutical properties and blood-brain barrier (BBB) penetration. Gratifyingly, some research in this area is moving away from the traditional quaternary pyridinium oximes AChE reactivators, while still employing the necessary reactivation group (oximes

Donepezil attenuates hippocampal neuronal damage and cognitive deficits after global cerebral ischemia in gerbils.

PubMed

Min, Dongyu; Mao, Xiaoyuan; Wu, Kuncan; Cao, Yonggang; Guo, Feng; Zhu, Shu; Xie, Ni; Wang, Lei; Chen, Tianbao; Shaw, Chris; Cai, Jiqun

2012-02-21

Decreased cerebral blood flow causes cognitive impairments and neuronal injury in vascular dementia. In the present study, we reported that donepezil, a cholinesterase inhibitor, improved transient global cerebral ischemia-induced spatial memory impairment in gerbils. Treatment with 5mg/kg of donepezil for 21 consecutive days following a 10-min period of ischemia significantly inhibited delayed neuronal death in the hippocampal CA1 region. In Morris water maze test, memory impairment was significantly improved by donepezil treatment. Western blot analysis showed that donepezil treatment prevented reductions in p-CaMKII and p-CREB protein levels in the hippocampus. These results suggest that donepezil attenuates the memory deficit induced by transient global cerebral ischemia and this neuroprotection may be associated with the phosphorylation of CaMKII and CERB in the hippocampus. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Effects of cholinesterase inhibitors on the activities and protein levels of cholinesterases in the cerebrospinal fluid of patients with Alzheimer's disease: a review of recent clinical studies.

PubMed

Darreh-Shori, T; Soininen, H

2010-02-01

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by cognitive decline associated with a deficit in cholinergic function. Inhibitors of acetylcholinesterase (AChE) and/or butyrylcholinesterase (BuChE), such as donepezil, galantamine or rivastigmine, are widely prescribed as symptomatic treatments for AD. These agents exhibit a wide variation in their pharmacological properties. Here we review clinical data from 1998 to 2009 investigating the effect of different cholinesterase inhibitor treatments on the levels and activities of cholinesterases in the cerebrospinal fluid (CSF) of AD patients. These studies suggest that treatment with rapidly-reversible cholinesterase inhibitors (e.g. donepezil, galantamine, tacrine) are associated with marked and significant upregulation of AChE activities and protein levels in the CSF of AD patients. In contrast, pseudo-irreversible cholinesterase inhibition (e.g. rivastigmine) is associated with a significant decrease in both CSF AChE and BuChE activities, with no upregulation of CSF protein levels. Additionally, donepezil is associated with a decrease in the level of the AChE-R isoform relative to the synaptic AChE-S isoform, whereas rivastigmine seems to increase this ratio. These findings suggest that these agents exert different effects on CSF cholinesterases. The clinical effects of these pharmacological differences are yet to be fully established.

Possible Overlapping Time Frames of Acquisition and Consolidation Phases in Object Memory Processes: A Pharmacological Approach

ERIC Educational Resources Information Center

Akkerman, Sven; Blokland, Arjan; Prickaerts, Jos

2016-01-01

In previous studies, we have shown that acetylcholinesterase inhibitors and phosphodiesterase inhibitors (PDE-Is) are able to improve object memory by enhancing acquisition processes. On the other hand, only PDE-Is improve consolidation processes. Here we show that the cholinesterase inhibitor donepezil also improves memory performance when…

Different Cholinesterase Inhibitor Effects on CSF Cholinesterases in Alzheimer Patients

PubMed Central

Nordberg, Agneta; Darreh-Shori, Taher; Peskind, Elaine; Soininen, Hilkka; Mousavi, Malahat; Eagle, Gina; Lane, Roger

2014-01-01

Background The current study aimed to compare the effects of different cholinesterase inhibitors on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities and protein levels, in the cerebrospinal fluid (CSF) of Alzheimer disease (AD) patients. Methods and Findings AD patients aged 50–85 years were randomized to open-label treatment with oral rivastigmine, donepezil or galantamine for 13 weeks. AChE and BuChE activities were assayed by Ellman’s colorimetric method. Protein levels were assessed by enzyme-linked immunosorbent assay (ELISA). Primary analyses were based on the Completer population (randomized patients who completed Week 13 assessments). 63 patients were randomized to treatment. Rivastigmine was associated with decreased AChE activity by 42.6% and decreased AChE protein levels by 9.3%, and decreased BuChE activity by 45.6% and decreased BuChE protein levels by 21.8%. Galantamine decreased AChE activity by 2.1% and BuChE activity by 0.5%, but increased AChE protein levels by 51.2% and BuChE protein levels by10.5%. Donepezil increased AChE and BuChE activities by 11.8% and 2.8%, respectively. Donepezil caused a 215.2%increase in AChE and 0.4% increase in BuChE protein levels. Changes in mean AChE-Readthrough/Synaptic ratios, which might reflect underlying neurodegenerative processes, were 1.4, 0.6, and 0.4 for rivastigmine, donepezil and galantamine, respectively. Conclusion The findings suggest pharmacologically-induced differences between rivastigmine, donepezil and galantamine. Rivastigmine provides sustained inhibition of AChE and BuChE, while donepezil and galantamine do not inhibit BuChE and are associated with increases in CSF AChE protein levels. The clinical implications require evaluation. PMID:19199870

Different cholinesterase inhibitor effects on CSF cholinesterases in Alzheimer patients.

PubMed

Nordberg, Agneta; Darreh-Shori, Taher; Peskind, Elaine; Soininen, Hilkka; Mousavi, Malahat; Eagle, Gina; Lane, Roger

2009-02-01

The current study aimed to compare the effects of different cholinesterase inhibitors on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities and protein levels, in the cerebrospinal fluid (CSF) of Alzheimer disease (AD) patients. AD patients aged 50-85 years were randomized to open-label treatment with oral rivastigmine, donepezil or galantamine for 13 weeks. AChE and BuChE activities were assayed by Ellman's colorimetric method. Protein levels were assessed by enzyme-linked immunosorbent assay (ELISA). Primary analyses were based on the Completer population (randomized patients who completed Week 13 assessments). 63 patients were randomized to treatment. Rivastigmine was associated with decreased AChE activity by 42.6% and decreased AChE protein levels by 9.3%, and decreased BuChE activity by 45.6% and decreased BuChE protein levels by 21.8%. Galantamine decreased AChE activity by 2.1% and BuChE activity by 0.5%, but increased AChE protein levels by 51.2% and BuChE protein levels by 10.5%. Donepezil increased AChE and BuChE activities by 11.8% and 2.8%, respectively. Donepezil caused a 215.2% increase in AChE and 0.4% increase in BuChE protein levels. Changes in mean AChE-Readthrough/Synaptic ratios, which might reflect underlying neurodegenerative processes, were 1.4, 0.6, and 0.4 for rivastigmine, donepezil and galantamine, respectively. The findings suggest pharmacologically-induced differences between rivastigmine, donepezil and galantamine. Rivastigmine provides sustained inhibition of AChE and BuChE, while donepezil and galantamine do not inhibit BuChE and are associated with increases in CSF AChE protein levels. The clinical implications require evaluation.

Differential inhibition of [3H]-oxotremorine-M and [3H]-quinuclinidyl benzilate binding to muscarinic receptors in rat brain membranes with acetylcholinesterase inhibitors.

PubMed

Lockhart, B; Closier, M; Howard, K; Steward, C; Lestage, P

2001-04-01

The potential interaction of acetylcholinesterase inhibitors with cholinergic receptors may play a significant role in the therapeutic and/or side-effects associated with this class of compound. In the present study, the capacity of acetylcholinesterase inhibitors to interact with muscarinic receptors was assessed by their ability to displace both [3H]-oxotremorine-M and [3H]-quinuclinidyl benzilate binding in rat brain membranes. The [3H]-quinuclinidyl benzilate/[3H]-oxotremorine-M affinity ratios permitted predictions to be made of either the antagonist or agonist properties of the different compounds. A series of compounds, representative of the principal classes of acetylcholinesterase inhibitors, displaced [3H]-oxotremorine-M binding with high-to-moderate potency (ambenonium>neostigmine=pyridostigmine=tacrine>physostigmine> edrophonium=galanthamine>desoxypeganine) whereas only ambenonium and tacrine displaced [3H]-quinuclinidyl benzilate binding. Inhibitors such as desoxypeganine, parathion and gramine demonstrated negligible inhibition of the binding of both radioligands. Scatchard plots constructed from the inhibition of [3H]-oxotremorine-M binding in the absence and presence of different inhibitors showed an unaltered Bmax and a reduced affinity constant, indicative of potential competitive or allosteric mechanisms. The capacity of acetylcholinesterase inhibitors, with the exception of tacrine and ambenonium, to displace bound [3H]-oxotremorine-M in preference to [3H]quinuclinidyl benzilate predicts that the former compounds could act as potential agonists at muscarinic receptors. Moreover, the rank order for potency in inhibiting acetylcholinesterase (ambenonium>neostigmine=physostigmine =tacrine>pyridostigmine=edrophonium=galanthamine >desoxypeganine>parathion>gramine) indicated that the most effective inhibitors of acetylcholinesterase also displaced [3H]-oxotremorine-M to the greatest extent. The capacity of these inhibitors to displace [3H

AChE Inhibitors and NMDA Receptor Antagonists in Advanced Alzheimer's Disease.

PubMed

Glynn-Servedio, Brianna E; Ranola, Trisha Seys

2017-09-01

The objective of this article is to review the available evidence for duration of treatment with, and considerations for discontinuation of, acetylcholinesterase inhibitors and N-methyl-d-aspartate receptor antagonists in Alzheimer's disease. Literature searches of clinical trials and meta-analyses were conducted using PubMed with the search terms Alzheimer's, dementia, donepezil, galantamine, memantine, and rivastigmine. References from included trials were also used to find additional citations. 2,925 articles were initially identified. Twenty-one studies were included that looked at the use of acetylcholinesterase inhibitors and/or memantine in the treatment of moderate-to-severe Alzheimer's dementia. Several clinical trials have demonstrated small improvements in measures of cognition and activities of daily living with medications used to treat dementia. However, not all patients will benefit from treatment, and the impact of treatment on long-term outcomes, including institutionalization, remains unclear. This paper reviews the available data to support the use of acetylcholinesterase inhibitors and/or memantine in patients with advanced Alzheimer's disease, including those in nursing facilities, and reviews recommendations for consideration of therapy discontinuation. The evidence to support a specific time frame for discontinuation of Alzheimer's disease treatment is limited. It is reasonable to stop a medication if there is no noticeable benefit after the first three months of treatment or once a patient's dementia progresses to a point where there would be no meaningful benefit from continued therapy.

Discovering New Acetylcholinesterase Inhibitors by Mining the Buzhongyiqi Decoction Recipe Data.

PubMed

Cui, Lu; Wang, Yu; Liu, Zhihong; Chen, Hongzhuan; Wang, Hao; Zhou, Xinxin; Xu, Jun

2015-11-23

Myasthenia gravis (MG) is a neuromuscular disease that is conventionally treated with acetylcholinesterase (AChE) inhibitors, which may not fully remove the symptom for many reasons. When AChE inhibitors do not work, Chinese patients turn to Chinese medicine, such as the Buzhongyiqi decoction (BD), to treat MG. By elucidating the relations between the herbs of the Buzhongyiqi decoction recipe and AChE inhibitors with structure-based and ligand-based drug design methods and chemoinformatics approaches, we have found the key active components of BD. Using these key active components as templates, we have discovered five new AChE inhibitors through virtual screening of a commercial compound library. The new AChE inhibitors have been confirmed with Ellman assays. This study demonstrates that lead identification can be inspired by elucidating Chinese medicine. Since BD is a mixture, further studies against other drug targets are needed.

Safety and Efficacy of Donepezil in Children and Adolescents with Autism: Neuropsychological Measures

PubMed Central

Johnson, Cynthia R.; McAuliffe-Bellin, Sarah; Murray, Patricia Jo; Hardan, Antonio Y.

2011-01-01

Abstract Objective There has been recent interest in the use of cognitive enhancing drugs, such as cholinesterase inhibitors, as a possible treatment for executive functioning (EF) deficits in autism spectrum disorder (ASD). The goal of this study was to assess the tolerability, safety, and efficacy of donepezil on EF in a sample of children and adolescents with ASD. Method Thirty-four children and adolescents with ASD (age range 8–17 years; IQ >75) were enrolled in a 10-week, double-blind, placebo-controlled trial of donepezil (doses of 5 and 10 mg), followed by a 10-week open label trial for placebo nonresponders. Results The effect of donepezil treatment on EF was examined. Despite improvement on a number of EF measures, no statistically significant between-group differences were found (with gains observed for both the placebo and donepezil groups). Conclusions The results suggest that short-term treatment with donepezil may have limited impact on cognitive functioning in ASD. Future controlled trials may need to consider a longer treatment period to detect significant gains on EF measures. PMID:21309696

Pharmacokinetic and pharmacodynamic properties of cholinesterase inhibitors donepezil, tacrine, and galantamine in aged and young Lister hooded rats.

PubMed

Goh, Catherine W; Aw, Chiu Cheong; Lee, Jasinda H; Chen, Christopher P; Browne, Edward R

2011-03-01

Physiological alterations that may change pharmacological response accompany aging. Pharmacokinetic/pharmacodynamic properties of cholinesterase inhibitors (ChEIs) used in the treatment of Alzheimer's disease, donepezil, tacrine, and galantamine, were investigated in an aged Lister hooded rat model. Intravenous and oral 6-h blood sampling profiles in old (30 months old) and young (7 months old) rats revealed pharmacokinetic changes similar to those in humans with an approximately 40% increase in C(max) of galantamine and prolonged t(1/2) (1.4-fold) and mean residence time (1.5-fold) of donepezil. Tacrine disposition was maintained with age, and area under the concentration-time curve and clearance in old rats were similar to those in young rats for all drugs tested as was bioavailability. Old rats showed a trend of increased pharmacodynamic sensitivity (<20%) to ChEIs in cholinesterase activity assays, which was attributed to pharmacokinetic effects because a trend of higher blood and brain concentrations was seen in the old rats although brain/blood ratios remained unaffected. Enhanced cholinergic-mediated behaviors such as tremor, hypothermia, salivation, and lacrimation were also observed in the old rats, which could not be accounted for by a similar magnitude of change in pharmacokinetics. A decrease in expression of muscarinic acetylcholine receptor subtype 2 detected in old rat brains was postulated to play a role. Greater age effects in both pharmacokinetics and pharmacodynamics of donepezil and tacrine were seen in previous studies with Fischer 344 rats, indicating a potential risk in overreliance on this rat strain for aging studies.

Evaluation of neuroprotective effect of quercetin with donepezil in scopolamine-induced amnesia in rats.

PubMed

Pattanashetti, Laxmi Adiveppa; Taranalli, Ashok D; Parvatrao, Vinay; Malabade, Rohit H; Kumar, Dushyant

2017-01-01

The objective of this study was to evaluate the neuroprotective effect of quercetin with donepezil in scopolamine-induced amnesia in rats. Five groups of adult male Wistar rats (12 months old) weighing 180-200 g ( n = 6) were used. The normal control group received normal saline and test group animals were pretreated orally with quercetin (25 mg/kg), donepezil (3 mg/kg), and a combination of quercetin (25 mg/kg) with donepezil (3 mg/kg), respectively, dosed at every 24 h interval for 14 consecutive days, afterward amnesia was induced by scopolamine (3 mg/kg) on the 14 th day through intraperitoneal route. Cognitive performance was assessed by the Morris water maze, elevated plus maze, and passive avoidance paradigm. Acetylcholinesterase enzyme (AchE) level, biochemical markers such as lipid peroxidase (LPO), glutathione (GSH), β amyloid 1-42 level, and histopathological study of rat brain were estimated. Statistical analysis was done by one-way analysis of variance, followed by Dunnett's post hoc test. P ≥ 0.05 was considered statistically significant. Pretreatment with quercetin, donepezil, and their combination showed a significant increase in escape latency, step-through latency, and decreased transfer latency in respective cognitive models of the Morris water maze, passive avoidance test, and elevated plus maze. Further coadministration significantly decreased AchE level, β amyloid 1-42 level as compared to individual therapy. Biochemical markers such as elevated GSH, decreased LPO were observed, and histopathological studies revealed the reversal of neuronal damage in the treatment group ( P < 0.05) as compared to scopolamine-treated control group. Pretreatment with quercetin potentiates the action of donepezil in scopolamine-induced amnesia in rats. The improved cognitive memory could be due to the synergistic effect of the drugs by decreasing AchE level, β amyloid 1-42 level, and antioxidant action in rat brain.

Evaluation of neuroprotective effect of quercetin with donepezil in scopolamine-induced amnesia in rats

PubMed Central

Pattanashetti, Laxmi Adiveppa; Taranalli, Ashok D.; Parvatrao, Vinay; Malabade, Rohit H.; Kumar, Dushyant

2017-01-01

Objective: The objective of this study was to evaluate the neuroprotective effect of quercetin with donepezil in scopolamine-induced amnesia in rats. Materials and Methods: Five groups of adult male Wistar rats (12 months old) weighing 180–200 g (n = 6) were used. The normal control group received normal saline and test group animals were pretreated orally with quercetin (25 mg/kg), donepezil (3 mg/kg), and a combination of quercetin (25 mg/kg) with donepezil (3 mg/kg), respectively, dosed at every 24 h interval for 14 consecutive days, afterward amnesia was induced by scopolamine (3 mg/kg) on the 14th day through intraperitoneal route. Cognitive performance was assessed by the Morris water maze, elevated plus maze, and passive avoidance paradigm. Acetylcholinesterase enzyme (AchE) level, biochemical markers such as lipid peroxidase (LPO), glutathione (GSH), β amyloid1-42level, and histopathological study of rat brain were estimated. Statistical analysis was done by one-way analysis of variance, followed by Dunnett's post hoc test. P ≥ 0.05 was considered statistically significant. Results: Pretreatment with quercetin, donepezil, and their combination showed a significant increase in escape latency, step-through latency, and decreased transfer latency in respective cognitive models of the Morris water maze, passive avoidance test, and elevated plus maze. Further coadministration significantly decreased AchE level, β amyloid1-42level as compared to individual therapy. Biochemical markers such as elevated GSH, decreased LPO were observed, and histopathological studies revealed the reversal of neuronal damage in the treatment group (P < 0.05) as compared to scopolamine-treated control group. Conclusion: Pretreatment with quercetin potentiates the action of donepezil in scopolamine-induced amnesia in rats. The improved cognitive memory could be due to the synergistic effect of the drugs by decreasing AchE level, β amyloid1-42level, and antioxidant action in rat

A molecular dynamics study of components of the ginger (Zingiber officinale) extract inside human acetylcholinesterase: implications for Alzheimer disease.

PubMed

Cuya, Teobaldo; Baptista, Leonardo; Celmar Costa França, Tanos

2017-11-23

Components of ginger (Zingiber officinale) extracts have been described as potential new drug candidates against Alzheimer disease (AD), able to interact with several molecular targets related to the AD treatment. However, there are very few theoretical studies in the literature on the possible mechanisms of action by which these compounds can work as potential anti-AD drugs. For this reason, we performed here docking, molecular dynamic simulations and mmpbsa calculations on four components of ginger extracts former reported as active inhibitors of human acetylcholinesterase (HssAChE), and compared our results to the known HssAChE inhibitor and commercial drug in use against AD, donepezil (DNP). Our findings points to two among the compounds studied: (E)-1,7-bis(4-hydroxy-3-methoxyphenyl)hept-4-en-3-on and 1-(3,4-dihydroxy-5-methoxyphenyl)-7-(4-hydroxy-3- ethoxyphenyl) heptane-3,5-diyl diacetate, as promising new HssAChE inhibitors that could be as effective as DNP. We also mapped the binding of the studied compounds in the different binding pockets inside HssAChE and established the preferred interactions to be favored in the design of new and more efficient inhibitors.

Investigating the binding interactions of the anti-Alzheimer's drug donepezil with CYP3A4 and P-glycoprotein.

PubMed

McEneny-King, Alanna; Edginton, Andrea N; Rao, Praveen P N

2015-01-15

The anti-Alzheimer's agent donepezil is known to bind to the hepatic enzyme CYP3A4, but its relationship with the efflux transporter P-glycoprotein (P-gp) is not as well elucidated. We conducted in vitro inhibition studies of donepezil using human recombinant CYP3A4 and P-gp. These studies show that donepezil is a weak inhibitor of CYP3A4 (IC50=54.68±1.00μM) whereas the reference agent ketoconazole exhibited potent inhibition (CYP3A4 IC50=0.20±0.01μM). P-gp inhibition studies indicate that donepezil exhibits better inhibition relative to CYP3A4 (P-gp EC50=34.85±4.63μM) although it was less potent compared to ketoconazole (P-gp EC50=9.74±1.23μM). At higher concentrations, donepezil exhibited significant inhibition of CYP3A4 (69%, 84% and 87% inhibition at 100, 250 and 500μM, respectively). This indicates its potential to cause drug-drug interactions with other CYP3A4 substrates upon co-administration; however, this scenario is unlikely in vivo due to the low therapeutic concentrations of donepezil. Similarly, donepezil co-administration with P-gp substrates or inhibitors is unlikely to result in beneficial or adverse drug interactions. The molecular docking studies show that the 5,6-dimethoxyindan-1-one moiety of donepezil was oriented closer to the heme center in CYP3A4 whereas in the P-gp binding site, the protonated benzylpiperidine pharmacophore of donepezil played a major role in its binding ability. Energy parameters indicate that donepezil complex with both CYP3A4 and P-gp was less stable (CDOCKER energies=-15.05 and -4.91kcal/mol, respectively) compared to the ketoconazole-CYP3A4 and P-gp complex (CDOCKER energies=-41.89 and -20.03kcal/mol, respectively). Copyright © 2014 Elsevier Ltd. All rights reserved.

Cholinergic interactions between donepezil and prucalopride in human colon: potential to treat severe intestinal dysmotility

PubMed Central

Broad, J; Kung, V W S; Boundouki, G; Aziz, Q; De Maeyer, J H; Knowles, C H; Sanger, G J

2013-01-01

BACKGROUND AND PURPOSE Cholinesterase inhibitors such as neostigmine are used for acute colonic pseudo-obstruction, but cardio-bronchial side-effects limit use. To minimize side-effects, lower doses could be combined with a 5-HT4 receptor agonist, which also facilitates intestinal cholinergic activity. However, safety concerns, especially in the elderly, require drugs with good selectivity of action. These include the AChE inhibitor donepezil (used for Alzheimer's disease, with reduced cardio-bronchial liability) and prucalopride, the first selective, clinically available 5-HT4 receptor agonist. This study examined their individual and potential synergistic activities in human colon. EXPERIMENTAL APPROACH Neuronally mediated muscle contractions and relaxations of human colon were evoked by electrical field stimulation (EFS) and defined phenotypically as cholinergic, nitrergic or tachykinergic using pharmacological tools; the effects of drugs were determined as changes in ‘area under the curve’. KEY RESULTS Prucalopride increased cholinergically mediated contractions (EC50 855 nM; 33% maximum increase), consistent with its ability to stimulate intestinal motility; donepezil (477%) and neostigmine (2326%) had greater efficacy. Concentrations of donepezil (30–100 nM) found in venous plasma after therapeutic doses had minimal ability to enhance cholinergic activity. However, donepezil (30 nM) together with prucalopride (3, 10 μM) markedly increased EFS-evoked contractions compared with prucalopride alone (P = 0.04). For example, the increases observed with donepezil and prucalopride 10 μM together or alone were, respectively, 105 ± 35%, 4 ± 6% and 35 ± 21% (n = 3–7, each concentration). CONCLUSIONS AND IMPLICATIONS Potential synergy between prucalopride and donepezil activity calls for exploration of this combination as a safer, more effective treatment of colonic pseudo-obstruction. PMID:24032987

Donepezil improves episodic memory in young individuals vulnerable to the effects of sleep deprivation.

PubMed

Chuah, Lisa Y M; Chong, Delise L; Chen, Annette K; Rekshan, William R; Tan, Jiat-Chow; Zheng, Hui; Chee, Michael W L

2009-08-01

We investigated if donepezil, a long-acting orally administered cholinesterase inhibitor, would reduce episodic memory deficits associated with 24 h of sleep deprivation. Double-blind, placebo-controlled, crossover study involving 7 laboratory visits over 2 months. Participants underwent 4 functional MRI scans; 2 sessions (donepezil or placebo) followed a normal night's sleep, and 2 sessions followed a night of sleep deprivation. The study took place in a research laboratory. 26 young, healthy volunteers with no history of any sleep, psychiatric, or neurologic disorders. 5 mg of donepezil was taken once daily for approximately 17 days. Subjects were scanned while performing a semantic judgment task and tested for word recognition outside the scanner 45 minutes later. Sleep deprivation increased the frequency of non-responses at encoding and impaired delayed recognition. No benefit of donepezil was evident when participants were well rested. When sleep deprived, individuals who showed greater performance decline improved with donepezil, whereas more resistant individuals did not benefit. Accompanying these behavioral effects, there was corresponding modulation of task-related activation in functionally relevant brain regions. Brain regions identified in relation to donepezil-induced alteration in non-response rates could be distinguished from regions relating to improved recognition memory. This suggests that donepezil can improve delayed recognition in sleep-deprived persons by improving attention as well as enhancing memory encoding. Donepezil reduced decline in recognition performance in individuals vulnerable to the effects of sleep deprivation. Additionally, our findings demonstrate the utility of combined fMRI-behavior evaluation in psychopharmacological studies.

Age-Related Decline in Brain and Hepatic Clearance of Amyloid-Beta is Rectified by the Cholinesterase Inhibitors Donepezil and Rivastigmine in Rats.

PubMed

Mohamed, Loqman A; Qosa, Hisham; Kaddoumi, Amal

2015-05-20

In Alzheimer's disease (AD), accumulation of brain amyloid-β (Aβ) depends on imbalance between production and clearance of Aβ. Several pathways for Aβ clearance have been reported including transport across the blood-brain barrier (BBB) and hepatic clearance. The incidence of AD increases with age and failure of Aβ clearance correlates with AD. The cholinesterase inhibitors (ChEIs) donepezil and rivastigmine are used to ease the symptoms of dementia associated with AD. Besides, both drugs have been reported to provide neuroprotective and disease-modifying effects. Here, we investigated the effect of ChEIs on age-related reduced Aβ clearance. Findings from in vitro and in vivo studies demonstrated donepezil and rivastigmine to enhance (125)I-Aβ40 clearance. Also, the increase in brain and hepatic clearance of (125)I-Aβ40 was more pronounced in aged compared to young rats, and was associated with significant reduction in brain Aβ endogenous levels determined by ELISA. Furthermore, the enhanced clearance was concomitant with up-regulation in the expression of Aβ major transport proteins P-glycoprotein and LRP1. Collectively, our findings that donepezil and rivastigmine enhance Aβ clearance across the BBB and liver are novel and introduce an additional mechanism by which both drugs could affect AD pathology. Thus, optimizing their clinical use could help future drug development by providing new drug targets and possible mechanisms involved in AD pathology.

Donepezil Improves Episodic Memory in Young Individuals Vulnerable to the Effects of Sleep Deprivation

PubMed Central

Chuah, Lisa Y.M.; Chong, Delise L.; Chen, Annette K.; Rekshan, William R.; Tan, Jiat-Chow; Zheng, Hui; Chee, Michael W.L.

2009-01-01

Study Objectives: We investigated if donepezil, a long-acting orally administered cholinesterase inhibitor, would reduce episodic memory deficits associated with 24 h of sleep deprivation. Design: Double-blind, placebo-controlled, crossover study involving 7 laboratory visits over 2 months. Participants underwent 4 functional MRI scans; 2 sessions (donepezil or placebo) followed a normal night's sleep, and 2 sessions followed a night of sleep deprivation. Setting: The study took place in a research laboratory. Participants: 26 young, healthy volunteers with no history of any sleep, psychiatric, or neurologic disorders. Interventions: 5 mg of donepezil was taken once daily for approximately 17 days. Measurements and Results: Subjects were scanned while performing a semantic judgment task and tested for word recognition outside the scanner 45 minutes later. Sleep deprivation increased the frequency of non-responses at encoding and impaired delayed recognition. No benefit of donepezil was evident when participants were well rested. When sleep deprived, individuals who showed greater performance decline improved with donepezil, whereas more resistant individuals did not benefit. Accompanying these behavioral effects, there was corresponding modulation of task-related activation in functionally relevant brain regions. Brain regions identified in relation to donepezil-induced alteration in non-response rates could be distinguished from regions relating to improved recognition memory. This suggests that donepezil can improve delayed recognition in sleep-deprived persons by improving attention as well as enhancing memory encoding. Conclusions: Donepezil reduced decline in recognition performance in individuals vulnerable to the effects of sleep deprivation. Additionally, our findings demonstrate the utility of combined fMRI–behavior evaluation in psychopharmacological studies. Citation: Chuah LYM; Chong DL; Chen AK; Rekshan WR; Tan JC; Zheng H; Chee MWL. Donepezil

[Donepezil in patients with Alzheimer's disease--a critical appraisal of the AD2000 study].

PubMed

Kaiser, Thomas; Florack, Christiane; Franz, Heinrich; Sawicki, Peter T

2005-03-15

The AD2000 study was a randomized placebo-controlled trial, the effects of donepezil, a cholinesterase inhibitor, in patients with Alzheimer's disease. It was the first long-term RCT not sponsored by the pharmaceutical industry. The study did not show any significant effect on patient-relevant outcomes. However, donepezil had a significant effect on cognitive scores. More patients taking donepezil stopped treatment due to adverse events, even when taking only 5 mg once daily. There are major concerns regarding the conduction of the AD2000 study as well as the presentation of the results. Much less patients than previously planned have been recruited, resulting in a low statistical power to detect a significant difference between both treatments. In addition, no true intention-to-treat analysis based on the first randomization is presented. The validity of the AD2000 trial has to be questioned. However, there is still insufficient evidence to support the claim that cholinesterase inhibitors have beneficial effects on patient-relevant outcomes in patients with Alzheimer's disease. The change of cognitive performance as measured by different scales does not necessarily correspond to substantial changes in patient-relevant outcomes. In conclusion, the widespread use of cholinesterase inhibitors in patients with Alzheimer's disease is not supported by current evidence. Long-term-randomized controlled trials focusing on patient-relevant outcomes instead of cognitive scores are urgently needed.

Novel multi-target-directed ligands for Alzheimer's disease: Combining cholinesterase inhibitors and 5-HT6 receptor antagonists. Design, synthesis and biological evaluation.

PubMed

Więckowska, Anna; Kołaczkowski, Marcin; Bucki, Adam; Godyń, Justyna; Marcinkowska, Monika; Więckowski, Krzysztof; Zaręba, Paula; Siwek, Agata; Kazek, Grzegorz; Głuch-Lutwin, Monika; Mierzejewski, Paweł; Bienkowski, Przemysław; Sienkiewicz-Jarosz, Halina; Knez, Damijan; Wichur, Tomasz; Gobec, Stanislav; Malawska, Barbara

2016-11-29

As currently postulated, a complex treatment may be key to an effective therapy for Alzheimer's disease (AD). Recent clinical trials in patients with moderate AD have shown a superior effect of the combination therapy of donepezil (a selective acetylcholinesterase inhibitor) with idalopirdine (a 5-HT 6 receptor antagonist) over monotherapy with donepezil. Here, we present the first report on the design, synthesis and biological evaluation of a novel class of multifunctional ligands that combines a 5-HT 6 receptor antagonist with a cholinesterase inhibitor. Novel multi-target-directed ligands (MTDLs) were designed by combining pharmacophores directed against the 5-HT 6 receptor (1-(phenylsulfonyl)-4-(piperazin-1-yl)-1H-indole) and cholinesterases (tacrine or N-benzylpiperidine analogues). In vitro evaluation led to the identification of tacrine derivative 12 with well-balanced potencies against the 5-HT 6 receptor (K b  = 27 nM), acetylcholinesterase and butyrylcholinesterase (IC 50 hAChE  = 12 nM, IC 50 hBuChE  = 29 nM). The compound also showed good in vitro blood-brain-barrier permeability (PAMPA-BBB assay), which was confirmed in vivo (open field study). Central cholinomimetic activity was confirmed in vivo in rats using a scopolamine-induced hyperlocomotion model. A novel class of multifunctional ligands with compound 12 as the best derivative in a series represents an excellent starting point for the further development of an effective treatment for AD. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

A reversed-phase compatible thin-layer chromatography autography for the detection of acetylcholinesterase inhibitors.

PubMed

Ramallo, I Ayelen; García, Paula; Furlan, Ricardo L E

2015-11-01

A dual readout autographic assay to detect acetylcholinesterase inhibitors present in complex matrices adsorbed on reversed-phase or normal-phase thin-layer chromatography plates is described. Enzyme gel entrapment with an amphiphilic copolymer was used for assay development. The effects of substrate and enzyme concentrations, pH, incubation time, and incubation temperature on the sensitivity and the detection limit of the assay were evaluated. Experimental design and response surface methodology were used to optimize conditions with a minimum number of experiments. The assay allowed the detection of 0.01% w/w of physostigmine in both a spiked Sonchus oleraceus L. extract chromatographed on normal phase and a spiked Pimenta racemosa (Mill.) J.W. Moore leaf essential oil chromatographed on reversed phase. Finally, the reversed-phase thin-layer chromatography assay was applied to reveal the presence of an inhibitor in the Cymbopogon citratus (DC.) Stapf essential oil. The developed assay is able to detect acetylcholinesterase inhibitors present in complex matrixes that were chromatographed in normal phase or reversed-phase thin-layer chromatography. The detection limit for physostigmine on both normal and reversed phase was of 1×10(-4) μg. The results can be read by a change in color and/or a change in fluorescence. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Switching From Donepezil to Rivastigmine Is Well Tolerated: Results of an Open-Label Safety and Tolerability Study

PubMed Central

Sadowsky, Carl H.; Farlow, Martin R.; Atkinson, Leone; Steadman, Jennifer; Koumaras, Barbara; Chen, Michael; Mirski, Dario

2005-01-01

Background: Transitioning patients between cholinesterase inhibitors was thought to require a washout period to avoid cholinergic toxicity; however, evidence suggests that abrupt discontinuation of donepezil may lead to cognitive decline. We evaluated the safety and tolerability of an immediate switch from donepezil to rivastigmine. Method: This is an analysis of the safety and tolerability data from the first 28 days of an open-label, multicenter, prospective trial, conducted from August 2002 to August 2003, in which patients satisfying NINCDS-ADRDA criteria for probable Alzheimer's disease were administered rivastigmine 1.5 mg b.i.d. within 24 to 36 hours of donepezil discontinuation. Results are compared with adverse event rates from a retrospective analysis of a pivotal, placebo-controlled trial examining patients not previously treated with a cholinesterase inhibitor. Results: Fifty-eight of 61 patients completed the first 28 days, with no suspected drug-related discontinuations during this period. Incidence of overall gastrointestinal adverse events at day 7 was 8.2%, and at day 28 was 11.5%. The corresponding rate for rivastigmine-treated patients in the retrospective analysis of the pivotal trial for day 7 was 3.3%. Conclusion: These study results suggest that transitioning patients from donepezil to rivastigmine without a washout period is safe and well tolerated. PMID:15841194

Design, synthesis and biological evaluation of novel 6H-benzo[c]chromen-6-one, and 7,8,9,10-tetrahydro-benzo[c]chromen-6-one derivatives as potential cholinesterase inhibitors.

PubMed

Gulcan, Hayrettin Ozan; Unlu, Serdar; Esiringu, Ilker; Ercetin, Tugba; Sahin, Yasemin; Oz, Demet; Sahin, Mustafa Fethi

2014-10-01

Hydroxylated 6H-benzo[c]chromen-6-one derivatives (i.e., urolithins) are the main bioavailable metabolites, and biomarkers of ellagitannins present in various nutrition. Although these dietaries, the sources of urolithins, are employed in folk medicine as cognitive enhancer in the treatment of Alzheimer's Disease, urolithins have negligible potential to inhibit acetylcholinesterase and butyrylcholinesterase enzymes, the validated targets of Alzheimer's Disease. Therefore, within this research, a series of 6H-benzo[c]chromen-6-one, and 7,8,9,10-tetrahydro-benzo[c]chromen-6-one derivatives has been designed, synthesized, and their biological activities were evaluated as potential acetylcholinesterase and butyrylcholinesterase inhibitors. The compounds synthesized exerted comparable activity in comparison to rivastigmine, galantamine, and donepezil both in in vitro and in vivo studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

A combinatorial feature selection approach to describe the QSAR of dual site inhibitors of acetylcholinesterase.

PubMed

Asadabadi, Ebrahim Barzegari; Abdolmaleki, Parviz; Barkooie, Seyyed Mohsen Hosseini; Jahandideh, Samad; Rezaei, Mohammad Ali

2009-12-01

Regarding the great potential of dual binding site inhibitors of acetylcholinesterase as the future potent drugs of Alzheimer's disease, this study was devoted to extraction of the most effective structural features of these inhibitors from among a large number of quantitative descriptors. To do this, we adopted a unique approach in quantitative structure-activity relationships. An efficient feature selection method was emphasized in such an approach, using the confirmative results of different routine and novel feature selection methods. The proposed methods generated quite consistent results ensuring the effectiveness of the selected structural features.

Design and synthesis of dual inhibitors of acetylcholinesterase and serotonin transporter targeting potential agents for Alzheimer's disease.

PubMed

Kogen, Hiroshi; Toda, Narihiro; Tago, Keiko; Marumoto, Shinji; Takami, Kazuko; Ori, Mayuko; Yamada, Naho; Koyama, Kazuo; Naruto, Shunji; Abe, Kazumi; Yamazaki, Reina; Hara, Takao; Aoyagi, Atsushi; Abe, Yasuyuki; Kaneko, Tsugio

2002-10-03

Highly efficient acetylcholinesterase (AChE) and serotonin transporter (SERT) dual inhibitors, (S)-4 and (R)-13 were designed and synthesized on the basis of the hypothetical model of AChE active site. Both compounds showed potent inhibitory activities against AChE and SERT. [structure: see text

Early postnatal maternal deprivation in rats induces memory deficits in adult life that can be reversed by donepezil and galantamine.

PubMed

Benetti, Fernando; Mello, Pâmela Billig; Bonini, Juliana Sartori; Monteiro, Siomara; Cammarota, Martín; Izquierdo, Iván

2009-02-01

Early postnatal maternal deprivation is known to cause long-lasting neurobiological effects. Here, we investigated whether some of the cognitive aspects of these deficits might be related to a disruption of the cholinergic system. Pregnant Wistar rats were individually housed and maintained on a 12:12h light/dark cycle with food and water freely available. The mothers were separated from their pups for 3h per day from postnatal day 1 (PND-1) to PND-10. To do that, the dams were moved to a different cage and the pups maintained in the original home cage, which was transferred to a different room kept at 32 degrees C. After they reached 120-150 days of age, maternal-deprived and non-deprived animals were either sacrificed for brain acetylcholinesterase measurement, or trained and tested in an object recognition task and in a social recognition task as described by Rossato et al. (2007) [Rossato, J.I., Bevilaqua, L. R.M., Myskiw, J.C., Medina, J.H., Izquierdo, I., Cammarota, M. 2007. On the role hippocampal synthesis in the consolidation and reconsolidation of object recognition memory. Learn. Mem. 14, 36-46] and Lévy et al. (2003) [Lévy, F., Melo. A.I., Galef. B.G. Jr., Madden, M., Fleming. A.S. 2003. Complete maternal deprivation affects social, but not spatial, learning in adult rats. Dev. Psychobiol. 43, 177-191], respectively. There was increased acetylcholinesterase activity in hippocampus and perirhinal cortex of the deprived animals. In addition, they showed a clear impairment in memory of the two recognition tasks measured 24h after training. Oral administration of the acetylcholinesterase inhibitors, donepezil or galantamine (1mg/kg) 30min before training reversed the memory impairments caused by maternal deprivation. The findings suggest that maternal deprivation affects memory processing at adulthood through a change in brain cholinergic systems.

Synthesis and study of thiocarbonate derivatives of choline as potential inhibitors of acetylcholinesterase.

PubMed

Boyle, N A; Talesa, V; Giovannini, E; Rosi, G; Norton, S J

1997-09-12

Fourteen alkyl and aryl thiocarbonate derivatives of choline were synthesized and studied as potential inhibitors of acetylcholinesterase (AChE). Twelve of the compounds inhibited AChEs derived from calf forebrain, human red blood cells, and octopus brain ranging from low to moderately high inhibition potency. The concentration of each inhibitory compound giving 50% inhibition of enzyme activity (IC50 values, which ranged from 1 x 10(-2) to 8 x 10(-7) M) was determined and is reported; inhibitor constants (Ki values) for the most inhibitory compounds, (1-pentylthiocarbonyl)choline chloride and (1-heptylthiocarbonyl)choline chloride, were calculated from kinetic data and are also reported. The inhibitors are competitive with substrate, and they are not hydrolyzed by the AChE activities. Certain of these new compounds may provide direction for the development of new drugs that have anticholinesterase activity and may be used for the treatment of Alzheimer's disease.

Combination benefit of cognitive rehabilitation plus donepezil for Alzheimer's disease patients.

PubMed

Matsuzono, Kosuke; Hishikawa, Nozomi; Takao, Yoshiki; Wakutani, Yosuke; Yamashita, Toru; Deguchi, Kentaro; Abe, Koji

2016-02-01

Alzheimer's disease (AD) is one of the most important diseases in aging society, and non-drug therapy might be an alternative therapeutic approach. Thus, we evaluated the add-on effect of cognitive rehabilitation on AD patients under donepezil treatment. We retrospectively analyzed 55 AD patients with a Mini-Mental State Examination score of 15-25, dividing them into two groups depending on whether they were receiving ambulatory cognitive rehabilitation (group D + R, n = 32) or not (group D, n = 23) in Kurashiki Heisei Hospital over 1 year. The present cognitive rehabilitation included physical therapy, occupational therapy and speech therapy for 1-2 h once or twice a week. Between group D and group D + R, there was no significant difference in baseline data, such as age, Mini-Mental State Examination score, periventricular hyperintensity on magnetic resonance imaging, deep white matter hyperintensity on magnetic resonance imaging or donepezil dose (4.1 mg/day). At 1 year later, however, the Mini-Mental State Examination score improved only in group D + R from 21.7 to 24.0 (**P < 0.001), whereas that of group D remained at 21.5 with both groups of donepezil 5.0 mg/day. The combination of cognitive rehabilitation plus a choline esterase inhibitor donepezil showed a better effect for the cognitive function of AD patients than drug only therapy at 1 year. © 2015 Japan Geriatrics Society.

Effects of Anticholinesterases on Catalysis and Induced Conformational Change of the Peripheral Anionic Site of Murine Acetylcholinesterase

PubMed Central

Tong, Fan; Islam, Rafique M.; Carlier, Paul R.; Ma, Ming; Ekström, Fredrik; Bloomquist, Jeffrey R.

2013-01-01

Conventional insecticides targeting acetylcholinesterase (AChE) typically show high mammalian toxicities and because there is resistance to these compounds in many insect species, alternatives to established AChE inhibitors used for pest control are needed. Here we used a fluorescence method to monitor interactions between various AChE inhibitors and the AChE peripheral anionic site, which is a novel target for new insecticides acting on this enzyme. The assay uses thioflavin-T as a probe, which binds to the peripheral anionic site of AChE and yields an increase in fluorescent signal. Three types of AChE inhibitors were studied: catalytic site inhibitors (carbamate insecticides, edrophonium, and benzylpiperidine), peripheral site inhibitors (tubocurarine, ethidium bromide, and propidium iodide), and bivalent inhibitors (donepezil, BW284C51, and a series of bis(n)-tacrines). All were screened on murine AChE to compare and contrast changes of peripheral site conformation in the TFT assay with catalytic inhibition. All the inhibitors reduced thioflavin-T fluorescence in a concentration-dependent manner with potencies (IC50) ranging from 8 nM for bis(6)-tacrine to 159 μM for benzylpiperidine. Potencies in the fluorescence assay were correlated well with their potencies for enzyme inhibition (R2 = 0.884). Efficacies for reducing thioflavin-T fluorescence ranged from 23–36% for catalytic site inhibitors and tubocurarine to near 100% for ethidium bromide and propidium iodide. Maximal efficacies could be reconciled with known mechanisms of interaction of the inhibitors with AChE. When extended to pest species, we anticipate these findings will assist in the discovery and development of novel, selective bivalent insecticides acting on AChE. PMID:24003261

Recent developments in the synthesis of acetylcholinesterase inhibitors.

PubMed

Marco, José L; Carreiras, M Carmo

2003-09-01

The acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities of a series of pyrano[2,3-b]quinolines (2, 3), [1,8]naphthyridines (5, 6), 4-amino-2,3-diaryl-5,6,7,8-tetrahydrofuro[2,3-b]quinolines (11-13)/ 4-amino-6,7,8,9-tetrahydro-2,3-diphenyl-5H-cyclohepta[e]furo[2,3-b]pyridine (14), 4-amino-5,6,7,8-tetrahydro-2,3-diphenylthieno[2,3-b]quinoline (15)/ 4-amino-6,7,8,9-tetrahydro-2,3-diphenyl-5H-cyclohepta[e]thieno[2,3-b]pyridine (16) are described. These compounds are tacrine analogues that have been prepared from readily available polyfunctionalized ethyl [6-amino-5-cyano-4H-pyran]-3-carboxylates (9, 10), ethyl [6-amino-5-cyanopyridine]-3-carboxylates (7, 8), 2-amino-3-cyano-4,5-diarylfurans (17-19) and 2-amino-3-cyano-4,5-diphenylthiophene (20) via Friedländer condensation with selected ketones. These compounds are competitive and, in a few cases, non-competitive inhibitors for AChE, the most potent being compound (14), though three-fold less active than tacrine. The BuChE inhibitory activity is only significant in compounds 11 and 14, ten-fold less active than tacrine. Furthermore, the products 12 and 13 are selective and moderate AChE inhibitors.

Potentiation by cholinesterase inhibitors of cholinergic activity in rat isolated stomach and colon.

PubMed

Jarvie, Emma M; Cellek, Selim; Sanger, Gareth J

2008-01-01

Acetylcholinesterase (AChE) inhibitors stimulate gastrointestinal (GI) motility and are potential treatments of conditions associated with inadequate GI motility. The ability of itopride to facilitate neuronally (predominantly cholinergic) mediated contractions of rat isolated stomach, evoked by electrical field stimulation (EFS), has been compared with other cholinesterase inhibitors and with tegaserod, a clinically effective prokinetic and non-selective 5-HT(4) receptor agonist which also facilitates GI cholinergic function. Neostigmine greatly increased EFS-evoked contractions over a narrow concentration range (0.01-1 microM; 754+/-337% facilitation at 1 microM); higher concentrations (1, 3 microM) also increased muscle tension. Donepezil increased EFS-evoked contractions gradually over the full range of concentrations (0.01-10 microM; maximum increase 516+/-20% at 10 microM). Itopride increased the contractions even more gradually, rising to 188+/-84% at 10 microM. The butyrylcholinesterase inhibitor iso-OMPA 0.01-10 microM also increased EFS-evoked contractions, to a maximum of 36+/-5.0% at 10 microM, similar to that caused by tegaserod (35+/-5.2% increase at 1 microM). The effects of tegaserod, but not itopride were inhibited by the 5-HT(4) receptor antagonist SB-204070A 0.3 microM. In rat isolated colon, neostigmine was again the most efficacious, causing a defined maximum increase in EFS-evoked contractions (343+/-82% at 10 microM), without changing muscle tension. Maximum increases caused by donepezil and itopride were, respectively, 57.6+/-20 and 43+/-15% at 10 microM. These data indicate that the abilities of different AChE inhibitors to increase GI cholinergic activity differ markedly. Understanding the reasons is essential if AChE inhibitors are to be optimally developed as GI prokinetics.

Efficacy and safety of donepezil, galantamine, and rivastigmine for the treatment of Alzheimer’s disease: A systematic review and meta-analysis

PubMed Central

Hansen, Richard A; Gartlehner, Gerald; Webb, Aaron P; Morgan, Laura C; Moore, Charity G; Jonas, Daniel E

2008-01-01

Pharmacologic treatments for Alzheimer’s disease include the cholinesterase inhibitors donepezil, galantamine, and rivastigmine. We reviewed their evidence by searching MEDLINE®, Embase, The Cochrane Library, and the International Pharmaceutical Abstracts from 1980 through 2007 (July) for placebo-controlled and comparative trials assessing cognition, function, behavior, global change, and safety. Thirty-three articles on 26 studies were included in the review. Meta-analyses of placebo-controlled data support the drugs’ modest overall benefits for stabilizing or slowing decline in cognition, function, behavior, and clinical global change. Three open-label trials and one double-blind randomized trial directly compared donepezil with galantamine and rivastigmine. Results are conflicting; two studies suggest no differences in efficacy between compared drugs, while one study found donepezil to be more efficacious than galantamine, and one study found rivastigmine to be more efficacious than donepezil. Adjusted indirect comparison of placebo-controlled data did not find statistically significant differences among drugs with regard to cognition, but found the relative risk of global response to be better with donepezil and rivastigmine compared with galantamine (relative risk = 1.63 and 1.42, respectively). Indirect comparisons also favored donepezil over galantamine with regard to behavior. Across trials, the incidence of adverse events was generally lowest for donepezil and highest for rivastigmine. PMID:18686744

Inhibitor Profile of bis(n)-tacrines and N-methylcarbamates on Acetylcholinesterase from Rhipicephalus (Boophilus) microplus and Phlebotomus papatasi

USDA-ARS?s Scientific Manuscript database

The cattle tick, Rhipicephalus (Boophilus) microplus (Bm), and the sand fly, Phlebotomus papatasi (Pp), are disease vectors to cattle and humans, respectively. The purpose of this study was to characterize the inhibitor profile of acetylcholinesterases from Bm (BmAChE1) and Pp (PpAchE) compared to h...

Template-based de novo design for type II kinase inhibitors and its extented application to acetylcholinesterase inhibitors.

PubMed

Su, Bo-Han; Huang, Yi-Syuan; Chang, Chia-Yun; Tu, Yi-Shu; Tseng, Yufeng J

2013-10-31

There is a compelling need to discover type II inhibitors targeting the unique DFG-out inactive kinase conformation since they are likely to possess greater potency and selectivity relative to traditional type I inhibitors. Using a known inhibitor, such as a currently available and approved drug or inhibitor, as a template to design new drugs via computational de novo design is helpful when working with known ligand-receptor interactions. This study proposes a new template-based de novo design protocol to discover new inhibitors that preserve and also optimize the binding interactions of the type II kinase template. First, sorafenib (Nexavar) and nilotinib (Tasigna), two type II inhibitors with different ligand-receptor interactions, were selected as the template compounds. The five-step protocol can reassemble each drug from a large fragment library. Our procedure demonstrates that the selected template compounds can be successfully reassembled while the key ligand-receptor interactions are preserved. Furthermore, to demonstrate that the algorithm is able to construct more potent compounds, we considered kinase inhibitors and other protein dataset, acetylcholinesterase (AChE) inhibitors. The de novo optimization was initiated using a template compound possessing a less than optimal activity from a series of aminoisoquinoline and TAK-285 inhibiting type II kinases, and E2020 derivatives inhibiting AChE respectively. Three compounds with greater potency than the template compound were discovered that were also included in the original congeneric series. This template-based lead optimization protocol with the fragment library can help to design compounds with preferred binding interactions of known inhibitors automatically and further optimize the compounds in the binding pockets.

Design, synthesis and evaluation of some N-methylenebenzenamine derivatives as selective acetylcholinesterase (AChE) inhibitor and antioxidant to enhance learning and memory.

PubMed

Shrivastava, Sushant K; Srivastava, Pavan; Upendra, T V R; Tripathi, Prabhash Nath; Sinha, Saurabh K

2017-02-15

Series of some 3,5-dimethoxy-N-methylenebenzenamine and 4-(methyleneamino)benzoic acid derivatives comprising of N-methylenebenzenamine nucleus were designed, synthesized, characterized, and assessed for their acetylcholinesterase (AChE), butyrylcholinesterase (BChE) inhibitory, and antioxidant activity thereby improving learning and memory in rats. The IC 50 values of all the compound along with standard were determined on AChE and BChE enzyme. The free radical scavenging activity was also assessed by in vitro DPPH (2,2-diphenyl-1-picryl-hydrazyl) and hydrogen peroxide radical scavenging assay. The selective inhibitions of all compounds were observed against AChE in comparison with standard donepezil. The enzyme kinetic study of the most active compound 4 indicated uncompetitive AChE inhibition. The docking studies of compound 4 exhibited the worthy interaction on active-site gorge residues Phe330 and Trp279 responsible for its high affinity towards AChE, whereas lacking of the BChE inhibition was observed due to a wider gorge binding site and absence of important aromatic amino acids interactions. The ex vivo study confirmed AChE inhibition abilities of compound 4 at brain site. Further, a considerable decrease in escape latency period of the compound was observed in comparison with standard donepezil through in vivo Spatial Reference Memory (SRM) and Spatial Working Memory (SWM) models which showed the cognition-enhancing potential of compound 4. The in vivo reduced glutathione (GSH) estimation on rat brain tissue homogenate was also performed to evaluate free radical scavenging activity substantiated the antioxidant activity in learning and memory. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of donepezil on increased regional cerebral blood flow in the posterior cingulate cortex of a patient with Parkinson's disease dementia.

PubMed

Imamura, Keiko; Wada-Isoe, Kenji; Kowa, Hisanori; Tanabe, Yoshio; Nakashima, Kenji

2008-01-01

It has been reported that the cholinesterase inhibitor, donepezil, improves cognitive decline in patients with Parkinson's disease dementia (PDD). However, this improvement was dominant for frontal lobe dysfunction, and the increase in the Mini-Mental State Examination (MMSE) score was minimal. We report a PDD patient with a decline of regional cerebral blood flow (rCBF) in the posterior cingulate cortex, precunei, and bilateral parietotemporal association cortex, as determined by single-photon emission computed tomography (SPECT) using the easy Z-scores imaging system (e-ZIS). Upon administration of donepezil, both the rCBF and MMSE score increased. The effectiveness of donepezil may vary based on the rCBF pattern in PDD.

Memantine in patients with Alzheimer's disease receiving donepezil: new analyses of efficacy and safety for combination therapy.

PubMed

Atri, Alireza; Molinuevo, José L; Lemming, Ole; Wirth, Yvonne; Pulte, Irena; Wilkinson, David

2013-01-01

Memantine and cholinesterase inhibitors potentially offer additional benefits in Alzheimer's disease (AD) when used together. This study assessed the efficacy and safety of combination treatment with memantine added to stable donepezil in patients with moderate to severe AD, and in a subset with moderate AD. Post hoc meta-analyses of data combined from two 24-week, randomised, double-blind, placebo-controlled trials of memantine 20 mg/day versus placebo, added to a stable cholinesterase inhibitor, were conducted. Data were included for all patients receiving donepezil 10 mg/day with Mini-Mental State Examination (MMSE) scores < 20 (n = 510). Efficacy was assessed using measures of cognition, function, and global status. Furthermore, marked clinical worsening, defined as concurrent deterioration from baseline in the three main efficacy domains, and safety, measured by treatment-emergent adverse events, were assessed. Analyses were performed for patients with moderate to severe AD (MMSE 5-19; MOD-SEV subgroup), and also for patients with moderate AD (MMSE 10-19; MOD subgroup; n = 367). At week 24, in the MOD-SEV subgroup, patients receiving memantine added to donepezil significantly outperformed those receiving placebo added to donepezil in measures of cognition (P < 0.0001), function (P = 0.02), and global status (P = 0.010), with standardised mean differences (SMDs) of 0.36, 0.21, and 0.23, respectively (all last observation carried forward). Similarly, in the MOD subgroup, significant benefits were observed for cognition (P = 0.008), function (P = 0.04) and global status (P = 0.008), with SMDs of 0.28, 0.21, and 0.28, respectively. Significantly fewer patients receiving memantine added to donepezil showed marked clinical worsening than those receiving placebo added to donepezil, in both subgroups (MOD-SEV: 8.7% versus 20.4%, P = 0.0002; MOD: 5.9% versus 15.0%, P = 0.006). The incidence of adverse events was similar between treatment groups. These results support

alpha,beta-Dehydrophenylalanine choline esters, a new class of reversible inhibitors of human acetylcholinesterase and butyrylcholinesterase.

PubMed

Grigoryan, Hasmik A; Hambardzumyan, Artur A; Mkrtchyan, Marina V; Topuzyan, Vigen O; Halebyan, Ghukas P; Asatryan, Ruben S

2008-01-10

Our goal was to design, synthesize, and evaluate new cholinesterase inhibitors. Fourteen dehydroamino acids esterified to choline and to its ternary analog were synthesized by a new method that gave a yield of 84-93%. The potency of the amino acid ester derivatives was tested by measuring K(i) values for inhibition of human red cell acetylcholinesterase and human plasma butyrylcholinesterase. The most potent compound was a choline ester of dehydrophenylalanine where the amine group of the amino acid was derivatized with a benzoyl group containing a methoxy in the 2-position, CH(3)O(C(6)H(4))CONHC(CHC(6)H(5))COOCH(2)CH(2)N(+)(CH(3))(3). This compound was a strong inhibitor of both human acetylcholinesterase and human butyrylcholinesterase, with K(i) values of 10 microM and 0.08 microM, respectively. These K(i) values are comparable to that of Rivastigmine. Docking of the most potent compound into the active site of human butyrylcholinesterase showed that the lowest energy model had two benzene rings oriented towards Trp 82 and Tyr 332 whereas the positively charged nitrogen group was stabilized by Trp 231. This orientation placed the ester group 3.89 A from the active site Ser 198, a distance too far for covalent bonding, explaining why the esters are inhibitors rather than substrates. This class of anticholinesterase agents has the potential for therapeutic utility in the treatment of disorders of the cholinergic system.

A benzothiazole/piperazine derivative with acetylcholinesterase inhibitory activity: Improvement in streptozotocin-induced cognitive deficits in rats.

PubMed

Demir Özkay, Ümide; Can, Özgür Devrim; Sağlık, Begüm Nurpelin; Turan, Nazlı

2017-12-01

Acetylcholinesterase (AChE) inhibitors are frequently prescribed to mitigate the cognitive decline in Alzheimer's disease. Thus, we investigated the possible efficacy of the AChE inhibitor 2-[(6-Nitro-2-benzothiazolyl)amino]-2-oxoethyl4-[2-(N,N-dimethylamino)ethyl] piperazine-1 carbodithioate (BPCT) in a streptozotocin (STZ)-induced Alzheimer's disease model (SADM). First, we analyzed the molecular interaction of BPCT with AChE via a docking study. Then, the cognitive effects of BPCT (10 and 20mg/kg) were evaluated in intracerebroventricular STZ- and vehicle-administered rats with the elevated plus maze (EPM), Morris water maze (MWM), and active avoidance (AA) tests. Locomotor activity was also assessed. Docking analysis indicated significant binding of BPCT to the AChE active site. In behavioral tests, STZ administration impaired cognitive performance in SADM rats versus control rats. Treatment with donepezil or BPCT significantly decreased the prolonged 2nd retention transfer latency and 2nd retention latency time values of the SADM group in the EPM and MWM tests, respectively. Further, prolonged latency times were decreased and reduced frequency of avoidance events were increased in the AA test. Locomotor activity between groups was not different. BPCT appears to function as a central AChE inhibitor, and its improvement of deficits in SADM rats suggests that it has therapeutic potential in Alzheimer's disease. Copyright © 2017 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Influence of various force fields in estimating the binding affinity of acetylcholinesterase inhibitors using fast pulling of ligand scheme

NASA Astrophysics Data System (ADS)

Tam, Nguyen Minh; Vu, Khanh B.; Vu, Van V.; Ngo, Son Tung

2018-06-01

Acetylcholinesterase (AChE) is considered as one of the most favored drug targets for Alzheimer's disease. The effects of different force fields (FFs) on ranking affinity of acetylcholinesterase inhibitors were obtained using the fast pulling of ligand (FPL) method in steered-molecular dynamics (SMD) simulations. GROMOS, AMBER, CHARMM, and OPLS-AA FFs were investigated in this work. The pulling work derived with GROMOS FF has the strongest correlation and smallest error compared with experimental binding affinity. Moreover, the CPU consumption in the calculations using GROMOS FF is the lowest, which could allow us to rank affinity of a large number of AChE ligands.

Dihydroagarofuranoid Sesquiterpenes as Acetylcholinesterase Inhibitors from Celastraceae Plants: Maytenus disticha and Euonymus japonicus.

PubMed

Alarcón, Julio; Cespedes, Carlos L; Muñoz, Evelyn; Balbontin, Cristian; Valdes, Francisco; Gutierrez, Margarita; Astudillo, Luis; Seigler, David S

2015-12-02

Natural cholinesterase inhibitors have been found in many biological sources. Nine compounds with agarofuran (epoxyeudesmane) skeletons were isolated from seeds and aerial parts of Maytenus disticha and Euonymus japonicus. The identification and structural elucidation of compounds were based on spectroscopic data analyses. All compounds had inhibitory acetylcholinesterase (AChE) activity. These natural compounds, which possessed mixed or uncompetitive mechanisms of inhibitory activity against AChE, may be considered as models for the design and development of new naturally occurring drugs for management strategies for neurodegenerative diseases. This is the first report of these chemical structures for seeds of M. disticha.

Inhibitors of Acetylcholinesterase Derived from 7-Methoxytacrine and Their Effects on the Choline Transporter CHT1.

PubMed

Kristofikova, Zdenka; Ricny, Jan; Soukup, Ondrej; Korabecny, Jan; Nepovimova, Eugenie; Kuca, Kamil; Ripova, Daniela

2017-01-01

Reversible acetylcholinesterase inhibitors are used in Alzheimer disease therapy. However, tacrine and its derivatives have severe side effects. Derivatives of the tacrine analogue 7-methoxytacrine (MEOTA) are less toxic. We evaluated new derivatives of 7-MEOTA (2 homodimers linked by 2 C4-C5 chains and 5 N-alkylated C4-C8 side chain derivatives) in vitro, using the rat hippocampal choline transporter CHT1. Some derivatives were effective inhibitors of rat acetylcholinesterase and comparable with 7-MEOTA. All derivatives were able to inhibit CHT1, probably via quaternary ammonium, and this interaction could be involved in the enhancement of their detrimental side effects and/or in the attenuation of their promising effects. Under conditions of disrupted lipid rafts, the unfavorable effects of some derivatives were weakened. Only tacrine was probably able to stereospecifically interact with the naturally occurring amyloid-β isoform and to simultaneously stimulate CHT1. Some derivatives, when coincubated with amyloid β, did not influence CHT1. All derivatives also increased the fluidity of the cortical membranes. The N-alkylated derivative of 7-MEOTA bearing from C4 side chains appears to be the most promising compound and should be evaluated in future in vivo research. © 2016 S. Karger AG, Basel.

Syntheses of coumarin-tacrine hybrids as dual-site acetylcholinesterase inhibitors and their activity against butylcholinesterase, Aβ aggregation, and β-secretase.

PubMed

Sun, Qi; Peng, Da-Yong; Yang, Sheng-Gang; Zhu, Xiao-Lei; Yang, Wen-Chao; Yang, Guang-Fu

2014-09-01

Exploring small-molecule acetylcholinesterase (AChE) inhibitors to slow the breakdown of acetylcholine (Ach) represents the mainstream direction for Alzheimer's disease (AD) therapy. As the first acetylcholinesterase inhibitor approved for the clinical treatment of AD, tacrine has been widely used as a pharmacophore to design hybrid compounds in order to combine its potent AChE inhibition with other multi-target profiles. In present study, a series of novel tacrine-coumarin hybrids were designed, synthesized and evaluated as potent dual-site AChE inhibitors. Moreover, compound 1g was identified as the most potent candidate with about 2-fold higher potency (Ki=16.7nM) against human AChE and about 2-fold lower potency (Ki=16.1nM) against BChE than tacrine (Ki=35.7nM for AChE, Ki=8.7nM for BChE), respectively. In addition, some of the tacrine-coumarin hybrids showed simultaneous inhibitory effects against both Aβ aggregation and β-secretase. We therefore conclude that tacrine-coumarin hybrid is an interesting multifunctional lead for the AD drug discovery. Copyright © 2014 Elsevier Ltd. All rights reserved.

Geissoschizine methyl ether, a corynanthean-type indole alkaloid from Uncaria rhynchophylla as a potential acetylcholinesterase inhibitor.

PubMed

Yang, Zhong-Duo; Duan, Dong-Zhu; Du, Juan; Yang, Ming-Jun; Li, Shuo; Yao, Xiao-Jun

2012-01-01

Geissoschizine methyl ether (1), a newly discovered strong acetylcholinesterase (AChE) inhibitor, along with six weakly active alkaloids, vallesiachotamine (2), hisuteine (3), hirsutine (4), isorhynchophylline (5), cisocorynoxeine (6) and corynoxeine (7) have been isolated from Uncaria rhynchophylla. Geissoschizine methyl ether (1) inhibited 50% of AChE activity at concentrations of 3.7 ± 0.3 µg mL(-1) while the IC(50) value of physostigmine as a standard was 0.013 ± 0.002 µg mL(-1). The mode of AChE inhibition by 1 was reversible and non-competitive. In addition, molecular modelling was performed to explore the binding mode of inhibitor 1 at the active site of AChE.

Beneficial effect of donepezil augmentation for the management of comorbid schizophrenia and dementia.

PubMed

Stryjer, Rafael; Strous, Rael D; Bar, Faina; Werber, Edith; Shaked, Ginette; Buhiri, Yosef; Kotler, Moshe; Weizman, Abraham; Rabey, Jose M

2003-01-01

Comorbid schizophrenia and dementia is a common clinical phenomenon; however, management of the coexisting illnesses remains incomplete. Donepezil, a cholinesterase inhibitor, may be beneficial for the management of symptoms of Alzheimer's disease, a disease in which cholinergic pathways in the cerebral cortex and basal forebrain are well known to be compromised. Furthermore, impaired cognition in elderly schizophrenic patients has been observed to be more than two thirds; however, there are no published controlled studies reporting the use of cholinesterase inhibitors in the management of schizophrenia in patients with associated dementia. In this study, six patients with chronic schizophrenia and comorbid dementia were administered donepezil, 5 mg, in single-blind fashion as augmentation to their standard antipsychotic medication for a 4-week period. Patients were evaluated with the Mini Mental State Examination (MMSE); Alzheimer's Disease Assessment Scale, Cognitive subscale; Positive and Negative Symptom Scale (PANSS); and the Clinical Global Impression (CGI) scales. A significant improvement was noted in MMSE scores (P < 0.01) and for CGI scores (P < 0.01). In addition, three patients demonstrated improvement on the PANSS. Donepezil appears to be an effective treatment for the management of symptoms of dementia accompanying patients with comorbid schizophrenia and dementia. Since cholinergic dysfunction may be present in some patients with schizophrenia, the authors' findings further demonstrate the possibility that this disorder may be managed with cholinergic medications as augmenting agents, at least in this specific subpopulation of patients with comorbid dementia. To confirm the findings of this preliminary trial, further investigation is mandated with a larger sample of subjects in the context of a double-blind medication trial.

Oximes: Inhibitors of Human Recombinant Acetylcholinesterase. A Structure-Activity Relationship (SAR) Study

PubMed Central

Sepsova, Vendula; Karasova, Jana Zdarova; Korabecny, Jan; Dolezal, Rafael; Zemek, Filip; Bennion, Brian J.; Kuca, Kamil

2013-01-01

Acetylcholinesterase (AChE) reactivators were developed for the treatment of organophosphate intoxication. Standard care involves the use of anticonvulsants (e.g., diazepam), parasympatolytics (e.g., atropine) and oximes that restore AChE activity. However, oximes also bind to the active site of AChE, simultaneously acting as reversible inhibitors. The goal of the present study is to determine how oxime structure influences the inhibition of human recombinant AChE (hrAChE). Therefore, 24 structurally different oximes were tested and the results compared to the previous eel AChE (EeAChE) experiments. Structural factors that were tested included the number of pyridinium rings, the length and structural features of the linker, and the number and position of the oxime group on the pyridinium ring. PMID:23959117

Combined Memantine and Donepezil Treatment Improves Behavioral and Psychological Symptoms of Dementia-Like Behaviors in Olfactory Bulbectomized Mice.

PubMed

Yabuki, Yasushi; Matsuo, Kazuya; Hirano, Koga; Shinoda, Yasuharu; Moriguchi, Shigeki; Fukunaga, Kohji

2017-01-01

Memantine, an uncompetitive N-methyl-D-aspartate receptor antagonist, and the cholinesterase inhibitor, donepezil, are approved in most countries for treating moderate-to-severe Alzheimer's disease (AD). These drugs have different molecular targets; thus, it is expected that the effects of combined treatment would be synergistic. Some reports do show memantine/donepezil synergy in ameliorating cognition in AD model animals, but their combined effects on behavioral and psychological symptoms of dementia (BPSD)-like behaviors have not been addressed. Here, we investigate combined memantine/donepezil effects on cognitive impairment and BPSD-like behaviors in olfactory bulbectomized (OBX) mice. Interestingly, combined administration synergistically improved both depressive-like behaviors and impaired social interaction in OBX mice, whereas only weak synergistic effects on cognitive performance were seen. To address mechanisms underlying these effects, we used in vivo microdialysis study and observed impaired nicotine-induced serotonin (5-HT) release in OBX mouse hippocampus. Combined memantine/donepezil administration, but not single administration of either, significantly antagonized the decrease in nicotine-induced 5-HT release seen in OBX mouse hippocampus. Furthermore, decreased autophosphorylation of calcium/calmodulin dependent protein kinase II (CaMKII) was rescued in hippocampal CA1 and dentate gyrus of OBX mice by combined memantine/donepezil administration. These results suggest that improvement of BPSD-like behaviors by the co-administration of both drugs is in part mediated by enhanced 5-HT release and CaMKII activity in OBX mouse hippocampus. © 2016 S. Karger AG, Basel.

Synthesis and biological evaluation of a series of dithiocarbamates as new cholinesterase inhibitors.

PubMed

Altıntop, Mehlika D; Gurkan-Alp, A Selen; Ozkay, Yusuf; Kaplancıklı, Zafer A

2013-08-01

In the present paper, a novel series of dithiocarbamates was synthesized via the treatment of 4-(trifluoromethyl)benzyl chloride with appropriate sodium salts of N,N-disubstituted dithiocarbamic acids. The chemical structures of the compounds were elucidated by (1) H NMR, mass spectral data, and elemental analyses. Each derivative was evaluated for its ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) using a modification of Ellman's spectrophotometric method. The most potent AChE inhibitor was found as compound 2g (IC50  = 0.53 ± 0.001 µM) followed by compounds 2f (IC50  = 0.74 ± 0.001 µM) and 2j (IC50  = 0.89 ± 0.002 µM) when compared with donepezil (IC50  = 0.048 ± 0.001 µM). Compounds 2f and 2g were more effective than donepezil (IC50  = 7.88 ± 0.52 µM) on BuChE inhibition. Compounds 2f and 2g exhibited the inhibitory effect on BuChE with IC50 values of 1.39 ± 0.041 and 3.64 ± 0.072 µM, respectively. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Donepezil improved memory in multiple sclerosis in a randomized clinical trial.

PubMed

Krupp, L B; Christodoulou, C; Melville, P; Scherl, W F; MacAllister, W S; Elkins, L E

2004-11-09

To determine the effect of donepezil in treating memory and cognitive dysfunction in multiple sclerosis (MS). This single-center double-blind placebo-controlled clinical trial evaluated 69 MS patients with cognitive impairment who were randomly assigned to receive a 24-week treatment course of either donepezil (10 mg daily) or placebo. Patients underwent neuropsychological assessment at baseline and after 24 weeks of treatment. The primary outcome was change in verbal learning and memory on the Selective Reminding Test (SRT). Secondary outcomes included other tests of cognitive function, patient-reported change in memory, and clinician-reported impression of cognitive change. Donepezil-treated patients showed significant improvement in memory performance on the SRT compared to placebo (p = 0.043). The benefit of donepezil remained significant after controlling for various covariates including age, Expanded Disability Status Scale, baseline SRT score, reading ability, MS subtype, and sex. Donepezil-treated patients did not show significant improvements on other cognitive tests, but were more than twice as likely to report memory improvement than those in the placebo group (p = 0.006). The clinician also reported cognitive improvement in almost twice as many donepezil vs placebo patients (p = 0.036). No serious adverse events related to study medication occurred, although more donepezil (34.3%) than placebo (8.8%) subjects reported unusual/abnormal dreams (p = 0.010). Donepezil improved memory in MS patients with initial cognitive impairment in a single center clinical trial. A larger multicenter investigation of donepezil in MS is warranted in order to more definitively assess the efficacy of this intervention.

Novel eugenol derivatives: Potent acetylcholinesterase and carbonic anhydrase inhibitors.

PubMed

Topal, Fevzi; Gulcin, Ilhami; Dastan, Arif; Guney, Murat

2017-01-01

Eugenol was used as starting material to obtain some phenolic compounds. The synthesis of these phenolic compounds was performed in a two-step procedure. The structures of the formed products (novel eugenol derivatives 1-6) have been determined on the basis of NMR spectroscopy and other spectroscopic methods. The compounds were tested in terms of carbonic anhydrase (CA) inhibition potency. Carbonic anhydrases (CAs, EC 4.2.1.1) are metalloenzymes, which catalyse the reaction between carbon dioxide (CO 2 ) and water (H 2 O), to generate bicarbonate (HCO 3 - ) and protons (H + ). CO 2 , HCO 3 - and H + are essential molecules and ions for many important physiologic processes occurring in all living organisms. Acetylcholinesterase (AChE, E.C.3.1.1.7) is found in high concentrations in the red blood cells and brain. Novel eugenol derivatives (1-6) were tested for the inhibition of two cytosolic CA isoforms I, and II (hCA I, and II) and AChE. These compounds demonstrated effective inhibitory profiles with Ki values in ranging of 113.48-738.69nM against hCA I, 92.35-530.81nM against hCA II, and 90.10-379.57nM against AChE, respectively. On the other hand, acetazolamide clinically used as CA inhibitor, shoed Ki value of 594.11nM against hCA I, and 120.68nM against hCA II, respectively. Also, AChE was inhibited by tacrine as an AChE inhibitor at the 71.18nM level. Copyright © 2016 Elsevier B.V. All rights reserved.

Multiple Ligands Targeting Cholinesterases and β-Amyloid: Synthesis, Biological Evaluation of Heterodimeric Compounds with Benzylamine Pharmacophore.

PubMed

Szałaj, Natalia; Bajda, Marek; Dudek, Katarzyna; Brus, Boris; Gobec, Stanislav; Malawska, Barbara

2015-08-01

Alzheimer's disease (AD) is a fatal and complex neurodegenerative disorder for which effective treatment remains the unmet challenge. Using donepezil as a starting point, we aimed to develop novel potential anti-AD agents with a multidirectional biological profile. We designed the target compounds as dual binding site acetylcholinesterase inhibitors, where the N-benzylamine pharmacophore is responsible for interactions with the catalytic anionic site of the enzyme. The heteroaromatic fragment responsible for interactions with the peripheral anionic site was modified and three different heterocycles were introduced: isoindoline, isoindolin-1-one, and saccharine. Based on the results of the pharmacological evaluation, we identified compound 8b with a saccharine moiety as the most potent and selective human acetylcholinesterase inhibitor (IC50  = 33 nM) and beta amyloid aggregation inhibitor. It acts as a non-competitive acetylcholinesterase inhibitor and is able to cross the blood-brain barrier in vitro. We believe that compound 8b represents an important lead compound for further development as potential anti-AD agent. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Randomized, Placebo-Controlled, Clinical Trial of Donepezil in Vascular Dementia

PubMed Central

Román, Gustavo C.; Salloway, Stephen; Black, Sandra E.; Royall, Donald R.; DeCarli, Charles; Weiner, Michael W.; Moline, Margaret; Kumar, Dinesh; Schindler, Rachel; Posner, Holly

2010-01-01

Background and Purpose We sought to assess the efficacy and safety of donepezil in patients with vascular dementia (VaD) fulfilling National Institute of Neurological Disorders and Stroke–Association Internationale pour la Recherche et l’Enseignement en Neurosciences criteria. Methods This international, multicenter, 24-week trial was conducted from March 2003 to August 2005. Patients (N=974; mean age, 73.0 years) with probable or possible VaD were randomized 2:1 to receive donepezil 5 mg/d or placebo. Coprimary outcome measures were scores on the Vascular-Alzheimer Disease Assessment Scale–Cognitive Subscale and Clinician’s Interview–Based Impression of Change, plus carer interview. Analyses were performed for the intent-to-treat population with the last-observation-carried-forward method. Results Compared with placebo, donepezil-treated patients showed significant improvement from baseline to end point on the Vascular-Alzheimer Disease Assessment Scale–Cognitive Subscale (least-squares mean difference, −1.156; 95% CI, −1.98 to −0.33; P<0.01) but not on the Clinician’s Interview–Based Impression of Change, plus carer interview. Patients with hippocampal atrophy who were treated with donepezil demonstrated stable cognition versus a decline in the placebo-treated group; in those without atrophy, cognition improved with donepezil versus relative stability with placebo. Results on secondary efficacy measures were inconsistent. The incidence of adverse events was similar across groups. Eleven deaths occurred in the donepezil group (1.7%), similar to rates previously reported for donepezil trials in VaD, whereas no deaths occurred in the placebo group. Conclusions Patients treated with donepezil 5 mg/d demonstrated significant improvement in cognitive, but not global, function. Donepezil was relatively well tolerated; adverse events were consistent with current labeling. Mortality in the placebo group was unexpectedly low. The differential

Acetylcholinesterase inhibitors and memantine in bipolar disorder: A systematic review and best evidence synthesis of the efficacy and safety for multiple disease dimensions.

PubMed

Veronese, Nicola; Solmi, Marco; Luchini, Claudio; Lu, Ru-Band; Stubbs, Brendon; Zaninotto, Leonardo; Correll, Christoph U

2016-06-01

Acetylcholinesterase inhibitors (AceI) and memantine might prove useful in bipolar disorder (BD) given their neuroprotective and pro-cognitive effects, as highlighted by several case reports. We aimed to systematically review the efficacy and safety of AceI and memantine across multiple outcome dimensions in BD. Systematic PubMed and SCOPUS search until 04/17/2015 without language restrictions. Included were randomized controlled trials (RCTs), open label studies and case series of AceI or memantine in BD patients reporting quantitative data on depression, mania, psychotic symptoms, global functioning, or cognitive performance. We summarized results using a best-evidence based synthesis. Out of 214 hits, 12 studies (RCTs=5, other designs=7, total n=422) were included. Donepezil (studies=5; treated=102 vs. placebo=21): there was strong evidence for no effect on mania and psychotic symptoms; low evidence indicating no effect on depression. Galantamine (studies=3; treated=21 vs. controls=20) (placebo=10, healthy subjects=10): there was strong evidence for no effect on mania; moderate evidence for no effect on depression; low evidence for no effect on global functioning. Memantine (studies=4; treated=152 vs. placebo=88): there was conflicting evidence regarding efficacy for mania, depression and global functioning. Paucity of RCTs; small sample size studies; heterogeneous design, outcome and patient characteristics. There is limited but converging evidence of no effect of AceI in BD, and conflicting evidence about memantine in BD. Too few studies of mostly medium/low quality and lacking sufficient numbers of patients in specific mood states, especially mania, contributed data, focusing solely on short-term/medium-term treatment, necessitating additional high-quality research to yield more definite results. Copyright © 2016 Elsevier B.V. All rights reserved.

Memantine and donepezil: a fixed drug combination for the treatment of moderate to severe Alzheimer's dementia.

PubMed

Owen, R T

2016-04-01

Donepezil (and other cholinesterase inhibitors [ChEIs]) and memantine are the mainstays of treatment in Alzheimer's dementia, addressing respectively, the cholinergic and glutamatergic dysregulation which underlies or results from its pathophysiology. To alleviate the pill burden and swallowing difficulties associated with the condition, a fixed drug combination of extended-release memantine and donepezil was developed. This combination was shown to be both bioequivalent to the components administered separately and could be administered sprinkled over soft food. The mode of action, pharmacokinetics, clinical efficacy and safety and tolerability of the combination are discussed together with the wider, often conflicting trial literature of combination versus monotherapy with memantine and ChEIs, their meta-analyses and treatment guidelines. Copyright 2016 Prous Science, S.A.U. or its licensors. All rights reserved.

Design, synthesis, pharmacological evaluation, QSAR analysis, molecular modeling and ADMET of novel donepezil-indolyl hybrids as multipotent cholinesterase/monoamine oxidase inhibitors for the potential treatment of Alzheimer's disease.

PubMed

Bautista-Aguilera, Oscar M; Esteban, Gerard; Bolea, Irene; Nikolic, Katarina; Agbaba, Danica; Moraleda, Ignacio; Iriepa, Isabel; Samadi, Abdelouahid; Soriano, Elena; Unzeta, Mercedes; Marco-Contelles, José

2014-03-21

The design, synthesis, and pharmacological evaluation of donepezil-indolyl based amines 7-10, amides 12-16, and carboxylic acid derivatives 5 and 11, as multipotent ASS234 analogs, able to inhibit simultaneously cholinesterase (ChE) and monoamine oxidase (MAO) enzymes for the potential treatment of Alzheimer's disease (AD), is reported. Theoretical studies using 3D-Quantitative Structure-Activity Relationship (3D-QSAR) was used to define 3D-pharmacophores for inhibition of MAO A/B, AChE, and BuChE enzymes. We found that, in general, and for the same substituent, amines are more potent ChE inhibitors (see compounds 12, 13 versus 7 and 8) or equipotent (see compounds 14, 15 versus 9 and 10) than the corresponding amides, showing a clear EeAChE inhibition selectivity. For the MAO inhibition, amides were not active, and among the amines, compound 14 was totally MAO A selective, while amines 15 and 16 were quite MAO A selective. Carboxylic acid derivatives 5 and 11 showed a multipotent moderate selective profile as EeACE and MAO A inhibitors. Propargylamine 15 [N-((5-(3-(1-benzylpiperidin-4-yl)propoxy)-1-methyl-1H-indol-2-yl)methyl)prop-2-yn-1-amine] resulted in the most potent hMAO A (IC50 = 5.5 ± 1.4 nM) and moderately potent hMAO B (IC50 = 150 ± 31 nM), EeAChE (IC50 = 190 ± 10 nM), and eqBuChE (IC50 = 830 ± 160 nM) inhibitor. However, the analogous N-allyl and the N-morpholine derivatives 16 and 14 deserve also attention as they show an attractive multipotent profile. To sum up, donepezil-indolyl hybrid 15 is a promising drug for further development for the potential prevention and treatment of AD. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Bivalent ligands derived from Huperzine A as acetylcholinesterase inhibitors.

PubMed

Haviv, H; Wong, D M; Silman, I; Sussman, J L

2007-01-01

The naturally occurring alkaloid Huperzine A (HupA) is an acetylcholinesterase (AChE) inhibitor that has been used for centuries as a Chinese folk medicine in the context of its source plant Huperzia Serrata. The potency and relative safety of HupA rendered it a promising drug for the ameliorative treatment of Alzheimer's disease (AD) vis-à-vis the "cholinergic hypothesis" that attributes the cognitive decrements associated with AD to acetylcholine deficiency in the brain. However, recent evidence supports a neuroprotective role for HupA, suggesting that it could act as more than a mere palliative. Biochemical and crystallographic studies of AChE revealed two potential binding sites in the active-site gorge of AChE, one of which, the "peripheral anionic site" at the mouth of the gorge, was implicated in promoting aggregation of the beta amyloid (Abeta) peptide responsible for the neurodegenerative process in AD. This feature of AChE facilitated the development of dual-site binding HupA-based bivalent ligands, in hopes of concomitantly increasing AChE inhibition potency by utilizing the "chelate effect", and protecting neurons from Abeta toxicity. Crystal structures of AChE allowed detailed modeling and docking studies that were instrumental in enhancing the understanding of underlying principles of bivalent inhibitor-enzyme dynamics. This monograph reviews two categories of HupA-based bivalent ligands, in which HupA and HupA fragments serve as building blocks, with a focus on the recently solved crystallographic structures of Torpedo californica AChE in complex with such bifunctional agents. The advantages and drawbacks of such structured-based drug design, as well as species differences, are highlighted and discussed.

Lead identification of acetylcholinesterase inhibitors-histamine H3 receptor antagonists from molecular modeling.

PubMed

Bembenek, Scott D; Keith, John M; Letavic, Michael A; Apodaca, Richard; Barbier, Ann J; Dvorak, Lisa; Aluisio, Leah; Miller, Kirsten L; Lovenberg, Timothy W; Carruthers, Nicholas I

2008-03-15

Currently, the only clinically effective treatment for Alzheimer's disease (AD) is the use of acetylcholinesterase (AChE) inhibitors. These inhibitors have limited efficacy in that they only treat the symptoms and not the disease itself. Additionally, they often have unpleasant side effects. Here we consider the viability of a single molecule having the actions of both an AChE inhibitor and histamine H(3) receptor antagonist. Both histamine H(3) receptor antagonists and AChE inhibitors improve and augment cholinergic neurotransmission in the cortex. However, whereas an AChE inhibitor will impart its effect everywhere, a histamine H(3) antagonist will raise acetylcholine levels mostly in the brain as its mode of action will primarily be on the central nervous system. Therefore, the combination of both activities in a single molecule could be advantageous. Indeed, studies suggest an appropriate dual-acting compound may offer the desired therapeutic effect with fewer unpleasant side effects [CNS Drugs2004, 18, 827]. Further, recent studies(2) indicate the peripheral anionic site (PAS) of AChE interacts with the beta-amyloid (betaA) peptide. Consequently, a molecule capable of disrupting this interaction may have a significant impact on the production of or the aggregation of betaA. This may result in slowing down the progression of the disease rather than only treating the symptoms as current therapies do. Here, we detail how the use of the available crystal structure information, pharmacophore modeling and docking (automated, manual, classical, and QM/MM) lead to the identification of an AChE inhibitor-histamine H(3) receptor antagonist. Further, based on our models we speculate that this dual-acting compound may interact with the PAS. Such a dual-acting compound may be able to affect the pathology of AD in addition to providing symptomatic relief.

In silico development of new acetylcholinesterase inhibitors.

PubMed

Pascoini, A L; Federico, L B; Arêas, A L F; Verde, B A; Freitas, P G; Camps, I

2018-04-19

In this work, we made use of fragment-based drug design (FBDD) and de novo design to obtain more powerful acetylcholinesterase (AChE) inhibitors. AChE is associated with Alzheimer's disease (AD). It was found that the cholinergic pathways in the cerebral cortex are compromised in AD and the accompanying cholinergic deficiency contributes to the cognitive deterioration of AD patients. In the FBDD approach, fragments are docked into the active site of the protein. As fragments are molecular groups with a low number of atoms, it is possible to study their interaction with localized amino acids. Once the interactions are measured, the fragments are organized by affinity and then linked together to form new molecules with a high degree of interaction with the active site. In the other approach, we used the de novo design technique starting from reference drugs used in the AD treatment. These drugs were broken into fragments (seeds). In the growing strategy, fragments were added to each seed, growing new molecules. In the linking strategy, two or more separated seeds were linked with different fragments. Both strategies combined produced a library of more than 2 million compounds. This library was filtered using absorption, distribution, metabolism, and excretion properties. The resulting library with around six thousand compounds was filtered again. In this case, structures with Tanimoto coefficients >.85 were discarded. The final library with 1500 compounds was submitted to docking studies. As a result, 10 compounds with better interaction energy than the reference drugs were obtained.

Elaborate ligand-based modeling coupled with QSAR analysis and in silico screening reveal new potent acetylcholinesterase inhibitors.

PubMed

Abuhamdah, Sawsan; Habash, Maha; Taha, Mutasem O

2013-12-01

Inhibition of the enzyme acetylcholinesterase (AChE) has been shown to alleviate neurodegenerative diseases prompting several attempts to discover and optimize new AChE inhibitors. In this direction, we explored the pharmacophoric space of 85 AChE inhibitors to identify high quality pharmacophores. Subsequently, we implemented genetic algorithm-based quantitative structure-activity relationship (QSAR) modeling to select optimal combination of pharmacophoric models and 2D physicochemical descriptors capable of explaining bioactivity variation among training compounds (r2(68)=0.94, F-statistic=125.8, r2 LOO=0.92, r2 PRESS against 17 external test inhibitors = 0.84). Two orthogonal pharmacophores emerged in the QSAR equation suggesting the existence of at least two binding modes accessible to ligands within AChE binding pocket. The successful pharmacophores were comparable with crystallographically resolved AChE binding pocket. We employed the pharmacophoric models and associated QSAR equation to screen the national cancer institute list of compounds. Twenty-four low micromolar AChE inhibitors were identified. The most potent gave IC50 value of 1.0 μM.

Synthesis of new N-benzylpiperidine derivatives as cholinesterase inhibitors with β-amyloid anti-aggregation properties and beneficial effects on memory in vivo.

PubMed

Więckowska, Anna; Więckowski, Krzysztof; Bajda, Marek; Brus, Boris; Sałat, Kinga; Czerwińska, Paulina; Gobec, Stanislav; Filipek, Barbara; Malawska, Barbara

2015-05-15

Due to the complex nature of Alzheimer's disease, multi-target-directed ligand approaches are one of the most promising strategies in the search for effective treatments. Acetylcholinesterase, butyrylcholinesterase and β-amyloid are the predominant biological targets in the search for new anti-Alzheimer's agents. Our aim was to combine both anticholinesterase and β-amyloid anti-aggregation activities in one molecule, and to determine the therapeutic potential in vivo. We designed and synthesized 28 new compounds as derivatives of donepezil that contain the N-benzylpiperidine moiety combined with the phthalimide or indole moieties. Most of these test compounds showed micromolar activities against cholinesterases and aggregation of β-amyloid, combined with positive results in blood-brain barrier permeability assays. The most promising compound 23 (2-(8-(1-(3-chlorobenzyl)piperidin-4-ylamino)octyl)isoindoline-1,3-dione) is an inhibitor of butyrylcholinesterase (IC50=0.72 μM) that has β-amyloid anti-aggregation activity (72.5% inhibition at 10 μM) and can cross the blood-brain barrier. Moreover, in an animal model of memory impairment induced by scopolamine, the activity of 23 was comparable to that of donepezil. The selected compound 23 is an excellent lead structure in the further search for new anti-Alzheimer's agents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Acetylcholinesterases of Blood-feeding Flies and Ticks

USDA-ARS?s Scientific Manuscript database

Acetylcholinesterase (AChE) is the biochemical target of organophosphate (OP) and carbamate pesticides for invertebrates, vertebrate nerve agents, and AChE inhibitors used to reduce effects of Alzheimer’s disease. Organophosphate pesticides (OPs) are widely used to control blood-feeding arthropods, ...

Differential efficacy of treatment with acetylcholinesterase inhibitors in patients with mild and moderate Alzheimer's disease over a 6-month period.

PubMed

López-Pousa, S; Turon-Estrada, A; Garre-Olmo, J; Pericot-Nierga, I; Lozano-Gallego, M; Vilalta-Franch, M; Hernández-Ferràndiz, M; Morante-Muñoz, V; Isern-Vila, A; Gelada-Batlle, E; Majó-Llopart, J

2005-01-01

There are various anticholinesterase inhibitors (AChEIs) for the symptomatic treatment of mild to moderate Alzheimer's disease (AD). All AChEIs have shown greater efficacy than placebo in randomized, double-blind, parallel-group clinical trials. No differential studies have yet been made of the efficacy between all AChEIs. The study aims to determine the differential efficacy of the AChEIs with respect to a historical sample of patients with AD that were not treated with AChEIs. An open-label, prospective, observational study with a retrospective control group was undertaken to examine the evolution of the cognitive function over a 6-month period. The patients were assessed with the Mini-Mental State Examination (MMSE) at study entry and at 6 months. A general linear model was applied for repeated measurements with the MMSE score as the dependent variable, treatment type as an independent variable and the severity of the deterioration, age and the MMSE baseline score as covariables. Of the sample of 147 patients, 40 initiated treatment with donepezil, 32 with galantamine, 30 with rivastigmine and 45 were part of a historical sample of the memory clinic patients between 1991 and 1996 that had not been treated with AChEIs. The average age was 73.7 years (SD = 6.9; range = 52-86), 67.3% were women, 78.2% of the cases were mild and the MMSE baseline score was 18.1 points (range = 11-27). No significant intergroup differences were observed in these variables. The average doses of donepezil, galantamine and rivastigmine were 5.87 mg/day (SD = 1.92), 14.81 mg/day (SD = 6.25) and 6.41 mg/day (SD = 1.82), respectively. At 6 months, the difference in the MMSE score with respect to the untreated group was 1.6 points for donepezil (95% CI 0.79-2.37; p < 0.001), 0.99 points for galantamine (95% CI 0.14-1.85; p = 0.01) and 0.90 points for rivastigmine (95% CI 0.05-1.74; p = 0.03). No significant differences were observed in the efficacy among the groups treated with AChEIs (p

Binding of 2-[18F]fluoro-CP-118,954 to mouse acetylcholinesterase: microPET and ex vivo Cerenkov luminescence imaging studies.

PubMed

Kim, Dong Hyun; Choe, Yearn Seong; Choi, Joon Young; Lee, Kyung-Han; Kim, Byung-Tae

2011-05-01

Acetylcholinesterase (AChE) has been an important cholinergic factor for the diagnosis of Alzheimer's disease (AD), because of reduced AChE activity in the postmortem brains of AD patients. We previously developed 5,7-dihydro-3-(2-(1-(2-[(18)F]fluorobenzyl)-4-piperidinyl)ethyl)-6H-pyrrolo(3,2,f)-1,2-benzisoxazol-6-one (2-[(18)F]fluoro-CP-118,954) for in vivo studies of AChE in mice. In the present study, we automated the synthesis of 2-[(18)F]fluoro-CP-118,954 for the routine use and evaluated the radioligand by microPET and ex vivo Cerenkov luminescence imaging of mouse AChE. 4-[(18)F]Fluoro-donepezil, another AChE inhibitor, was used for comparison. Automated syntheses of 2-[(18)F]fluoro-CP-118,954 and 4-[(18)F]fluoro-donepezil resulted in high radiochemical yields (25-33% and 30-40%) and high specific activity (27.1-35.4 and 29.7-37.3 GBq/μmol). Brain microPET images of two ICR mice injected with 2-[(18)F]fluoro-CP-118,954 demonstrated high uptake in the striatum (ROI analysis: 5.1 %ID/g for the first 30 min and 4.1 %ID/g for another 30 min), and a blocking study with injection of CP-118,954 into one of the mice at 30 min after radioligand injection led to complete blocking of radioligand uptake in the striatum (ROI analysis: 1.9 %ID/g), whereas (18)F-labeled donepezil did not show specific uptake in the striatum. In another set of experiments, the brain tissues (striatum, parietal cortex, frontal cortex and cerebellum) were excised after brain microPET/CT imaging of mouse injected with 2-[(18)F]fluoro-CP-118,954, and a high striatal uptake was also detected in ex vivo optical and microPET images (ROI analysis: 1.4 %ID/g) and in γ-counting data (2.1 %ID/g at 50 min post-injection) of the brain tissues. Taken together, these results demonstrated that 2-[(18)F]fluoro-CP-118,954 specifically binds to AChE in mouse brains. Copyright © 2011 Elsevier Inc. All rights reserved.

Donepezil for cancer fatigue: a double-blind, randomized, placebo-controlled trial.

PubMed

Bruera, Eduardo; El Osta, Badi; Valero, Vicente; Driver, Larry C; Pei, Be-Lian; Shen, Loren; Poulter, Valerie A; Palmer, J Lynn

2007-08-10

To evaluate the effectiveness of donepezil compared with placebo in cancer patients with fatigue as measured by the Functional Assessment for Chronic Illness Therapy-Fatigue (FACIT-F). Patients with fatigue score >or= 4 on a scale of 0 to 10 (0 = no fatigue, 10 = worst possible fatigue) for more than 1 week were included. Patients were randomly assigned to receive donepezil 5 mg or placebo orally every morning for 7 days. A research nurse contacted the patients by telephone daily to assess toxicity and fatigue level. All patients were offered open-label donepezil during the second week. FACIT-F and/or the Edmonton Symptom Assessment System (ESAS) were assessed at baseline, and days 8, 11, and 15. The FACIT-F fatigue subscale score on day 8 was considered the primary end point. Of 142 patients randomly assigned to treatment, 47 patients in the donepezil group and 56 in the placebo group were assessable for final analysis. Fatigue intensity improved significantly on day 8 in both donepezil and placebo groups. However, there was no significant difference in fatigue improvement by FACIT-F (P = .57) or ESAS (P = .18) between groups. In the open-label phase, fatigue intensity continued to be low as compared with baseline. No significant toxicities were observed. Donepezil was not significantly superior to placebo in the treatment of cancer-related fatigue.

Rapid Screening and Characterization of Acetylcholinesterase Inhibitors from Yinhuang Oral Liquid Using Ultrafiltration-liquid Chromatography-electrospray Ionization Tandem Mass Spectrometry

PubMed Central

Zhang, Haomin; Guo, Yinan; Meng, Lingwen; Sun, Hui; Yang, Yinping; Gao, Ying; Sun, Jiaming

2018-01-01

Background: At present, approximately 17–25 million people in the world suffer from Alzheimer's disease (AD). The most efficacious and acceptable therapeutic drug clinically are the acetylcholinesterase inhibitors (AChEIs). Yinhuang oral liquid is a Chinese medicine preparation which contains AChEIs according to the literatures. However, no strategy has been presented for rapid screening and identification of AChEIs from Yinhuang oral liquid. Objective: To develop a method for rapid screening and identification of AChEIs from Yinhuang oral liquid using ultrafiltration–liquid chromatography–electrospray ionization tandem mass spectrometry (UF-LC-ESI-MS/MS). Materials and Methods: In this study, UF incubation conditions such as enzyme concentration, incubation time, and incubation temperature were optimized so as to get better screening results. The AChEIs from Yinhuang oral liquid were identified by high-performance liquid chromatography-ESI-MS and the improved Ellman method was used for the AChE inhibitory activity test in vitro. Results: The results showed that Yinhuang oral liquid can inhibit the activity of AChE. We screened and identified seven compounds with potential AChE inhibitory activity from Yinhuang oral liquid, which provided experimental basis for the treatment and prevention of AD. Conclusion: The current technique was used to directly screen the active ingredients with acetylcholinesterase inhibition from complex traditional Chinese medicine, which was simple, rapid, accurate, and suitable for high-throughput screening of AChEI from complex systems. SUMMARY A UF-LC-ESI-MS/MS method for rapid screening and identification of AChEIs from Yinhuang oral liquid was developedSeven compounds were screened and identified with potential AChE inhibitory activity from Yinhuang oral liquidIt provided experimental basis of Yinhuang oral liquid for the treating and preventing AD. Abbreviations used: (AD): Alzheimer's disease; (UF

Synthesis, biological evaluation and molecular modelling of diversely functionalized heterocyclic derivatives as inhibitors of acetylcholinesterase/butyrylcholinesterase and modulators of Ca2+ channels and nicotinic receptors.

PubMed

Marco, José L; de los Ríos, Cristóbal; García, Antonio G; Villarroya, Mercedes; Carreiras, M Carmo; Martins, Carla; Eleutério, Ana; Morreale, Antonio; Orozco, M; Luque, F Javier

2004-05-01

The synthesis and the biological activity of compounds 5-40 as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), as well as modulators of voltage-dependent Ca(2+) channels and nicotinic receptors, are described. These molecules are tacrine analogues, which have been prepared from polyfunctionalized 6-amino-5-cyano-4H-pyrans, 6-amino-5-cyano-pyridines and 5-amino-2-aryl-3-cyano-1,3-oxazoles via Friedländer reaction with selected cycloalkanones. These compounds are moderate acetylcholinesterase and butyrylcholinesterase inhibitors, the BuChE/AChE selectivity of the most active molecules ranges from 10.0 (compound 29) to 76.9 (compound 16). Interestingly, the 'oxazolo-tacrine' derivatives are devoid of any activity. All compounds showed an important inhibitory effect on the nicotinic acetylcholine receptor. Most of them also blocked L-type Ca(2+) channels, and three of them, 64, 19 and 67, the non-L type of Ca(2+) channels. Molecular modelling studies suggest that these compounds might bind at the peripheral binding site of AChE, which opens the possibility to design inhibitors able to bind at both, the catalytic and peripheral binding sites of the enzyme.

High-performance liquid chromatography-mass spectrometry-based acetylcholinesterase assay for the screening of inhibitors in natural extracts.

PubMed

de Jong, Camiel F; Derks, Rico J E; Bruyneel, Ben; Niessen, Wilfried; Irth, Hubertus

2006-04-21

The present paper describes a High-performance liquid chromatography-mass spectrometry (LC-MS) methodology for the screening of acetylcholinesterase (AChE) inhibitors in natural extracts. AChE activity of sample components is monitored by a post-column biochemical assay that is based on the separate, sequential mixing of AChE and acetylcholine, respectively, with the HPLC eluate. AChE inhibitors are detected by measuring a decrease of product formation using electrospray MS. Ammonium bicarbonate was used as buffer in order to achieve optimum compatibility between biochemical assay and MS detection conditions. The assay is robust and stable for over 13 h and compares favourably with other AChE assays in terms of stability and sensitivity. IC(50) values of 9-aminoacridine, galanthamine, gallamine, (-)-huperzine A and thioflavin T were determined to be 0.12, 0.38, 6.4, 0.46 and 3.2 microM, respectively. The assay was used to effectively identify an AChE inhibitor present in a crude extract of Narcissus c.v. "Bridal Crown".

Complexity of acetylcholinesterases in biting flies and ticks

USDA-ARS?s Scientific Manuscript database

Acetylcholinesterase (AChE) inhibitors function as pesticides for invertebrates, vertebrate nerve agents, and medicine to reduce cognitive effects of Alzheimer’s disease. Organophosphate (OP) pesticides have been widely used to control biting flies and ticks, however, OP-resistance has compromised c...

The Evaluation of Benefit of Newly Prepared Reversible Inhibitors of Acetylcholinesterase and Commonly Used Pyridostigmine as Pharmacological Pretreatment of Soman-Poisoned Mice.

PubMed

Kassa, Jiří; Korábečný, Jan; Nepovimová, Eugenie

The ability of four newly prepared reversible inhibitors of acetylcholinesterase (6-chlorotacrine, 7-phenoxytacrine, compounds 1 and 2) and currently used carbamate pyridostigmine to increase the resistance of mice against soman and the efficacy of antidotal treatment of soman-poisoned mice was evaluated. The evaluation of the effect of pharmacological pretreatment is based on the identification of changes of soman-induced toxicity that was evaluated by the assessment of its LD50 value and its 95% confidence limit using probitlogarithmical analysis of death occurring within 24 h after administration of soman. 6-chlorotacrine was only able to markedly protect mice against acute toxicity of soman. In addition, the pharmacological pretreatment with 6-chlorotacrine or compound 2 was able to increase the efficacy of antidotal treatment (the oxime HI-6 in combination with atropine) of soman-poisoned mice. The other newly prepared reversible inhibitors of acetylcholinesterase (7-phenoxytacrine, compound 1) as well as commonly used pyridostigmine did not influence the efficacy of antidotal treatment. These findings demonstrate that pharmacological pretreatment of somanpoisoned mice can be promising and useful in the case of administration of 6-chlorotacrine and partly compound 2.

Cost-effectiveness of donepezil and memantine in moderate to severe Alzheimer's disease (the DOMINO-AD trial).

PubMed

Knapp, Martin; King, Derek; Romeo, Renée; Adams, Jessica; Baldwin, Ashley; Ballard, Clive; Banerjee, Sube; Barber, Robert; Bentham, Peter; Brown, Richard G; Burns, Alistair; Dening, Tom; Findlay, David; Holmes, Clive; Johnson, Tony; Jones, Robert; Katona, Cornelius; Lindesay, James; Macharouthu, Ajay; McKeith, Ian; McShane, Rupert; O'Brien, John T; Phillips, Patrick P J; Sheehan, Bart; Howard, Robert

2017-12-01

Most investigations of pharmacotherapy for treating Alzheimer's disease focus on patients with mild-to-moderate symptoms, with little evidence to guide clinical decisions when symptoms become severe. We examined whether continuing donepezil, or commencing memantine, is cost-effective for community-dwelling, moderate-to-severe Alzheimer's disease patients. Cost-effectiveness analysis was based on a 52-week, multicentre, double-blind, placebo-controlled, factorial clinical trial. A total of 295 community-dwelling patients with moderate/severe Alzheimer's disease, already treated with donepezil, were randomised to: (i) continue donepezil; (ii) discontinue donepezil; (iii) discontinue donepezil and start memantine; or (iv) continue donepezil and start memantine. Continuing donepezil for 52 weeks was more cost-effective than discontinuation, considering cognition, activities of daily living and health-related quality of life. Starting memantine was more cost-effective than donepezil discontinuation. Donepezil-memantine combined is not more cost-effective than donepezil alone. Robust evidence is now available to inform clinical decisions and commissioning strategies so as to improve patients' lives whilst making efficient use of available resources. Clinical guidelines for treating moderate/severe Alzheimer's disease, such as those issued by NICE in England and Wales, should be revisited. © 2016 The Authors. International Journal of Geriatric Psychiatry published by John Wiley & Sons Ltd. © 2016 The Authors. International Journal of Geriatric Psychiatry published by John Wiley & Sons Ltd.

New Inhibitors of the Peripheral Site in Acetylcholinesterase that Specifically Block Organophosphorylation

DTIC Science & Technology

2000-09-01

Interministerial de Ciencia y (donepezil, Arice Teenologia ( Programa Nacional de Tecnologia de los Procesos Qufmios, pt) in 1996. A third potent reversible...Molecular, Facultad de Ciencias Biol6gicas, Pontificia Universidad Cat6lica de Chile , Alameda 340, 114-D Santiago, Chile Running Title: Thioflavin T...2000 Medical Defense Review, Hunt Valley, Maryland, June 4-9, 2000. In press. De Ferrari, G.V., Mallender, W.D., Inestrosa, N.C., and Rosenberry, T.L

In situ monitoring of myenteric neuron activity using acetylcholinesterase-modified AlGaN/GaN solution-gate field-effect transistors.

PubMed

Müntze, Gesche Mareike; Pouokam, Ervice; Steidle, Julia; Schäfer, Wladimir; Sasse, Alexander; Röth, Kai; Diener, Martin; Eickhoff, Martin

2016-03-15

The response characteristics of acetylcholinesterase-modified AlGaN/GaN solution-gate field-effect transistors (AcFETs) are quantitatively analyzed by means of a kinetic model. The characterization shows that the covalent enzyme immobilization process yields reproducible AcFET characteristics with a Michaelis constant KM of (122 ± 4) μM for the immobilized enzyme layer. The increase of KM by a factor of 2.4 during the first four measurement cycles is attributed to partial denaturation of the enzyme. The AcFETs were used to record the release of acetylcholine (ACh) by neuronal tissue cultivated on the gate area upon stimulation by rising the extracellular K(+) concentration. The neuronal tissue constituted of isolated myenteric neurons from four to 12 days old Wistar rats, or sections from the muscularis propria containing the myenteric plexus from adult rats. For both cases the AcFET response was demonstrated to be related to the activity of the immobilized acetylcholinesterase using the reversible acetylcholinesterase blocker donepezil. A concentration response curve of this blocking agent revealed a half maximal inhibitory concentration of 40 nM which is comparable to values measured by complementary in vitro methods. Copyright © 2015 Elsevier B.V. All rights reserved.

A Novel Application of Multiscale Entropy in Electroencephalography to Predict the Efficacy of Acetylcholinesterase Inhibitor in Alzheimer's Disease

PubMed Central

Tsai, Ping-Huang; Liu, Fang-Chun; Tsao, Jenho; Wang, Yung-Hung; Lo, Men-Tzung

2015-01-01

Alzheimer's disease (AD) is the most common form of dementia. According to one hypothesis, AD is caused by the reduced synthesis of the neurotransmitter acetylcholine. Therefore, acetylcholinesterase (AChE) inhibitors are considered to be an effective therapy. For clinicians, however, AChE inhibitors are not a predictable treatment for individual patients. We aimed to disclose the difference by biosignal processing. In this study, we used multiscale entropy (MSE) analysis, which can disclose the embedded information in different time scales, in electroencephalography (EEG), in an attempt to predict the efficacy of AChE inhibitors. Seventeen newly diagnosed AD patients were enrolled, with an initial minimental state examination (MMSE) score of 18.8 ± 4.5. After 12 months of AChE inhibitor therapy, 7 patients were responsive and 10 patients were nonresponsive. The major difference between these two groups is Slope 2 (MSE6 to 20). The area below the receiver operating characteristic (ROC) curve of Slope 2 is 0.871 (95% CI = 0.69–1). The sensitivity is 85.7% and the specificity is 60%, whereas the cut-off value of Slope 2 is −0.024. Therefore, MSE analysis of EEG signals, especially Slope 2, provides a potential tool for predicting the efficacy of AChE inhibitors prior to therapy. PMID:26120358

Combination of human acetylcholinesterase and serum albumin sensing surfaces as highly informative analytical tool for inhibitor screening.

PubMed

Fabini, Edoardo; Tramarin, Anna; Bartolini, Manuela

2018-06-05

In the continuous research for potential drug lead candidates, the availability of highly informative screening methodologies may constitute a decisive element in the selection of best-in-class compounds. In the present study, a surface plasmon resonance (SPR)-based assay was developed and employed to investigate interactions between human recombinant AChE (hAChE) and four known ligands: galantamine, tacrine, donepezil and edrophonium. To this aim, a sensor chip was functionalized with hAChE using mild immobilization conditions to best preserve enzyme integrity. Binding affinities and, for the first time, kinetic rate constants for all drug-hAChE complexes formation/disruption were determined. Inhibitors were classified in two groups: slow-reversible and fast-reversible binders according to respective target residence time. Combining data obtained on drug-target residence time with data obtained on serum albumin binding levels, a good correlation with potency, plasma protein binding in vivo, and administration regimen was found. The outcomes of this work demonstrated that the developed SPR-based assay is suitable for the screening, the binding affinity ranking and the kinetic evaluation of hAChE inhibitors. The method proposed ensures a simpler and cost-effective assay to quantify kinetic rate constants for inhibitor-hAChE interaction as compared with other proposed and published methods. Eventually, the determination of residence time in combination with preliminary ADME studies might constitute a better tool to predict in vivo behaviour, a key information for the research of new potential drug candidates. Copyright © 2018 Elsevier B.V. All rights reserved.

Acetylcholinesterase-inhibitory activities of the extracts from sponges collected in mauritius waters.

PubMed

Beedessee, Girish; Ramanjooloo, Avin; Surnam-Boodhun, Rashmee; van Soest, Rob W M; Marie, Daniel E P

2013-03-01

Patients diagnosed with Alzheimer's disease (AD) show a characteristic neurochemical deficit of acetylcholine, especially in the basal forebrains. The use of acetylcholinesterase (AChE) inhibitors to retard the hydrolysis of acetylcholine has been suggested as a promising strategy for AD treatment. In this study, we evaluated the acetylcholinesterase inhibitory (AChEI) activities of 134 extracts obtained from 45 species of marine sponges. Thin-layer chromatography (TLC) and microplate assays reveal potent acetylcholinsterase inhibitory activities of two AcOEt extracts from the sponges Pericharax heteroraphis and Amphimedon navalis PULITZER-FINALI. We further investigated the inhibitory kinetics of the extracts and found them to display mixed competitive/noncompetitive inhibition and associated their inhibitory activity partly to terpenoids. Acetylcholinesterase inhibitors from marine organisms have been rarely studied, and this study demonstrated the potential of marine sponges as a source of pharmaceutical leads against neurodegenerative diseases. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

Effects of Cognitive-Communication Stimulation for Alzheimer's Disease Patients Treated with Donepezil.

ERIC Educational Resources Information Center

Chapman, Sandra Bond; Weiner, Myron F.; Rackley, Audette; Hynan, Linda S.; Zientz, Jennifer

2004-01-01

ds to growing evidence that active cognitive stimulation may slow the rate of verbal and functional decline and decrease negative emotional symptoms in AD when combined with acetylcholinesterase inhibitors, indicating a need to advance research in the area of cognitive treatments. The fact that AD is a progressive brain disease should not preclude…

Donepezil dosing strategies: pharmacokinetic considerations.

PubMed

Gomolin, Irving H; Smith, Candace; Jeitner, Thomas M

2011-10-01

Donepezil (Aricept) is a cholinesterase inhibitor approved for the treatment of Alzheimer's disease. Immediate release formulations of 5- and 10-mg tablets were approved by the Food and Drug Administration in the United States in 1996. In July 2010, the Food and Drug Administration approved a 23-mg sustained release (SR) formulation. The SR formulation may provide additional benefit to patients receiving 10 mg daily but the incidence of adverse reactions is increased. We derived plasma concentration profiles for higher dose immediate-release formulations (15 mg once daily, 10 mg twice daily, and 20 mg once daily) and for the profile anticipated to result from the 23-mg SR formulation. Our model predicts similar steady-state concentration profiles for 10 mg twice daily, 20 mg once daily, and 23 mg SR once daily. This provides the theoretical basis for incremental immediate release dose escalation to minimize the emergence of adverse reactions and the potential to offer a cost-effective alternative to the SR formulation with currently approved generic immediate release formulations. Copyright © 2011 American Medical Directors Association. Published by Elsevier Inc. All rights reserved.

Effects of the 5-HT6 receptor antagonist idalopirdine on extracellular levels of monoamines, glutamate and acetylcholine in the rat medial prefrontal cortex.

PubMed

Mørk, Arne; Russell, Rasmus Vinther; de Jong, Inge E M; Smagin, Gennady

2017-03-15

Idalopirdine (Lu AE58054) is a high affinity and selective antagonist for the human serotonin 5-HT 6 receptor (K i 0.83nM) in phase III development for mild-to-moderate Alzheimer's disease as an adjunct therapy to acetylcholinesterase inhibitors (AChEIs). We have studied the effects of idalopirdine on extracellular levels of monoamines, glutamate and acetylcholine in the medial prefrontal cortex (mPFC) of freely-moving rats using microdialysis. Idalopirdine (10mg/kg p.o.) increased extracellular levels of dopamine, noradrenaline and glutamate in the mPFC and showed a trend to increase serotonin levels. No effect was observed on acetylcholine levels. The AChEI donepezil (1.3mg/kg s.c.) significantly increased the levels of acetylcholine. Pretreatment with idalopirdine 2h prior to donepezil administration potentiated the effect of donepezil on extracellular acetylcholine levels. The idalopirdine potentiation of donepezil-induced increase in acetylcholine levels was also observed during local infusion of idalopirdine (6µg/ml) into the mPFC by reverse dialysis. The data from the current study may provide a mechanistic model for the pro-cognitive effects observed with administration of idalopirdine in donepezil-treated patients with Alzheimer's disease observed in the phase 2 studies (Wilkinson et al. 2014). Copyright © 2017 Elsevier B.V. All rights reserved.

Olfactory Deficits in MCI as Predictor of Improved Cognition on Donepezil

DTIC Science & Technology

2016-06-01

predicting which MCI patients are likely to improve cognitively with ACheI treatment is important. Hypotheses. 1. The acute decrease in UPSIT ( Odor ...NUMBER (include area code) 3 Table of Contents Introduction…………………………………………………………….………..…..4 Body …………………………………………………………………………………..4 Key Research...used to decide if the patient should receive treatment with a cholinesterase inhibitor like donepezil. BODY : 168 patients have been screened for

Automated Docking with Protein Flexibility in the Design of Femtomolar “Click Chemistry” Inhibitors of Acetylcholinesterase

PubMed Central

Morris, Garrett M.; Green, Luke G.; Radić, Zoran; Taylor, Palmer; Sharpless, K. Barry; Olson, Arthur J.; Grynszpan, Flavio

2013-01-01

The use of computer-aided structure-based drug design prior to synthesis has proven to be generally valuable in suggesting improved binding analogues of existing ligands.1 Here we describe the application of the program AutoDock2 to the design of a focused library that was used in the “click chemistry in-situ” generation of the most potent non-covalent inhibitor of the enzyme acetylcholinesterase (AChE) yet developed (Kd = ~100 fM).3 AutoDock version 3.0.5 has been widely distributed and successfully used to predict bound conformations of flexible ligands. Here, we also used a version of AutoDock which permits additional conformational flexibility in selected amino acid sidechains of the target protein. PMID:23451944

Sex and ESR1 genotype may influence the response to treatment with donepezil and rivastigmine in patients with Alzheimer's disease.

PubMed

Scacchi, Renato; Gambina, Giuseppe; Broggio, Elisabetta; Corbo, Rosa Maria

2014-06-01

Many factors could be responsible for the different response to treatment with the cholinesterase inhibitors (ChEIs) donepezil and rivastigmine in Alzheimer's disease (AD) patients. Sex and the variants of the estrogen receptor α (ESR1) gene are reported to modulate AD susceptibility or the course of the disease. The aim of the present study was to verify whether patient's sex and ESR1 genotype could influence the response to ChEI treatment, as there is evidence that estrogens affect cholinergic system functioning. Two ESR1 intronic polymorphisms (PvuII, rs2234693; XbaI, rs9340799) were examined in 184 AD patients: 157 were receiving treatment with donepezil or rivastigmine and 27 were receiving no treatment. Cognitive status was assessed using the mini mental state examination at four time points (1, 3, 9, and 15 months into therapy). Among the patients under treatment with either ChEI, the women responded more markedly than the men. As compared with the untreated patients, the effects of treatment were statistically significant for both donepezil and rivastigmine. A significant effect of ESR1 genotypes was observed for the donepezil-treated patients, among which those carrying at least one copy of P and X alleles showed a significantly lower cognitive decline than the noncarriers. The present data seem to confirm a sex-related influence on treatment, as the women seemed to be more sensitive to therapy and to have experienced less cognitive decline. ESR1 may be another gene contributing to interindividual variability in response to treatment with ChEIs. Copyright © 2013 John Wiley & Sons, Ltd.

Inhibitory effect of ebselen on cerebral acetylcholinesterase activity in vitro: kinetics and reversibility of inhibition.

PubMed

Martini, Franciele; Bruning, César Augusto; Soares, Suelen Mendonca; Nogueira, Cristina Wayne; Zeni, Gilson

2015-01-01

Ebselen is a synthetic organoselenium compound that has been considered a potential pharmacological agent with low toxicity, showing antioxidant, anti-inflammatory and neuroprotective effects. It is bioavailable, blood-brain barrier permeant and safe based on cellular toxicity and Phase I-III clinical trials. There is evidence that ebselen inhibits acetylcholinesterase (AChE) activity, an enzyme that plays a key role in the cholinergic system by hydrolyzing acetylcholine (ACh), in vitro and ex vivo. This system has a well-known relationship with cognitive process, and AChE inhibitors, such as donepezil and galantamine, have been used to treat cognitive deficits, mainly in the Alzheimer's Disease (AD). However, these drugs have poor bioavailability and a number of side effects, including gastrointestinal upsets and hepatotoxicity. In this way, this study aimed to evaluate the effect of ebselen on cerebral AChE activity in vitro and to determine the kinetic profile and the reversibility of inhibition by dialysis. Ebselen inhibited the cerebral AChE activity with an IC50 of 29 µM, similar to IC50 found with pure AChE from electric eel, demonstrating a mixed and reversible inhibition of AChE, since it increased Km and decreased Vmax. The AChE activity was recovered within 60 min of dialysis. Therefore, the use of ebselen as a therapeutic agent for treatment of AD should be considered, although memory behavior tasks are needed to support such hypothesis.

Patient adherence to transdermal rivastigmine after switching from oral donepezil: a retrospective claims database study.

PubMed

Tian, Haijun; Abouzaid, Safiya; Chen, Wei; Kahler, Kristijan H; Kim, Edward

2013-01-01

To examine patient adherence before and after switching from donepezil to the rivastigmine patch. This retrospective cohort study used the MarketScan Commercial and Medicare data sets (2004 to 2009). Patients with a diagnosis of Alzheimer disease who were new donepezil users and were subsequently switched to the rivastigmine patch were included. The proportion of days covered (PDC) and PDC difference between donepezil and the rivastigmine patch were calculated from the time of initiation to the switch, capped at 1 year after the first respective claim. PDC was calculated as the number of days with drugs available divided by the number of days in the respective follow-up periods. The sample included 772 patients (mean age 77 y; 58% female). The mean time between switching from donepezil to the rivastigmine patch was 579 (SD=317.3) days. The mean PDC for the rivastigmine patch was highest among patients who switched within 3 months (80.4% vs. 90.7%; P=0.04) and within 7 to 9 months (61.3% vs. 71.0%; P=0.05) of initiating donepezil. When adherence was analyzed in increments of 1 year, patients who switched to the rivastigmine patch within the first year of treatment had significantly greater adherence to rivastigmine compared with those who were on donepezil (PDC 69.3% vs. 60.6%; P=0.0004). Switching from donepezil to the rivastigmine patch seems to be associated with increased adherence, especially in patients who switched within the first year of initiating donepezil.

Effectiveness of donepezil, rivastigmine, and (+/-)huperzine A in counteracting the acute toxicity of organophosphorus nerve agents: comparison with galantamine.

PubMed

Aracava, Yasco; Pereira, Edna F R; Akkerman, Miriam; Adler, Michael; Albuquerque, Edson X

2009-12-01

Galantamine, a centrally acting cholinesterase (ChE) inhibitor and a nicotinic allosteric potentiating ligand used to treat Alzheimer's disease, is an effective and safe antidote against poisoning with nerve agents, including soman. Here, the effectiveness of galantamine was compared with that of the centrally active ChE inhibitors donepezil, rivastigmine, and (+/-)huperzine A as a pre- and/or post-treatment to counteract the acute toxicity of soman. In the first set of experiments, male prepubertal guinea pigs were treated intramuscularly with one of the test drugs and 30 min later challenged with 1.5 x LD(50) soman (42 microg/kg s.c.). All animals that were pretreated with galantamine (6-8 mg/kg), 3 mg/kg donepezil, 6 mg/kg rivastigmine, or 0.3 mg/kg (+/-)huperzine A survived the soman challenge, provided that they were also post-treated with atropine (10 mg/kg i.m.). However, only galantamine was well tolerated. In subsequent experiments, the effectiveness of specific treatment regimens using 8 mg/kg galantamine, 3 mg/kg donepezil, 6 mg/kg rivastigmine, or 0.3 mg/kg (+/-)huperzine A was compared in guinea pigs challenged with soman. In the absence of atropine, only galantamine worked as an effective and safe pretreatment in animals challenged with 1.0 x LD(50) soman. Galantamine was also the only drug to afford significant protection when given to guinea pigs after 1.0 x LD(50) soman. Finally, all test drugs except galantamine reduced the survival of the animals when administered 1 or 3 h after the challenge with 0.6 or 0.7 x LD(50) soman. Thus, galantamine emerges as a superior antidotal therapy against the toxicity of soman.

Esterase detoxification of acetylcholinesterase inhibitors using human liver samples in vitro

EPA Science Inventory

Organophosphate (OP) and N-methylcarbamate pesticides inhibit acetylcholinesterase (AChE), but differences in metabolism and detoxification can influence potency of these pesticides across and within species. Carboxylesterase (CaE) and A-esterase (paraoxonase, PON1) are consider...

Effectiveness of Donepezil, Rivastigmine, and (±)Huperzine A in Counteracting the Acute Toxicity of Organophosphorus Nerve Agents: Comparison with Galantamine

PubMed Central

Aracava, Yasco; Pereira, Edna F. R.; Akkerman, Miriam; Adler, Michael

2009-01-01

Galantamine, a centrally acting cholinesterase (ChE) inhibitor and a nicotinic allosteric potentiating ligand used to treat Alzheimer's disease, is an effective and safe antidote against poisoning with nerve agents, including soman. Here, the effectiveness of galantamine was compared with that of the centrally active ChE inhibitors donepezil, rivastigmine, and (±)huperzine A as a pre- and/or post-treatment to counteract the acute toxicity of soman. In the first set of experiments, male prepubertal guinea pigs were treated intramuscularly with one of the test drugs and 30 min later challenged with 1.5 × LD50 soman (42 μg/kg s.c.). All animals that were pretreated with galantamine (6–8 mg/kg), 3 mg/kg donepezil, 6 mg/kg rivastigmine, or 0.3 mg/kg (±)huperzine A survived the soman challenge, provided that they were also post-treated with atropine (10 mg/kg i.m.). However, only galantamine was well tolerated. In subsequent experiments, the effectiveness of specific treatment regimens using 8 mg/kg galantamine, 3 mg/kg donepezil, 6 mg/kg rivastigmine, or 0.3 mg/kg (±)huperzine A was compared in guinea pigs challenged with soman. In the absence of atropine, only galantamine worked as an effective and safe pretreatment in animals challenged with 1.0 × LD50 soman. Galantamine was also the only drug to afford significant protection when given to guinea pigs after 1.0 × LD50 soman. Finally, all test drugs except galantamine reduced the survival of the animals when administered 1 or 3 h after the challenge with 0.6 or 0.7 × LD50 soman. Thus, galantamine emerges as a superior antidotal therapy against the toxicity of soman. PMID:19741148

The Effect of Parathion on Red Blood Cell Acetylcholinesterase in the Wistar Rat.

PubMed

Bunya, Naofumi; Sawamoto, Keigo; Benoit, Hanif; Bird, Steven B

2016-01-01

Organophosphorus (OP) pesticide poisoning is a significant problem worldwide. Research into new antidotes for these acetylcholinesterase inhibitors, and even optimal doses for current therapies, is hindered by a lack of standardized animal models. In this study, we sought to characterize the effects of the OP pesticide parathion on acetylcholinesterase in a Wistar rat model that included comprehensive medical care. Methods. Male Wistar rats were intubated and mechanically ventilated and then poisoned with between 20 mg/kg and 60 mg/kg of intravenous parathion. Upon developing signs of poisoning, the rats were treated with standard critical care, including atropine, pralidoxime chloride, and midazolam, for up to 48 hours. Acetylcholinesterase activity was determined serially for up to 8 days after poisoning. Results. At all doses of parathion, maximal depression of acetylcholinesterase occurred at 3 hours after poisoning. Acetylcholinesterase recovered to nearly 50% of baseline activity by day 4 in the 20 mg/kg cohort and by day 5 in the 40 and 60 mg/kg cohorts. At day 8, most rats' acetylcholinesterase had recovered to roughly 70% of baseline. These data should be useful in developing rodent models of acute OP pesticide poisoning.

The Effect of Parathion on Red Blood Cell Acetylcholinesterase in the Wistar Rat

PubMed Central

Bunya, Naofumi; Sawamoto, Keigo; Benoit, Hanif

2016-01-01

Organophosphorus (OP) pesticide poisoning is a significant problem worldwide. Research into new antidotes for these acetylcholinesterase inhibitors, and even optimal doses for current therapies, is hindered by a lack of standardized animal models. In this study, we sought to characterize the effects of the OP pesticide parathion on acetylcholinesterase in a Wistar rat model that included comprehensive medical care. Methods. Male Wistar rats were intubated and mechanically ventilated and then poisoned with between 20 mg/kg and 60 mg/kg of intravenous parathion. Upon developing signs of poisoning, the rats were treated with standard critical care, including atropine, pralidoxime chloride, and midazolam, for up to 48 hours. Acetylcholinesterase activity was determined serially for up to 8 days after poisoning. Results. At all doses of parathion, maximal depression of acetylcholinesterase occurred at 3 hours after poisoning. Acetylcholinesterase recovered to nearly 50% of baseline activity by day 4 in the 20 mg/kg cohort and by day 5 in the 40 and 60 mg/kg cohorts. At day 8, most rats' acetylcholinesterase had recovered to roughly 70% of baseline. These data should be useful in developing rodent models of acute OP pesticide poisoning. PMID:27418928

Treatment effects between monotherapy of donepezil versus combination with memantine for Alzheimer disease: A meta-analysis.

PubMed

Chen, Ruey; Chan, Pi-Tuan; Chu, Hsin; Lin, Yu-Cih; Chang, Pi-Chen; Chen, Chien-Yu; Chou, Kuei-Ru

2017-01-01

This is the first meta-analysis to compare the treatment effects and safety of administering donepezil alone versus a combination of memantine and donepezil to treat patients with moderate to severe Alzheimer Disease, particularly regarding cognitive functions, behavioral and psychological symptoms in dementia (BPSD), and global functions. PubMed, Medline, Embase, PsycINFO, and Cochrane databases were used to search for English and non-English articles for inclusion in the meta-analysis to evaluate the effect size and incidence of adverse drug reactions of different treatments. Compared with patients who received donepezil alone, those who received donepezil in combination with memantine exhibited limited improvements in cognitive functions (g = 0.378, p < .001), BPSD (g = -0.878, p < .001) and global functions (g = -0.585, p = .004). Gradual titration of memantine plus a fixed dose and gradual titration of donepezil as well as a fixed dose and gradual titration of memantine resulted in limited improvements in cognitive functions(g = 0.371, p = .005), BPSD(g = -0.913, p = .001), and global functions(g = -0.371, p = .001). Both in the 24th week and at the final evaluation point, the combination of donepezil and memantine led to greater improvement in cognitive functions, BPSD, and global functions than did donepezil alone in patients with moderate to severe Alzheimer Disease.

Comparative Risk of Pneumonia Among New Users of Cholinesterase Inhibitors for Dementia

PubMed Central

Lai, Edward Chia-Cheng; Wong, Monera B.; Iwata, Isao; Zhang, Yinghong; Hsieh, Cheng-Yang; Yang, Yea-Huei Kao; Setoguchi, Soko

2015-01-01

OBJECTIVES To compare the risk of pneumonia among older patients receiving donepezil, galantamine, or rivastigmine for dementia. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study of a nationally representative 5% sample of Medicare beneficiaries 65 years or older who newly initiated cholinesterase inhibitor therapy between 2006 and 2009. MEASUREMENTS Pneumonia, defined as the presence of a diagnosis code for pneumonia as the primary diagnosis on an inpatient claim or on an emergency department claim followed by dispensing of appropriate antibiotics. We used Cox proportional hazards models to estimate the risk of pneumonia. We conducted secondary analyses and sensitivity analyses using alternative pneumonia definitions and adjustments by high-dimensional propensity scores to test the robustness of the results. RESULTS Among 35,570 new users of cholinesterase inhibitors (30,174 users of donepezil, 1176 users of galantamine, and 4220 users of rivastigmine), mean age was 82 years, 75% were women, and 82% were white. The cumulative incidence of pneumonia was 51.9 per 1000 person-years. Risk was significantly lower by 24% among rivastigmine users compared with donepezil users (hazard ratio [HR], 0.75; 95% CI, 0.60–0.93). Risk among galantamine users (HR, 0.87; 95% CI, 0.62–1.23) was not significantly different from risk among donepezil users. Results of secondary and sensitivity analyses were similar to the primary results. CONCLUSION The risk of pneumonia was lower among patients receiving rivastigmine compared with patients receiving donepezil. Additional studies are needed to confirm the findings of pneumonia risk between the oral and transdermal forms of rivastigmine and among users of galantamine. PMID:25912671

Acetylcholinesterase inhibitory properties of some benzoic acid derivatives

NASA Astrophysics Data System (ADS)

Yildiz, Melike; Kiliç, Deryanur; Ünver, Yaǧmur; Şentürk, Murat; Askin, Hakan; Küfrevioǧlu, Ömer Irfan

2016-04-01

Acetylcholinesterase (AChE) hydrolyses the neurotransmitter acetylcholine to acetic acid and choline. AChE inhibitors are used in treatment of several neurodegeneartive disorder and Alzheimer's disease. In the present study, inhibition of AChE with some benzoic acid derivatives were investigated. 3-Chloro-benzoic acid (1), 2-hydroxy-5-sulfobenzoic acid (2), 2-(sulfooxy) benzoic acid (3), 2-hydroxybenzoic acid (4), 2,3-dimethoxybenzoic (5), and 3,4,5-trimethoxybenzoic (6) were calculated IC50 values AChE enzyme. Kinetic investigations showed that similarly to AChE inhibitors. Benzoic acid derivatives (1-6) investigated are encouraging agents which may be used as lead molecules in order to derivative novel AChE inhibitors that might be useful in medical applications.

Isoindoline-1,3-dione derivatives targeting cholinesterases: design, synthesis and biological evaluation of potential anti-Alzheimer's agents.

PubMed

Guzior, Natalia; Bajda, Marek; Rakoczy, Jurand; Brus, Boris; Gobec, Stanislav; Malawska, Barbara

2015-04-01

Alzheimer's disease is a fatal neurodegenerative disorder with a complex etiology. Because the available therapy brings limited benefits, the effective treatment for Alzheimer's disease remains the unmet challenge. Our aim was to develop a new series of donepezil-based compounds endowed with inhibitory properties against cholinesterases and β-amyloid aggregation. We designed the target compounds as dual binding site acetylcholinesterase inhibitors with N-benzylamine moiety interacting with the catalytic site of the enzyme and an isoindoline-1,3-dione fragment interacting with the peripheral anionic site of the enzyme. The results of pharmacological evaluation lead us to identify a compound 3b as the most potent and selective human acetylcholinesterase inhibitor (hAChE IC50=0.361μM). Kinetic studies revealed that 3b inhibited acetylcholinesterase in non-competitive mode. The result of the parallel artificial membrane permeability assay for the blood-brain barrier indicated that the compound 3b would be able to cross the blood-brain barrier and reach its biological targets in the central nervous system. The selected compound 3b represents a potential lead structure for further development of anti-Alzheimer's agents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Screening of acetylcholinesterase inhibitors in marine organisms from the Caribbean Sea.

PubMed

Castellanos, Fabio; Amaya-García, Fabián; Tello, Edisson; Ramos, Freddy Alejandro; Umaña, Adriana; Puyana, Mónica; Resende, Jackson A L C; Castellanos, Leonardo

2018-06-04

The acetylcholinesterase inhibitory activity of 89 organic extracts from marine organisms was evaluated through a TLC bioautography methodology. Extracts from soft corals (Eunicea and Plexaura) were the most active compared with extracts from sponges. The bioguided chemical study of the most active extract, obtained from Pseudoplexaura porosa, led to the isolation of a diterpene with spectroscopic properties consistent to those published to the cembrane Steylolide. However, further analysis by X-ray diffraction indicated that the compound was the 14-acetoxycrassine (1), correcting the structure reported to the Styelolide. Additionally, the acetylcholinesterase inhibitory activity of fourteen cembranoids (2-15) isolated from soft corals Eunicea knighti and Pseudoplexaura flagellosa was evaluated. Cembranoids 2, 3 and 4 were the most active compounds in the TLC bioassay. Then, the most promising cembranoids, 14-acetoxycrassine (1) and asperdiol (2), were tested quantitatively and they exhibited IC 50 values of 1.40 ± 0.113 and 0.358 ± 0.130 μM, respectively.

Galantamine, an Acetylcholinesterase Inhibitor and Positive Allosteric Modulator of Nicotinic Acetylcholine Receptors, Attenuates Nicotine Taking and Seeking in Rats

PubMed Central

Hopkins, Thomas J; Rupprecht, Laura E; Hayes, Matthew R; Blendy, Julie A; Schmidt, Heath D

2012-01-01

Current smoking cessation pharmacotherapies have limited efficacy in preventing relapse and maintaining abstinence during withdrawal. Galantamine is an acetylcholinesterase inhibitor that also acts as a positive allosteric modulator of nicotinic acetylcholine receptors. Galantamine has recently been shown to reverse nicotine withdrawal-induced cognitive impairments in mice, which suggests that galantamine may function to prevent relapse in human smokers. However, there are no studies examining whether galantamine administration modulates nicotine self-administration and/or reinstatement of nicotine seeking in rodents. The present experiments were designed to determine the effects of galantamine administration on nicotine taking and reinstatement of nicotine-seeking behavior, an animal model of relapse. Moreover, the effects of galantamine on sucrose-maintained responding and sucrose seeking were also examined to determine whether galantamine's effects generalized to other reinforced behaviors. An inverted U-shaped dose-response curve was obtained when animals self-administered different unit doses of nicotine with the highest responding for 0.03 mg/kg per infusion of nicotine. Acute galantamine administration (5.0 mg/kg, i.p.) attenuated nicotine self-administration when animals were maintained on either a fixed-ratio 5 (FR5) or progressive ratio (PR) schedule of reinforcement. Galantamine administration also attenuated the reinstatement of nicotine-seeking behavior. No significant effects of galantamine on sucrose self-administration or sucrose reinstatement were noted. Acetylcholinesterase inhibitors have also been shown to produce nausea and vomiting in humans. However, at doses required to attenuate nicotine self-administration, no effects of galantamine on nausea/malaise as measured by pica were noted. These results indicate that increased extracellular acetylcholine levels and/or nicotinic acetylcholine receptor stimulation is sufficient to attenuate

Cholinoceptive and cholinergic properties of cardiomyocytes involving an amplification mechanism for vagal efferent effects in sparsely innervated ventricular myocardium.

PubMed

Kakinuma, Yoshihiko; Akiyama, Tsuyoshi; Sato, Takayuki

2009-09-01

Our recent studies have shown that, as indicated by vagal stimulation, an acetylcholinesterase inhibitor donepezil, an anti-Alzheimer's disease drug, prevents progression of heart failure in rats with myocardial infarction, and activates a common cell survival signal shared by acetylcholine (ACh) in vitro. On the basis of this and evidence that vagal innervation is extremely poor in the left ventricle, we assessed the hypothesis that ACh is produced by cardiomyocytes, which promotes its synthesis via a positive feedback mechanism. Rat cardiomyocytes expressed choline acetyltransferase (ChAT) in the cytoplasm and vesicular acetylcholine transporter with the vesicular structure identified by immunogold electron microscopy, suggesting that cardiomyocytes possess components for ACh synthesis. Intracellular ACh in rat cardiomyocytes was identified with physostigmine or donepezil. However, with atropine, the basal ACh content was reduced. In response to exogenous ACh or pilocarpine, cardiomyocytes increased the transcriptional activity of the ChAT gene through a muscarinic receptor and ChAT protein expression, and, finally, the intracellular ACh level was upregulated by pilocarpine. Knockdown of ChAT by small interfering RNA accelerated cellular energy metabolism, which is suppressed by ACh. Although physostigmine had a minimal effect on the ChAT promoter activity by inhibiting acetylcholinesterase, donepezil resulted in elevation of the activity, protein expression and intracellular ACh level even in the presence of sufficient physostigmine. Orally administered donepezil in mice increased the ChAT promoter activity in a reporter gene-transferred quadriceps femoris muscle and the amount of cardiac ChAT protein. These findings suggest that cardiomyocytes possess an ACh synthesis system, which is positively modulated by cholinergic stimuli. Such an amplification system in cardiomyocytes may contribute to the beneficial effects of vagal stimulation on the ventricles.

The effectiveness and cost-effectiveness of donepezil, galantamine, rivastigmine and memantine for the treatment of Alzheimer's disease (review of Technology Appraisal No. 111): a systematic review and economic model.

PubMed

Bond, M; Rogers, G; Peters, J; Anderson, R; Hoyle, M; Miners, A; Moxham, T; Davis, S; Thokala, P; Wailoo, A; Jeffreys, M; Hyde, C

2012-01-01

Alzheimer’s disease (AD) is the most commonly occurring form of dementia. It is predominantly a disease of later life, affecting 5% of those over 65 in the UK. Review and update guidance to the NHS in England and Wales on the clinical effectiveness and cost-effectiveness of donepezil, galantamine, rivastigmine [acetylcholinesterase inhibitors (AChEIs)] and memantine within their licensed indications for the treatment of AD, which was issued in November 2006 (amended September 2007 and August 2009). Electronic databases were searched for systematic reviews and/or metaanalyses, randomised controlled trials (RCTs) and ongoing research in November 2009 and updated in March 2010; this updated search revealed no new includable studies. The databases searched included The Cochrane Library (2009 Issue 4, Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trials), MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, PsycINFO, EconLit, ISI Web of Science Databases--Science Citation Index, Conference Proceedings Citation Index, and BIOSIS; the Centre for Reviews and Dissemination (CRD) databases--NHS Economic Evaluation Database, Health Technology Assessment, and Database of Abstracts of Reviews of Effects. The clinical effectiveness systematic review was undertaken following the principles published by the NHS CRD. We included RCTs whose population was people with AD. The intervention and comparators depended on disease severity, measured by the Mini Mental State Examination (MMSE). mild AD (MMSE 21-26)--donepezil, galantamine and rivastigmine; moderate AD (MMSE 10-20)--donepezil, galantamine, rivastigmine and memantine; severe AD (MMSE < 10)--memantine. Comparators: mild AD (MMSE 21-26)--placebo or best supportive care (BSC); moderate AD (MMSE 10-20)--donepezil, galantamine, rivastigmine, memantine, placebo or BSC; severe AD (MMSE < 10)--placebo or BSC. The outcomes were clinical, global, functional, behavioural, quality of

Inhibition of spicule elongation in sea urchin embryos by the acetylcholinesterase inhibitor eserine.

PubMed

Ohta, Kazumasa; Takahashi, Chifumi; Tosuji, Hiroaki

2009-08-01

The activity of acetylcholinesterase (AchE) increases rapidly after the gastrula stage of sea urchin development. In this report, changes in activity and in the molecular differentiation of AchE were investigated. AchE activity increased slightly during gastrulation and rose sharply thereafter, and was dependent on new RNA synthesis. No activity of butyrylcholinesterase was found. Morphogenesis in sea urchin embryos was inhibited by the AchE inhibitor eserine, which specifically inhibited arm rod formation but not body rod formation. Spicule formation and enzyme activity in cultured micromeres were inhibited by eserine in a dose-dependent manner. During gastrulation, two molecular forms of AchE were detected with polyacrylamide gel electrophoresis. The appearance of an additional band on the gel was consistent with the occurrence of a remarkable increase in the enzyme activity. This additional band appeared as a larger molecular form in Anthocidaris crassispina, Hemicentrotus pulcherrimus, Stomopneustes variolaris, and Strongylocentrotus nudus, and as a smaller form in Clypeaster japonicus and Temnopleurus hardwicki. These results suggest that the change in the molecular form of AchE induced a change in enzymatic activity that in turn may play a role in spicule elongation in sea urchin embryos.

Design, synthesis and structure-activity relationships of dual inhibitors of acetylcholinesterase and serotonin transporter as potential agents for Alzheimer's disease.

PubMed

Toda, Narihiro; Tago, Keiko; Marumoto, Shinji; Takami, Kazuko; Ori, Mayuko; Yamada, Naho; Koyama, Kazuo; Naruto, Shunji; Abe, Kazumi; Yamazaki, Reina; Hara, Takao; Aoyagi, Atsushi; Abe, Yasuyuki; Kaneko, Tsugio; Kogen, Hiroshi

2003-05-01

We have designed and synthesized a dual inhibitor of acetylcholinesterase (AChE) and serotonin transporter (SERT) as a novel class of treatment drugs for Alzheimer's disease on the basis of a hypothetical model of the AChE active site. Dual inhibitions of AChE and SERT would bring about greater therapeutic effects than AChE inhibition alone and avoid adverse peripheral effects caused by excessive AChE inhibition. Compound (S)-6j exhibited potent inhibitory activities against AChE (IC(50)=101 nM) and SERT (IC(50)=42 nM). Furthermore, (S)-6j showed inhibitory activities of both AChE and SERT in mice brain following oral administration.

Clinical Recommendations for the Use of Donepezil 23 mg in Moderate-to-Severe Alzheimer's Disease in the Asia-Pacific Region

PubMed Central

Sabbagh, Marwan; Han, SeolHeui; Kim, SangYun; Na, Hae-Ri; Lee, Jae-Hong; Kandiah, Nagaendran; Phanthumchinda, Kammant; Suthisisang, Chuthamanee; Senanarong, Vorapun; Pai, Ming-Chyi; Narilastri, Diatri; Sowani, Ajit M.; Ampil, Encarnita; Dash, Amitabh

2016-01-01

Background The ‘Asia-Pacific Expert Panel (APEX) for donepezil 23 mg’ met in November 2015 to review evidence for the recently approved high dose of donepezil and to provide recommendations to help physicians in Asia make informed clinical decisions about using donepezil 23 mg in patients with moderate-to-severe Alzheimer's disease (AD). Summary In a global phase III study (study 326) in patients with moderate-to-severe AD, donepezil 23 mg/day demonstrated significantly greater cognitive benefits versus donepezil 10 mg/day, with a between-treatment difference in mean change in the Severe Impairment Battery score of 2.2 points (p < 0.001) in the overall population and 3.1 points (p < 0.001) in patients with advanced AD. A subanalysis of study 326 demonstrated that the benefits and risks associated with donepezil 23 mg/day versus donepezil 10 mg/day in Asian patients with moderate-to-severe AD were comparable to those in the global study population. Key Message Donepezil 23 mg is a valuable treatment for patients with AD, particularly those with advanced disease. The APEX emphasized the importance of patient selection (AD severity, tolerability of lower doses of donepezil, and absence of contraindications), a stepwise titration strategy for dose escalation, and appropriate monitoring and counseling of patients and caregivers in the management of patients with AD. PMID:27703471

Esterase detoxification of acetylcholinesterase inhibitors by human or rat liver in vitro

EPA Science Inventory

Organophosphate (OP) and N-methylcarbamate pesticides inhibit acetylcholinesterase (AChE), but differences in metabolism and detoxification can influence potency of these pesticides across and within species. Carboxylesterase (CaE) and A-esterase (paraoxonase, PON) are considered...

Identification of molecular descriptors for design of novel Isoalloxazine derivatives as potential Acetylcholinesterase inhibitors against Alzheimer's disease.

PubMed

Gurung, Arun Bahadur; Aguan, Kripamoy; Mitra, Sivaprasad; Bhattacharjee, Atanu

2017-06-01

In Alzheimer's disease (AD), the level of Acetylcholine (ACh) neurotransmitter is reduced. Since Acetylcholinesterase (AChE) cleaves ACh, inhibitors of AChE are very much sought after for AD treatment. The side effects of current inhibitors necessitate development of newer AChE inhibitors. Isoalloxazine derivatives have proved to be promising (AChE) inhibitors. However, their structure-activity relationship studies have not been reported till date. In the present work, various quantitative structure-activity relationship (QSAR) building methods such as multiple linear regression (MLR), partial least squares ,and principal component regression were employed to derive 3D-QSAR models using steric and electrostatic field descriptors. Statistically significant model was obtained using MLR coupled with stepwise selection method having r 2  = .9405, cross validated r 2 (q 2 ) = .6683, and a high predictability (pred_r 2  = .6206 and standard error, pred_r 2 se = .2491). Steric and electrostatic contribution plot revealed three electrostatic fields E_496, E_386 and E_577 and one steric field S_60 contributing towards biological activity. A ligand-based 3D-pharmacophore model was generated consisting of eight pharmacophore features. Isoalloxazine derivatives were docked against human AChE, which revealed critical residues implicated in hydrogen bonds as well as hydrophobic interactions. The binding modes of docked complexes (AChE_IA1 and AChE_IA14) were validated by molecular dynamics simulation which showed their stable trajectories in terms of root mean square deviation and molecular mechanics/Poisson-Boltzmann surface area binding free energy analysis revealed key residues contributing significantly to overall binding energy. The present study may be useful in the design of more potent Isoalloxazine derivatives as AChE inhibitors.

Some enzymatic properties of brain Acetylcholinesterase from bluegill and channel catfish

USGS Publications Warehouse

Hogan, James W.; Knowles, Charles O.

1968-01-01

Using a manometric technique an acetylcholinesterase (EC 3.1.1.7, acetylcholine acetyl-hydrolase) was demonstrated in brain tissue from the bluegill, Lepomis macrochirus Rafinesque, and the channel catfish, Ictalurus punctatus (Walbaum). The activities were 19 and 37 μmoles acetylcholine hydrolyzed/milligram protein per hour for the bluegill and channel catfish enzymes, respectively. The optimum substrate concentration for the hydrolysis of acetylcholine was 10 mMfor the enzymes from both species. Generally, the catfish acetylcholinesterase was somewhat more susceptible than the bluegill to the inhibitors tested; however, the bluegill enzyme was more susceptible to inhibition by malathion and malaoxon.

Improvement of Visuo-spatial Function Assessed by Raven’s Colored Progressive Matrices in Dementia with Lewy Bodies by Donepezil Treatment

PubMed Central

Yoshino, Yuta; Mori, Takaaki; Yoshida, Taku; Toyota, Yasutaka; Shimizu, Hideaki; Iga, Jun-ichi; Nishitani, Shusaku; Ueno, Shu-ichi

2017-01-01

Objective Donepezil is used to improve cognitive impairment of dementia with Lewy bodies (DLB). Visuo-spatial dysfunction is a well-known symptom of DLB. Non-verbal Raven’s Colored Progressive Matrices (RCPM) were used to assess both visual perception and reasoning ability in DLB subjects treated with donepezil. Methods Twenty-one DLB patients (mean age, 78.7±4.5 years) were enrolled. RCPM assessment was performed at the time of starting donepezil and within one year after starting donepezil. Results There were significant improvements of RCPM in the total scores between one year donepezil treatment (p=0.013), in both Set A score (p=0.002) and Set AB score (p=0.015), but trend in the Set B score (p=0.083). Conclusion Donepezil is useful for improving visuo-spatial impairment in DLB, but not for problem-solving impairment. PMID:28783933

Design, synthesis, biological evaluation and docking study of 5-oxo-4,5-dihydropyrano[3,2-c]chromene derivatives as acetylcholinesterase and butyrylcholinesterase inhibitors.

PubMed

Khoobi, Mehdi; Alipour, Masoumeh; Sakhteman, Amirhossein; Nadri, Hamid; Moradi, Alireza; Ghandi, Mehdi; Emami, Saeed; Foroumadi, Alireza; Shafiee, Abbas

2013-10-01

A series of fused coumarins namely 5-oxo-4,5-dihydropyrano[3,2-c]chromenes linked to N-benzylpyridinium scaffold were synthesized and evaluated as acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitors. The 1-(4-fluorobenzyl)pyridinium derivative 6g showed the most potent anti-AChE activity (IC50 value=0.038 μM) and the highest AChE/BuChE selectivity (SI>48). The docking study permitted us to rationalize the observed structure-affinity relationships and to detect possible binding modes. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Donepezil for treatment of cognitive dysfunction in children with Down syndrome aged 10-17.

PubMed

Kishnani, Priya S; Heller, James H; Spiridigliozzi, Gail A; Lott, Ira; Escobar, Luis; Richardson, Sharon; Zhang, Richard; McRae, Thomas

2010-12-01

The objective of this 10-week, randomized, double-blind, placebo-controlled multicenter study was to assess the efficacy and safety of donepezil for the treatment of cognitive dysfunction exhibited by children with Down syndrome (DS). Intervention comprised donepezil (2.5-10 mg/day) in children (aged 10-17 years) with DS of mild-to-moderate severity. The primary measures were the Vineland-II Adaptive Behavior Scales (VABS-II) Parent/Caregiver Rating Form (PCRF) the sum of nine subdomain standardized scores and standard safety measures. Secondary measures included the VABS-II/PCRF scores on the following domains and their respective individual subdomains: Communication (receptive, expressive, and written); Daily Living Skills (personal, domestic, and community); Socialization (interpersonal relationships, play and leisure time, and coping skills), and scores on the Test of Verbal Expression and Reasoning, a subject-performance-based measure of expressive language. At baseline, 129 participants were assigned treatment with donepezil or placebo. During the double-blind phase, VABS II/PCRF sum of the nine subdomain standardized scores, called v-scores, improved significantly from baseline in both groups (P < 0.0001), with no significant between-group differences. This trial failed to demonstrate any benefit for donepezil versus placebo in children and adolescents with DS, although donepezil appeared to be well tolerated. © 2010 Wiley-Liss, Inc.

Acute effects of donepezil in healthy young adults underline the fractionation of executive functioning.

PubMed

Ginani, G E; Tufik, S; Bueno, O F A; Pradella-Hallinan, M; Rusted, J; Pompéia, S

2011-11-01

The cholinergic system is involved in the modulation of both bottom-up and top-down attentional control. Top-down attention engages multiple executive control processes, but few studies have investigated whether all or selective elements of executive functions are modulated by the cholinergic system. To investigate the acute effects of the pro-cholinergic donepezil in young, healthy volunteers on distinct components of executive functions we conducted a double-blind, placebo-controlled, independent-groups design study including 42 young healthy male participants who were randomly assigned to one of three oral treatments: glucose (placebo), donepezil 5 mg or donepezil 7.5 mg. The test battery included measures of different executive components (shifting, updating, inhibition, dual-task performance, planning, access to long-term memory), tasks that evaluated arousal/vigilance/visuomotor performance, as well as functioning of working memory subsidiary systems. Donepezil improved sustained attention, reaction times, dual-task performance and the executive component of digit span. The positive effects in these executive tasks did not correlate with arousal/visuomotor/vigilance measures. Among the various executive domains investigated donepezil selectively increased dual-task performance in a manner that could not be ascribed to improvement in arousal/vigilance/visuomotor performance nor working memory slave systems. Other executive tasks that rely heavily on visuospatial processing may also be modulated by the cholinergic system.

Acetylcholinesterase-independent protective effects of huperzine A against iron overload-induced oxidative damage and aberrant iron metabolism signaling in rat cortical neurons.

PubMed

Tao, Ling-Xue; Huang, Xiao-Tian; Chen, Yu-Ting; Tang, Xi-Can; Zhang, Hai-Yan

2016-11-01

Iron dyshomeostasis is one of the primary causes of neuronal death in Alzheimer's disease (AD). Huperzine A (HupA), a natural inhibitor of acetylcholinesterase (AChE), is a licensed anti-AD drug in China and a nutraceutical in the United Sates. Here, we investigated the protective effects of HupA against iron overload-induced injury in neurons. Rat cortical neurons were treated with ferric ammonium citrate (FAC), and cell viability was assessed with MTT assays. Reactive oxygen species (ROS) assays and adenosine triphosphate (ATP) assays were performed to assess mitochondrial function. The labile iron pool (LIP) level, cytosolic-aconitase (c-aconitase) activity and iron uptake protein expression were measured to determine iron metabolism changes. The modified Ellman's method was used to evaluate AChE activity. HupA significantly attenuated the iron overload-induced decrease in neuronal cell viability. This neuroprotective effect of HupA occurred concurrently with a decrease in ROS and an increase in ATP. Moreover, HupA treatment significantly blocked the upregulation of the LIP level and other aberrant iron metabolism changes induced by iron overload. Additionally, another specific AChE inhibitor, donepezil (Don), at a concentration that caused AChE inhibition equivalent to that of HupA negatively, influenced the aberrant changes in ROS, ATP or LIP that were induced by excessive iron. We provide the first demonstration of the protective effects of HupA against iron overload-induced neuronal damage. This beneficial role of HupA may be attributed to its attenuation of oxidative stress and mitochondrial dysfunction and elevation of LIP, and these effects are not associated with its AChE-inhibiting effect.

Acetylcholinesterase-independent protective effects of huperzine A against iron overload-induced oxidative damage and aberrant iron metabolism signaling in rat cortical neurons

PubMed Central

Tao, Ling-xue; Huang, Xiao-tian; Chen, Yu-ting; Tang, Xi-can; Zhang, Hai-yan

2016-01-01

Aim: Iron dyshomeostasis is one of the primary causes of neuronal death in Alzheimer's disease (AD). Huperzine A (HupA), a natural inhibitor of acetylcholinesterase (AChE), is a licensed anti-AD drug in China and a nutraceutical in the United Sates. Here, we investigated the protective effects of HupA against iron overload-induced injury in neurons. Methods: Rat cortical neurons were treated with ferric ammonium citrate (FAC), and cell viability was assessed with MTT assays. Reactive oxygen species (ROS) assays and adenosine triphosphate (ATP) assays were performed to assess mitochondrial function. The labile iron pool (LIP) level, cytosolic-aconitase (c-aconitase) activity and iron uptake protein expression were measured to determine iron metabolism changes. The modified Ellman's method was used to evaluate AChE activity. Results: HupA significantly attenuated the iron overload-induced decrease in neuronal cell viability. This neuroprotective effect of HupA occurred concurrently with a decrease in ROS and an increase in ATP. Moreover, HupA treatment significantly blocked the upregulation of the LIP level and other aberrant iron metabolism changes induced by iron overload. Additionally, another specific AChE inhibitor, donepezil (Don), at a concentration that caused AChE inhibition equivalent to that of HupA negatively, influenced the aberrant changes in ROS, ATP or LIP that were induced by excessive iron. Conclusion: We provide the first demonstration of the protective effects of HupA against iron overload-induced neuronal damage. This beneficial role of HupA may be attributed to its attenuation of oxidative stress and mitochondrial dysfunction and elevation of LIP, and these effects are not associated with its AChE-inhibiting effect. PMID:27498774

An HPLC-MS method for the quantification of new acetylcholinesterase inhibitor PC 48 (7-MEOTA-donepezil like compound) in rat plasma: Application to a pharmacokinetic study.

PubMed

Mzik, Martin; Korabecny, Jan; Nepovimova, Eugenie; Voříšek, Viktor; Palička, Vladimir; Kuca, Kamil; Zdarova Karasova, Jana

2016-05-01

A simple, rapid and sensitive method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed and validated for the quantitative determination in rat plasma of a new candidate for AD treatment, namely PC 48 (a 7-MEOTA-donepezil like compound) in rat plasma. Sample preparation involved pH adjustment with sodium hydroxide followed by solvent extraction with ethyl acetate:dichloromethane (80:20, v/v). The chromatographic separation was achieved on an Ascentis Express RP-Amide column (75 mm × 2.1mm, 2.7 μm) with a gradient mobile phase consisting of 0.05 M aqueous formic acid and acetonitrile. Detection was carried out using positive-ion electrospray tandem mass spectrometry on an LTQ XL system using the MS/MS CID (collision-induced dissociation) mode. The method was linear in the range 0.1-1000 ng/ml (r(2)=0.999) with a lower limit of quantitation of 0.1 ng/mL. Extraction recovery was in the range 63.5-72.1% for PC 48 and 70.5% for reserpine (internal standard, IS). Intra- and inter-day precisions measured as relative standard deviation were below 10.8% and accuracy was from -7.2% to 7.4%. The method was successfully applied to a pharmacokinetic study involving intramuscular application of 3.86 mg/kg PC 48 to rats for the first time. Pharmacokinetic parameters for PC 48 include Cmax 39.09 ± 4.45 ng/mL,Tmax 5.00 ± 3.08 min, AUC0-t 23374 ± 4045 min ng/mL and t1/2 1065 ± 246 min. Copyright © 2016 Elsevier B.V. All rights reserved.

A comparison of the efficacy of newly developed reversible inhibitors of acetylcholinesterase with commonly used pyridostigmine as pharmacological pre-treatment of soman-poisoned mice.

PubMed

Kassa, Jiri; Musilek, Kamil; Koomlova, Marketa; Bajgar, Jiri

2012-04-01

The ability of three newly developed reversible inhibitors of acetylcholinesterase (AChE) (K298, K344 and K474) and currently available carbamate pyridostigmine to increase the resistance of mice against soman and the efficacy of antidotal treatment of soman-poisoned mice was compared. Neither pyridostigmine nor new reversible inhibitors of AChE were able to increase the LD(50) value of soman. Thus, the pharmacological pre-treatment with pyridostigmine or newly synthesized inhibitors of AChE was not able to protect mice against soman-induced lethal acute toxicity. The pharmacological pre-treatment with pyridostigmine alone or with K474 was able to slightly increase the efficacy of antidotal treatment (the oxime HI-6 in combination with atropine) of soman-poisoned mice, but the increase in the efficacy of antidotal treatment was not significant. The other newly developed reversible inhibitors of AChF (K298, K344) were completely ineffective. These findings demonstrate that pharmacological pre-treatment of soman-poisoned mice with tested reversible inhibitors of AChF is not promising. © 2011 The Authors. Basic & Clinical Pharmacology & Toxicology © 2011 Nordic Pharmacological Society.

Design and prediction of new acetylcholinesterase inhibitor via quantitative structure activity relationship of huprines derivatives.

PubMed

Zhang, Shuqun; Hou, Bo; Yang, Huaiyu; Zuo, Zhili

2016-05-01

Acetylcholinesterase (AChE) is an important enzyme in the pathogenesis of Alzheimer's disease (AD). Comparative quantitative structure-activity relationship (QSAR) analyses on some huprines inhibitors against AChE were carried out using comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA), and hologram QSAR (HQSAR) methods. Three highly predictive QSAR models were constructed successfully based on the training set. The CoMFA, CoMSIA, and HQSAR models have values of r (2) = 0.988, q (2) = 0.757, ONC = 6; r (2) = 0.966, q (2) = 0.645, ONC = 5; and r (2) = 0.957, q (2) = 0.736, ONC = 6. The predictabilities were validated using an external test sets, and the predictive r (2) values obtained by the three models were 0.984, 0.973, and 0.783, respectively. The analysis was performed by combining the CoMFA and CoMSIA field distributions with the active sites of the AChE to further understand the vital interactions between huprines and the protease. On the basis of the QSAR study, 14 new potent molecules have been designed and six of them are predicted to be more active than the best active compound 24 described in the literature. The final QSAR models could be helpful in design and development of novel active AChE inhibitors.

Identification and characterization of potential impurities of donepezil.

PubMed

Krishna Reddy, K V S R; Moses Babu, J; Kumar, P Anil; Chandrashekar, E R R; Mathad, Vijayavitthal T; Eswaraiah, S; Reddy, M Satyanarayana; Vyas, K

2004-09-03

Five unknown impurities ranging from 0.05 to 0.2% in donepezil were detected by a simple isocratic reversed-phase high performance liquid chromatography (HPLC). These impurities were isolated from crude sample of donepezil using isocratic reversed-phase preparative high performance liquid chromatography. Based on the spectral data (IR, NMR and MS), the structures of these impurities were characterised as 5,6-dimethoxy-2-(4-pyridylmethyl)-1-indanone (impurity I), 4-(5,6-dimethoxy-2,3-dihydro-1H-2-indenylmethyl) piperidine (impurity II), 2-(1-benzyl-4-piperdylmethyl)-5,6-dimethoxy-1-indanol (impurity III) 1-benzyl-4(5,6-dimethoxy-2,3-dihydro-1H-2-indenylmethyl) piperidine (impurity IV) and 1,1-dibenzyl-4(5,6-dimethoxy-1-oxo-2,3-dihydro-2H-2-indenylmethyl)hexahydropyridinium bromide (impurity V). The synthesis of these impurities and their formation was discussed.

A fixed-dose combination of memantine extended-release and donepezil in the treatment of moderate-to-severe Alzheimer's disease.

PubMed

Deardorff, William James; Grossberg, George T

2016-01-01

Currently available therapies for the treatment of Alzheimer's disease (AD) consist of cholinesterase inhibitors (ChEIs), such as donepezil, and the N -methyl-D-aspartate receptor antagonist memantine. In December 2014, the US Food and Drug Administration approved Namzaric™, a once-daily, fixed-dose combination (FDC) of memantine extended-release (ER) and donepezil for patients with moderate-to-severe AD. The FDC capsule is bioequivalent to the coadministered individual drugs, and its bioavailability is similar when taken fasting, with food, or sprinkled onto applesauce. The combination of memantine and ChEIs in moderate-to-severe AD provides additional benefits to ChEI monotherapy across multiple domains and may delay the time to nursing home admission. A dedicated study of memantine ER compared to placebo in patients on a stable dose of a ChEI found statistically significant benefits on cognition and global status but not functioning. Treatment with memantine ER and donepezil is generally well tolerated, although higher doses of ChEIs are associated with more serious adverse events such as vomiting, syncope, and weight loss. Potential advantages of the FDC include a simpler treatment regimen, reduction in pill burden, and the ability to sprinkle the capsule onto soft foods. Patients who may benefit from the FDC include those with significant dysphagia, a history of poor compliance, or limited caregiver interaction. However, available evidence that these advantages would increase treatment adherence and persistence is conflicting, meaning that the added cost of switching patients from generic options to an FDC may not always be justified.

Cholinergic symptoms with low serum cholinesterase from therapeutic cholinesterase inhibitor toxicity.

PubMed

Leikin, Jerrold B; Braund, Victoria; DesLauris, Carol

2014-07-01

Although cholinesterase inhibitors have been frequently used in the treatment of Alzheimer disease, its effects on serum cholinesterase concentrations have been rarely described. We described significant depression of serum cholinesterase levels due to cholinesterase inhibitor toxicity from redundant use of donepezil and rivastigmine in a 78-year-old man. Recovery of serum cholinesterase level was noted upon drug discontinuation and cholinergic symptom resolution. Serum cholinesterase level can be used as a biomarker for central cholinesterase inhibitor toxicity.

Arisugacins A and B, novel and selective acetylcholinesterase inhibitors from Penicillium sp. FO-4259. I. Screening, taxonomy, fermentation, isolation and biological activity.

PubMed

Kuno, F; Otoguro, K; Shiomi, K; Iwai, Y; Omura, S

1996-08-01

An in vitro screening method for selective acetylcholinesterase (AChE) inhibitors was established. Inhibitory activity of AChE and butyrylcholinesterase (BuChE) was measured and the culture broths of microorganisms that showed selective inhibition against AChE were characterized. By using this method, a strain producing the novel and selective inhibitors of AChE, arisugacins A and B, was picked out among over seven thousand microorganisms tested. Arisugacins were obtained as white powders from the culture broth together with three known compounds, territrems B and C and cyclopenin that also showed selective inhibition against AChE. Arisugacins and territrems are members of the meroterpenoid compounds. They showed potent inhibitory activities against AChE with IC50 values in range of 1.0 approximately 25.8 nM. Furthermore, they showed greater than 2,000-fold more potent inhibition against AChE than BuChE.

Effect of Moringa oleifera flower extract on larval trypsin and acetylcholinesterase activities in Aedes aegypti.

PubMed

Pontual, Emmanuel Viana; Napoleão, Thiago Henrique; Dias de Assis, Caio Rodrigo; de Souza Bezerra, Ranilson; Xavier, Haroudo Satiro; Navarro, Daniela Maria do Amaral Ferraz; Coelho, Luana Cassandra Breitenbach Barroso; Paiva, Patrícia Maria Guedes

2012-03-01

Aedes aegypti control is crucial to reducing dengue fever. Aedes aegypti larvae have developed resistance to organophosporous insecticides and the use of natural larvicides may help manage larval resistance by increasing elements in insecticide rotation programs. Here, we report on larvicidal activity of Moringa oleifera flower extract against A. aegypti L(1), L(2), L(3), and L(4) as well as the effect of flower extract on gut trypsin and whole-larval acetylcholinesterase from L(4.) In addition, the heated flower extract was investigated for larvicidal activity against L(4) and effect on larval gut trypsin. Moringa oleifera flower extract contains a proteinaceous trypsin inhibitor (M. oleifera flower trypsin inhibitor, MoFTI), triterpene (β-amyrin), sterol (β-sitosterol) as well as flavonoids (kaempferol and quercetin). Larvicidal activity was detected against L(2), L(3), and L(4) (LC(50) of 1.72%, 1.67%, and 0.92%, respectively). Flower extract inhibited L(4) gut trypsin (MoFTI K(i) = 0.6 nM) and did not affect acetylcholinesterase activity. In vivo assay showed that gut trypsin activity from L(4) treated with M. oleifera flower extract decreased over time (0-1,440 min) and was strongly inhibited (98.6%) after 310 min incubation; acetylcholinesterase activity was not affected. Thermal treatment resulted in a loss of trypsin inhibitor and larvicidal activities, supporting the hypothesis that flower extract contains a proteinaceous trypsin inhibitor that may be responsible for the deleterious effects on larval mortality. © 2012 Wiley Periodicals, Inc.

The effect of stimulation therapy and donepezil on cognitive function in Alzheimer's disease. A community based RCT with a two-by-two factorial design.

PubMed

Andersen, Fred; Viitanen, Matti; Halvorsen, Dag S; Straume, Bjørn; Wilsgaard, Tom; Engstad, Torgeir A

2012-07-19

Progressive neurodegeneration in Alzheimer's disease (AD) induces cognitive deterioration, and there is controversy regarding the optimal treatment strategy in early AD. Stimulation therapy, including physical exercise and cholinesterase inhibitors are both reported to postpone cognitive deterioration in separate studies. We aimed to study the effect of stimulation therapy and the additional effect of donepezil on cognitive function in early AD. A two-by-two factorial trial comprising stimulation therapy for one year compared to standard care to which a randomized double-blinded placebo controlled trial with donepezil was added. Nine rural municipalities in Northern Norway. 187 participants 65 years and older with a recent diagnosis of mild or moderate AD were included in the study of which 146 completed a one-year follow-up. In five municipalities the participants received stimulation therapy whereas participants in four received standard care. All participants were randomised double-blindly to donepezil or placebo and tested with three different cognitive tests four times during the one-year study period. Changes in MMSE sum score.Secondary outcome: Changes in ADAS-Cog and Clock Drawing Test. MMSE scores remained unchanged amongst AD participants receiving stimulation therapy and those receiving standard care. The results were consistent for ADAS-Cog and Clock Drawing Test. No time trend differences were found during one-year follow-up between groups receiving stimulation therapy versus standard care or between donepezil versus placebo. In rural AD patients non-pharmacological and pharmacological therapy did not improve outcome compared with standard care but all groups retained cognitive function during one year follow-up. Other studies are needed to confirm these results. ClinicalTrials.gov (Identifier: NCT00443014). EudraCT database (no 2004-002613-37).

Acetamide Derivatives of Chromen-2-ones as Potent Cholinesterase Inhibitors.

PubMed

Prasad, Suchita; Kumar, Bipul; Kumar, Shiv; Chand, Karam; Kamble, Shashank S; Gautam, Hemant K; Sharma, Sunil K

2017-08-01

Alzheimer's disease (AD), a neurodegenerative disorder, is a serious medical issue worldwide with drastic social consequences. Inhibition of cholinesterase is one of the rational and effective approaches to retard the symptoms of AD and, hence, consistent efforts are being made to develop efficient anti-cholinesterase agents. In pursuit of this, a series of 19 acetamide derivatives of chromen-2-ones were synthesized and evaluated for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory potential. All the synthesized compounds exhibited significant anti-AChE and anti-BChE activity, with IC 50 values in the range of 0.24-10.19 μM and 0.64-30.08 μM, respectively, using donepezil hydrochloride as the standard. Out of 19 compounds screened, 3 compounds, viz. 22, 40, and 43, caused 50% inhibition of AChE at 0.24, 0.25, and 0.25 μM, respectively. A kinetic study revealed them to be mixed-type inhibitors, binding with both the CAS and PAS sites of AChE. The above-selected compounds were found to be effective inhibitors of AChE-induced and self-mediated Aβ 1-42 aggregation. ADMET predictions demonstrated that these compounds may possess suitable blood-brain barrier (BBB) permeability. Hemolytic assay results revealed that these compounds did not lyse human RBCs up to a thousand times of their IC 50 value. MTT assays performed for the shortlisted compounds showed them to be negligibly toxic after 24 h of treatment with the SH-SY5Y neuroblastoma cells. These results provide insights for further optimization of the scaffolds for designing the next generation of compounds as lead cholinesterase inhibitors. © 2017 Deutsche Pharmazeutische Gesellschaft.

Tissue distribution of human acetylcholinesterase and butyrylcholinesterase messenger RNA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jbilo, O.; Barteles, C.F.; Chatonnet, A.

1994-12-31

Tissue distribution of human acetyicholinesterase and butyryicholinesterase messenger RNA. 1 Cholinesterase inhibitors occur naturally in the calabar bean (eserine), green potatoes (solanine), insect-resistant crab apples, the coca plant (cocaine) and snake venom (fasciculin). There are also synthetic cholinesterase inhibitors, for example man-made insecticides. These inhibitors inactivate acetyicholinesterase and butyrylcholinesterase as well as other targets. From a study of the tissue distribution of acetylcholinesterase and butyrylcholinesterase mRNA by Northern blot analysis, we have found the highest levels of butyrylcholinesterase mRNA in the liver and lungs, tissues known as the principal detoxication sites of the human body. These results indicate that butyrylcholinesterasemore » may be a first line of defense against poisons that are eaten or inhaled.« less

Nursing home placement in the Donepezil and Memantine in Moderate to Severe Alzheimer's Disease (DOMINO-AD) trial: secondary and post-hoc analyses.

PubMed

Howard, Robert; McShane, Rupert; Lindesay, James; Ritchie, Craig; Baldwin, Ashley; Barber, Robert; Burns, Alistair; Dening, Tom; Findlay, David; Holmes, Clive; Jones, Robert; Jones, Roy; McKeith, Ian; Macharouthu, Ajay; O'Brien, John; Sheehan, Bart; Juszczak, Edmund; Katona, Cornelius; Hills, Robert; Knapp, Martin; Ballard, Clive; Brown, Richard G; Banerjee, Sube; Adams, Jessica; Johnson, Tony; Bentham, Peter; Phillips, Patrick P J

2015-12-01

Findings from observational studies have suggested a delay in nursing home placement with dementia drug treatment, but findings from a previous randomised trial of patients with mild-to-moderate Alzheimer's disease showed no effect. We investigated the effects of continuation or discontinuation of donepezil and starting of memantine on subsequent nursing home placement in patients with moderate-to-severe Alzheimer's disease. In the randomised, double-blind, placebo-controlled Donepezil and Memantine in Moderate to Severe Alzheimer's Disease (DOMINO-AD) trial, community-living patients with moderate-to-severe Alzheimer's disease (who had been prescribed donepezil continuously for at least 3 months at a dose of 10 mg for at least the previous 6 weeks and had a score of between 5 and 13 on the Standardised Mini-Mental State Examination) were recruited from 15 secondary care memory centres in England and Scotland and randomly allocated to continue donepezil 10 mg per day without memantine, discontinue donepezil without memantine, discontinue donepezil and start memantine 20 mg per day, or continue donepezil 10 mg per day and start memantine 20 mg per day, for 52 weeks. After 52 weeks, choice of treatment was left to participants and their physicians. Place of residence was recorded during the first 52 weeks of the trial and then every 26 weeks for a further 3 years. A secondary outcome of the trial, reported in this study, was nursing home placement: an irreversible move from independent accommodation to a residential caring facility. Analyses restricted to risk of placement in the first year of follow-up after the patients had completed the double-blind phase of the trial were post-hoc. The DOMINO-AD trial is registered with the ISRCTN Registry, number ISRCTN49545035. Between Feb 11, 2008, and March 5, 2010, 73 (25%) patients were randomly assigned to continue donepezil without memantine, 73 (25%) to discontinue donepezil without memantine, 76 (26%) to discontinue

A fixed-dose combination of memantine extended-release and donepezil in the treatment of moderate-to-severe Alzheimer’s disease

PubMed Central

Deardorff, William James; Grossberg, George T

2016-01-01

Currently available therapies for the treatment of Alzheimer’s disease (AD) consist of cholinesterase inhibitors (ChEIs), such as donepezil, and the N-methyl-D-aspartate receptor antagonist memantine. In December 2014, the US Food and Drug Administration approved Namzaric™, a once-daily, fixed-dose combination (FDC) of memantine extended-release (ER) and donepezil for patients with moderate-to-severe AD. The FDC capsule is bioequivalent to the coadministered individual drugs, and its bioavailability is similar when taken fasting, with food, or sprinkled onto applesauce. The combination of memantine and ChEIs in moderate-to-severe AD provides additional benefits to ChEI monotherapy across multiple domains and may delay the time to nursing home admission. A dedicated study of memantine ER compared to placebo in patients on a stable dose of a ChEI found statistically significant benefits on cognition and global status but not functioning. Treatment with memantine ER and donepezil is generally well tolerated, although higher doses of ChEIs are associated with more serious adverse events such as vomiting, syncope, and weight loss. Potential advantages of the FDC include a simpler treatment regimen, reduction in pill burden, and the ability to sprinkle the capsule onto soft foods. Patients who may benefit from the FDC include those with significant dysphagia, a history of poor compliance, or limited caregiver interaction. However, available evidence that these advantages would increase treatment adherence and persistence is conflicting, meaning that the added cost of switching patients from generic options to an FDC may not always be justified. PMID:27757016

The selective positive allosteric M1 muscarinic receptor modulator PQCA attenuates learning and memory deficits in the Tg2576 Alzheimer's disease mouse model.

PubMed

Puri, Vanita; Wang, Xiaohai; Vardigan, Joshua D; Kuduk, Scott D; Uslaner, Jason M

2015-01-01

We have recently shown that the M1 muscarinic receptor positive allosteric modulator, PQCA, improves cognitive performance in rodents and non-human primates administered the muscarinic receptor antagonist scopolamine. The purpose of the present experiments was to characterize the effects of PQCA in a model more relevant to the disease pathology of Alzheimer's disease. Tg2576 transgenic mice that have elevated Aβ were tested in the novel object recognition task to characterize recognition memory as a function of age and treatment with the PQCA. The effects of PQCA were compared to the acetylcholinesterase inhibitor donepezil, the standard of care for Alzheimer's disease. In addition, the effect of co-administering PQCA and donepezil was evaluated. Aged Tg2576 mice demonstrated a deficit in recognition memory that was significantly attenuated by PQCA. The positive control donepezil also reversed the deficit. Furthermore, doses of PQCA and donepezil that were inactive on their own were found to improve recognition memory when given together. These studies suggest that M1 muscarinic receptor positive allosteric modulation can ameliorate memory deficits in disease relevant models of Alzheimer's disease. These data, combined with our previous findings demonstrating PQCA improves scopolamine-induced cognitive deficits in both rodents and non-human primates, suggest that M1 positive allosteric modulators have therapeutic potential for the treatment of Alzheimer's disease. Copyright © 2015 Elsevier B.V. All rights reserved.

Adverse Events With Sustained-Release Donepezil in Alzheimer Disease: Relation to Body Mass Index.

PubMed

Lee, Chunsoo; Lee, Kyungsang; Yu, Hyewon; Ryu, Seung-Ho; Moon, Seok Woo; Han, Changsu; Lee, Jun-Young; Lee, Young Min; Kim, Shin-Gyeom; Kim, Ki Woong; Lee, Dong Woo; Kim, Seong Yoon; Lee, Sang-Yeol; Bae, Jae Nam; Jung, Young-Eun; Kim, Jeong Lan; Kim, Byung-Soo; Shin, Il-Seon; Kim, Young Hoon; Kim, Bong Jo; Kang, Hyo Shin; Myung, Woojae; Carroll, Bernard J; Kim, Doh Kwan

2017-08-01

Sustained-release, high-dose (23 mg/d) donepezil has been approved for treatment of moderate to severe Alzheimer disease (AD). Based on a previous clinical trial, body weight of less than 55 kg is a risk factor for adverse events with donepezil 23 mg/d treatment in global population. To clarify whether this finding is consistent across ethnic groups that vary in absolute body mass, we recruited Korean patients aged 45 to 90 years with moderate to severe AD who had been receiving standard donepezil immediate release 10 mg/d for at least 3 months. After screening, we analyzed a final cohort of 166 patients who received donepezil 23 mg/d for 24 weeks to compare the occurrence of treatment-emergent adverse events (TEAEs) between patients with high versus low body mass index (BMI) based on the World Health Organization overweight criteria for Asian populations (23 kg/m). Treatment-emergent adverse events were reported by 79.45% of patients in the lower BMI group and 58.06% of patients in the higher BMI group (odds ratio, 2.79; 95% confidence interval, 1.39-5.63; χ = 7.58, P = 0.006). In a multivariable survival analysis, the group with lower BMI showed a higher occurrence of TEAEs (hazard ratio, 1.83; 95% confidence interval, 1.25-2.68; P = 0.002). In Korean patients with moderate to severe AD receiving high-dose donepezil over 24 weeks, TEAEs were significantly more common in those with lower BMI (not clinically overweight), especially nausea. This finding may inform clinical practice for Asian patients.

The effect of funding sources on donepezil randomised controlled trial outcome: a meta-analysis.

PubMed

Killin, Lewis O J; Russ, Tom C; Starr, John M; Abrahams, Sharon; Della Sala, Sergio

2014-04-07

To investigate whether there is a difference in the treatment effect of donepezil on cognition in Alzheimer disease between industry-funded and independent randomised controlled trials. Fixed effects meta-analysis of standardised effects of donepezil on cognition as measured by the Mini Mental State Examination and the Alzheimer's Disease Assessment Scale-cognitive subscale. Studies included in the meta-analyses reported in the National Institute for Health and Care Excellence (NICE) technical appraisal 217 updated with new studies through a PubMed search. Inclusion criteria were double-blind, placebo-controlled trials of any length comparing patients diagnosed with probable Alzheimer disease (according to the NINCDS-ADRDA/DSM-III/IV criteria) taking any dosage of donepezil. Studies of combination therapies (eg, donepezil and memantine) were excluded, as were studies that enrolled patients with a diagnosis of Alzheimer disease associated with other disorders (eg, Parkinson's disease and Down's syndrome). Our search strategy identified 14 relevant trials (4 independent) with suitable data. Trials sponsored by pharmaceutical companies reported a larger effect of donepezil on standardised cognitive tests than trials published by independent research groups (standardised mean difference (SMD)=0.46, 95% CI 0.37 to 0.55 vs SMD=0.33, 95% CI 0.18 to 0.48, respectively). This difference remained when only data representing change up to 12 weeks from baseline were analysed (industry SMD=0.44, 95% CI 0.34 to 0.53 vs independent SMD=0.35, 95% CI 0.18 to 0.52). Analysis revealed that the effect of funding as a moderator variable of study heterogeneity was not statistically significant at either time point. The effect size of donepezil on cognition is larger in industry-funded than independent trials and this is not explained by the longer duration of industry-funded trials. The lack of a statistically significant moderator effect may indicate that the differences are due to

Protease inhibitors and indoleamines selectively inhibit cholinesterases in the histopathologic structures of Alzheimer disease.

PubMed Central

Wright, C I; Guela, C; Mesulam, M M

1993-01-01

Neurofibrillary tangles and amyloid plaques express acetylcholinesterase and butyrylcholinesterase activity in Alzheimer disease. We previously reported that traditional acetylcholinesterase inhibitors such as BW284C51, tacrine, and physostigmine were more potent inhibitors of the acetylcholinesterase in normal axons and cell bodies than of the acetylcholinesterase in plaques and tangles. We now report that the reverse pattern is seen with indoleamines (such as serotonin and its precursor 5-hydroxytryptophan), carboxypeptidase inhibitor, and the nonspecific protease inhibitor bacitracin. These substances are more potent inhibitors of the cholinesterases in plaques and tangles than of those in normal axons and cell bodies. These results show that the enzymatic properties of plaque and tangle-associated cholinesterases diverge from those of normal axons and cell bodies. The selective susceptibility to bacitracin and carboxypeptidase inhibitor indicates that the catalytic sites of plaque and tangle-bound cholinesterases are more closely associated with peptidase or protease-like properties than the catalytic sites of cholinesterases in normal axons and cell bodies. This shift in enzymatic affinity may lead to the abnormal protein processing that is thought to play a major role in the pathogenesis of Alzheimer disease. The availability of pharmacological and dietary means for altering brain indoleamines raises therapeutic possibilities for inhibiting the abnormal cholinesterase activity associated with Alzheimer disease. Images PMID:8421706

Iminosugars as a new class of cholinesterase inhibitors.

PubMed

Decroocq, Camille; Stauffert, Fabien; Pamlard, Olivier; Oulaïdi, Farah; Gallienne, Estelle; Martin, Olivier R; Guillou, Catherine; Compain, Philippe

2015-02-15

To further extend the scope of iminosugar biological activity, a systematic structure-activity relationship investigation has been performed by synthesizing and evaluating as cholinesterase inhibitors a library of twenty-three iminoalditols with different substitutions and stereochemistry patterns. These compounds have been evaluated in vitro for the inhibition of cholinesterases (different sources of acetylcholinesterase and butyrylcholinesterase). Some compounds have IC50 values in the micromolar range and display significant inhibition selectivity for butyrylcholinesterase over acetylcholinesterase. These are the first examples of iminosugar-based inhibitors of cholinesterases. Copyright © 2015 Elsevier Ltd. All rights reserved.

Donepezil treatment and Alzheimer disease: can the results of randomized clinical trials be applied to Alzheimer disease patients in clinical practice?

PubMed

Tinklenberg, Jared R; Kraemer, Helena C; Yaffe, Kristine; Ross, Leslie; Sheikh, Javaid; Ashford, John W; Yesavage, Jerome A; Taylor, Joy L

2007-11-01

To determine if results from randomized clinical trials of donepezil in Alzheimer disease (AD) patients can be applied to AD patients in clinical practice by comparing the findings from a Nordic one-year randomized AD donepezil trial with data from a one-year prospective, observational study of AD patients. AD patients from a consortium of California sites were systematically followed for at least one year. Their treatment regimens, including prescription of donepezil, were determined by their individual physician according to his or her usual criteria. The 148 California patients treated with donepezil had a one-year decline of 1.3 (3.5 SD) points on the Mini-Mental State Exam compared to a decline of 3.3 (4.4 SD) in the 158 AD patients who received no anti-Alzheimer drugs. The Mini-Mental State Exam decline in Nordic sample was approximately 0.25 points for the 91 patients receiving donepezil and approximately 2.2 for the 98 placebo patients. The overall effect sizes were estimated at about 0.49 in both studies. The California data were further analyzed using propensity methods; after taking into account differences that could bias prescribing decisions, benefits associated with taking donepezil remained. A comparison of a randomized clinical trial of donepezil in AD patients and this observational study indicates that if appropriate methodological and statistical precautions are undertaken, then results from randomized clinical trials can be predictive with AD patients in clinical practice. This California study supports the modest effectiveness of donepezil in AD patients having clinical characteristics similar to those of the Nordic study.

Impact of donepezil hydrochloride on the care burden of family caregivers of patients with Alzheimer's disease.

PubMed

Hashimoto, Mamoru; Yatabe, Yusuke; Kaneda, Keiichiro; Honda, Kazuki; Ikeda, Manabu

2009-12-01

To evaluate the impact of donepezil hydrochloride on the care burden on family members of patients with Alzheimer's disease (AD). At present, donepezil is the only drug approved for the treatment of AD in Japan. Although the care burden on primary caregivers of AD patients comprises both physical and psychological burdens and donepezil is recognized to improve cognitive dysfunction and associated symptoms, there are few data on the effects of the drug on the care burden. Of the uninstitutionalized AD patients who visited a dementia clinic between June 2008 and May 2009 with their primary family caregivers, 416 subjects who satisfied the enrollment criteria were registered for the study. All participants provided informed consent. Assessment included changes in scores on the Japanese version of the Zarit Caregiver Burden Interview (J-ZBI) and the Mini-Mental State Examination (MMSE), as well as the presence of behavioral and psychological symptoms of dementia (BPSD). Caregivers answered the questionnaires at baseline and after 12 weeks treatment with donepezil (starting dose 3 mg, p.o., once daily, followed by 5 mg after 1 or 2 weeks). There were significant changes in mean scores on the J-ZBI (-1.9 +/- 9.5; P < 0.01) and MMSE (+0.9 +/- 2.9; P < 0.01) from baseline to Week 12, without significant correlation between these two scores. In patients with BPSD, there was a significant decrease in J-ZBI scores over the 12 weeks (P = 0.013); in contrast, in patients without BPSD, the decrease in the J-ZBI score did not reach statistical significance (P = 0.418). The results indicate that donepezil improves cognitive function and some of the BPSD. As a possible consequence of improvements in BPSD, donepezil may also reduce caregivers' burden.

Designing Second Generation Anti-Alzheimer Compounds as Inhibitors of Human Acetylcholinesterase: Computational Screening of Synthetic Molecules and Dietary Phytochemicals

PubMed Central

Amat-ur-Rasool, Hafsa; Ahmed, Mehboob

2015-01-01

Alzheimer's disease (AD), a big cause of memory loss, is a progressive neurodegenerative disorder. The disease leads to irreversible loss of neurons that result in reduced level of acetylcholine neurotransmitter (ACh). The reduction of ACh level impairs brain functioning. One aspect of AD therapy is to maintain ACh level up to a safe limit, by blocking acetylcholinesterase (AChE), an enzyme that is naturally responsible for its degradation. This research presents an in-silico screening and designing of hAChE inhibitors as potential anti-Alzheimer drugs. Molecular docking results of the database retrieved (synthetic chemicals and dietary phytochemicals) and self-drawn ligands were compared with Food and Drug Administration (FDA) approved drugs against AD as controls. Furthermore, computational ADME studies were performed on the hits to assess their safety. Human AChE was found to be most approptiate target site as compared to commonly used Torpedo AChE. Among the tested dietry phytochemicals, berberastine, berberine, yohimbine, sanguinarine, elemol and naringenin are the worth mentioning phytochemicals as potential anti-Alzheimer drugs The synthetic leads were mostly dual binding site inhibitors with two binding subunits linked by a carbon chain i.e. second generation AD drugs. Fifteen new heterodimers were designed that were computationally more efficient inhibitors than previously reported compounds. Using computational methods, compounds present in online chemical databases can be screened to design more efficient and safer drugs against cognitive symptoms of AD. PMID:26325402

Designing Second Generation Anti-Alzheimer Compounds as Inhibitors of Human Acetylcholinesterase: Computational Screening of Synthetic Molecules and Dietary Phytochemicals.

PubMed

Amat-Ur-Rasool, Hafsa; Ahmed, Mehboob

2015-01-01

Alzheimer's disease (AD), a big cause of memory loss, is a progressive neurodegenerative disorder. The disease leads to irreversible loss of neurons that result in reduced level of acetylcholine neurotransmitter (ACh). The reduction of ACh level impairs brain functioning. One aspect of AD therapy is to maintain ACh level up to a safe limit, by blocking acetylcholinesterase (AChE), an enzyme that is naturally responsible for its degradation. This research presents an in-silico screening and designing of hAChE inhibitors as potential anti-Alzheimer drugs. Molecular docking results of the database retrieved (synthetic chemicals and dietary phytochemicals) and self-drawn ligands were compared with Food and Drug Administration (FDA) approved drugs against AD as controls. Furthermore, computational ADME studies were performed on the hits to assess their safety. Human AChE was found to be most approptiate target site as compared to commonly used Torpedo AChE. Among the tested dietry phytochemicals, berberastine, berberine, yohimbine, sanguinarine, elemol and naringenin are the worth mentioning phytochemicals as potential anti-Alzheimer drugs The synthetic leads were mostly dual binding site inhibitors with two binding subunits linked by a carbon chain i.e. second generation AD drugs. Fifteen new heterodimers were designed that were computationally more efficient inhibitors than previously reported compounds. Using computational methods, compounds present in online chemical databases can be screened to design more efficient and safer drugs against cognitive symptoms of AD.

Flavoring extracts of Hemidesmus indicus roots and Vanilla planifolia pods exhibit in vitro acetylcholinesterase inhibitory activities.

PubMed

Kundu, Anish; Mitra, Adinpunya

2013-09-01

Acetylcholinesterase inhibitors (AChEIs) are important for treatment of Alzheimer's disease and other neurological disorders. Search for potent and safe AChEIs from plant sources still continues. In the present work, we explored fragrant plant extracts that are traditionally used in flavoring foods, namely, Hemidesmus indicus and Vanilla planifolia, as possible sources for AChEI. Root and pod extracts of H. indicus and V. planifolia, respectively, produce fragrant phenolic compounds, 2-hydroxy-4-methoxybenzaldehyde (MBALD) and 4-hydroxy-3-methoxybenzaldehyde (vanillin). These methoxybenzaldehydes were shown to have inhibitory potential against acetylcholinesterase (AChE). Vanillin (IC50 = 0.037 mM) was detected as more efficient inhibitor than MBALD (IC50 = 0.047 mM). This finding was supported by kinetic analysis. Thus, plant-based food flavoring agents showed capacity in curing Alzheimer's disease and other neurological dysfunctions.

EEG SPECTRA, BEHAVIORAL STATES AND MOTOR ACTIVITY IN RATS EXPOSED TO ACETYLCHOLINESTERASE INHIBITOR CHLORPYRIFOS.

EPA Science Inventory

Exposure to organophosphate pesticides (OP) has been associated with sleep disorders: insomnia and ?excessive dreaming'. However neuronal mechanisms of these effects have not been analyzed. OP inhibit acetylcholinesterase activity leading to a hyperativity of the brain cholin...

Acetylcholinesterase inhibitors for electroconvulsive therapy-induced cognitive side effects: a systematic review.

PubMed

Henstra, Marieke J; Jansma, Elise P; van der Velde, Nathalie; Swart, Eleonora L; Stek, Max L; Rhebergen, Didi

2017-05-01

Electroconvulsive therapy (ECT) is an effective treatment for severe late-life depression; however, ECT-induced cognitive side effects frequently occur. The cholinergic system is thought to play an important role in the pathogenesis. We systematically reviewed the evidence for acetylcholinesterase inhibitors (Ache-I) to prevent or reduce ECT-induced cognitive side effects. A systematic search was performed in Pubmed, EMBASE, PsychINFO, and the Cochrane database to identify clinical trials investigating the effect of Ache-I on ECT-induced cognitive side effects. Key search terms included all synonyms for ECT and Ache-I. Risk of bias assessment was conducted by using the Cochrane Collaboration's tool. Five clinical trials were eligible for inclusion. All studies focused on cognitive functioning as primary endpoint, but assessment of cognitive functioning varied widely in time point of assessment and in cognitive tests that were used. There was also great variety in study medication, route and time of administration and dosages, duration of drug administration, and ECT techniques. Finally, only two out of five studies were considered at low risk of bias. Despite the aforementioned shortcomings, without exception, all studies demonstrated significantly better cognitive performance in individuals treated with Ache-I. Despite large heterogeneity in studies, Ache-I appear to have beneficial effects on ECT-induced cognitive side effects, supporting an association with the cholinergic system in ECT-induced cognitive impairment. Methodological sound studies controlling for putative confounders are warranted. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Synthesis and acetylcholinesterase inhibitory activity of polyhydroxylated sulfated steroids: structure/activity studies.

PubMed

Richmond, Victoria; Murray, Ana P; Maier, Marta S

2013-11-01

Disulfated and trisulfated steroids have been synthesized from cholesterol and their acetylcholinesterase inhibitory activity has been evaluated. In our studies we have found that the activity was not only dependent on the location of the sulfate groups but on their configurations. 2β,3α,6α-trihydroxy-5α-cholestan-6-one trisulfate (18) was the most active steroid with an IC50 value of 15.48 μM comparable to that of 2β,3α-dihydroxy-5α-cholestan-6-one disulfate (1). Both compounds were found to be less active than the reference compound eserine. The butyrylcholinesterase activity of 1 and 18 was one magnitude lower than that against acetylcholinesterase revealing a selective inhibitor profile. Copyright © 2013 Elsevier Inc. All rights reserved.

Pharmacokinetics and pharmacodynamics of a novel Acetylcholinesterase Inhibitor, DMNG-3.

PubMed

Xin-Guo, Zhang; Kou, Fei; Guo-Di, Ma; Tang, Peng; Zhong-Duo, Yang

2016-01-01

DMNG-3(3β-Methyl-[2-(4-nitrophenoxy)ethyl]-amino]con-5-enine), is a new and the potentially most potent acetylcholinesterase inhibitor recently obtained from conessine by N-demethylation and nucleophilic substitution reaction. In the present study, a step-down passive avoidance test was used to investigate whether DMNG-3 could modulate impairment of learning and memory induced by scopolamine, and a high performance liquid chromatography(HPLC) method for the determination of DMNG-3 in biological samples was applied to study its pharmacokinetics and tissues distribution. Separation was achieved on C18 column using a mobile phase consisting methanol-water (70:30, v/v) at a flow rate of 1.0ml/min. The intra- and inter-day precisions were good and the RSD was all lower than 1.30%. The mean absolute recovery of DMNG-3 in plasma ranged from 88.55 to 96.45 %. Our results showed oral administration of DMNG-3(10,25,50 mg/kg/day) can significantly improve the latency and number of errors and had a positive effect of improvement of learning and memory in mice in passive avoidance tests. The elimination half-life (T1/2) was 14.07±1.29, 15.87±1.03h, and the total clearance (CL) values were 0.70±0.11, 0.78±0.13 L/h/kg, respectively. The pharmacokinetic studies showed that DMNG-3 has a slowly clearance and large distribution volume in experimental animals, and its disposition is linear over the range of doses tested. The liver, small intestine, stomach, and large intestine were the major distribution tissues of DMNG-3 in mice. It was found that DMNG-3 could be detected in brain, suggesting that DMNG-3 can cross the blood-brain barrier. The present study shows that DMNG-3 can be possible developed as a new drug for the treatment of Alzheimer's disease in the future.

Rivastigmine: the advantages of dual inhibition of acetylcholinesterase and butyrylcholinesterase and its role in subcortical vascular dementia and Parkinson's disease dementia.

PubMed

Kandiah, Nagaendran; Pai, Ming-Chyi; Senanarong, Vorapun; Looi, Irene; Ampil, Encarnita; Park, Kyung Won; Karanam, Ananda Krishna; Christopher, Stephen

2017-01-01

Several studies have demonstrated clinical benefits of sustained cholinesterase inhibition with rivastigmine in Alzheimer's disease (AD) and Parkinson's disease dementia (PDD). Unlike donepezil and galantamine that selectively inhibit acetylcholinesterase (AChE; EC 3.1.1.7), rivastigmine is a unique cholinesterase inhibitor with both AChE and butyrylcholinesterase (BuChE; EC 3.1.1.8) inhibitory activity. Rivastigmine is also available as transdermal patch that has been approved by the US Food and Drug Administration for the treatment of mild, moderate, and severe AD as well as mild-to-moderate PDD. In this review, we explore the role of BuChE inhibition in addition to AChE inhibition with rivastigmine in the outcomes of cognition, global function, behavioral symptoms, and activities of daily living. Additionally, we review the evidence supporting the use of dual AChE-BuChE inhibitory activity of rivastigmine as a therapeutic strategy in the treatment of neurological disorders, with a focus on the role of rivastigmine in subcortical dementias such as vascular dementia (VaD) and PDD. Toward this objective, we performed a literature search in PubMed and Ovid with limits to articles published in the English language before June 2016. The available evidence from the literature suggests that the dual inhibition of AChE and BuChE may afford additional therapeutic potential of rivastigmine in subcortical dementias (subcortical VaD and PDD) with benefits on cognition and behavioral symptoms. Rivastigmine was found to specifically benefit executive dysfunction frequently observed in subcortical dementias; however, large randomized clinical studies are warranted to support these observations.

Improved thin-layer chromatography bioautographic assay for the detection of actylcholinesterase inhibitors in plants.

PubMed

Yang, Zhong-Duo; Song, Zhu-Wen; Ren, Jin; Yang, Ming-Jun; Li, Shuo

2011-01-01

Thin-layer chromatography (TLC) bioautographic method is a simple and rapid method to screen acetylcholinesterase inhibitors from plant extracts. However, the high consumption of enzyme (6 U/mL) in current methods makes the procedure expensive, which is an obstacle to scientific research centers lacking funding. To develop a new low-cost TLC bioautographic method. A series of compounds, as substrates, were synthesised and their ability to be hydrolysed by acetylcholinesterase was evaluated by the HPLC method. 4-Methoxyphenyl acetate (14) was proved to be an appropriate substrate for TLC bioautographic assay. Therefore a new and cheap TLC bioautographic assay was set up. The mechanism of this new method is that the enzyme converts 4-methoxylphenyl acetate into 4-methoxyphenol, which reacts with a solution of potassium ferricyanide ([K₃(FeCN)₆]) and iron chloride hexahydrate (FeCl₃·6H₂O) to make an aquamarine blue coloured background on the TLC plates. Regions of the TLC plate which contain acetylcholinesterase inhibitors show up as light yellow spots against the background. The consumption of enzyme (1 U/mL) in the new method is low and the detection limit of two known acetylcholinesterase inhibitors, huperzine A (0.0001 μg) and physostigmine (0.001 μg), for this assay are close to published values. A low-cost TLC bioautographic method was developed, which will benefit research groups pursuing natural acetylcholinesterase inhibitors. Copyright © 2011 John Wiley & Sons, Ltd.

Modulators of Acetylcholinesterase Activity: From Alzheimer's Disease to Anti-Cancer Drugs.

PubMed

Lazarevic-Pasti, Tamara; Leskovac, Andreja; Momic, Tatjana; Petrovic, Sandra; Vasic, Vesna

2017-01-01

Acetylcholinesterase (AChE) is involved in the termination of impulse transmission by rapid hydrolysis of the neurotransmitter acetylcholine in numerous cholinergic pathways in the central and peripheral nervous systems. The enzyme inactivation leads to acetylcholine accumulation, hyperstimulation of nicotinic and muscarinic receptors, and disrupted neurotransmission. Hence, acetylcholinesterase inhibitors, interacting with the enzyme as their primary target, are applied as relevant drugs for different neurodegenerative diseases (such as Alzheimer's and Parkinson's) as well as toxins. At the same time, there are increasing evidence that in non-neuronal context, AChE is involved in the regulation of cell proliferation, differentiation, apoptosis and cell-cell interaction. An irregular expression of AChE has been found in different types of tumors, suggesting the involvement of AChE in the regulation of tumor development. Having all this in mind, there is a possibility that some AChE inhibitors could be used as anti-cancer agents. This contribution will discuss a broad range of possible application of different AChE inhibitors as drugs, from well-known anti-Alzheimer's disease drugs to their use in cancer treatment in future. Emphasis will be put on various known AChE inhibitors classes, whose application as drugs could be controversy, as well as on newly investigated natural products, which can also modulate AChE activity. It is not clear a patient treated for neurodegenerative condition prone to increased risk for some types of cancer and vice versa. This is necessary to keep in mind during rational drug design process for all therapies, which are based on AChE as a target molecule. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Population pharmacokinetic approach to evaluate the effect of CYP2D6, CYP3A, ABCB1, POR and NR1I2 genotypes on donepezil clearance

PubMed Central

Noetzli, Muriel; Guidi, Monia; Ebbing, Karsten; Eyer, Stephan; Wilhelm, Laurence; Michon, Agnès; Thomazic, Valérie; Stancu, Ioana; Alnawaqil, Abdel-Messieh; Bula, Christophe; Zumbach, Serge; Gaillard, Michel; Giannakopoulos, Panteleimon; von Gunten, Armin; Csajka, Chantal; Eap, Chin B

2014-01-01

Aims A large interindividual variability in plasma concentrations has been reported in patients treated with donepezil, the most frequently prescribed antidementia drug. We aimed to evaluate clinical and genetic factors influencing donepezil disposition in a patient population recruited from a naturalistic setting. Methods A population pharmacokinetic study was performed including data from 129 older patients treated with donepezil. The patients were genotyped for common polymorphisms in the metabolic enzymes CYP2D6 and CYP3A, in the electron transferring protein POR and the nuclear factor NR1I2 involved in CYP activity and expression, and in the drug transporter ABCB1. Results The average donepezil clearance was 7.3 l h−1 with a 30% interindividual variability. Gender markedly influenced donepezil clearance (P < 0.01). Functional alleles of CYP2D6 were identified as unique significant genetic covariate for donepezil clearance (P < 0.01), with poor metabolizers and ultrarapid metabolizers demonstrating, respectively, a 32% slower and a 67% faster donepezil elimination compared with extensive metabolizers. Conclusion The pharmacokinetic parameters of donepezil were well described by the developed population model. Functional alleles of CYP2D6 significantly contributed to the variability in donepezil disposition in the patient population and should be further investigated in the context of individual dose optimization to improve clinical outcome and tolerability of the treatment. PMID:24433464

Population pharmacokinetic approach to evaluate the effect of CYP2D6, CYP3A, ABCB1, POR and NR1I2 genotypes on donepezil clearance.

PubMed

Noetzli, Muriel; Guidi, Monia; Ebbing, Karsten; Eyer, Stephan; Wilhelm, Laurence; Michon, Agnès; Thomazic, Valérie; Stancu, Ioana; Alnawaqil, Abdel-Messieh; Bula, Christophe; Zumbach, Serge; Gaillard, Michel; Giannakopoulos, Panteleimon; von Gunten, Armin; Csajka, Chantal; Eap, Chin B

2014-07-01

A large interindividual variability in plasma concentrations has been reported in patients treated with donepezil, the most frequently prescribed antidementia drug. We aimed to evaluate clinical and genetic factors influencing donepezil disposition in a patient population recruited from a naturalistic setting. A population pharmacokinetic study was performed including data from 129 older patients treated with donepezil. The patients were genotyped for common polymorphisms in the metabolic enzymes CYP2D6 and CYP3A, in the electron transferring protein POR and the nuclear factor NR1I2 involved in CYP activity and expression, and in the drug transporter ABCB1. The average donepezil clearance was 7.3 l h(-1) with a 30% interindividual variability. Gender markedly influenced donepezil clearance (P < 0.01). Functional alleles of CYP2D6 were identified as unique significant genetic covariate for donepezil clearance (P < 0.01), with poor metabolizers and ultrarapid metabolizers demonstrating, respectively, a 32% slower and a 67% faster donepezil elimination compared with extensive metabolizers. The pharmacokinetic parameters of donepezil were well described by the developed population model. Functional alleles of CYP2D6 significantly contributed to the variability in donepezil disposition in the patient population and should be further investigated in the context of individual dose optimization to improve clinical outcome and tolerability of the treatment. © 2014 The British Pharmacological Society.

Correlation of cholinergic drug induced quenching of acetylcholinesterase bound thioflavin-T fluorescence with their inhibition activity

NASA Astrophysics Data System (ADS)

Islam, Mullah Muhaiminul; Rohman, Mostofa Ataur; Gurung, Arun Bahadur; Bhattacharjee, Atanu; Aguan, Kripamoy; Mitra, Sivaprasad

2018-01-01

The development of new acetylcholinesterase inhibitors (AChEIs) and subsequent assay of their inhibition efficiency is considered to be a key step for AD treatment. The fluorescence intensity of thioflavin-T (ThT) bound in the active site of acetylcholinesterase (AChE) quenches substantially in presence of standard AChEI drugs due to the dynamic replacement of the fluorophore from the AChE active site as confirmed from steady state emission as well as time-resolved fluorescence anisotropy measurement and molecular dynamics simulation in conjunction with docking calculation. The parametrized % quenching data for individual system shows excellent correlation with enzyme inhibition activity measured independently by standard Ellman AChE assay method in a high throughput plate reader system. The results are encouraging towards design of a fluorescence intensity based AChE inhibition assay method and may provide a better toolset to rapidly evaluate as well as develop newer AChE-inhibitors for AD treatment.

Small molecular floribundiquinone B derived from medicinal plants inhibits acetylcholinesterase activity

PubMed Central

Jiang, Li; Qin, Rui; Su, Qiang; Chen, Fuxue; Du, Dongshu; Shu, Yilai; Chou, Kuo-Chen

2017-01-01

Being a neurodegenerative disorder, Alzheimer's disease (AD) is the one of the most terrible diseases. And acetylcholinesterase (AChE) is considered as an important target for treating AD. Acetylcholinesterase inhibitors (AChEI) are considered to be one of the effective drugs for the treatment of AD. The aim of this study is to find a novel potential AChEI as a drug for the treatment of AD. In this study, instead of using the synthetic compounds, we used those extracted from plants to investigate the interaction between floribundiquinone B (FB) and AChE by means of both the experimental approach such as fluorescence spectra, ultraviolet-visible (UV-vis) absorption spectrometry, circular dichroism (CD) and the theoretical approaches such as molecular docking. The findings reported here have provided many useful clues and hints for designing more effective and less toxic drugs against Alzheimer's disease. PMID:28915661

The Effect of the Association between Donepezil and Choline Alphoscerate on Behavioral Disturbances in Alzheimer's Disease: Interim Results of the ASCOMALVA Trial.

PubMed

Carotenuto, Anna; Rea, Raffaele; Traini, Enea; Fasanaro, Angiola Maria; Ricci, Giovanna; Manzo, Valentino; Amenta, Francesco

2017-01-01

Behavioral and psychological symptoms of dementia (BPSD) are a group of psychological reactions, psychiatric symptoms, and behaviors commonly found in Alzheimer's disease (AD). Four clusters of BPSD have been described: mood disorders (depression, anxiety, and apathy), psychotic symptoms (delusions and hallucinations), aberrant motor behaviors (pacing, wandering, and other purposeless behaviors), and inappropriate behaviors (agitation, disinhibition, and euphoria). Most of them are attributed to acetylcholine deficiency. To evaluate if a higher amount of acetylcholine obtained by associating donepezil and choline alphoscerate might have a favorable effect on BPSD. BPSD were measured at baseline and after 24 months in 113 mild/moderate AD patients, included in the double-blind randomized trial ASCOMALVA, by the Neuropsychiatric Inventory (NPI). Two matched groups were compared: group A treated with donepezil (10 mg/day) plus choline alphoscerate (1200 mg/day), and group B treated with donepezil (10 mg/day) plus placebo. Data of NPI revealed a significant decrease of BPSD severity and distress of the caregiver in patients of group A compared with group B. Mood disorders (depression, anxiety and apathy) were significantly decreased in subjects treated with donepezil and choline alphoscerate, while their severity and frequency was increased in the other group. Patients treated with donepezil plus choline alphoscerate showed a lower level of behavioral disturbances than subjects treated with donepezil only, suggesting that the association can have beneficial effects.

A New Acetylcholinesterase Inhibitor from Green Glycosylation of Trachyloban-19-oic Acid by Mucor plumbeus.

PubMed

Santos, Gabriel F Dos; Takahashi, Jacqueline A

2017-01-01

The in vitro metabolism of a widespread natural product, trachyloban-19-oic acid (1), by the fungal species Mucor plumbeus was studied in a sucrose-yeast liquid medium. Two products were isolated, and their structures were determined by spectroscopic means as 7β-hydroxytrachyloban-19-oic acid (5) and trachyloban-19-O-β-D-glucopyranosyl ester (6). To the best of our knowledge, compound 6 is herein reported by the first time in the literature. These compounds were assayed for acetylcholinesterase inhibition along with some related compounds. Compound 6 showed the highest acetylcholinesterase inhibitory activity at 10000 µg/mL among the tested compounds, a result (92.89%) comparable to the activity of the positive control, galanthamine (94.21%). Therefore, biotransformation of the natural product 1 by M. plumbeus produced a novel compound with potential as a new lead to develop anti-Alzheimer medicines.

Discorhabdin alkaloids from Antarctic Latrunculia spp. sponges as a new class of cholinesterase inhibitors.

PubMed

Botić, Tanja; Defant, Andrea; Zanini, Pietro; Žužek, Monika Cecilija; Frangež, Robert; Janussen, Dorte; Kersken, Daniel; Knez, Željko; Mancini, Ines; Sepčić, Kristina

2017-08-18

The brominated pyrroloiminoquinone alkaloids discorhabdins B, L and G and 3-dihydro-7,8- dehydrodiscorhabdin C, isolated from methanol extracts of two specimens of Latrunculia sp. sponges collected near the Antarctic Peninsula, are here demonstrated for the first time to be reversible competitive inhibitors of cholinesterases. They showed K i for electric eel acetylcholinesterase of 1.6-15.0 μM, for recombinant human acetylcholinesterase of 22.8-98.0 μM, and for horse serum butyrylcholinesterase of 5.0-76.0 μM. These values are promising when compared to the current cholinesterase inhibitors used for treatment of patients with Alzheimer's disease, to counteract the acetylcholine deficiency in the brain. Good correlation was obtained between IC 50 data and results by molecular docking calculation on the binding interactions within the acetylcholinesterase active site, which also indicated the moieties in discorhabdin structures involved. To avoid unwanted peripheral side effects that can appear in patients using some acetylcholinesterase inhibitors, electrophysiological experiments were carried out on one of the most active of these compounds, discorhabdin G, which confirmed that it had no detectable undesirable effects on neuromuscular transmission and skeletal muscle function. These findings are promising for development of cholinesterase inhibitors based on the scaffold of discorhabdins, as potential new agents for treatment of patients with Alzheimer's disease. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Cholinesterase Inhibitors Improve Both Memory and Complex Learning in Aged Beagle Dogs

PubMed Central

Araujo, Joseph A.; Greig, Nigel H.; Ingram, Donald K.; Sandin, Johan; de Rivera, Christina; Milgram, Norton W.

2016-01-01

Similar to patients with Alzheimer’s disease (AD), dogs exhibit age-dependent cognitive decline, amyloid-β (Aβ) pathology, and evidence of cholinergic hypofunction. The present study sought to further investigate the role of cholinergic hypofunction in the canine model by examining the effect of the cholinesterase inhibitors phenserine and donepezil on performance of two tasks, a delayed non-matching-to-position task (DNMP) designed to assess working memory, and an oddity discrimination learning task designed to assess complex learning, in aged dogs. Phenserine (0.5 mg/kg; PO) significantly improved performance on the DNMP at the longest delay compared to wash-out and partially attenuated scopolamine-induced deficits (15 μg/kg; SC). Phenserine also improved learning on a difficult version of an oddity discrimination task compared to placebo, but had no effect on an easier version. We also examined the effects of three doses of donepezil (0.75, 1.5, and 6 mg/kg; PO) on performance of the DNMP. Similar to the results with phenserine, 1.5 mg/kg of donepezil improved performance at the longest delay compared to baseline and wash-out, indicative of memory enhancement. These results further extend the findings of cholinergic hypofunction in aged dogs and provide pharmacological validation of the canine model with a cholinesterase inhibitor approved for use in AD. Collectively, these studies support utilizing the aged dog in future screening of therapeutics for AD, as well as for investigating the links among cholinergic function, Aβ pathology, and cognitive decline. PMID:21593569

Distinctive Effect of Donepezil Treatment on P300 and N200 Subcomponents of Auditory Event-Related Evoked Potentials in Alzheimer Disease Patients.

PubMed

Vaitkevičius, Arūnas; Kaubrys, Gintaras; Audronytė, Eglė

2015-07-03

Latency of P300 subcomponent of event-related potentials (ERPs) increases in Alzheimer disease (AD) patients, which correlate well with cognitive impairment. Cholinesterase inhibitors (ChEIs) reduce P300 latency in AD patients with parallel improvement in cognition. It is not known whether N200 response to ChEIs is similar to that of P300. The aim of this study was to evaluate and compare characteristics of P300 and N200 in AD patients, treatment-naïve and on stable donepezil treatment, matched by age, education, sex, and cognitive function. We recruited 22 consecutive treatment-naïve AD patients (AD-N group), 22 AD patients treated with a stable donepezil dose of 10 mg/day for at least 3 months (AD-T group), and 50 healthy controls were recruited. Neuropsychological testing (MMSE, ADAS-Cog, and additional tests) and ERP recording was performed and analyzed. All groups did not differ according to age, duration of education, or sex (p>0.05). AD-N and AD-T groups did not differ according to cognitive function. The AD-T group had longer duration of disease than the AD-N group (p<0.001). The AD-T and AD-N groups did not differ in P300 latencies (p=0.49). N200 latency was longer in the AD-T group (p<0.001). The general linear model showed that significant predictors of P300 latency were age (p=0.019) and AD treatment status (p<0.001). Duration of AD was a significant predictor of N200 latency (p=0.004). The response of N200 latency to donepezil treatment differs from the response of P300. P300 is a better marker of ChEI treatment-dependent cognitive functions. N200 is more dependent on the duration of AD.

Efficient method for high-throughput virtual screening based on flexible docking: discovery of novel acetylcholinesterase inhibitors.

PubMed

Mizutani, Miho Yamada; Itai, Akiko

2004-09-23

A method of easily finding ligands, with a variety of core structures, for a given target macromolecule would greatly contribute to the rapid identification of novel lead compounds for drug development. We have developed an efficient method for discovering ligand candidates from a number of flexible compounds included in databases, when the three-dimensional (3D) structure of the drug target is available. The method, named ADAM&EVE, makes use of our automated docking method ADAM, which has already been reported. Like ADAM, ADAM&EVE takes account of the flexibility of each molecule in databases, by exploring the conformational space fully and continuously. Database screening has been made much faster than with ADAM through the tuning of parameters, so that computational screening of several hundred thousand compounds is possible in a practical time. Promising ligand candidates can be selected according to various criteria based on the docking results and characteristics of compounds. Furthermore, we have developed a new tool, EVE-MAKE, for automatically preparing the additional compound data necessary for flexible docking calculation, prior to 3D database screening. Among several successful cases of lead discovery by ADAM&EVE, the finding of novel acetylcholinesterase (AChE) inhibitors is presented here. We performed a virtual screening of about 160 000 commercially available compounds against the X-ray crystallographic structure of AChE. Among 114 compounds that could be purchased and assayed, 35 molecules with various core structures showed inhibitory activities with IC(50) values less than 100 microM. Thirteen compounds had IC(50) values between 0.5 and 10 microM, and almost all their core structures are very different from those of known inhibitors. The results demonstrate the effectiveness and validity of the ADAM&EVE approach and provide a starting point for development of novel drugs to treat Alzheimer's disease.

Concentration of Donepezil in the Cerebrospinal Fluid of AD Patients: Evaluation of Dosage Sufficiency in Standard Treatment Strategy.

PubMed

Valis, Martin; Masopust, Jiri; Vysata, Oldrich; Hort, Jakub; Dolezal, Rafael; Tomek, Jiri; Misik, Jan; Kuca, Kamil; Karasova, Jana Zdarova

2017-01-01

Although some studies have described the pharmacokinetics and pharmacodynamics of donepezil in the peripheral compartment, studies focused on drug transport across the blood-brain barrier are still very rare. To our knowledge, the fluctuation in the cerebrospinal fluid concentration of donepezil after administration of the drug has not been described in the literature so far. We recruited 16 patients regularly taking a standard therapeutic dose of donepezil (10 mg per day). All patients (Caucasian race) were treated for at least three months with a stable dose of 10 mg per day prior to sample collection. Patients were divided into two groups depending on the time of plasma and cerebrospinal fluid sampling: 12 h (n = 9; 4 M/5F aged 78.68 ± 7.35 years) and 24 h (n = 7; 3 M/4F aged 77.14 ± 5.87 years) after donepezil administration. The cerebrospinal fluid sample was collected by standard lumbar puncture technique using a single-use traumatic needle. The samples were analysed on an Agilent 1260 Series liquid chromatograph comprising a degasser, a quaternary pump, a light-tight autosampler unit set, a thermostated column compartment, and a UV/VIS detector. Agilent ChemStation software, the statistical software Prism4, version 5.0 (GraphPad Software, USA), and IBM ® SPSS ® Statistics were used for the analysis of the results. The difference in plasma concentration of donepezil after 12 h (mean ± SEM; 39.99 ± 5.90 ng/ml) and after 24 h (29.38 ± 1.71 ng/ml) was nonsignificant. In contrast, the donepezil concentration in the cerebrospinal fluid was significantly higher in the 24-h interval (7.54 ± 0.55 ng/ml) compared with the 12-h interval (5.19 ± 0.83 ng/ml, which is ~70 % based on mean cerebrospinal fluid values). Based on these data, it is plausible to predict that donepezil might produce a stronger AChE inhibition in the brain at 24 h compared with 12 h following the administration. This information may help physicians

Therapeutic and prophylactic utility of the memory-enhancing drug donepezil hydrochloride on cognition of patients undergoing electroconvulsive therapy: a randomized controlled trial.

PubMed

Prakash, Jyoti; Kotwal, Atul; Prabhu, Hra

2006-09-01

Substantial progress has been made in identifying how the treatment parameters used in electroconvulsive therapy (ECT) impact its cognitive side effects. However, there is limited information regarding the role of memory enhancers in post-ECT cognitive disturbances. We evaluated the therapeutic and prophylactic efficacy of the memory-enhancing drug donepezil hydrochloride on cognition of patients undergoing ECT. A triple blind (the study subjects, clinician assessing the cognition, and the data analyst were unaware of subject allocation for trial assessment) randomized controlled trial was carried out in a General Hospital Psychiatry Unit. Subjects were randomized into 2 groups. One group received ECT with placebo, whereas the other group received ECT and donepezil (a memory-enhancing drug). Study participants were assessed in post-ECT period to analyze cognitive deficits and to compare the differences in 2 groups, as regards recovery of various aspects of cognition. The post-ECT recovery of various components of cognition was more rapid in patients using donepezil as compared to those not given donepezil (P < 0.05). This significant improvement in recovery time among patients receiving donepezil bears therapeutic implication in immediate post-ECT cognitive deficits.

Exploration of a Library of 3,4-(Methylenedioxy)aniline-Derived Semicarbazones as Dual Inhibitors of Monoamine Oxidase and Acetylcholinesterase: Design, Synthesis, and Evaluation.

PubMed

Tripathi, Rati K P; Rai, Gopal K; Ayyannan, Senthil R

2016-06-06

A library of 3,4-(methylenedioxy)aniline-derived semicarbazones was designed, synthesized, and evaluated as monoamine oxidase (MAO) and acetylcholinesterase (AChE) inhibitors for the treatment of neurodegenerative diseases. Most of the new compounds selectively inhibited MAO-B and AChE, with IC50 values in the micro- or nanomolar ranges. Compound 16, 1-(2,6-dichlorobenzylidene)-4-(benzo[1,3]dioxol-5-yl)semicarbazide presented a balanced multifunctional profile of MAO-A (IC50 =4.52±0.032 μm), MAO-B (IC50 =0.059±0.002 μm), and AChE (IC50 =0.0087±0.0002 μm) inhibition without neurotoxicity. Kinetic studies revealed that compound 16 exhibits competitive and reversible inhibition against MAO-A and MAO-B, and mixed-type inhibition against AChE. Molecular docking studies further revealed insight into the possible interactions within the enzyme-inhibitor complexes. The most active compounds were found to interact with the enzymes through hydrogen bonding and hydrophobic interactions. Additionally, in silico molecular properties and ADME properties of the synthesized compounds were calculated to explore their drug-like characteristics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Concentration-Dependent Interactions of the Organophosphates Chlorpyrifos Oxon and Methyl Paraoxon with Human Recombinant Acetylcholinesterase

PubMed Central

Kaushik, R.; Rosenfeld, Clint A.; Sultatos, L.G.

2007-01-01

For many decades it has been thought that oxygen analogs (oxons) of organophosphorus insecticides phosphylate the catalytic site of acetylcholinesterase by a mechanism that follows simple Michaelis-Menten kinetics. More recently, the interactions of at least some oxons have been shown to be far more complex, and likely involve binding of oxons to a second site on acetylcholinesterase that modulates the inhibitory capacity of other oxon molecules at the catalytic site. The current study has investigated the interactions of chlorpyrifos oxon and methyl paraoxon with human recombinant acetylcholinesterase. Both chlorpyrifos oxon and methyl paraoxon were found to have ki’s that change as a function of oxon concentration. Furthermore, 10 nM chlorpyrifos oxon resulted in a transient increase in acetylthiocholine hydrolysis, followed by inhibition. Moreover, in the presence of 100 nM chlorpyrifos oxon, acetylthiocholine was found to influence both the Kd (binding affinity) and k2 (phosphorylation constant) of this oxon. Collectively, these results demonstrate that the interactions of chlorpyrifos oxon and methyl paraoxon with acetylcholinesterase cannot be described by simple Michaelis-Menten kinetics, but instead support the hypothesis that these oxons bind to a secondary site on acetylcholinesterase, leading to activation/inhibition of the catalytic site, depending on the nature of the substrate and inhibitor. Additionally, these data raise questions regarding the adequacy of estimating risk of low levels of insecticide exposure from direct extrapolation of insecticide dose-response curves since the capacity of individual oxon molecules at low oxon levels could be greater than individual oxon molecules in vivo associated with the dose response curve. PMID:17467020

Antidepressant, anxiolytic and procognitive effects of rivastigmine and donepezil in the chronic mild stress model in rats.

PubMed

Papp, Mariusz; Gruca, Piotr; Lason-Tyburkiewicz, Magdalena; Willner, Paul

2016-04-01

The treatment of depression in old age is complicated by frequent co-morbidity with cognitive impairment. Anti-dementia drugs have some efficacy to improve cognitive performance and there is an inconsistent literature regarding the effect of such drugs on depressive symptoms. Here, we have investigated whether anti-dementia drugs would have antidepressant-like and pro-cognitive effects in a well-validated animal model of depression and cognitive impairment, chronic mild stress (CMS). Rats were subjected to CMS for a total of 8 weeks. After 2 weeks, subgroups of stressed and non-stressed animals were treated daily, for 5 weeks followed by 1 week of drug withdrawal, with vehicle, imipramine (10 mg/kg), rivastigmine (2 mg/kg), donepezil (0.3 mg/kg) or memantine (5 mg/kg). Sucrose intake was tested weekly, and animals were also tested in the elevated plus maze (at week 7) and in an object recognition task (at weeks 7 and 8). CMS decreased sucrose intake, had an anxiogenic effect in the elevated plus maze, and impaired performance in the object recognition test. Imipramine, rivastigmine and donepezil normalized performance in all three tests. Memantine had anxiolytic and pro-cognitive effects, but did not reverse CMS-induced anhedonia. The fact that all three anti-dementia drugs reversed CMS-induced cognitive impairment and that cholinesterase inhibitors, but not memantine, have antidepressant-like effects in this model suggest that different mechanisms may underlie CMS-induced anhedonia and cognitive impairment. We discuss the clinical implications of these findings.

Rivastigmine: the advantages of dual inhibition of acetylcholinesterase and butyrylcholinesterase and its role in subcortical vascular dementia and Parkinson’s disease dementia

PubMed Central

Kandiah, Nagaendran; Pai, Ming-Chyi; Senanarong, Vorapun; Looi, Irene; Ampil, Encarnita; Park, Kyung Won; Karanam, Ananda Krishna; Christopher, Stephen

2017-01-01

Several studies have demonstrated clinical benefits of sustained cholinesterase inhibition with rivastigmine in Alzheimer’s disease (AD) and Parkinson’s disease dementia (PDD). Unlike donepezil and galantamine that selectively inhibit acetylcholinesterase (AChE; EC 3.1.1.7), rivastigmine is a unique cholinesterase inhibitor with both AChE and butyrylcholinesterase (BuChE; EC 3.1.1.8) inhibitory activity. Rivastigmine is also available as transdermal patch that has been approved by the US Food and Drug Administration for the treatment of mild, moderate, and severe AD as well as mild-to-moderate PDD. In this review, we explore the role of BuChE inhibition in addition to AChE inhibition with rivastigmine in the outcomes of cognition, global function, behavioral symptoms, and activities of daily living. Additionally, we review the evidence supporting the use of dual AChE−BuChE inhibitory activity of rivastigmine as a therapeutic strategy in the treatment of neurological disorders, with a focus on the role of rivastigmine in subcortical dementias such as vascular dementia (VaD) and PDD. Toward this objective, we performed a literature search in PubMed and Ovid with limits to articles published in the English language before June 2016. The available evidence from the literature suggests that the dual inhibition of AChE and BuChE may afford additional therapeutic potential of rivastigmine in subcortical dementias (subcortical VaD and PDD) with benefits on cognition and behavioral symptoms. Rivastigmine was found to specifically benefit executive dysfunction frequently observed in subcortical dementias; however, large randomized clinical studies are warranted to support these observations. PMID:28458525

BCHE and CYP2D6 genetic variation in Alzheimer's disease patients treated with cholinesterase inhibitors.

PubMed

Chianella, Caterina; Gragnaniello, Daniela; Maisano Delser, Pierpaolo; Visentini, Maria Francesca; Sette, Elisabetta; Tola, Maria Rosaria; Barbujani, Guido; Fuselli, Silvia

2011-11-01

Cholinesterase inhibitors are commonly prescribed to patients with Alzheimer's disease (AD) to enhance cholinergic neurotransmission. Differential response to these treatments has been observed, and claims have been made that individual genetic variants may influence the pharmacokinetic and pharmacodynamic properties of these drugs. Here we assess the effects of genetic variation at two loci involved in the activity of cholinesterase inhibitors on longitudinal clinical change in AD patients being treated with donepezil, galantamine, and rivastigmine. This was an open study in which 171 Italian AD patients treated with donepezil (n = 92), galantamine (n = 33), or rivastigmine (n = 46) were enrolled. Response to treatment was quantified by grading the patient's cognitive state (Mini-Mental State Examination) and the patient's ability to perform normal daily activities (Activities of Daily Living, Instrumental Activities of Daily Living) at baseline and after 6 and 12 months of treatment. Genetic variation was comprehensively characterized and analyzed at two loci: CYP2D6, which is involved in donepezil and galantamine metabolism, and BCHE, which codes for an enzyme (butyrylcholinesterase) which is both target and metabolizer of rivastigmine. APOE (coding for apolipoprotein E), which is associated with the risk of AD and inefficacy of specific AD treatments, was genotyped to control for patient stratification. The influence of the CYP2D6 and BCHE genotype on clinical changes after 12 months was evaluated by several tests of association. After 1 year of treatment, 29, 12, and 12 of the patients receiving donepezil, galantamine, and rivastigmine, respectively, showed a cognitive decrement, while eight patients interrupted the therapy before 12 months of treatment. No significant differences between the three treatments were observed in terms of response and tolerability. Non-responders show a higher proportion of BCHE and CYP2D6 mutated alleles, but

Olfactory Deficits in MCI as Predictor of Improved Cognition on Donepezil

DTIC Science & Technology

2014-04-01

rivastigmine , and are being followed at the scheduled time-points as per the intent-to-treat principle employed in this study. The data obtained will be...the intent-to-treat principle, and in secondary analyses we will combine the data in patients who receive donepezil or galantamine or rivastigmine

Effects of harmine, an acetylcholinesterase inhibitor, on spatial learning and memory of APP/PS1 transgenic mice and scopolamine-induced memory impairment mice.

PubMed

He, Dandan; Wu, Hui; Wei, Yue; Liu, Wei; Huang, Fei; Shi, Hailian; Zhang, Beibei; Wu, Xiaojun; Wang, Changhong

2015-12-05

Harmine, a β-carboline alkaloid present in Peganum harmala with a wide spectrum of pharmacological activities, has been shown to exert strong inhibition against acetylcholinesterase in vitro. However, whether it can rescue the impaired cognition has not been elucidated yet. In current study, we examined its effects on scopolamine-induced memory impairment mice and APP/PS1 transgenic mice, one of the models for Alzheimer's disease, using Morris Water Maze test. In addition, whether harmine could penetrate blood brain barrier, interact with and inhibit acetylcholinesterase, and activate downstream signaling network was also investigated. Our results showed that harmine (20mg/kg) administered by oral gavage for 2 weeks could effectively enhance the spatial cognition of C57BL/6 mice impaired by intraperitoneal injection of scopolamine (1mg/kg). Meanwhile, long-term consumption of harmine (20mg/kg) for 10 weeks also slightly benefited the impaired memory of APP/PS1 mice. Furthermore, harmine could pass through blood brain barrier, penetrate into the brain parenchyma shortly after oral administration, and modulate the expression of Egr-1, c-Jun and c-Fos. Molecular docking assay disclosed that harmine molecule could directly dock into the catalytic active site of acetylcholinesterase, which was partially confirmed by its in vivo inhibitory activity on acetylcholinesterase. Taken together, all these results suggested that harmine could ameliorate impaired memory by enhancement of cholinergic neurotransmission via inhibiting the activity of acetylcholinesterase, which may contribute to its clinical use in the therapy of neurological diseases characterized with acetylcholinesterase deficiency. Copyright © 2015 Elsevier B.V. All rights reserved.

Lead finding for acetyl cholinesterase inhibitors from natural origin: structure activity relationship and scope.

PubMed

Mukherjee, P K; Satheeshkumar, N; Venkatesh, P; Venkatesh, M

2011-03-01

Acetylcholinesterase (AChE) inhibitors are considered as promising therapeutic agents for the treatment of several neurological disorders such as Alzheimer's disease (AD), senile dementia, ataxia and myasthenia gravis. There are only few synthetic medicines with adverse effects, available for treatment of cognitive dysfunction and memory loss associated with these diseases. A variety of plants has been reported to possess AChE inhibitory activity and so may be relevant to the treatment of neurodegenerative disorders such as AD. Hence, developing potential AChE inhibitors from botanicals is the need of the day. This review will cover some of the promising acetylcholinesterase inhibitors isolated from plants with proven in vitro and in vivo activities with concern to their structure activity relationship.

Safety and Preliminary Efficacy of the Acetylcholinesterase Inhibitor Huperzine A as a Treatment for Cocaine Use Disorder

PubMed Central

Verrico, Christopher D.; Newton, Thomas F.; Mahoney, James J.; Thompson-Lake, Daisy G. Y.

2016-01-01

Background: Cholinergic transmission is altered by drugs of abuse and contributes to psychostimulant reinforcement. In particular, acetylcholinesterase inhibitors, like huperzine A, may be effective as treatments for cocaine use disorder. Methods: The current report describes results from a double-blind, placebo-controlled study in which participants (n=14–17/group) were randomized to huperzine A (0.4 or 0.8mg) or placebo. Participants received randomized infusions of cocaine (0 and 40mg, IV) on days 1 and 9. On day 10, participants received noncontingent, randomized infusions of cocaine (0 and 20mg, IV) before making 5 choices to receive additional infusions. Results: Huperzine A was safe and well-tolerated and compared with placebo, treatment with huperzine A did not cause significant changes in any cocaine pharmacokinetic parameters (all P>.05). Time-course and peak effects analyses show that treatment with 0.4mg of huperzine A significantly attenuated cocaine-induced increases of “Any Drug Effect,” “High,” “Stimulated,” “Willing to Pay,” and “Bad Effects” (all P>.05). Conclusions: The current study represents a significant contribution to the addiction field since it serves as the first published report on the safety and potential efficacy of huperzine A as a treatment for cocaine use disorder. PMID:26364275

9-Substituted acridine derivatives as acetylcholinesterase and butyrylcholinesterase inhibitors possessing antioxidant activity for Alzheimer's disease treatment.

PubMed

Makhaeva, Galina F; Lushchekina, Sofya V; Boltneva, Natalia P; Serebryakova, Olga G; Rudakova, Elena V; Ustyugov, Alexey A; Bachurin, Sergey O; Shchepochkin, Alexander V; Chupakhin, Oleg N; Charushin, Valery N; Richardson, Rudy J

2017-11-01

We investigated the inhibitory activity of 4 groups of novel acridine derivatives against acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and carboxylesterase (CaE) using the methods of enzyme kinetics and molecular docking. Antioxidant activity of the compounds was determined using the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS + ) radical decolorization assay as their ability to scavenge free radicals. Analysis of the esterase profiles and antiradical activities of the acridine derivatives showed that 9-aryl(heteroaryl)-N-methyl-9,10-dihydroacridines have a high radical-scavenging activity but low potency as AChE and BChE inhibitors, whereas 9-aryl(heteroaryl)-N-methyl-acridinium tetrafluoroborates effectively inhibit cholinesterases but do not exhibit antiradical activity. In contrast, a group of derivatives of 9-heterocyclic amino-N-methyl-9,10-dihydroacridine has been found that combine effective inhibition of AChE and BChE with rather high radical-scavenging activity. The results of molecular docking well explain the observed features in the efficacy, selectivity, and mechanism of cholinesterase inhibition by the acridine derivatives. Thus, in a series of acridine derivatives we have found compounds possessing dual properties of effective and selective cholinesterase inhibition together with free radical scavenging, which makes promising the use of the acridine scaffold to create multifunctional drugs for the therapy of neurodegenerative diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

Rational Design and Multibiological Profiling of Novel Donepezil-Trolox Hybrids against Alzheimer's Disease, with Cholinergic, Antioxidant, Neuroprotective, and Cognition Enhancing Properties.

PubMed

Cai, Pei; Fang, Si-Qiang; Yang, Xue-Lian; Wu, Jia-Jia; Liu, Qiao-Hong; Hong, Hao; Wang, Xiao-Bing; Kong, Ling-Yi

2017-11-15

A novel series of donepezil-trolox hybrids were designed, synthesized, and evaluated as multifunctional ligands against Alzheimer's disease (AD). Biological assays showed that these derivatives possessed moderate to good inhibitory activities against acetylcholinesterase (AChE) and monoamine oxidase B (MAO-B) as well as remarkable antioxidant effects. The optimal compound 6d exhibited balanced functions with good inhibition against hAChE (IC 50 = 0.54 μM) and hMAO-B (IC 50 = 4.3 μM), significant antioxidant activity (41.33 μM IC 50 by DPPH method, 1.72 and 1.79 trolox equivalent by ABTS and ORAC methods), excellent copper chelation, and Aβ 1-42 aggregation inhibition effect. Furthermore, cellular tests indicated that 6d has very low toxicity and is capable of combating oxidative toxin (H 2 O 2 , rotenone, and oligomycin-A) induced neurotoxicity. Most importantly, oral administration of 6d demonstrated notable improvements on cognition and spatial memory against scopolamine-induced acute memory deficit as well as d-galactose (d-gal) and AlCl 3 induced chronic oxidative stress in a mouse model without acute toxicity and hepatotoxicity. In summary, both in vitro and in vivo results suggested that 6d is a valuable candidate for the development of a safe and effective anti-Alzheimer's drug.

Effect of donepezil in patients with Alzheimer's disease previously untreated or treated with memantine or nootropic agents in Germany: an observational study.

PubMed

Klinger, Tatjana; Ibach, Bernd; Schoenknecht, Peter; Kamleiter, Martin; Silver, Gabrielle; Schroeder, Johannes; Mielke, Ruediger

2005-05-01

This open-label, prospective, observational, Post-Marketing Surveillance (PMS) study assessed the efficacy and safety of donepezil in patients who had been switched from therapies currently used in Germany to treat Alzheimer's disease (AD), such as memantine and nootropics, due to insufficient efficacy or poor tolerability. A treatment-naive population was included as a comparator. Patients with AD were treated with donepezil and observed for a period of approximately 3 months. A cognitive assessment was made using the Mini-Mental State Examination (MMSE). Quality of life (QoL) was assessed by the investigators who answered the question 'How did therapy with donepezil influence the QoL of the patient and/or his family over the observation period?' and was graded using three ratings: improved/unchanged/worsened. Adverse events (AEs) were also monitored. A total of 913 patients entered the study (mean +/- SD MMSE score 18.03 +/- 5.34). Efficacy assessments were analyzed for three groups: an overall group of patients who had received any form of prior AD drug therapy (N+ group; n = 709); a subgroup of patients from the N+ group who had received prior memantine therapy only (M+ group; n = 111) and patients who were drug treatment naive (N- group; n = 204). In the evaluable population donepezil improved MMSE scores by 2.21 +/- 3.47 points on average, with similar improvements observed in all three groups. QoL was judged to be improved in at least 70% of patients, again with similar results obtained for all three groups. Donepezil was well tolerated, with 85 of 913 (9.3%) patients reporting AEs. The most common AEs were those typically seen with cholinergic therapies (i.e., diarrhoea, vomiting and nausea). In this observational PMS study, donepezil was shown to be efficacious and well tolerated in patients who were being insufficiently treated with memantine or nootropic therapy. The magnitude of response was similar to that observed in patients who were previously

Influence of sildenafil and donepezil administration on the serum redox balance in experimentally induced lower limb critical ischemia.

PubMed

Constantinescu, Mihaela Ioana; Constantinescu, Dan Petru; Andercou, Aurel; Mironiuc, Ion Aurel

2013-01-01

Chronic lower limb ischemia (CLLI) leads to endothelial cell dysfunctions and endothelial lesions. The use of substances that release nitric oxide and activate endothelial nitric oxide synthase has proved to be useful in increasing angiogenesis and arteriogenesis under critical ischemia conditions. To investigate the therapeutic effect of Sildenafil and Donepezil with a vasodilating action in experimentally induced CLLI and on serum redox homeostasis. The research was performed in 3 groups of rats (n=10 animals/group) with experimentally induced CLLI: group I - control group; group II - animals treated postoperatively with a therapeutic dose of sildenafil, and group III - animals treated postoperatively with a therapeutic dose of donepezil. Oxidative stress (OS) indicators (malondialdehyde - MDA, protein carbonyls - PC), antioxidant (AO) defense indicators (reduced glutathione - GSH and oxidized glutathione - GSSH), and ceruloplasmin (CP) were determined on days 7, 14, 21 and 30. Statistical processing was performed using the Excel application (Microsoft Office 2007), with the StatsDirect v.2.7.2 software. Changes in OS were evidenced in all groups on account of a decrease in MDA and PC. The greatest OS decrease in all groups was on day 30. AO defence changes were represented by decreased levels of GSH and GSSG in all groups, at the studied moments. Intracellular AO defense in the cytosol, nucleus and mitochondria was similar in all groups, (decreased GSH, GSSG and GSH/GSSG ratio). We found increased extracellular levels of GSH, GSSG, and CP and increased extracellular GSH/GSSG ratio at level compared to values on day 7. 1) The administration of sildenafil (group II) and donepezil (group III) has favorable effects on reducing OS in experimentally induced CLLI. 2) Sildenafil and Donepezil administration stimulates extracellular AO defense on account of CP. 3) Sildenafil and Donepezil administration influences intracellular redox homeostasis on account of the GSH

Rivastigmine in the treatment of Alzheimer’s disease: an update

PubMed Central

Onor, Maria Luisa; Trevisiol, Marianna; Aguglia, Eugenio

2007-01-01

Alzheimer’s disease is the most common form of dementia in industrialized countries. In the European Union, about 54% of dementia cases are believed to be due to Alzheimer’s disease. The condition is an age-related neurodegenerative disorder characterized by multiple cognitive deficiencies, including loss of memory, judgment, and comprehension. These manifestations are accompanied by behavioral and mood disturbances. Although no cure has yet been discovered for Alzheimer’s disease, symptomatic therapies are now widely available and offer significant relief to patients and benefits to caregivers in terms of reduced care burden. At the start of the 21st century, health technology assessments recommended three agents for the symptomatic treatment of mild to moderate Alzheimer disease: rivastigmine, donepezil, and galantamine. Rivastigmine (Exelon®, Novartis Basel—Switzerland) is a slowly reversible inhibitor of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), while donepezil (Aricept®, Pfizer, New York, USA) and galantamine (Reminyl®, Janssen, New Jersey,USA) show no functional inhibition of BuChE, and are considered AChE-selective, rapidly-reversible inhibitors. The efficacy of all three agents has been evaluated in large, double-blind, placebo-controlled clinical trials of up to 6 months’ duration. Rivastigmine treatment in mild to moderate Alzheimer’s disease improves cognition, activities of daily living, and global function. PMID:18044073

Genetic testing in combination with preventive donepezil treatment for patients with amnestic mild cognitive impairment: an exploratory economic evaluation of personalized medicine.

PubMed

Djalalov, Sandjar; Yong, Jean; Beca, Jaclyn; Black, Sandra; Saposnik, Gustavo; Musa, Zahra; Siminovitch, Katherine; Moretti, Myla; Hoch, Jeffrey S

2012-12-01

To evaluate the cost effectiveness of genetic screening for the apolipoprotein (APOE) ε4 allele in combination with preventive donepezil treatment in comparison with the standard of care for amnestic mild cognitive impairment (AMCI) patients in Canada. We performed a cost-effectiveness analysis using a Markov model with a societal perspective and a time horizon of 30 years. For each strategy, we calculated quality-adjusted life-years (QALYs), using utilities from the literature. Costs were also based on the literature and, when appropriate, Ontario sources. One-way and probabilistic sensitivity analyses were performed. Expected value of perfect information (EVPI) analysis was conducted to explore the value of future research. The base case results in our exploratory study suggest that the combination of genetic testing and preventive donepezil treatment resulted in a gain of 0.027 QALYs and an incremental cost of $1,015 (in 2009 Canadian dollars [Can$]), compared with the standard of care. The incremental cost-effectiveness ratio (ICER) for the base case was Can$38,016 per QALY. The ICER was sensitive to the effectiveness of donepezil in slowing the rate of progression to Alzheimer's disease (AD), utility in AMCI patients, and AD and donepezil treatment costs. EVPI analysis showed that additional information on these parameters would be of value. Using presently available clinical evidence, this exploratory study illustrates that genetic testing combined with preventive donepezil treatment for AMCI patients may be economically attractive. Since our results were based on a secondary post hoc analysis, our study alone is insufficient to warrant recommending APOE genotyping in AMCI patients. Future research on the effectiveness of preventive donepezil as a targeted therapy is recommended.

Concentration-dependent interactions of the organophosphates chlorpyrifos oxon and methyl paraoxon with human recombinant acetylcholinesterase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaushik, R.; Rosenfeld, Clint A.; Sultatos, L.G.

2007-06-01

For many decades it has been thought that oxygen analogs (oxons) of organophosphorus insecticides phosphorylate the catalytic site of acetylcholinesterase by a mechanism that follows simple Michaelis-Menten kinetics. More recently, the interactions of at least some oxons have been shown to be far more complex and likely involve binding of oxons to a second site on acetylcholinesterase that modulates the inhibitory capacity of other oxon molecules at the catalytic site. The current study has investigated the interactions of chlorpyrifos oxon and methyl paraoxon with human recombinant acetylcholinesterase. Both chlorpyrifos oxon and methyl paraoxon were found to have k {sub i}'smore » that change as a function of oxon concentration. Furthermore, 10 nM chlorpyrifos oxon resulted in a transient increase in acetylthiocholine hydrolysis, followed by inhibition. Moreover, in the presence of 100 nM chlorpyrifos oxon, acetylthiocholine was found to influence both the K {sub d} (binding affinity) and k {sub 2} (phosphorylation constant) of this oxon. Collectively, these results demonstrate that the interactions of chlorpyrifos oxon and methyl paraoxon with acetylcholinesterase cannot be described by simple Michaelis-Menten kinetics but instead support the hypothesis that these oxons bind to a secondary site on acetylcholinesterase, leading to activation/inhibition of the catalytic site, depending on the nature of the substrate and inhibitor. Additionally, these data raise questions regarding the adequacy of estimating risk of low levels of insecticide exposure from direct extrapolation of insecticide dose-response curves since the capacity of individual oxon molecules at low oxon levels could be greater than individual oxon molecules in vivo associated with the dose-response curve.« less

Acetylcholinesterase of the sand fly, Phlebotomus papatasi (Scopoli): cDNA sequence, baculovirus expression, and biochemical properties

PubMed Central

2013-01-01

L. longipalpis. Recombinant P. papatasi AChE1 was expressed in the baculovirus system and characterized as an insect acetylcholinesterase with substrate preference for acetylthiocholine and inhibition at high substrate concentration. Enzyme activity was strongly inhibited by eserine, BW284c51, malaoxon, and paraoxon, and was insensitive to the butyrylcholinesterase inhibitors ethopropazine and iso-OMPA. Conclusions Results presented here enable the screening and identification of PpAChE mutations resulting in the genotype for insensitive PpAChE. Use of the recombinant P. papatasi AChE1 will facilitate rapid in vitro screening to identify novel PpAChE inhibitors, and comparative studies on biochemical kinetics of inhibition. PMID:23379291

Graphene quantum dots for ultrasensitive detection of acetylcholinesterase and its inhibitors

NASA Astrophysics Data System (ADS)

Li, Nan; Wang, Xuewan; Chen, Jie; Sun, Lei; Chen, Peng

2015-09-01

Graphene quantum dots (GQDs) are emerging zero-dimensional materials promising a wide spectrum of novel applications including development of optical sensors. Herein, a GQD-based fluorometric sensor is devised to detect acetylcholinesterase (AChE, a critical enzyme in central nervous system and neuromuscular junctions) with an ultralow detection limit (0.58 pM with S/N of 5.0), using a photoluminescence ‘turn-off’ mechanism. This simple ‘mix-and-detect’ platform can also be employed to sense a variety of compounds that can directly or indirectly inhibit the enzymatic activities of AChE, such as nerve gases, pesticides, and therapeutic drugs. As the proof-of-concept demonstrations, we show the sensitive detection of paraoxon (a pesticide), tacrine (a drug to treat Alzheimer’s disease), and dopamine (an important neurotransmitter).

An observational clinical study of the efficacy and tolerability of donepezil in the treatment of Alzheimer's disease.

PubMed

Hager, Klaus; Calabrese, Pasquale; Frölich, Lutz; Göbel, Claus; Berger, Frank M

2003-01-01

An open-label, observational Post-Marketing Surveillance (PMS) study was undertaken in Germany to examine the efficacy and tolerability of donepezil in routine clinical practice. Alzheimer's disease (AD) patients were treated with donepezil (5 or 10 mg once daily) and observed for a period of approximately 3 months. Study assessments included the Mini-Mental State Examination (MMSE), the Nurses' Observation Scale for Geriatric Patients (NOSGER), and adverse events (AEs). A total of 2,092 patients (mean age 73.0 years; mean +/- SD MMSE score 17.8 +/- 5.8) were included in the efficacy assessments. MMSE and NOSGER scores showed statistically significant improvements in the total patient population and in the subpopulations with severe AD or AD with concomitant Parkinsonian symptoms (ADPS cohort). AEs were reported in a total of 12% of patients and were mostly due to peripheral cholinergic effects. In this observational PMS study, donepezil was shown to be an effective and well-tolerated therapy in the overall patient population, in patients with severe AD, and in the ADPS cohort. Copyright 2003 S. Karger AG, Basel

High dose rivastigmine in the symptom management of Lewy body dementia.

PubMed

Nour, Joseph Marwan; Chouliaras, Leonidas; Hickey, Lilian

2016-11-29

A man presented in late 2004 at the age of 65 with a decline in memory. He was diagnosed with Lewy body dementia and started on 3 mg rivastigmine a day, which made a marked clinical improvement. He lived with the illness for 10 years, over which time the dose of acetylcholinesterase inhibitors (ChEI) he took rose to two 9.5 mg rivastigmine patches and 7.5 mg donepezil, significantly above British National Formulary (BNF) limits. He demonstrated clear clinical response to ChEI and showed improvements in alertness and functioning. He did not exhibit life-threatening cardiac side effects and his death in 2014 was not related to the ChEI. 2016 BMJ Publishing Group Ltd.

Maintenance Treatment of Depression in Old Age: A Randomized, Double-blind, Placebo-Controlled Evaluation of the Efficacy and Safety of Donepezil Combined with Antidepressant Pharmacotherapy

PubMed Central

Reynolds, Charles F.; Butters, Meryl A.; Lopez, Oscar; Pollock, Bruce G.; Dew, Mary Amanda; Mulsant, Benoit H.; Lenze, Eric J.; Holm, Margo; Rogers, Joan C.; Mazumdar, Sati; Houck, Patricia R.; Begley, Amy; Anderson, Stewart; Karp, Jordan F.; Miller, Mark D.; Whyte, Ellen M.; Stack, Jacqueline; Gildengers, Ariel; Szanto, Katalin; Bensasi, Salem; Kaufer, Daniel I.; Kamboh, M. Ilyas; DeKosky, Steven T.

2010-01-01

Context Cognitive impairment in late-life depression is a core feature of the illness. Objective to test whether donepezil + antidepressant is superior to placebo + antidepressant in (1) improving cognitive performance and instrumental activities of daily living and (2) reducing recurrences of depression over two years of maintenance treatment. Design Randomized, double-blind, placebo controlled maintenance trial. Setting university clinic Main Outcome Measures global neuropsychological performance, cognitive instrumental ADL, and recurrent depression. Results Donepezil + antidepressant temporarily improved global cognition (treatment by time interaction F = 3.78, df = 2, 126, p = .03), but effect sizes were small (Cohen’s d = 0.27: group difference at 1 year). A marginal benefit to cognitive instrumental ADL was also observed (treatment by time interaction; F = 2.94; df = 2, 137, p = 0.06). The donepezil group was more likely to experience recurrent major depression: 35% [95% CI: 24%, 46%] versus 19% [95% CI: 9%, 29%] (log rank chi squared = 3.97, p = .05); hazard ratio = 2.09 [95% CI: 1.00, 4.41]. Post-hoc subgroup analyses showed that, of 57 participants with mild cognitive impairment, 3/30 on donepezil (10%; 95% CI: 0, 21%) and 9/27 on placebo (33%; 95% CI: 16%, 51%) converted to dementia over two years (Fisher exact p = 0.05). The MCI subgroup had a 44 percent recurrence rate of major depression on donepezil verses 12% on placebo (LR=4.91, p=.03). The subgroup with normal cognition (n = 73) showed no benefit on donepezil or increase in recurrence of major depression. Conclusion Whether ChEI should be used as augmentation in the maintenance treatment of late-life depression depends upon a careful weighing of risks and benefits in those with MCI. In cognitively intact patients, donepezil appears to have no clear benefit for preventing progression to MCI/dementia or recurrence of depression. PMID:21199965

Cholinesterase inhibitors for patients with Alzheimer's disease: systematic review of randomised clinical trials

PubMed Central

Kaduszkiewicz, Hanna; Zimmermann, Thomas; Beck-Bornholdt, Hans-Peter; van den Bussche, Hendrik

2005-01-01

Objectives Pharmacological treatment of Alzheimer's disease focuses on correcting the cholinergic deficiency in the central nervous system with cholinesterase inhibitors. Three cholinesterase inhibitors are currently recommended: donepezil, rivastigmine, and galantamine. This review assessed the scientific evidence for the recommendation of these agents. Data sources The terms “donepezil”, “rivastigmine”, and “galantamine”, limited by “randomized-controlled-trials” were searched in Medline (1989-November 2004), Embase (1989-November 2004), and the Cochrane Database of Systematic Reviews without restriction for language. Study selection All published, double blind, randomised controlled trials examining efficacy on the basis of clinical outcomes, in which treatment with donepezil, rivastigmine, or galantamine was compared with placebo in patients with Alzheimer's disease, were included. Each study was assessed independently, following a predefined checklist of criteria of methodological quality. Results 22 trials met the inclusion criteria. Follow-up ranged from six weeks to three years. 12 of 14 studies measuring the cognitive outcome by means of the 70 point Alzheimer's disease assessment scale—cognitive subscale showed differences ranging from 1.5 points to 3.9 points in favour of the respective cholinesterase inhibitors. Benefits were also reported from all 12 trials that used the clinician's interview based impression of change scale with input from caregivers. Methodological assessment of all studies found considerable flaws—for example, multiple testing without correction for multiplicity or exclusion of patients after randomisation. Conclusion Because of flawed methods and small clinical benefits, the scientific basis for recommendations of cholinesterase inhibitors for the treatment of Alzheimer's disease is questionable. PMID:16081444

Effects of novel tacrine-related cholinesterase inhibitors in the reversal of 3-quinuclidinyl benzilate-induced cognitive deficit in rats--Is there a potential for Alzheimer's disease treatment?

PubMed

Misik, Jan; Korabecny, Jan; Nepovimova, Eugenie; Kracmarova, Alzbeta; Kassa, Jiri

2016-01-26

Inhibitors of cholinesterase are important drugs for therapy of Alzheimer's disease and the search for new modifications is extensive, including dual inhibitors or multi-target hybrid compounds. The aim of the present study was a preliminary evaluation of pro-cognitive effects of newly-developed 7-MEOTA-donepezil like hybrids (compounds no. 1 and 2) and N-alkylated tacrine derivatives (compounds no. 3 and 4) using an animal model of pharmacologically-induced cognitive deficit. Male Wistar rats were subjected to tests of learning and memory in a water maze and step-through passive avoidance task. Cognitive impairment was induced by 3-quinuclidinyl benzilate (QNB, 2mgkg(-1)), administered intraperitoneally 1h before training sessions. Cholinesterase inhibitors were administered as a single therapeutic dose following the QNB at 30min at the following dose rates; 1 (25.6mgkg(-1)), 2 (12.3mgkg(-1)), 3 (5.7mgkg(-1)), 4 (5.2mgkg(-1)). The decrease in total path within the 10-swim session (water maze), the preference for target quadrant (water maze) and the entrance latency (passive avoidance) were taken as indicators of learning ability in rats. The effects of novel compounds were compared to that of standards tacrine (5.2mgkg(-1)) and donepezil (2.65mgkg(-1)). QNB significantly impaired spatial navigation as well as fear learning. Generally, the performance of rats was improved when treated with novel inhibitors and this effect reached efficiency of standard donepezil at selected doses. There was a significant improvement in the groups treated with compounds 2 and 3 in all behavioral tasks. The rest of the novel compounds succeed in the passive avoidance test. In summary, the potential of novel inhibitors (especially compounds 2 and 3) was proved and further detailed evaluation of these compounds as potential drugs for Alzheimer's disease treatment is proposed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

An evaluation of the inhibition of human butyrylcholinesterase and acetylcholinesterase by the organophosphate chlorpyrifos oxon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shenouda, Josephine; Green, Paula; Sultatos, Lester, E-mail: sultatle@umdnj.ed

2009-12-01

Acetylcholinesterase (EC 3.1.1.7) and butyrylcholinesterase (EC 3.1.1.8) are enzymes that belong to the superfamily of alpha/beta-hydrolase fold proteins. While they share many characteristics, they also possess many important differences. For example, whereas they have about 54% amino acid sequence identity, the active site gorge of acetylcholinesterase is considerably smaller than that of butyrylcholinesterase. Moreover, both have been shown to display simple and complex kinetic mechanisms, depending on the particular substrate examined, the substrate concentration, and incubation conditions. In the current study, incubation of butyrylthiocholine in a concentration range of 0.005-3.0 mM, with 317 pM human butyrylcholinesterase in vitro, resulted inmore » rates of production of thiocholine that were accurately described by simple Michaelis-Menten kinetics, with a K{sub m} of 0.10 mM. Similarly, the inhibition of butyrylcholinesterase in vitro by the organophosphate chlorpyrifos oxon was described by simple Michaelis-Menten kinetics, with a k{sub i} of 3048 nM{sup -1} h{sup -1}, and a K{sub D} of 2.02 nM. In contrast to inhibition of butyrylcholinesterase, inhibition of human acetylcholinesterase by chlorpyrifos oxon in vitro followed concentration-dependent inhibition kinetics, with the k{sub i} increasing as the inhibitor concentration decreased. Chlorpyrifos oxon concentrations of 10 and 0.3 nM gave k{sub i}s of 1.2 and 19.3 nM{sup -1} h{sup -1}, respectively. Although the mechanism of concentration-dependent inhibition kinetics is not known, the much smaller, more restrictive active site gorge of acetylcholinesterase almost certainly plays a role. Similarly, the much larger active site gorge of butyrylcholinesterase likely contributes to its much greater reactivity towards chlorpyrifos oxon, compared to acetylcholinesterase.« less

Acetylcholinesterase inhibition starting from extracts of Bauhinia variegata L., Bauhinia var. candida (Aiton) Buch.-Ham., and Bauhinia ungulata L.

PubMed

Santos, Kamilla Monteiro dos; Gonçalves, Priscila Sant'Ana; Paiva, Maria José Nunes de; Lacerda, Guilherme Araújo

2011-01-01

A treatment to the Alzheimer's disease consists inhibition of the acetylcholinesterase, which is responsible for the acetylcholine control in the synapses. We have investigated the potential of inhibition of the acetylcholinesterase produced by hexane extracts of leaves, branches, and flowers from three Bauhinia specimens, which is based on the technique of thin layer chromatography and on identifying the organ of the plant that possesses larger concentration of inhibitors. Retention factor analysis shows values of 0.31aA, 0.31aA, and 0.46aB for flowers B. variegata, B. var. candida, and B. ungulata, respectively. The flower extract of B. ungulata is the most suitable for further studies on this inhibition.

Design, facile synthesis, and evaluation of novel spiro- and pyrazolo[1,5-c]quinazolines as cholinesterase inhibitors: Molecular docking and MM/GBSA studies.

PubMed

Gálvez, Jaime; Polo, Stivens; Insuasty, Braulio; Gutiérrez, Margarita; Cáceres, Daniela; Alzate-Morales, Jans H; De-la-Torre, Pedro; Quiroga, Jairo

2018-03-07

Given the wide spectrum of biological uses of pyrazolo[1,5-c]quinazoline and spiro-quinazoline derivatives as anticancer, anti-inflammatory analgesic agents, and their therapeutic applications in neurodegenerative disorders, it is compulsory to find easy, efficient, and simple methods to obtain and chemically diversify these families of compounds, thereby improving their biological applications. In this paper, we report the design and eco-friendly two-step synthesis of novel, fused spiro-pyrazolo[1,5-c]quinazoline derivatives as cholinesterase inhibitors. In addition, we studied their protein-ligand interactions via molecular docking and MM/GBSA calculations for a further rational design of more potent inhibitors. In first step, 2-(1H-pyrazol-5-yl)anilines were obtained through microwave (MW) assisted solvent-free/catalyst-free conditions and the second step involved the synthesis of the spiro-pyrazolo[1,5-c]quinazolines by a cyclocondensation reaction between 2-(1H-pyrazol-5-yl)anilines and cyclic ketones, or acetophenones, using stirring at room temperature. The compounds were obtained in high purity, good yields (50-97%), and at varying reaction times. The spiro-compounds were evaluated as acetylcholinesterase and butyrylcholinesterase inhibitors (AChEIs/BuChEIs) respectively, and the most potent compound exhibited a moderate AChE inhibitory activity (5f: IC 50  = 84 μM). Molecular docking studies indicated that the binding mode of the compound 5f share common characteristics with the galantamine/donepezil-AChE complexes. Moreover, free binding energy (ΔG) calculations showed a good agreement with the experimental biological activity values. Our theoretical results indicated that halogen bond interactions could be involved with differential potency of these compounds and provide a new starting point to design novel pyrazolo[1,5-c]quinazolines as new anti-Alzheimer agents. Copyright © 2018. Published by Elsevier Ltd.

Rivastigmine reverses cognitive deficit and acetylcholinesterase activity induced by ketamine in an animal model of schizophrenia.

PubMed

Zugno, Alexandra I; Julião, Ricardo Filipe; Budni, Josiane; Volpato, Ana Maria; Fraga, Daiane B; Pacheco, Felipe D; Deroza, Pedro F; Luca, Renata D; de Oliveira, Mariana B; Heylmann, Alexandra S; Quevedo, João

2013-09-01

Schizophrenia is one of the most disabling mental disorders that affects up to 1 % of the population worldwide. Although the causes of this disorder remain unknown, it has been extensively characterized by a broad range of emotional, ideational and cognitive impairments. Studies indicate that schizophrenia affects neurotransmitters such as dopamine, glutamate and acetylcholine. Recent studies suggest that rivastigmine (an acetylcholinesterase inhibitor) is important to improve the cognitive symptoms of schizophrenia. Therefore, the present study evaluated the protective effect of rivastigmine against the ketamine-induced behavioral (hyperlocomotion and cognitive deficit) and biochemical (increase of acetylcholinesterase activity) changes which characterize an animal model of schizophrenia in rats. Our results indicated that rivastigmine was effective to improve the cognitive deficit in different task (immediate memory, long term memory and short term memory) induced by ketamine in rats. Moreover, we observed that rivastigmina reversed the increase of acetylcholinesterase activity induced by ketamine in the cerebral cortex, hippocampus and striatum. However, rivastigmine was not able to prevent the ketamine-induced hyperlocomotion. In conslusion, ours results indicate that cholinergic system might be an important therapeutic target in the physiopathology of schizophrenia, mainly in the cognition, but additional studies should be carried.

Acetylcholinesterases of Rhipicephalus (Boophilus) microplus – Multiple gene expression presents an opportune model system for elucidation of multiple functions of AChEs.

USDA-ARS?s Scientific Manuscript database

Acetylcholinesterase (AChE) is a key neural enzyme of both vertebrates and invertebrates, and is the biochemical target of organophosphate and carbamate pesticides for invertebrates, as well as vertebrate nerve agents, e.g., soman, tabun, VX, and others. AChE inhibitors are also key drugs among thos...

Design of multi-target compounds as AChE, BACE1, and amyloid-β(1-42) oligomerization inhibitors: in silico and in vitro studies.

PubMed

Hernández-Rodríguez, Maricarmen; Correa-Basurto, José; Martínez-Ramos, Federico; Padilla-Martínez, Itzia Irene; Benítez-Cardoza, Claudia G; Mera-Jiménez, Elvia; Rosales-Hernández, Martha Cecilia

2014-01-01

Despite great efforts to develop new therapeutic strategies against Alzheimer's disease (AD), the acetylcholinesterase inhibitors (AChEIs): donepezil, rivastigmine, and galantamine, have been used only as a palliative therapeutic approach. However, the pathogenesis of AD includes several factors such as cholinergic hypothesis, amyloid-β (Aβ) aggregation, and oxidative stress. For this reason, the design of compounds that target the genesis and progression of AD could offer a therapeutic benefit. We have designed a set of compounds (M-1 to M-5) with pharmacophore moieties to inhibit the release, aggregation, or toxicity of Aβ, act as AChEIs and have antioxidant properties. Once the compounds were designed, we analyzed their physicochemical parameters and performed docking studies to determine their affinity values for AChE, β-site amyloid-protein precursor cleaving enzyme 1 (BACE1), and the Aβ monomer. The best ligands, M-1 and M-4, were then synthesized, chemically characterized, and evaluated in vitro. The in vitro studies showed that these compounds inhibit AChE (M-1 Ki = 0.12 and M-4 Ki = 0.17 μM) and BACE1 (M-1 IC50 = 15.1 and M-4 IC50 = 15.4 nM). They also inhibit Aβ oligomerization and exhibit antioxidant activity. In addition, these compounds showed low cytotoxicity in microglial cells. For these reasons, they are promising for future use as drugs in AD mice transgenic models.

Inhibitory effects of isatin Mannich bases on carbonic anhydrases, acetylcholinesterase, and butyrylcholinesterase.

PubMed

Ozgun, Dilan Ozmen; Yamali, Cem; Gul, Halise Inci; Taslimi, Parham; Gulcin, Ilhami; Yanik, Telat; Supuran, Claudiu T

2016-12-01

The effects of isatin Mannich bases incorporating (1-[piperidin-1-yl (P1)/morpholin-4-yl (P2)/N-methylpiperazin-1-yl (P3)]methyl)-1H-indole-2,3-dione) moieties against human (h) carbonic anhydrase (CA, EC 4.2.1.1) isoenzymes hCA I and hCA II, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) enzymes were evaluated. P1-P3 demonstrated impressive inhibition profiles against AChE and BChE and also inhibited both CAs at nanomolar level. These inhibitory effects were more powerful in all cases than the reference compounds used for all these enzymes. This study suggests that isatin Mannich bases P1-P3 are good candidate compounds especially for the development of new cholinesterase inhibitors since they were 2.2-5.9 times better inhibitors than clinically used drug Tacrine.

Protective effects of NMDA receptor antagonist, memantine, against senescence of PC12 cells: A possible role of nNOS and combined effects with donepezil.

PubMed

Ota, Hidetaka; Ogawa, Sumito; Ouchi, Yasuyoshi; Akishita, Masahiro

2015-12-01

Alzheimer disease (AD) is a neurodegenerative disorder characterized by cognitive dysfunction. The pathology of AD is mainly related to amyloid ß (Aß)-peptides, but glutamate-mediated toxicity is also one of the main processes of memory impairment in AD. Glutamate is the main excitatory neurotransmitter in the central nervous system (CNS) and is particularly involved in synaptic plasticity, memory, and learning. Memantine is a low-affinity voltage-dependent noncompetitive antagonist at glutamatergic NMDA receptors. Here,we investigated whether memantine protects against glutamate-induced senescence. In PC12 cells, treatment with glutamate induced senescent phenotypes as judged by the cell appearance and senescence-associated ß-galactosidase (SA-ßgal) in parallel with decreased SIRT1 and increased p53 expression. However, treatment with memantine decreased glutamate-induced senescent PC12 cells and reversed the changes in SIRT1 and p53 expression. Glutamate is known to stimulate the production of NO and O2(-) and has the capacity to generate ONOO(-) in the CNS. Therefore, we investigated whether glutamate activates nNOS and memantine reverses it. Treatment with glutamate increased nNOS expression, activity, and production of NO,whereas memantine blocked them. Next, the in vivo effects of memantine on cognitive function in senescence-accelerated mouse prone 8 (SAMP8), as a model of AD, were investigated. In the Morris water maze test, SAMP8 showed a marked decline in performance, but memantine administration improved it. Moreover, neuronal senescence and the level of oxidative stress in the hippocampus were decreased by memantine. Finally, the effects of combination treatment with memantine and donepezil, a cholinesterase inhibitor, were investigated. We observed additive effects of memantine and donepezil on the senescent phenotype of PC12 cells and the hippocampus of SAMP8. These results indicate that inhibition of the NMDA receptor by memantine leads to a

A DKP Cyclo(L-Phe-L-Phe) Found in Chicken Essence Is a Dual Inhibitor of the Serotonin Transporter and Acetylcholinesterase

PubMed Central

Tsuruoka, Nobuo; Beppu, Yoshinori; Koda, Hirofumi; Doe, Nobutaka; Watanabe, Hiroshi; Abe, Keiichi

2012-01-01

Diketopiperazines (DKPs) are naturally-occurring cyclic dipeptides with a small structure and are found in many organisms and in large amounts in some foods and beverages. We found that a chicken essence beverage, which is popular among Southeast Asians as a traditional remedy and a rich source of DKPs, inhibited the serotonin transporter (SERT) and suppressed serotonin uptake from rat brain synaptosomes, which prompted us to isolate and identify the active substance(s). We purified a SERT inhibitor from the chicken essence beverage and identified it as the DKP cyclo(L-Phe-L-Phe). Interestingly, it was a naturally occurring dual inhibitor that inhibited both SERT and acetylcholinesterase (AChE) in vitro. The DKP increased extracellular levels of the cerebral monoamines serotonin, norepinephrine, and dopamine in the medial prefrontal cortex and acetylcholine in the ventral hippocampus of freely moving rats when administered orally. Moreover, cyclo(L-Phe-L-Phe) significantly shortened escape latency in the water maze test in depressed mice previously subjected to a repeated open-space swimming task, which induces a depression-like state. Cyclo(L-Phe-L-Phe) also significantly improved accuracy rates in a radial maze test in rats and increased step-through latencies in a passive avoidance test in mice with scopolamine-induced amnesia. These animal test results suggest that cyclo(L-Phe-L-Phe), which is present abundantly in some foods such as chicken essence, may abrogate the onset of depression and, thus, contribute to preventing the development of Alzheimer’s disease and other dementia, because senile depression is a risk factor for dementia. PMID:23209830

Neuroprotective effects of Danggui-Jakyak-San on rat stroke model through antioxidant/antiapoptotic pathway.

PubMed

Kim, Sang-Ho; Chung, Dae-Kyoo; Lee, Young Joon; Song, Chang-Hyun; Ku, Sae-Kwang

2016-07-21

Dangui-Jakyak-San (DJ) is a traditional Korean medicinal polyherb, prescribed typically in patients with insufficient blood supply in Eastern Asia. The DJ also has been reported to have neuroprotective effects in vitro and in vivo studies. The therapeutic potential of DJ was examined in stroke rat model, in comparison with donepezil, a reversible acetylcholinesterase inhibitor. Ischemic stroke rat model was induced by surgery of permanent occlusion of middle cerebral artery (pMCAO). The model was orally administered with distilled water (pMCAO control), donepezil at 10mg/kg (Donepezil) and DJ at 200, 100 and 50mg/kg (DJ 200, DJ 100 and DJ 50, respectively). Sham had the same surgery excepting for the pMCAO, and it was administered with distilled water (sham control). After the administration for 28 days, the groups of DJ exhibited dose-dependent reduction in infarct/defect volumes with improvement in sensorimotor and cognitive motor function, comparing to pMCAO control. The DJ treatments seemed to enhance antiapoptotic and antioxidant effects; increases in antiapoptotic expressions (STAT3 and Pim-1) and decreases in lipid peroxidation (MDA) together with increases in contents of endogenous antioxidant (GSH) and activities of antioxidant enzymes (catalase and SOD). The histopathological analyses revealed significant reduction in neuronal apoptosis (caspase-3 and PARP) and neuronal degradation with atrophy and degeneration, in the DJ treatments. Furthermore, the oxidative stresses (nitrotyrosine as an iNOS factor and 4-HNE as a marker of lipid peroxidation) were observed mild. Although the similar neuroprotective effects were observed, the body weight loss was scarcely alleviated in Donepezil comparing to pMCAO control. These suggest that DJ ameliorate the neurological dysfunction of cerebral ischemia through augmentation of antioxidant defense system and up-regulation of STAT3 and Pim-1. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Auditory training changes temporal lobe connectivity in 'Wernicke's aphasia': a randomised trial.

PubMed

Woodhead, Zoe Vj; Crinion, Jennifer; Teki, Sundeep; Penny, Will; Price, Cathy J; Leff, Alexander P

2017-07-01

Aphasia is one of the most disabling sequelae after stroke, occurring in 25%-40% of stroke survivors. However, there remains a lack of good evidence for the efficacy or mechanisms of speech comprehension rehabilitation. This within-subjects trial tested two concurrent interventions in 20 patients with chronic aphasia with speech comprehension impairment following left hemisphere stroke: (1) phonological training using 'Earobics' software and (2) a pharmacological intervention using donepezil, an acetylcholinesterase inhibitor. Donepezil was tested in a double-blind, placebo-controlled, cross-over design using block randomisation with bias minimisation. The primary outcome measure was speech comprehension score on the comprehensive aphasia test. Magnetoencephalography (MEG) with an established index of auditory perception, the mismatch negativity response, tested whether the therapies altered effective connectivity at the lower (primary) or higher (secondary) level of the auditory network. Phonological training improved speech comprehension abilities and was particularly effective for patients with severe deficits. No major adverse effects of donepezil were observed, but it had an unpredicted negative effect on speech comprehension. The MEG analysis demonstrated that phonological training increased synaptic gain in the left superior temporal gyrus (STG). Patients with more severe speech comprehension impairments also showed strengthening of bidirectional connections between the left and right STG. Phonological training resulted in a small but significant improvement in speech comprehension, whereas donepezil had a negative effect. The connectivity results indicated that training reshaped higher order phonological representations in the left STG and (in more severe patients) induced stronger interhemispheric transfer of information between higher levels of auditory cortex.Clinical trial registrationThis trial was registered with EudraCT (2005-004215-30, https

Donepezil is associated with decreased in-hospital mortality as a result of pneumonia among older patients with dementia: A retrospective cohort study.

PubMed

Abe, Yasuko; Shimokado, Kentaro; Fushimi, Kiyohide

2018-02-01

Pneumonia is one of the major causes of mortality in older adults. As the average lifespan has extended and new modalities to prevent or treat pneumonia are developed, the factors that affect the length of hospital stay (LHS) and in-hospital mortality of older patients with pneumonia have changed. The object of the present study was to determine the factors associated with LHS and mortality as a result of pneumonia among older patients with dementia. With a retrospective cohort study design, we used the data derived from the Japanese Administrative Database and diagnosis procedure combination/per diem payment system (DPC/PDPS) database. There were 39 336 admissions of older patients for pneumonia between August 2010 and March 2012. Patients with incomplete data were excluded, leaving 25 602 patients for analysis. Having dementia decreased mortality (OR 0.71, P < 0.001) and increased LHS. Multiple logistic regression analysis identified donepezil as an independent factor that decreased mortality in patients with dementia (OR 0.36, P < 0.001). Donepezil was prescribed for 28.7% of these patients, and their mortality rate was significantly lower than those of patients with dementia who were not treated with donepezil and of patients without dementia. The mortality rate was higher for patients with dementia who were not treated with donepezil compared with patients who did not have dementia. All other factors that influenced LHS and mortality were similar to those reported by others. Donepezil seems to decrease in-hospital mortality as a result of pneumonia among older patients with dementia. Geriatr Gerontol Int 2018; 18: 269-275. © 2017 Japan Geriatrics Society.

Altered binding of thioflavin t to the peripheral anionic site of acetylcholinesterase after phosphorylation of the active site by chlorpyrifos oxon or dichlorvos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sultatos, L.G.; Kaushik, R.

2008-08-01

The peripheral anionic site of acetylcholinesterase, when occupied by a ligand, is known to modulate reaction rates at the active site of this important enzyme. The current report utilized the peripheral anionic site specific fluorogenic probe thioflavin t to determine if the organophosphates chlorpyrifos oxon and dichlorvos bind to the peripheral anionic site of human recombinant acetylcholinesterase, since certain organophosphates display concentration-dependent kinetics when inhibiting this enzyme. Incubation of 3 nM acetylcholinesterase active sites with 50 nM or 2000 nM inhibitor altered both the B{sub max} and K{sub d} for thioflavin t binding to the peripheral anionic site. However, thesemore » changes resulted from phosphorylation of Ser203 since increasing either inhibitor from 50 nM to 2000 nM did not alter further thioflavin t binding kinetics. Moreover, the organophosphate-induced decrease in B{sub max} did not represent an actual reduction in binding sites, but instead likely resulted from conformational interactions between the acylation and peripheral anionic sites that led to a decrease in the rigidity of bound thioflavin t. A drop in fluorescence quantum yield, leading to an apparent decrease in B{sub max}, would accompany the decreased rigidity of bound thioflavin t molecules. The organophosphate-induced alterations in K{sub d} represented changes in binding affinity of thioflavin t, with diethylphosphorylation of Ser203 increasing K{sub d}, and dimethylphosphorylation of Ser203 decreasing K{sub d}. These results indicate that chlorpyrifos oxon and dichlorvos do not bind directly to the peripheral anionic site of acetylcholinesterase, but can affect binding to that site through phosphorylation of Ser203.« less

Synergistic Increase of Serum BDNF in Alzheimer Patients Treated with Cerebrolysin and Donepezil: Association with Cognitive Improvement in ApoE4 Cases

PubMed Central

Alvarez, Irene; Iglesias, Olalla; Crespo, Ignacio; Figueroa, Jesus; Aleixandre, Manuel; Linares, Carlos; Granizo, Elias; Garcia-Fantini, Manuel; Marey, Jose; Masliah, Eliezer; Winter, Stefan; Muresanu, Dafin; Moessler, Herbert

2016-01-01

Background: Low circulating brain derived neurotrophic factor may promote cognitive deterioration, but the effects of neurotrophic and combination drug therapies on serum brain derived neurotrophic factor were not previously investigated in Alzheimer’s disease. Methods: We evaluated the effects of Cerebrolysin, donepezil, and the combined therapy on brain derived neurotrophic factor serum levels at week 16 (end of Cerebrolysin treatment) and week 28 (endpoint) in mild-to-moderate Alzheimer’s disease patients. Results: Cerebrolysin, but not donepezil, increased serum brain derived neurotrophic factor at week 16, while the combination therapy enhanced it at both week 16 and study endpoint. Brain derived neurotrophic factor responses were significantly higher in the combination therapy group than in donepezil and Cerebrolysin groups at week 16 and week 28, respectively. Brain derived neurotrophic factor increases were greater in apolipoprotein E epsilon-4 allele carriers, and higher brain derived neurotrophic factor levels were associated with better cognitive improvements in apolipoprotein E epsilon-4 allele patients treated with Cerebrolysin and the combined therapy. Conclusion: Our results indicate a synergistic action of Cerebrolysin and donepezil to increase serum brain derived neurotrophic factor and delaying cognitive decline, particularly in Alzheimer’s disease cases with apolipoprotein E epsilon-4 allele. PMID:27207906

A novel once-daily fixed-dose combination of memantine extended release and donepezil for the treatment of moderate to severe Alzheimer's disease: two phase I studies in healthy volunteers.

PubMed

Boinpally, Ramesh; Chen, Laishun; Zukin, Stephen R; McClure, Natalie; Hofbauer, Robert K; Periclou, Antonia

2015-07-01

Combining two standard-of-care medications for Alzheimer's disease (AD) into a single once-daily dosage unit may improve treatment adherence, facilitate drug administration, and reduce caregiver burden. A new fixed-dose combination (FDC) capsule containing 28 mg memantine extended release (ER) and 10 mg donepezil was evaluated for bioequivalence with co-administered commercially available memantine ER and donepezil, and for bioavailability with regard to food intake. Two phase I, single-dose, randomized, open-label, crossover studies were conducted in 18- to 45-year-old healthy individuals. In MDX-PK-104 study, fasting participants (N = 38) received co-administered memantine ER and donepezil or the FDC. In MDX-PK-105 study, participants (N = 36) received three treatments: intact FDC taken while fasting or after a high-fat meal, or FDC contents sprinkled on applesauce while fasting. Standard pharmacokinetic parameters for memantine and donepezil were calculated from the plasma concentration time-curve using non-compartmental analyses. Linear mixed-effects models were used to compare: (a) FDC versus co-administered individual drugs; (b) FDC fasted versus with food; and (c) FDC sprinkled on applesauce versus FDC intact, both fasted. Safety parameters were also evaluated. The FDC capsule was bioequivalent to co-administered memantine ER and donepezil. There was no significant food effect on the bioavailability of the FDC components. There were no clinically relevant differences in time to maximum plasma concentration or safety profiles across treatments. An FDC capsule containing 28 mg memantine ER and 10 mg donepezil is bioequivalent to commercially available memantine ER and donepezil, and bioavailability is not affected by food intake or sprinkling of capsule contents on applesauce.

Binding free energy calculations to rationalize the interactions of huprines with acetylcholinesterase.

PubMed

Nascimento, Érica C M; Oliva, Mónica; Andrés, Juan

2018-05-01

In the present study, the binding free energy of a family of huprines with acetylcholinesterase (AChE) is calculated by means of the free energy perturbation method, based on hybrid quantum mechanics and molecular mechanics potentials. Binding free energy calculations and the analysis of the geometrical parameters highlight the importance of the stereochemistry of huprines in AChE inhibition. Binding isotope effects are calculated to unravel the interactions between ligands and the gorge of AChE. New chemical insights are provided to explain and rationalize the experimental results. A good correlation with the experimental data is found for a family of inhibitors with moderate differences in the enzyme affinity. The analysis of the geometrical parameters and interaction energy per residue reveals that Asp72, Glu199, and His440 contribute significantly to the network of interactions between active site residues, which stabilize the inhibitors in the gorge. It seems that a cooperative effect of the residues of the gorge determines the affinity of the enzyme for these inhibitors, where Asp72, Glu199, and His440 make a prominent contribution.

Binding free energy calculations to rationalize the interactions of huprines with acetylcholinesterase

NASA Astrophysics Data System (ADS)

Nascimento, Érica C. M.; Oliva, Mónica; Andrés, Juan

2018-03-01

In the present study, the binding free energy of a family of huprines with acetylcholinesterase (AChE) is calculated by means of the free energy perturbation method, based on hybrid quantum mechanics and molecular mechanics potentials. Binding free energy calculations and the analysis of the geometrical parameters highlight the importance of the stereochemistry of huprines in AChE inhibition. Binding isotope effects are calculated to unravel the interactions between ligands and the gorge of AChE. New chemical insights are provided to explain and rationalize the experimental results. A good correlation with the experimental data is found for a family of inhibitors with moderate differences in the enzyme affinity. The analysis of the geometrical parameters and interaction energy per residue reveals that Asp72, Glu199, and His440 contribute significantly to the network of interactions between active site residues, which stabilize the inhibitors in the gorge. It seems that a cooperative effect of the residues of the gorge determines the affinity of the enzyme for these inhibitors, where Asp72, Glu199, and His440 make a prominent contribution.

Binding free energy calculations to rationalize the interactions of huprines with acetylcholinesterase

NASA Astrophysics Data System (ADS)

Nascimento, Érica C. M.; Oliva, Mónica; Andrés, Juan

2018-05-01

In the present study, the binding free energy of a family of huprines with acetylcholinesterase (AChE) is calculated by means of the free energy perturbation method, based on hybrid quantum mechanics and molecular mechanics potentials. Binding free energy calculations and the analysis of the geometrical parameters highlight the importance of the stereochemistry of huprines in AChE inhibition. Binding isotope effects are calculated to unravel the interactions between ligands and the gorge of AChE. New chemical insights are provided to explain and rationalize the experimental results. A good correlation with the experimental data is found for a family of inhibitors with moderate differences in the enzyme affinity. The analysis of the geometrical parameters and interaction energy per residue reveals that Asp72, Glu199, and His440 contribute significantly to the network of interactions between active site residues, which stabilize the inhibitors in the gorge. It seems that a cooperative effect of the residues of the gorge determines the affinity of the enzyme for these inhibitors, where Asp72, Glu199, and His440 make a prominent contribution.

Effects of pharmacological treatments on hippocampal NCAM1 and ERK2 expression in epileptic rats with cognitive dysfunction

PubMed Central

Kong, Qingxia; Min, Xia; Sun, Ran; Gao, Jianying; Liang, Ruqing; Li, Lei; Chu, Xu

2016-01-01

The present study aimed to investigate the effects of various pharmacological agents on the hippocampal expression of neural cell adhesion molecule 1 (NCAM1) and extracellular signal-regulated kinase 2 (ERK2) in epileptic rats with cognitive dysfunction. The experiments were conducted using 120 Wistar rats: 20 controls and 100 with pilocarpine-induced status epilepticus (SE). The SE rats were randomly assigned to 5 groups (n=20/group) that received daily treatments for 1 month with one of the following: (i) saline (no effect on epilepsy); (ii) carbamazepine (an anticonvulsant); (iii) oxcarbazepine (an anticonvulsant); (iv) aniracetam (a nootropic); or (v) donepezil (an acetylcholinesterase inhibitor). Spatial learning and memory were assessed using a Morris Water Maze (MWM). Hippocampal tissue was assessed for NCAM1 and ERK2 messenger RNA (mRNA) expression by reverse transcription polymerase chain reaction, and protein expression by immunochemistry. The results revealed that SE rats had significantly poorer MWM performances compared with controls (P<0.01). Performance in SE rats was improved with donepezil treatment (P<0.01), but declined with carbamazepine (P<0.01). Compared with controls, saline-treated SE rats exhibited increased hippocampal NCAM1 mRNA expression (P<0.01). Among SE rats, NCAM1 mRNA expression was highest in those treated with donepezil, followed by aniracetam-, saline-, oxcarbazepine- and carbamazepine-treated rats. Compared to controls, saline-treated SE rats exhibited decreased hippocampal ERK2 mRNA expression (P<0.01). Among SE rats, ERK2 mRNA expression was highest in those treated with donepezil, followed by aniracetam, saline, oxcarbazepine and carbamazepine. NCAM1 and ERK2 protein expression levels were parallel to those of the mRNA. In saline-treated SE rats, hippocampal ERK2 expression was decreased and NCAM1 expression was increased; thus, these two molecules may be involved in the impairment of spatial memory. Carbamazepine augmented

Cholinesterase inhibitors from botanicals

PubMed Central

Ahmed, Faiyaz; Ghalib, Raza Murad; Sasikala, P.; Ahmed, K. K. Mueen

2013-01-01

Alzheimer's disease (AD) is a progressive neurodegenerative disease, wherein a progressive loss of cholinergic synapses occurs in hippocampus and neocortex. Decreased concentration of the neurotransmitter, acetylcholine (ACh), appears to be critical element in the development of dementia, and the most appropriate therapeutic approach to treat AD and other form of dementia is to restore acetylcholine levels by inhibiting both major form of cholinesterase: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Consequently, researches have focused their attention towards finding cholinesterase inhibitors from natural products. A large number of such inhibitors have been isolated from medicinal plants. This review presents a comprehensive account of the advances in field of cholinesterase inhibitor phytoconstituents. The structures of some important phytoconstituents (collected through www.Chemspider.com) are also presented and the scope for future research is discussed. PMID:24347920

Induction of plasma acetylcholinesterase activity in mice challenged with organophosphorus poisons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duysen, Ellen G.; Lockridge, Oksana, E-mail: olockrid@unmc.edu

2011-09-01

The restoration of plasma acetylcholinesterase activity in mice following inhibition by organophosphorus pesticides and nerve agents has been attributed to synthesis of new enzyme. It is generally assumed that activity levels return to normal, are stable and do not exceed the normal level. We have observed over the past 10 years that recovery of acetylcholinesterase activity levels in mice treated with organophosphorus agents (OP) exceeds pretreatment levels and remains elevated for up to 2 months. The most dramatic case was in mice treated with tri-cresyl phosphate and tri-ortho-cresyl phosphate, where plasma acetylcholinesterase activity rebounded to a level 250% higher thanmore » the pretreatment activity. The present report summarizes our observations on plasma acetylcholinesterase activity in mice treated with chlorpyrifos, chlorpyrifos oxon, diazinon, tri-ortho-cresyl phosphate, tri-cresyl phosphate, tabun thiocholine, parathion, dichlorvos, and diisopropylfluorophosphate. We have developed a hypothesis to explain the excess acetylcholinesterase activity, based on published observations. We hypothesize that acetylcholinesterase activity is induced when cells undergo apoptosis and that consequently there is a rise in the level of plasma acetylcholinesterase. - Highlights: > Acetylcholinesterase activity is induced by organophosphorus agents. > AChE induction is related to apoptosis. > Induction of AChE activity by OP is independent of BChE.« less

Natural products as sources of new lead compounds for the treatment of Alzheimer's disease.

PubMed

Huang, Ling; Su, Tao; Li, Xingshu

2013-01-01

Alzheimer's disease (AD) is the most prevalent form of dementia and affects approximately 24 million people worldwide. One possible approach for the treatment of this disease is the restoration of the level of acetylcholine (ACh) through the inhibition of acetylcholinesterase (AChE) with reversible inhibitors. Naturally occurring alkaloids are an important source of AChE inhibitors. Galantamine and huperzine A have been used for the clinical treatment of AD patients. In this review, we summarise the natural products and their derivatives that were reported to act as AChE inhibitors for the treatment of AD in 2010-2013. Several characteristics were summarised from the literature results: 1) Amongst all of the natural products with AChE inhibitory activity, alkaloids appear to be the most promising compound class. 2) Coumarins, flavonoids, stilbenes, and other natural products are also important AChE inhibitors from natural products. Among these inhibitors, 146 (IC50 = 0.573 µM) was identified as the most potent AChE inhibitor. 3) A coumarin derivative (117, IC50 = 0.11 nM) exhibited more than 100-fold superior activity compared with the reference drug donepezil hydrochloride (IC50 = 14 nM). In conclusion, natural products and their derivatives are promising leads for the development of new drugs for the future treatment of AD.

Synthesis and Biological Evaluation of Benzochromenopyrimidinones as Cholinesterase Inhibitors and Potent Antioxidant, Non-Hepatotoxic Agents for Alzheimer's Disease.

PubMed

Dgachi, Youssef; Bautista-Aguilera, Oscar M; Benchekroun, Mohamed; Martin, Hélène; Bonet, Alexandre; Knez, Damijan; Godyń, Justyna; Malawska, Barbara; Gobec, Stanislav; Chioua, Mourad; Janockova, Jana; Soukup, Ondrej; Chabchoub, Fakher; Marco-Contelles, José; Ismaili, Lhassane

2016-05-14

We report herein the straightforward two-step synthesis and biological assessment of novel racemic benzochromenopyrimidinones as non-hepatotoxic, acetylcholinesterase inhibitors with antioxidative properties. Among them, compound 3Bb displayed a mixed-type inhibition of human acetylcholinesterase (IC50 = 1.28 ± 0.03 μM), good antioxidant activity, and also proved to be non-hepatotoxic on human HepG2 cell line.

A double-blind placebo-controlled cross-over clinical trial of DONepezil In Posterior cortical atrophy due to underlying Alzheimer's Disease: DONIPAD study.

PubMed

Ridha, Basil H; Crutch, Sebastian; Cutler, Dawn; Frost, Christopher; Knight, William; Barker, Suzie; Epie, Norah; Warrington, Elizabeth K; Kukkastenvehmas, Riitta; Douglas, Jane; Rossor, Martin N

2018-05-01

The study investigated whether donepezil exerts symptomatic benefit in patients with posterior cortical atrophy (PCA), an atypical variant of Alzheimer's disease. A single-centre, double-blind, placebo-controlled, cross-over clinical trial was performed to assess the efficacy of donepezil in patients with PCA. Each patient received either donepezil (5 mg once daily in the first 6 weeks and 10 mg once daily in the second 6 weeks) or placebo for 12 weeks. After a 2-week washout period, each patient received the other treatment arm during the following 12 weeks followed by another 2-week washout period. The primary outcome was the Mini-Mental State Examination (MMSE) at 12 weeks. Secondary outcome measures were five neuropsychological tests reflecting parieto-occipital function. Intention-to-treat analysis was used. For each outcome measure, carry-over effects were first assessed. If present, then analysis was restricted to the first 12-week period. Otherwise, the standard approach to the analysis of a 2 × 2 cross-over trial was used. Eighteen patients (13 females) were recruited (mean age 61.6 years). There was a protocol violation in one patient, who subsequently withdrew from the study due to gastrointestinal side effects. There was statistically significant (p < 0.05) evidence of a carry-over effect on MMSE. Therefore, the analysis of treatment effect on MMSE was restricted to the first 12-week period. Treatment effect at 6 weeks was statistically significant (difference = 2.5 in favour of donepezil, 95% CI 0.1 to 5.0, p < 0.05). Treatment effect at 12 weeks was close, but not statistically significant (difference = 2.0 in favour of donepezil, 95% CI -0.1 to 4.5, p > 0.05). There were no statistically significant treatment effects on any of the five neuropsychological tests, except for digit span at 12 weeks (higher by 0.5 digits in favour of placebo, 95% CI 0.1 to 0.9). Gastrointestinal side effects occurred most frequently, affecting 13/18 subjects (72%), and

Cholinesterase inhibitors: a patent review (2007 - 2011).

PubMed

de los Ríos, Cristóbal

2012-08-01

Cholinesterase inhibitors participate in the maintenance of the levels of the neurotransmitter acetylcholine by inhibiting the enzymes implicated in its degradation, namely, butyrylcholinesterase and acetylcholinesterase. This pharmacological action has an important role in several diseases, including neurodegenerative diseases such as Alzheimer's. This article reviews recent advances in the development of cholinesterase enzyme inhibitors, covering the development of new chemical entities, new pharmaceutical formulations with known inhibitors or treatments in combination with other drug families. The development of cholinesterase inhibitors has to face several issues, including the fact that the principal indication for these drugs, Alzheimer's disease, is not currently believed to derivate from a cholinergic deficiency, although most of the drugs clinically used for these disease are cholinesterase inhibitors. Moreover, the adverse effects found when administering cholinesterase inhibitors limit their use in other diseases, such as gastrointestinal diseases, glaucoma, or analgesia.

Identification of potential herbal inhibitor of acetylcholinesterase associated Alzheimer's disorders using molecular docking and molecular dynamics simulation.

PubMed

Seniya, Chandrabhan; Khan, Ghulam Jilani; Uchadia, Kuldeep

2014-01-01

Cholinesterase inhibitors (ChE-Is) are the standard for the therapy of AD associated disorders and are the only class of approved drugs by the Food and Drug Administration (FDA). Additionally, acetylcholinesterase (AChE) is the target for many Alzheimer's dementia drugs which block the function of AChE but have some side effects. Therefore, in this paper, an attempt was made to elucidate cholinesterase inhibition potential of secondary metabolite from Cannabis plant which has negligible or no side effect. Molecular docking of 500 herbal compounds, against AChE, was performed using Autodock 4.2 as per the standard protocols. Molecular dynamics simulations have also been carried out to check stability of binding complex in water for 1000 ps. Our molecular docking and simulation have predicted high binding affinity of secondary metabolite (C28H34N2O6) to AChE. Further, molecular dynamics simulations for 1000 ps suggest that ligand interaction with the residues Asp72, Tyr70-121-334, and Phe288 of AChE, all of which fall under active site/subsite or binding pocket, might be critical for the inhibitory activity of AChE. This approach might be helpful to understand the selectivity of the given drug molecule in the treatment of Alzheimer's disease. The study provides evidence for consideration of C28H34N2O6 as a valuable small ligand molecule in treatment and prevention of AD associated disorders and further in vitro and in vivo investigations may prove its therapeutic potential.

Identification of Potential Herbal Inhibitor of Acetylcholinesterase Associated Alzheimer's Disorders Using Molecular Docking and Molecular Dynamics Simulation

PubMed Central

Seniya, Chandrabhan; Khan, Ghulam Jilani; Uchadia, Kuldeep

2014-01-01

Cholinesterase inhibitors (ChE-Is) are the standard for the therapy of AD associated disorders and are the only class of approved drugs by the Food and Drug Administration (FDA). Additionally, acetylcholinesterase (AChE) is the target for many Alzheimer's dementia drugs which block the function of AChE but have some side effects. Therefore, in this paper, an attempt was made to elucidate cholinesterase inhibition potential of secondary metabolite from Cannabis plant which has negligible or no side effect. Molecular docking of 500 herbal compounds, against AChE, was performed using Autodock 4.2 as per the standard protocols. Molecular dynamics simulations have also been carried out to check stability of binding complex in water for 1000 ps. Our molecular docking and simulation have predicted high binding affinity of secondary metabolite (C28H34N2O6) to AChE. Further, molecular dynamics simulations for 1000 ps suggest that ligand interaction with the residues Asp72, Tyr70-121-334, and Phe288 of AChE, all of which fall under active site/subsite or binding pocket, might be critical for the inhibitory activity of AChE. This approach might be helpful to understand the selectivity of the given drug molecule in the treatment of Alzheimer's disease. The study provides evidence for consideration of C28H34N2O6 as a valuable small ligand molecule in treatment and prevention of AD associated disorders and further in vitro and in vivo investigations may prove its therapeutic potential. PMID:25054066

Acetylcholinesterases from Elapidae snake venoms: biochemical, immunological and enzymatic characterization.

PubMed

Frobert, Y; Créminon, C; Cousin, X; Rémy, M H; Chatel, J M; Bon, S; Bon, C; Grassi, J

1997-05-23

We analyzed 45 batches of venom from 20 different species belonging to 11 genera from the 3 main families of venomous snakes (Elapidae, Viperidae and Crotalidae). We found high acetylcholinesterase (AChE) activity in all venoms from Elapidae, except in those from the Dendroaspis genus. AChE was particularly abundant in Bungarus venoms which contain up to 8 mg of enzyme per gram of dried venom. We could not detect acetylcholinesterase activity in any batch of venom from Viperidae or Crotalidae. Titration of active sites with an organophosphorous agent (MPT) revealed that the AChE of all venoms have similar turnovers (6000 to 8000 s(-1)) which are clearly higher than those of Torpedo and mammalian enzymes but lower than that of Electrophorus. AChEs from the venom of elapid snakes of the Bungarus, Naja, Ophiophagus and Haemacatus genera were purified by affinity chromatography. SDS-PAGE analysis and sucrose gradient centrifugation demonstrated that AChE is exclusively present as a nonamphiphilic monomer. These enzymes are true AChEs, hydrolyzing acetylthiocholine faster than propionylthiocholine and butyrylthiocholine and exhibiting excess substrate inhibition. Twenty-seven different monoclonal antibodies directed against AChE from Bungarus fasciatus venom were raised in mice. Half of them recognized exclusively the Bungarus enzyme while the others cross-reacted with AChEs from other venoms. Polyspecific mAbs were used to demonstrate that venoms from Dendroaspis, which contain the AChE inhibitor fasciculin but lack AChE activity, were also devoid of immunoreactive AChE protein. AChE inhibitors acting at the active site (edrophonium, tacrine) and at the peripheral site (propidium, fasciculin), as well as bis-quaternary ligands (BW284C51, decamethonium), were tested against the venom AChEs from 11 different species. All enzymes had a very similar pattern of reactivity with regard to the different inhibitors, with the exception of fasciculin. AChEs from Naja and

Acetylcholinesterase activity in Clytia hemisphaerica (Cnidaria).

PubMed

Denker, Elsa; Chatonnet, Arnaud; Rabet, Nicolas

2008-09-25

Cholinesterase activity is known in representatives of all living organisms phyla but the origin of the cholinergic system as known in bilaterian animals is still undeciphered. In particular the implication of cholinesterases in the nervous system of non-bilaterian Metazoa is not well known. We thus chose to investigate this activity in the Clytia hemisphaerica (Cnidaria) medusa. In toto histochemical staining revealed an acetylcholinesterase activity in the tentacle bulbs but not in the nervous system. Sequences homologous to acetylcholinesterase were searched within Clytia ESTs and compared to other sequences found in public databases.

Design, synthesis and preliminary structure-activity relationship investigation of nitrogen-containing chalcone derivatives as acetylcholinesterase and butyrylcholinesterase inhibitors: a further study based on Flavokawain B Mannich base derivatives.

PubMed

Liu, Haoran; Fan, Haoqun; Gao, Xiaohui; Huang, Xueqing; Liu, Xianjun; Liu, Linbo; Zhou, Chao; Tang, Jingjing; Wang, Qiuan; Liu, Wukun

2016-08-01

In order to study the structure-activity relationship of Flavokawain B Mannich-based derivatives as acetylcholinesterase (AChE) inhibitors in our recent investigation, 20 new nitrogen-containing chalcone derivatives (4 a-8d) were designed, synthesized, and evaluated for AChE inhibitory activity in vitro. The results suggested that amino alkyl side chain of chalcone dramatically influenced the inhibitory activity against AChE. Among them, compound 6c revealed the strongest AChE inhibitory activity (IC50 value: 0.85 μmol/L) and the highest selectivity against AChE over BuChE (ratio: 35.79). Enzyme kinetic study showed that the inhibition mechanism of compound 6c against AChE was a mixed-type inhibition. The molecular docking assay showed that this compound can both bind with the catalytic site and the peripheral site of AChE.

Progress in studies of huperzine A, a natural cholinesterase inhibitor from Chinese herbal medicine.

PubMed

Wang, Rui; Yan, Han; Tang, Xi-can

2006-01-01

Huperzine A (HupA), a novel alkaloid isolated from the Chinese herb Huperzia serrata, is a potent, highly specific and reversible inhibitor of acetylcholinesterase(AChE). Compared with tacrine, donepezil, and rivastigmine, HupA has better penetration through the blood-brain barrier, higher oral bioavailability, and longer duration of AChE inhibitory action. HupA has been found to improve cognitive deficits in a broad range of animal models. HupA possesses the ability to protect cells against hydrogen peroxide, beta-amyloid protein (or peptide), glutamate, ischemia and staurosporine-induced cytotoxicity and apoptosis. These protective effects are related to its ability to attenuate oxidative stress, regulate the expression of apoptotic proteins Bcl-2, Bax, P53, and caspase-3, protect mitochondria, upregulate nerve growth factor and its receptors, and interfere with amyloid precursor protein metabolism. Antagonizing effects of HupA on N-methyl-D-aspartate receptors and potassium currents may also contribute to its neuroprotection as well. Pharmacokinetic studies in rodents, canines, and healthy human volunteers indicated that HupA was absorbed rapidly, distributed widely in the body, and eliminated at a moderate rate with the property of slow and prolonged release after oral administration. Animal and clinical safety tests showed that HupA had no unexpected toxicity, particularly the dose-limiting hepatotoxicity induced by tacrine. The phase IV clinical trials in China have demonstrated that HupA significantly improved memory deficits in elderly people with benign senescent forgetfulness, and patients with Alzheimer disease and vascular dementia, with minimal peripheral cholinergic side effects and no unexpected toxicity. HupA can also be used as a protective agent against organophosphate intoxication.

Olfactory Deficits in MCI as Predictor of Improved Cognition on Donepezil

DTIC Science & Technology

2015-04-01

those of the author( s ) and should not be construed as an official Department of the Army position, policy or decision unless so designated by other...Improved Cognition on Donepezil. 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) Davangere Devanand, M.D. Betty Diamond 5d. PROJECT NUMBER...5e. TASK NUMBER E-Mail: dpd3@cumc.columbia.edu 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) AND ADDRESS(ES) 8

AOP description: Acetylcholinesterase inhibition

EPA Science Inventory

This adverse outcome pathway (AOP) leverages existing knowledge in the open literature to describe the linkage between inhibition of acetylcholinesterase (AChE) and the subsequent mortality resulting from impacts at cholinergic receptors. The AOP takes a chemical category approa...

New pyridine derivatives as inhibitors of acetylcholinesterase and amyloid aggregation.

PubMed

Pandolfi, Fabiana; De Vita, Daniela; Bortolami, Martina; Coluccia, Antonio; Di Santo, Roberto; Costi, Roberta; Andrisano, Vincenza; Alabiso, Francesco; Bergamini, Christian; Fato, Romana; Bartolini, Manuela; Scipione, Luigi

2017-12-01

A new series of pyridine derivatives with carbamic or amidic function has been designed and synthesized to act as cholinesterase inhibitors. The synthesized compounds were tested toward EeAChE and hAChE and toward eqBChE and hBChE. The carbamate 8 was the most potent hAChE inhibitor (IC 50  = 0.153 ± 0.016 μM) while the carbamate 11 was the most potent inhibitor of hBChE (IC 50  = 0.828 ± 0.067 μM). A molecular docking study indicated that the carbamate 8 was able to bind AChE by interacting with both CAS and PAS, in agreement with the mixed inhibition mechanism. Furthermore, the carbamates 8, 9 and 11 were able to inhibit Aβ 42 self-aggregation and possessed quite low toxicity against human astrocytoma T67 and HeLa cell lines, being the carbamate 8 the less toxic compound on both cell lines. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Inhibition properties of propolis extracts to some clinically important enzymes.

PubMed

Baltas, Nimet; Yildiz, Oktay; Kolayli, Sevgi

2016-01-01

The present study was conducted to envisage inhibition effects of propolis on the crucial enzymes, urease, xanthine oxidase (XO) and acetylcholinesterase (AChE). Some of the antioxidant properties of the propolis samples were determined using the total phenolic content (TPE) and total flavonoids in the eight different ethanolic propolis extracts (EPE) samples. Inhibition values of the enzymes were expressed as inhibition concentration (IC 50 ; mg/mL or μg/mL) causing 50% inhibition of the enzymes with donepezil, acetohydroxamic acid and allopurinol as reference inhibitors. All the propolis extracts exhibited variable inhibition effects on these enzymes, but the higher the phenolic contents the lower the inhibitions values (IC 50 = 0.074 to 1.560 mg/mL). IC 50 values of the P5 propolis sample having the highest TPE, obtained from Zonguldak, for AChE, urease and XO were 0.081 ± 0.009, 0.080 ± 0.006 and 0.074 ± 0.011 μg/mL, respectively. The EPE proved to be a good source of inhibitor agents that can be used as natural inhibitors to serve human health.

In Vitro and In Vivo Metabolism and Inhibitory Activities of Vasicine, a Potent Acetylcholinesterase and Butyrylcholinesterase Inhibitor

PubMed Central

Liu, Wei; Shi, Xiaoyuan; Yang, Yadi; Cheng, Xuemei; Liu, Qing; Han, Han; Yang, Baohua; He, Chunyong; Wang, Yongli; Jiang, Bo; Wang, Zhengtao; Wang, Changhong

2015-01-01

Vasicine (VAS), a potential natural cholinesterase inhibitor, exhibited promising anticholinesterase activity in preclinical models and has been in development for treatment of Alzheimer’s disease. This study systematically investigated the in vitro and in vivo metabolism of VAS in rat using ultra performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight mass spectrometry. A total of 72 metabolites were found based on a detailed analysis of their 1H- NMR and 13C NMR data. Six key metabolites were isolated from rat urine and elucidated as vasicinone, vasicinol, vasicinolone, 1,2,3,9-tetrahydropyrrolo [2,1-b] quinazolin-3-yl hydrogen sulfate, 9-oxo-1,2,3,9-tetrahydropyrrolo [2,1-b] quinazolin-3-yl hydrogen sulfate, and 1,2,3,9-tetrahydropyrrolo [2,1-b] quinazolin-3-β-D-glucuronide. The metabolic pathway of VAS in vivo and in vitro mainly involved monohydroxylation, dihydroxylation, trihydroxylation, oxidation, desaturation, sulfation, and glucuronidation. The main metabolic soft spots in the chemical structure of VAS were the 3-hydroxyl group and the C-9 site. All 72 metabolites were found in the urine sample, and 15, 25, 45, 18, and 11 metabolites were identified from rat feces, plasma, bile, rat liver microsomes, and rat primary hepatocyte incubations, respectively. Results indicated that renal clearance was the major excretion pathway of VAS. The acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of VAS and its main metabolites were also evaluated. The results indicated that although most metabolites maintained potential inhibitory activity against AChE and BChE, but weaker than that of VAS. VAS undergoes metabolic inactivation process in vivo in respect to cholinesterase inhibitory activity. PMID:25849329

Role of acetylcholinesterase in lung cancer

PubMed Central

Xi, Hui-Jun; Wu, Ren-Pei; Liu, Jing-Jing; Zhang, Ling-Juan; Li, Zhao-Shen

2015-01-01

Acetylcholinesterase (AChE) plays a key role in catalytic hydrolysis of cholinergic neurotransmitters. Intensive research has proven the involvement of this protein in novel functions, such as cell adhesion, differentiation, and proliferation. In addition, several recent studies have indicated that acetylcholinesterase is potentially a marker and regulator of apoptosis. Importantly, AChE is also a promising tumor suppressor. In this review, we briefly summarize the involvement of AChE in apoptosis and cancer, focusing on the role of AChE in lung cancer, as well as the therapeutic consideration of AChE for cancer therapy. PMID:26273392

Ortho effects in quantitative structure-activity relationships for acetylcholinesterase inhibition by aryl carbamates.

PubMed

Lin, Gialih; Liu, Yu-Chen; Lin, Yan-Fu; Wu, Yon-Gi

2004-10-01

Ortho-substituted phenyl-N-butyl carbamates (1-9) are characterized as "pseudo-pseudo-substrate" inhibitors of acetylcholinesterase. Since the inhibitors protonate at pH 7.0 buffer solution, the virtual inhibition constants (K'is) of the protonated inhibitors are calculated from the equation, - logK'i = - logKi - logKb. The logarithms of the inhibition constant (Ki), the carbamylation constant (k(c)), and the bimolecular inhibition constant (k(i)) for the enzyme inhibitions by carbamates 1-9 are multiply linearly correlated with the Hammett para-substituent constant (sigma(p)), the Taft-Kutter-Hansch ortho steric constant (E(S)), and the Swan-Lupton ortho polar constant (F). Values of rho, delta, and f for the - logKi-, logk(c)-, and logk(i)-correlations are -0.6, -0.16, 0.7; 0.11, 0.03, -0.3; and - 0.5, - 0.12, 0.4, respectively. The Ki step further divides into two steps: 1) the pre-equilibrium protonation of the inhibitors, Kb step and 2) formation of a negatively charged enzyme-inhibitor Michaelis-Menten complex--virtual inhibition, K'i step. The Ki step has little ortho steric enhancement effect; moreover, the k(c)step is insensitive to the ortho steric effect. The f value of 0.7 for the Ki step indicates that ortho electron-withdrawing substituents of the inhibitors accelerate the inhibition reactions from the ortho polar effect; however, the f value of -0.3 for the k(c)step implies that ortho electron-withdrawing substituents of the inhibitors lessen the inhibition reactions from the ortho polar effect.

A point mutation in the acetylcholinesterase-1 gene is associated with chlorpyrifos resistance in the plant bug Apolygus lucorum.

PubMed

Wu, Shuwen; Zuo, Kairan; Kang, Zhaokui; Yang, Yihua; Oakeshott, John G; Wu, Yidong

2015-10-01

Control of Chinese Apolygus lucorum relies heavily on organophosphate insecticides. Here we describe resistance to the organophosphate chlorpyrifos in an A. lucorum strain, BZ-R, which was developed from a field-collected strain (BZ) by selection with chlorpyrifos in the laboratory. BZ-R showed 21-58 fold resistance to chlorpyrifos compared with the laboratory reference strain LSF and another susceptible strain, BZ-S, derived from BZ. BZ-R also showed several fold resistance to two other organophosphates and a carbamate. No synergism of chlorpyrifos by metabolic enzyme inhibitors nor any increase in detoxifying enzyme activities were observed in BZ-R. No sequence differences in acetylcholinesterase-2 were found to be associated with the resistance but the frequency of an alanine to serine substitution at position 216 of acetylcholinesterase-1 was 100% in BZ-R, ∼21-23% in SLF and BZ, and 0% in BZ-S. A single generation treatment of chlorpyrifos on the BZ strain also increased its frequency of the serine substitution to 64%. Recombinantly expressed acetylcholinesterase-1 carrying the serine substitution was about five fold less sensitive to inhibition by chlorpyrifos oxon than the wild-type enzyme. Quantitative real-time PCR found no differences in ace1 or ace2 expression levels among the strains tested. Thus the chlorpyrifos resistance is strongly associated with the serine substituted acetylcholinesterase-1. An equivalent substitution has been found to confer resistance to many organophosphate and carbamate insecticides in four other insect species. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Nicotinic Receptor, galantamine and Alzheimer disease].

PubMed

Arroyo, G; Aldea, M; Fuentealba, J; García, A G

Population aging has increased and will drastically increase the prevalence of Alzheimer disease. The disease develops inexorably towards a syndrome of marked cognitive impairment, accompanied of emotional alterations and profound changes of personality. The patient loses its autonomy, and requires special attention of caregivers; this leads to a decrease of the quality of life, not only of the patient but also of its caregivers and family. The reduction of the number of functional nicotinic receptors in brain keeps pace with neurological symptoms and the severity of the disease (cholinergic theory of Alzheimer disease). There is a pleyade of data and observations reinforcing the idea that improving cholinergic neurotransmission is an investment in memory. Up to now, although with limited success, this improvement has been achieved only with the reversible inhibitors of acetylcholinesterase tacrine, rivastigmine and donepezil, available in the clinic since a few years. The last approved has been galantamine that in spite of being a modest inhibitor of acetylcholinesterase, improves memory (ADAS cog test) and slows down cognitive impairment of Alzheimer patients. To explain this therapeutic effect, a second mechanism of action for galantamine has been suggested, the positive allosteric modulation of presynaptic nicotinic receptors, that will favour the release of acetylcholine and other neurotransmitters involved in memory formation. Furthermore, galantamine possesses neuroprotectant antiapoptotic effects, according to recent data from our laboratory. These effects provide new ideas and therapeutic targets that might help to find novel and efficacious treatments for patients suffering Alzheimer disease.

Cholinesterases, a target of pharmacology and toxicology.

PubMed

Pohanka, Miroslav

2011-09-01

Cholinesterases are a group of serine hydrolases that split the neurotransmitter acetylcholine (ACh) and terminate its action. Of the two types, butyrylcholinesterase and acetylcholinesterase (AChE), AChE plays the key role in ending cholinergic neurotransmission. Cholinesterase inhibitors are substances, either natural or man-made that interfere with the break-down of ACh and prolong its action. Hence their relevance to toxicology and pharmacology. The present review summarizes current knowledge of the cholinesterases and their inhibition. Particular attention is paid to the toxicology and pharmacology of cholinesterase-related inhibitors such as nerve agents (e.g. sarin, soman, tabun, VX), pesticides (e.g. paraoxon, parathion, malathion, malaoxon, carbofuran), selected plants and fungal secondary metabolites (e.g. aflatoxins), drugs for Alzheimer's disease (e.g. huperzine, metrifonate, tacrine, donepezil) and Myasthenia gravis (e.g. pyridostigmine) treatment and other compounds (propidium, ethidium, decamethonium). The crucial role of the cholinesterases in neural transmission makes them a primary target of a large number of cholinesterase-inhibiting drugs and toxins. In pharmacology, this has relevance to the treatment of neurodegenerative disorders.

The lignicolous fungus Trametes versicolor (L.) Lloyd (1920): a promising natural source of antiradical and AChE inhibitory agents.

PubMed

Janjušević, Ljiljana; Karaman, Maja; Šibul, Filip; Tommonaro, Giuseppina; Iodice, Carmine; Jakovljević, Dragica; Pejin, Boris

2017-12-01

This study aimed to determine antiradical (DPPH • and • OH) and acetylcholinesterase (AChE) inhibitory activities along with chemical composition of autochtonous fungal species Trametes versicolor (Serbia). A total of 38 phenolic compounds with notable presence of phenolic acids were identified using HPLC/MS-MS. Its water extract exhibited the highest antiradical activity against • OH (3.21 μg/mL), among the rest due to the presence of gallic, p-coumaric and caffeic acids. At the concentration of 100 μg/mL, the same extract displayed a profound AChE inhibitory activity (60.53%) in liquid, compared to donepezil (89.05%), a drug in clinical practice used as positive control. The flavonoids baicalein and quercetin may be responsible compounds for the AChE inhibitory activity observed. These findings have demonstrated considerable potential of T. versicolor water extract as a natural source of antioxidant(s) and/or AChE inhibitor(s) to be eventually used as drug-like compounds or food supplements in the treatment of Alzheimer's disease.

Relevance of Donepezil in Enhancing Learning and Memory in Special Populations: A Review of the Literature

ERIC Educational Resources Information Center

Yoo, J. Helen; Valdovinos, Maria G.; Williams, Dean C.

2007-01-01

This review discusses the laboratory and clinical research supporting the rationale for the efficacy of donepezil (Aricept[R] USA) in enhancing cognition in autism, Alzheimer disease, Down syndrome, traumatic brain injury, Attention Deficit Hyperactivity Disorder (ADHD), and schizophrenia. While preliminary animal models have shown effective,…

Risk of combined exposure of birds to cyanobacterial biomass containing microcystins, acetylcholinesterase inhibitor and anticoagulant.

PubMed

Ondracek, Karel; Bandouchova, Hana; Damkova, Veronika; Hilscherova, Klara; Kral, Jiri; Osickova, Jitka; Mlcakova, Veronika; Pohanka, Miroslav; Skochova, Hana; Vitula, Frantisek; Treml, Frantisek; Pikula, Jiri

2012-01-01

The objective of this study was to examine the hypothesis that a combination of cyanobacterial biomass containing microcystins, acetylcholinesterase inhibitor and anticoagulant can enhance avian toxic effects produced by single exposures only. A total of 48 two-month-old Japanese quails (Coturnix coturnix japonica) with average body weight of 160 g were randomly divided into 8 experimental groups of six birds and sex ratio of 1:1. Experimental groups of control Japanese quails (C) and birds exposed to single and combined sub-lethal doses of paraoxon (P), bromadiolone (B), and microcystins in cyanobacterial biomass (M) included: C, P, P+B, B, B+M, P+M, M, and P+B+M. During the 10-day exposure birds in the respective groups received biomass containing 61.62 µg microcystins daily (i.e. 26.54 µg MC-RR, 7.62 µg MC-YR and 27.39 µg MC-LR), two 250 μg/kg doses of paraoxon, and two 500 mg/kg doses of bromadiolone. Group responses were compared using standard plasma biochemistry and antioxidant/oxidative stress parameters in tissues. While single and double combinations of toxicants induced responses in individual biochemical parameters measured and evaluated using univariate statistical analysis, those in the triple exposure were most extensive. The principal component analysis of antioxidant/oxidative stress parameters (glutathione reductase, lipid peroxidation, and ferric reducing antioxidant power) in tissues (liver, kidney, heart, brain, lungs, gonads, and pectoralis major muscle) clearly separated the triple group (P+B+M) from all single and double exposure groups and the control and indicated thus marked joint effects in the overall pattern of antioxidant/oxidative stress responses of this group. The separation was driven by the modification of the ferric reducing antioxidant power levels in heart and brain and the cardiac lipid peroxidation level, in particular. This experiment contributes to the understanding of the pathogenic mechanisms of combined sub

Virtual screening and biological evaluation of piperazine derivatives as human acetylcholinesterase inhibitors.

PubMed

Varadaraju, Kavitha Raj; Kumar, Jajur Ramanna; Mallesha, Lingappa; Muruli, Archana; Mohana, Kikkeri Narasimha Shetty; Mukunda, Chethan Kumar; Sharanaiah, Umesha

2013-01-01

The piperazine derivatives have been shown to inhibit human acetylcholinesterase. Virtual screening by molecular docking of piperazine derivatives 1-(1,4-benzodioxane-2-carbonyl) piperazine (K), 4-(4-methyl)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S1), and 4-(4-chloro)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S3) has been shown to bind at peripheral anionic site and catalytic sites, whereas 4-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S4) and 4-(2,5-dichloro)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S7) do not bind either to peripheral anionic site or catalytic site with hydrogen bond. All the derivatives have differed in number of H-bonds and hydrophobic interactions. The peripheral anionic site interacting molecules have proven to be potential therapeutics in inhibiting amyloid peptides aggregation in Alzheimer's disease. All the piperazine derivatives follow Lipinski's rule of five. Among all the derivatives 1-(1,4-benzodioxane-2-carbonyl) piperazine (K) was found to have the lowest TPSA value.

Virtual Screening and Biological Evaluation of Piperazine Derivatives as Human Acetylcholinesterase Inhibitors

PubMed Central

Varadaraju, Kavitha Raj; Kumar, Jajur Ramanna; Mallesha, Lingappa; Muruli, Archana; Mohana, Kikkeri Narasimha Shetty; Mukunda, Chethan Kumar; Sharanaiah, Umesha

2013-01-01

The piperazine derivatives have been shown to inhibit human acetylcholinesterase. Virtual screening by molecular docking of piperazine derivatives 1-(1,4-benzodioxane-2-carbonyl) piperazine (K), 4-(4-methyl)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S1), and 4-(4-chloro)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S3) has been shown to bind at peripheral anionic site and catalytic sites, whereas 4-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S4) and 4-(2,5-dichloro)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S7) do not bind either to peripheral anionic site or catalytic site with hydrogen bond. All the derivatives have differed in number of H-bonds and hydrophobic interactions. The peripheral anionic site interacting molecules have proven to be potential therapeutics in inhibiting amyloid peptides aggregation in Alzheimer's disease. All the piperazine derivatives follow Lipinski's rule of five. Among all the derivatives 1-(1,4-benzodioxane-2-carbonyl) piperazine (K) was found to have the lowest TPSA value. PMID:24288651

Synthesis and biological evaluation of 3-thiazolocoumarinyl Schiff-base derivatives as cholinesterase inhibitors.

PubMed

Raza, Rabia; Saeed, Aamer; Arif, Mubeen; Mahmood, Shamsul; Muddassar, Muhammad; Raza, Ahsan; Iqbal, Jamshed

2012-10-01

On the basis of the observed biological activity of the coumarins, a new set of 3-thiazolocoumarinyl Schiff-base derivatives with chlorine, hydroxy and methoxy functional group substitutions were designed and synthesized. These compounds were tested against acetylcholinesterase from Electrophorus electricus and butyrylcholinesterase from horse serum and their structure-activity relationship was established. Studies revealed them as the potential inhibitors of cholinesterase (acetylcholinesterase and butyrylcholinesterase). The 3f was found to be most potent against acetylcholinesterase with K(i) value of 1.05 ± 0.3 μM and 3l showed excellent inhibitory action against butyrylcholinesterase with K(i) value of 0.041 ± 0.002 μM. The synthesized compounds were also docked into the active sites of the homology models of acetylcholinesterase and butyrylcholinesterase to predict the binding modes of these compounds. It was predicted that most of the compounds have similar binding modes with reasonable binding affinities. Our docking studies have also shown that these synthesized compounds have better interaction patterns with butyrylcholinesterase over acetylcholinesterase. The main objective of the study was to develop new potent and selective compounds, which might be further optimized to prevent the progression of the Alzheimer's disease and could provide symptomatic treatment. © 2012 John Wiley & Sons A/S.

Autoantibodies to acetylcholinesterase revisited.

PubMed

Geen, J; Hadjikoutis, S; Strachan, A; Hullin, D A; Hogg, S I; Wiles, C M

2000-05-01

A sensitive and specific enzyme linked immunosorbent assay (ELISA) utilizing human recombinant acetylcholinesterase has been employed for the detection of human antibodies to human acetylcholinesterase. The method can detect allogenic antibodies to the Yt(a) form of human erythrocyte AChE. Adaptation of this ELISA method allowed the IgG subclass typing of IgG anti-AChE antibodies, which could help to determine the possible role of these antibodies in the aetiology of any neurological conditions. Routine serological investigations established the AChE phenotype of each of the patients recruited, to determine whether anti-AChE antibodies were allogenic or autogenic in origin. These techniques were used to determine the incidence of autoantibodies to AChE in patients with neurological conditions, including the subtypes of motor neuron disease. The data presented are not consistent with earlier reports of a high incidence of autoantibodies to AChE in amyotrophic lateral sclerosis and progressive muscular atrophy.

Development of 3D-QSAR model for acetylcholinesterase inhibitors using a combination of fingerprint, molecular docking, and structure-based pharmacophore approaches

EPA Science Inventory

Acetylcholinesterase (AChE), a serine hydrolase vital for regulating the neurotransmitter acetylcholine in animals, has been used as a target for drugs and pesticides. With the increasing availability of AChE crystal structures, with or without ligands bound, structure-based appr...

Longitudinal MRI findings from the vitamin E and Donepezil treatment study for MCI

PubMed Central

Jack, Clifford R.; Petersen, Ronald C.; Grundman, Michael; Jin, Shelia; Gamst, Anthony; Ward, Chadwick P.; Sencakova, Drahomira; Doody, Rachelle S.; Thal, Leon J.

2009-01-01

The vitamin E and donepezil trial for the treatment of amnestic mild cognitive impairment (MCI) was conducted at 69 centers in North America; 24 centers participated in an MRI sub study. The objective of this study was to evaluate the effect of treatment on MRI atrophy rates; and validate rate measures from serial MRI as indicators of disease progression in multi center therapeutic trials for MCI. Annual percent change (APC) from baseline to follow-up was measured for hippocampus, entorhinal cortex, whole brain, and ventricle in the 131 subjects who remained in the treatment study and completed technically satisfactory baseline and follow-up scans. Although a non-significant trend toward slowing of hippocampal atrophy rates was seen in APOE ∈4 carriers treated with donepezil; no treatment effect was confirmed for any MRI measure in either treatment group. For each of the four brain atrophy rate measures, APCs were greater in subjects who converted to AD than non-converters, and were greater in APOE ∈4 carriers than non-carriers. MRI APCs and changes in cognitive test performance were uniformly correlated in the expected direction (all p < 0.000). Results of this study support the feasibility of using MRI as an outcome measure of disease progression in multi center therapeutic trials for MCI. PMID:17452062

Preparation, in vitro evaluation and molecular modelling of pyridinium-quinolinium/isoquinolinium non-symmetrical bisquaternary cholinesterase inhibitors.

PubMed

Komloova, Marketa; Horova, Anna; Hrabinova, Martina; Jun, Daniel; Dolezal, Martin; Vinsova, Jarmila; Kuca, Kamil; Musilek, Kamil

2013-12-15

Two series of non-symmetrical bisquaternary pyridinium-quinolinium and pyridinium-isoquinolinium compounds were prepared as molecules potentially applicable in myasthenia gravis treatment. Their inhibitory ability towards human recombinant acetylcholinesterase and human plasmatic butyrylcholinesterase was determined and the results were compared to the known effective inhibitors such as ambenonium dichloride, edrophonium bromide and experimental compound BW284C51. Two compounds, 1-(10-(pyridinium-1-yl)decyl)quinolinium dibromide and 1-(12-(pyridinium-1-yl)dodecyl)quinolinium dibromide, showed very promising affinity for acetylcholinesterase with their IC50 values reaching nM inhibition of acetylcholinesterase. These most active compounds also showed satisfactory selectivity towards acetylcholinesterase and they seem to be very promising as leading structures for further modifications and optimization. Two of the most promising compounds were examined in the molecular modelling study in order to find the possible interactions between the ligand and tested enzyme. Copyright © 2013 Elsevier Ltd. All rights reserved.

Preparation and evaluation of carriers for detection of cholinesterase inhibitors.

PubMed

Vetchý, David; Pitschmann, Vladimír; Vetchá, Martina; Kašparovský, Tomáš; Matějovský, Lukáš

2015-01-01

The aim of the study was to use methods of pharmaceutical technology, and prepare carriers in the form of pellets suitable as a filling of detection tubes for enzymatic detection of cholinesterase inhibitors. The enzymatic detection was based on enzymatic hydrolysis of acetylthiocholine iodide and the subsequent colour reaction of its hydrolysis product with Ellman's reagent. The suitable carriers should be in the form of white, regular and sufficiently mechanically resistant particles of about 1 mm allowing it to capture the enzyme during the impregnation process and ensuring its high activity for enzymatic detection. Carriers consisting of microcrystalline cellulose, lactose, povidone, and sodium carboxymethyl cellulose were prepared using extrusion-spheronization method under three different drying conditions in either a hot air oven or a microwave oven. Subsequently, the carriers were impregnated with acetylcholinesterase and their size, shape, mechanical resistance, bulk, tapped and pycnometric density, Hausner ratio, intraparticular and total tapped porosity, and activity were measured and recorded. In this procedure, carriers with different physical parameters and different acetylcholinesterase activity were evaluated. It was found that higher acetylcholinesterase activity was associated not only with a higher intraparticular porosity but also with more regular particles characterized by high sphericity and low total tapped porosity. This unique finding is important for the preparation of detection tubes based on enzymatic detection which is still irreplaceable especially in the field of detection and analysis of super-toxic cholinesterase inhibitors.

Kinetic Modelling of Infection Tracers [18F]FDG, [68Ga]Ga-Citrate, [11C]Methionine, and [11C]Donepezil in a Porcine Osteomyelitis Model.

PubMed

Jødal, Lars; Jensen, Svend B; Nielsen, Ole L; Afzelius, Pia; Borghammer, Per; Alstrup, Aage K O; Hansen, Søren B

2017-01-01

Positron emission tomography (PET) is increasingly applied for infection imaging using [ 18 F]FDG as tracer, but uptake is unspecific. The present study compares the kinetics of [ 18 F]FDG and three other PET tracers with relevance for infection imaging. A juvenile porcine osteomyelitis model was used. Eleven pigs underwent PET/CT with 60-minute dynamic PET imaging of [ 18 F]FDG, [ 68 Ga]Ga-citrate, [ 11 C]methionine, and/or [ 11 C]donepezil, along with blood sampling. For infectious lesions, kinetic modelling with one- and two-tissue-compartment models was conducted for each tracer. Irreversible uptake was found for [ 18 F]FDG and [ 68 Ga]Ga-citrate; reversible uptake was found for [ 11 C]methionine (two-tissue model) and [ 11 C]donepezil (one-tissue model). The uptake rate for [ 68 Ga]Ga-citrate was slow and diffusion-limited. For the other tracers, the uptake rate was primarily determined by perfusion (flow-limited uptake). Net uptake rate for [ 18 F]FDG and distribution volume for [ 11 C]methionine were significantly higher for infectious lesions than for correspondingly noninfected tissue. For [ 11 C]donepezil in pigs, labelled metabolite products appeared to be important for the analysis. The kinetics of the four studied tracers in infection was characterized. For clinical applications, [ 18 F]FDG remains the first-choice PET tracer. [ 11 C]methionine may have a potential for detecting soft tissue infections. [ 68 Ga]Ga-citrate and [ 11 C]donepezil were not found useful for imaging of osteomyelitis.

Exploring the multifunctionality of thioflavin- and deferiprone-based molecules as acetylcholinesterase inhibitors for potential application in Alzheimer's disease.

PubMed

Telpoukhovskaia, Maria A; Patrick, Brian O; Rodríguez-Rodríguez, Cristina; Orvig, Chris

2013-04-05

Alzheimer's disease (AD) is a devastating neurodegenerative disease that affects millions of people worldwide. With no prevention or cure available, this progressive disease has a significant impact on society - dementia patients and their caretakers, healthcare systems, and the economy. Previously, we have reported initial developments of multifunctional drug candidates for AD based on two scaffolds - thioflavin-T and deferiprone. Individually, these molecules have shown several favorable functionalities, including dissociation of toxic amyloid-β aggregates, antioxidant and/or metal chelating ability that can pacify reactive oxygen species, plaque targeting, and blood-brain barrier penetration. In this work, the two scaffolds are augmented with a new functionality - acetylcholinesterase inhibition. This functionality is incorporated by derivatization with a carbamate group, which is the active group in some AD drugs currently in the market. We present the rationale for designing three novel compounds, their synthesis and characterization, including X-ray crystallographic data, and encouraging results from in vitro and computational acetylcholinesterase inhibition studies. Also, we evaluate the compounds as potential drug candidates by Lipinski's rules and cytotoxicity studies in a neuronal cell line. Overall, we demonstrate the feasibility of improving on two well established scaffolds, as well as show in vitro efficacy plus initial mode of action and biological compatibility data.

Butyrylcholinesterase K and Apolipoprotein E-ɛ4 Reduce the Age of Onset of Alzheimer's Disease, Accelerate Cognitive Decline, and Modulate Donepezil Response in Mild Cognitively Impaired Subjects.

PubMed

De Beaumont, Louis; Pelleieux, Sandra; Lamarre-Théroux, Louise; Dea, Doris; Poirier, Judes

2016-10-04

Genetic heterogeneity in amnestic mild cognitively impaired (aMCI) subjects could lead to variations in progression rates and response to cholinomimetic agents. Together with the apolipoprotein E4 (APOE-ɛ4) gene, butyrylcholinesterase (BCHE) has become recently one of the few Alzheimer's disease (AD) susceptibility genes with distinct pharmacogenomic properties. To validate candidate genes (APOE/BCHE) which display associations with age of onset of AD and donepezil efficacy in aMCI subjects. Using the Petersen et al. (2005) study on vitamin E and donepezil efficacy in aMCI, we contrasted the effects of BCHE and APOE variants on donepezil drug response using the Alzheimer's Disease Assessment Score-Cognition (ADAS-Cog) scale. Independently, we assessed the effects of APOE/BCHE genotypes on age of onset and cortical choline acetyltransferase activity in autopsy-confirmed AD and age-matched control subjects. Statistical analyses revealed a significant earlier age of onset in AD for APOE-ɛ4, BCHE-K*, and APOE-ɛ4/BCHE-K* carriers. Among the carriers of APOE-ɛ4 and BCHE-K*, the benefit of donepezil was evident at the end of the three-year follow-up. The responder's pharmacogenomic profile is consistent with reduced brain cholinergic activity measured in APOE-ɛ4 and BCHE-K* positive subjects. APOE-ɛ4 and BCHE-K* positive subjects display an earlier age of onset of AD, an accelerated cognitive decline and a greater cognitive benefits to donepezil therapy. These results clearly emphasize the necessity of monitoring potential pharmacogenomic effects in this population of subjects, and suggest enrichment strategies for secondary prevention trials involving prodromal AD subjects.

SERUM ACETYLCHOLINESTERASE LEVEL IN THE PATIENTS OF OPIOID (BROWN SUGAR) DEPENDENCE

PubMed Central

Shah, Nilesh; Dave, Kirti

1992-01-01

The authors compared the serum acetylcholinesterase level in the patients of brown sugar dependence and the normal volunteers. Significantly lower level of serum acetylcholinesterase was found in patients of brown sugar dependence. PMID:21776148

Pharmacogenetic studies in Alzheimer disease.

PubMed

Zúñiga Santamaría, T; Yescas Gómez, P; Fricke Galindo, I; González González, M; Ortega Vázquez, A; López López, M

2018-06-10

Alzheimer disease (AD) is the most common cause of dementia and is considered one of the main causes of disability and dependence affecting quality of life in elderly people and their families. Current pharmacological treatment includes acetylcholinesterase inhibitors (donepezil, galantamine, rivastigmine) and memantine; however, only one-third of patients respond to treatment. Genetic factors have been shown to play a role in this inter-individual variability in drug response. We review pharmacogenetic reports of AD-modifying drugs, the pharmacogenetic biomarkers included, and the phenotypes evaluated. We also discuss relevant methodological considerations for the design of pharmacogenetic studies into AD. A total of 33 pharmacogenetic reports were found; the majority of these focused on the variability in response to and metabolism of donepezil. Most of the patients included were from Caucasian populations, although some studies also include Korean, Indian, and Brazilian patients. CYP2D6 and APOE are the most frequently studied biomarkers. The associations proposed are controversial. Potential pharmacogenetic biomarkers for AD have been identified; however, it is still necessary to conduct further research into other populations and to identify new biomarkers. This information could assist in predicting patient response to these drugs and contribute to better treatment decision-making in a context as complex as aging. Copyright © 2018 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

[Effect of acetylcholine and acetylcholinesterase on the activity of contractile vacuole of Amoeba proteus].

PubMed

Bagrov, Ia Iu; Manusova, N B

2011-01-01

Acetylcholine (ACh, 1 microM) stimulates activity of the contractile vacuole of proteus. The effect of ACh is not mimicked by its analogs which are not hydrolyzed by acetylcholinesterase (AChE), i. e., carbacholine and 5-methylfurmethide. The effect of ACh is not sensitive to the blocking action of M-cholinolytics, atropine and mytolone, but is suppressed by N-cholinolytic, tubocurarine. The inhibitors of AChE, eserine (0.01 microM) and armine (0.1 microM), suppress the effect of ACh on amoeba contractile vacuole. ACh does not affect activation of contractile vacuole induced by arginine-vasopressin (1 microM), but it blocks such effect of opiate receptors agonist, dynorphin A1-13 (0.01 microM). This effect of ACh is also suppressed by the inhibitors of AChE. These results suggest that, in the above-described effects of ACh, AChE acts not as an antagonist, but rather as a synergist.

Synthesis and in vitro evaluation of new derivatives of 2-substituted-6-fluorobenzo[d]thiazoles as cholinesterase inhibitors.

PubMed

Imramovský, Aleš; Pejchal, Vladimír; Štěpánková, Šárka; Vorčáková, Katarína; Jampílek, Josef; Vančo, Ján; Šimůnek, Petr; Královec, Karel; Brůčková, Lenka; Mandíková, Jana; Trejtnar, František

2013-04-01

A series of novel cholinesterase inhibitors based on 2-substituted 6-fluorobenzo[d]thiazole were synthesised and characterised by IR, (1)H, (13)C and (19)F NMR spectroscopy and HRMS. Purity was checked by elemental analyses. The novel carbamates were tested for their ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The toxicity of the most active compounds was investigated using a standard in vitro test with HepG2 cells, and the ratio between biological activity and toxicity was determined. In addition, the toxicity of the most active compounds was evaluated against MCF7 cells using the xCELLigence system. Structure-activity relationships reflecting the dependence of cholinesterase inhibitors on the lipophilicity of the compounds as well as on the Taft polar and steric substituent constants are discussed. The specific orientation of the inhibitors in the binding site of acetylcholinesterase was determined using molecular docking of the most active compound. Copyright © 2013 Elsevier Ltd. All rights reserved.

Microwave-Assisted Cytochemistry: Accelerated Visualization of Acetylcholinesterase at Motor Endplates

DTIC Science & Technology

2001-01-01

ofAcetylcholinesterase at Motor Endplates John P. Petrali and Kenneth R. Mills INTRODUCTION Acetylcholinesterase (AChE) is the modulating enzyme of cholin ...utilized for this study was the Pelco 3440, 800 W. The animal used was the haired guinea pig, which was euthanatized by an overdose of Na pentobarbital

Associations of centrally acting ACE inhibitors with cognitive decline and survival in Alzheimer's disease.

PubMed

Fazal, Karim; Perera, Gayan; Khondoker, Mizanur; Howard, Robert; Stewart, Robert

2017-07-01

Cognitive improvement has been reported in patients receiving centrally acting angiotensin-converting enzyme inhibitors (C-ACEIs). To compare cognitive decline and survival after diagnosis of Alzheimer's disease between people receiving C-ACEIs, non-centrally acting angiotensin-converting enzyme inhibitors (NC-ACEIs), and neither. Routine Mini-Mental State Examination (MMSE) scores were extracted in 5260 patients receiving acetylcholinesterase inhibitors and analysed against C-/NC-ACEI exposure at the time of Alzheimer's disease diagnosis. In the 9 months after Alzheimer's disease diagnosis, MMSE scores significantly increased by 0.72 and 0.19 points per year in patients on C-ACEIs and neither respectively, but deteriorated by 0.61 points per year in those on NC-ACEIs. There were no significant group differences in score trajectories from 9 to 36 months and no differences in survival. In people with Alzheimer's disease receiving acetylcholinesterase inhibitors, those also taking C-ACEIs had stronger initial improvement in cognitive function, but there was no evidence of longer-lasting influence on dementia progression. R.S. has received research funding from Pfizer, Lundbeck, Roche, Janssen and GlaxoSmithKline. © The Royal College of Psychiatrists 2017. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) license.

Lower Acetylcholinesterase Activity among Children Living with Flower Plantation Workers

PubMed Central

Suarez-Lopez, Jose R.; Jacobs, David R.; Himes, John H.; Alexander, Bruce H.; Lazovich, DeAnn; Gunnar, Megan

2012-01-01

BACKGROUND Children of workers exposed to pesticides are at risk of secondary pesticide exposure. We evaluated the potential for lower acetylcholinesterase activity in children cohabiting with fresh-cut flower plantation workers, which would be expected from organophosphate and carbamate insecticide exposure. Parental home surveys were performed and acetylcholinesterase activity was measured in 277 children aged 4–9 years in the study of Secondary Exposure to Pesticides among Infants, Children and Adolescents (ESPINA). Participants lived in a rural county in Ecuador with substantial flower plantation activity. RESULTS Mean acetylcholinesterase activity was 3.14 U/ml, standard deviation (SD): 0.49. It was lower by 0.09 U/ml (95% confidence interval (CI) −0.19, −0.001) in children of flower workers (57% of participants) than non-flower workers’ children, after adjustment for gender, age, height-for-age, hemoglobin concentration, income, pesticide use within household lot, pesticide use by contiguous neighbors, examination date and residence distance to nearest flower plantation. Using a 4 level polychotomous acetylcholinesterase activity dependent variable, flower worker cohabitation (vs. not) had odds ratio 3.39 (95% CI 1.19, 9.64) for being <15th percentile compared to the highest tertile. Children cohabitating for ≥5 years (vs. never) had OR of 4.11 (95% CI: 1.17, 14.38) of AChE activity within <15th percentile compared to the highest tertile. CONCLUSIONS Cohabitation with a flower worker was related to lower acetylcholinesterase activity in children. This supports the hypothesis that the amount of take-home pesticides from flower workers suffices to decrease acetylcholinesterase activity, with lower activity associated with longer exposure. PMID:22405996

Protection against Acetylcholinesterase Inhibitor Toxicity by Alpha- Adrenergic Agonists

DTIC Science & Technology

1992-10-28

acetvlthiocholine iodide (substrate). and 6.9 mM Dithiosnitrobenzoic acid . The absorbance at 412 nm was recorded for 2 rain. 1~1 RESULTS PART I...however, the drug has been shown to be quite effective in limiting seizure production in the audiogenic 1261 and kainic acid [31 animal models of...acetyicholinesterase inhibitor soman. Neurosci.Ltt. 78: 107-112. 3. Baran, H., Hortnagi, H. and Homykiewicz, 0. (1989). Kainic acid -induced seizures

Nicotinic receptor-dependent and -independent effects of galantamine, an acetylcholinesterase inhibitor, on the non-neuronal acetylcholine system in C2C12 cells.

PubMed

Oikawa, Shino; Mano, Asuka; Iketani, Mitsue; Kakinuma, Yoshihiko

2015-11-01

We previously reported that satellite cells possess the ability to produce angiogenic factors, including fibroblast growth factor (FGF)-2 and vascular endothelial growth factor (VEGF) in vivo. However, whether C2C12 cells possess a non-neuronal cholinergic system (NNCS) or non-neuronal ACh (NNA) remains to be studied; therefore, we investigated the system using C2C12 cells and its regulatory mechanisms. C2C12 cells synthesized ACh, the level of which was comparable with that of cardiomyocytes, and the synthesis was augmented by the acetylcholinesterase inhibitor galantamine. The ChAT promoter activity was upregulated by nicotine or galantamine, partly through nicotinic receptors for both agents as well as through a non-nicotinic receptor pathway for galantamine. Further, VEGF secretion by C2C12 cells was also increased by nicotine or galantamine through nicotinic receptors as well as partly through non-nicotinic pathways in the case of galantamine. These results suggest that C2C12 cells are equipped with NNCS or NNA, which is positively regulated through nicotinic or non-nicotinic pathways, particularly in the case of galantamine. These results provide a novel concept that myogenic cells expressing NNA can be a therapeutic target for regulating angiogenic factor synthesis. Copyright © 2015 Elsevier B.V. All rights reserved.

Isorhamnetin and Quercetin Derivatives as Anti-Acetylcholinesterase Principles of Marigold (Calendula officinalis) Flowers and Preparations.

PubMed

Olennikov, Daniil N; Kashchenko, Nina I; Chirikova, Nadezhda K; Akobirshoeva, Anzurat; Zilfikarov, Ifrat N; Vennos, Cecile

2017-08-02

Marigold ( Calendula officinalis L.) is one of the most common and widespread plants used medicinally all over the world. The present study aimed to evaluate the anti-acetylcholinesterase activity of marigold flowers, detect the compounds responsible and perform chemical analysis of marigold commercial products. Analysis of 23 varieties of C. officinalis flowers introduced into Siberia allowed us to select the Greenheart Orange variety due to the superior content of flavonoids (46.87 mg/g) and the highest inhibitory activity against acetylcholinesterase (IC 50 63.52 µg/mL). Flavonoids, isorhamnetin and quercetin derivatives were revealed as potential inhibitors with the application of high-performance liquid chromatography (HPLC) activity-based profiling. Investigation of the inhibitory activity of isorhamnetin glycosides demonstrated the maximal potency for isorhamnetin-3- О -(2'',6''-di-acetyl)-glucoside (IC 50 51.26 μM) and minimal potency for typhaneoside (isorhamnetin-3- O -(2'',6''-di-rhamnosyl)-glucoside; IC 50 94.92 µM). Among quercetin derivatives, the most active compound was quercetin-3- О -(2'',6''-di-acetyl)-glucoside (IC 50 36.47 µM), and the least active component was manghaslin (quercetin-3- O -(2'',6''-di-rhamnosyl)-glucoside; IC 50 94.92 µM). Some structure-activity relationships were discussed. Analysis of commercial marigold formulations revealed a reduced flavonoid content (from 7.18-19.85 mg/g) compared with introduced varieties. Liquid extract was the most enriched preparation, characterized by 3.10 mg/mL of total flavonoid content, and infusion was the least enriched formulation (0.41 mg/mL). The presented results suggest that isorhamnetin and quercetin and its glycosides can be considered as potential anti-acetylcholinesterase agents.

Attention Measures of Accuracy, Variability, and Fatigue Detect Early Response to Donepezil in Alzheimer's Disease: A Randomized, Double-blind, Placebo-Controlled Pilot Trial.

PubMed

Vila-Castelar, Clara; Ly, Jenny J; Kaplan, Lillian; Van Dyk, Kathleen; Berger, Jeffrey T; Macina, Lucy O; Stewart, Jennifer L; Foldi, Nancy S

2018-04-09

Donepezil is widely used to treat Alzheimer's disease (AD), but detecting early response remains challenging for clinicians. Acetylcholine is known to directly modulate attention, particularly under high cognitive conditions, but no studies to date test whether measures of attention under high load can detect early effects of donepezil. We hypothesized that load-dependent attention tasks are sensitive to short-term treatment effects of donepezil, while global and other domain-specific cognitive measures are not. This longitudinal, randomized, double-blind, placebo-controlled pilot trial (ClinicalTrials.gov Identifier: NCT03073876) evaluated 23 participants newly diagnosed with AD initiating de novo donepezil treatment (5 mg). After baseline assessment, participants were randomized into Drug (n = 12) or Placebo (n = 11) groups, and retested after approximately 6 weeks. Cognitive assessment included: (a) attention tasks (Foreperiod Effect, Attentional Blink, and Covert Orienting tasks) measuring processing speed, top-down accuracy, orienting, intra-individual variability, and fatigue; (b) global measures (Alzheimer's Disease Assessment Scale-Cognitive Subscale, Mini-Mental Status Examination, Dementia Rating Scale); and (c) domain-specific measures (memory, language, visuospatial, and executive function). The Drug but not the Placebo group showed benefits of treatment at high-load measures by preserving top-down accuracy, improving intra-individual variability, and averting fatigue. In contrast, other global or cognitive domain-specific measures could not detect treatment effects over the same treatment interval. The pilot-study suggests that attention measures targeting accuracy, variability, and fatigue under high-load conditions could be sensitive to short-term cholinergic treatment. Given the central role of acetylcholine in attentional function, load-dependent attentional measures may be valuable cognitive markers of early treatment response.

Synthesis, cytotoxicity and molecular modelling studies of new phenylcinnamide derivatives as potent inhibitors of cholinesterases.

PubMed

Saeed, Aamer; Mahesar, Parvez Ali; Zaib, Sumera; Khan, Muhammad Siraj; Matin, Abdul; Shahid, Mohammad; Iqbal, Jamshed

2014-05-06

The present study reports the synthesis of cinnamide derivatives and their biological activity as inhibitors of both cholinesterases and anticancer agents. Controlled inhibition of brain acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) may slow neurodegeneration in Alzheimer's diseases (AD). The anticholinesterase activity of phenylcinnamide derivatives was determined against Electric Eel acetylcholinesterase (EeAChE) and horse serum butyrylcholinesterase (hBChE) and some of the compounds appeared as moderately potent inhibitors of EeAChE and hBChE. The compound 3-(2-(Benzyloxy)phenyl)-N-(3,4,5-trimethoxyphenyl)acrylamide (3i) showed maximum activity against EeAChE with an IC50 0.29 ± 0.21 μM whereas 3-(2-chloro-6-nitrophenyl)-N-(3,4,5-trimethoxyphenyl)acrylamide (3k) was proved to be the most potent inhibitor of hBChE having IC50 1.18 ± 1.31 μM. To better understand the enzyme-inhibitor interaction of the most active compounds toward cholinesterases, molecular modelling studies were carried out on high-resolution crystallographic structures. The anticancer effects of synthesized compounds were also evaluated against cancer cell line (lung carcinoma). The compounds may be useful leads for the design of a new class of anticancer drugs for the treatment of cancer and cholinesterase inhibitors for Alzheimer's disease (AD). Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Protection of human muscle acetylcholinesterase from soman by pyridostigmine bromide.

PubMed

Maselli, Ricardo A; Henderson, John D; Ng, Jarae; Follette, David; Graves, Gregory; Wilson, Barry W

2011-04-01

Pretreatment with pyridostigmine bromide (PB) of human intercostal muscle fibers exposed to the irreversible acetylcholinesterase (AChE) inhibitor soman was investigated. Muscles were pretreated with 3 × 10(-6) M PB or saline for 20 minutes, then exposed to 10(-7) M soman for 10 minutes. AChE of muscles treated with soman alone was inhibited >95%. In contrast, PB pretreatment of soman-exposed bundles protected 20% of AChE activity. AChE of bundles exposed to PB alone recovered after 4 hours, but bundles exposed to both PB and soman did not. Soman-induced reduction of resting membrane potentials and increment of amplitudes and decay times of miniature endplate potentials (MEPPs) were partially corrected by PB pretreatment. In vitro pretreatment of human muscles with PB protected up to 20% of muscle AChE and ameliorated some deleterious effects on endplate physiology induced by soman. Copyright © 2011 Wiley Periodicals, Inc.

Understanding the molecular mechanism of aryl acylamidase activity of acetylcholinesterase - An in silico study.

PubMed

Chinnadurai, Raj Kumar; Saravanaraman, Ponne; Boopathy, Rathanam

2015-08-15

Acetylcholinesterase (AChE) exhibits two different activities, namely esterase and aryl acylamidase (AAA). Unlike esterase, AAA activity of AChE is inhibited by the active site inhibitors while remaining unaffected by the peripheral anionic site inhibitors. This differential inhibitory pattern of active and peripheral anionic site inhibitors on the AAA activity remains unanswered. To answer this, we investigated the mechanism of binding and trafficking of AAA substrates using in silico tools. Molecular docking of serotonin and AAA substrates (o-nitroacetanilide, and o-nitrotrifluoroacetanilide,) onto AChE shows that these compounds bind at the side door of AChE. Thus, we conceived that the AAA substrates prefer the side door to reach the active site for their catalysis. Further, steered molecular dynamics simulations show that the force required for binding and trafficking of the AAA substrate through the side door is comparatively lesser than their dissociation (900kJ/mol/nm). Among the two substrates, o-nitrotrifluoroacetanilide required lesser force (380kJ/mol/nm) than o-nitroacetanilide the (550kJ/mol/nm) for its binding, thus validating o-nitrotrifluoroacetanilide as a better substrate. With these observations, we resolve that the AAA activity of AChE is mediated through its side door. Therefore, binding of PAS inhibitors at the main door of AChE remain ineffective against AAA activity. Copyright © 2015 Elsevier Inc. All rights reserved.

Surface display and bioactivity of Bombyx mori acetylcholinesterase on Pichia pastoris

USDA-ARS?s Scientific Manuscript database

To construct the Pichia pastoris (P. pastoris) cell surface display system of Bombyx mori acetylcholinesterase (BmAChE), the gene for the anchor protein (AGa1) was obtained from Saccharomyces cerevisiae and was fused with the modified Bombyx mori acetylcholinesterase gene (bmace) and transformed int...

Characterization of monoclonal antibodies that strongly inhibit Electrophorus electricus acetylcholinesterase.

PubMed

Remy, M H; Frobert, Y; Grassi, J

1995-08-01

In this study, we describe three different monoclonal antibodies (mAbs Elec-403, Elec-408, and Elec-410) directed against Electrophorus electricus acetylcholinesterase (AChE) which were selected as inhibitors for this enzyme. Two of these antibodies (Elec-403 and Elec-410), recognized overlapping but different epitopes, competed with snake venom toxin fasciculin for binding to the enzyme, and thus apparently recognized the peripheral site of AChE. In addition, the binding of Elec-403 was antagonized by 1,5-bis(4-allyldimethylammoniumphenyl)pentan-3-one dibromide (BW284C51) and propidium, indicating that the corresponding epitope encompassed the anionic site involved in the binding of these low-molecular-mass inhibitors. The third mAb (Elec-408), was clearly bound to another site on the AChE molecule, and its inhibitory effect was cumulative with those of Elec-403, Elec-410, and fasciculin. All mAbs bound AChE with high affinity and were as strong inhibitors with an apparent Ki values less than 0.1 nM. Elec-403 was particularly efficient with an inhibitory activity similar to that of fasciculin. Inhibition was observed with both charged (acetylthiocholine) and neutral substrates (o-nitrophenyl acetate) and had the characteristics of a non-competitive process. Elec-403 and Elec-410 probably exert their effect by triggering allosteric transitions from the peripheral site to the active site. The epitope recognized by mAb Elec-408 has not been localized, but it may correspond to a new regulatory site on AChE.

Virtual screening using MTiOpenScreen and PyRx 0,8 revealed ZINC95486216 as a human acetylcholinesterase inhibitor candidate

NASA Astrophysics Data System (ADS)

Sulistyo Dwi K., P.; Arindra Trisna, W.; Vindri Catur P., W.; Wijayanti, Erna; Ichsan, Mochammad

2016-03-01

One of the efforts to prevent Alzheimer's disease becomes more severe is by inhibiting the activity of Human acetylcholinesterase enzyme (PDB ID: 4BDT). In this study, virtual screening againts 885 natural compounds from AfroDB has been done using MTIOpenScreen and this step has been successful in identifying ZINC15121024 (-12,9) and ZINC95486216 (-12,7) as the top rank compounds. This data then strengthened by the results of second docking step using Autodock software that has been integrated in PyRx 0.8 software. From this stage, ZINC95486216 (-11,3 kcal/mol) is a compound with the most negative binding affinity compared with four Alzheimer's drugs that have been officially used to date including Rivastigmine (-6,3 Kcal/mol), Donepenzil (-7.9 kcal/mol), Galantamine (-8.4 kcal/mol), and Huprine W (-7.3 kcal/mol). In addition, based on the results of the 2D and 3D visualization using LigPlus and PyMol softwares, respectively, known that the five compounds above are equally capable of binding to several amino acids (Trp 286, Phe295, and Tyr341) located in the active site of Human Acetylcholinesterase enzyme.

Gold nanoclusters-Cu(2+) ensemble-based fluorescence turn-on and real-time assay for acetylcholinesterase activity and inhibitor screening.

PubMed

Sun, Jian; Yang, Xiurong

2015-12-15

Based on the specific binding of Cu(2+) ions to the 11-mercaptoundecanoic acid (11-MUA)-protected AuNCs with intense orange-red emission, we have proposed and constructed a novel fluorescent nanomaterials-metal ions ensemble at a nonfluorescence off-state. Subsequently, an AuNCs@11-MUA-Cu(2+) ensemble-based fluorescent chemosensor, which is amenable to convenient, sensitive, selective, turn-on and real-time assay of acetylcholinesterase (AChE), could be developed by using acetylthiocholine (ATCh) as the substrate. Herein, the sensing ensemble solution exhibits a marvelous fluorescent enhancement in the presence of AChE and ATCh, where AChE hydrolyzes its active substrate ATCh into thiocholine (TCh), and then TCh captures Cu(2+) from the ensemble, accompanied by the conversion from fluorescence off-state to on-state of the AuNCs. The AChE activity could be detected less than 0.05 mU/mL within a good linear range from 0.05 to 2.5 mU/mL. Our proposed fluorescence assay can be utilized to evaluate the AChE activity quantitatively in real biological sample, and furthermore to screen the inhibitor of AChE. As far as we know, the present study has reported the first analytical proposal for sensing AChE activity in real time by using a fluorescent nanomaterials-Cu(2+) ensemble or focusing on the Cu(2+)-triggered fluorescence quenching/recovery. This strategy paves a new avenue for exploring the biosensing applications of fluorescent AuNCs, and presents the prospect of AuNCs@11-MUA-Cu(2+) ensemble as versatile enzyme activity assay platforms by means of other appropriate substrates/analytes. Copyright © 2015 Elsevier B.V. All rights reserved.

Mechanism of Acetylcholinesterase Inhibition by Fasciculin: A 5-ns Molecular Dynamics Simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tai, Kaihsu; Shen, T Y.; Henchman, Richard H.

Our previous molecular dynamics simulation (10 ns) of mouse acetylcholinesterase (EC 3.1.1.7) revealed complex fluctuation of the enzyme active site gorge. Now we report a 5-ns simulation of acetylcholinesterase complexed with fasciculin 2. Fasciculin 2 binds to the gorge entrance of acetylcholinesterase with excellent complementarity and many polar and hydrophobic interactions. In this simulation of the protein-protein complex, where fasciculin 2 appears to sterically block access of ligands to the gorge, again we observe a two-peaked probability distribution of the gorge width. When fasciculin is present, the gorge width distribution is altered such that the gorge is more likely tomore » be narrow. Moreover, there are large increases in the opening of alternative passages, namely, the side door (near Thr 75) and the back door (near Tyr 449). Finally, the catalytic triad arrangement in the acetylcholinesterase active site is disrupted with fasciculin bound. These data support that, in addition to the steric obstruction seen in the crystal structure, fasciculin may inhibit acetylcholinesterase by combined allosteric and dynamical means. Additional data from these simulations can be found at http://mccammon.ucsd.edu/.« less

Development of a 3D-QSAR model for acetylcholinesterase inhibitors using a combination of fingerprint, docking, and structure-based pharmacophore approaches - Conference Abstract

EPA Science Inventory

Acetylcholinesterase (AChE), a serine hydrolase vital for regulating the neurotransmitter acetylcholine in animals, has been used as a target for drugs and pesticides. With the increasing availability of AChE crystal structures, with or without ligands bound, structure-based appr...

Effectiveness and Safety of Donepezil in Hispanic Patients with Alzheimer’s Disease: A 12-Week Open-Label Study

PubMed Central

Lopez, Oscar L.; Mackell, Joan A.; Sun, Yijun; Kassalow, Laurent M.; Xu, Yikang; McRae, Thomas; Li, Honglan

2009-01-01

Background Hispanics represent 10% of the U.S. population and are the fastest growing group. Studies show a higher prevalence and incidence of Alzheimer’s disease (AD) in Hispanics than in the non-Hispanic white population, with an earlier age of onset. Among the currently estimated 200,000 Hispanics with AD, a significant number remain undiagnosed and untreated, and Hispanic participation in AD clinical trials has been historically low. This study evaluated the efficacy and safety of donepezil hydrochloride (donepezil) in Hispanics with mild-to-moderate AD. Methods In this multicenter, open-label, 12-week study conducted in the United States, subjects were Hispanic men or women aged ≥50 years with a diagnosis of mild-to-moderate AD (DSMV-IV and NINCDS/ADRDA criteria), with Mini-Mental State Examination (MMSE) scores of 10–26 (inclusive) at screening. Subjects were treated with donepezil 5 mg/day for 6 weeks followed by 10 mg/day for 6 weeks. Clinical evaluation was performed at baseline, week 6 and week 12. Cognitive improvement was measured using the MMSE, Fuld Object Memory Evaluation (FOME) and Symbol Digit Modality Test (SDMT). Behavioral symptoms and associated caregiver distress were assessed with the Neuropsychiatric Inventory (NPI). Results One-hundred-six patients with mild-to-moderate AD (mean age 68.6 years) were enrolled (intent to treat, n=97); most chose to have assessments conducted in Spanish. With 12 weeks of treatment, subjects showed statistically significant improvement from baseline on MMSE (P<0.0001), FOME retrieval (P=0.0042), FOME repeated retrieval (P=0.0020) and SDMT correct scores (P<0.0001). The NPI subdomain “apathy/indifference” showed statistically significant improvement (P=0.0010). The NPI Caregiver Distress scale (NPI-D) total score was statistically significantly improved (P=0.0500), suggesting a positive impact on relieving caregivers’ burden associated with patient behavior. Most patients tolerated the treatment

Isorhamnetin and Quercetin Derivatives as Anti-Acetylcholinesterase Principles of Marigold (Calendula officinalis) Flowers and Preparations

PubMed Central

Kashchenko, Nina I.; Chirikova, Nadezhda K.; Akobirshoeva, Anzurat; Zilfikarov, Ifrat N.; Vennos, Cecile

2017-01-01

Marigold (Calendula officinalis L.) is one of the most common and widespread plants used medicinally all over the world. The present study aimed to evaluate the anti-acetylcholinesterase activity of marigold flowers, detect the compounds responsible and perform chemical analysis of marigold commercial products. Analysis of 23 varieties of C. officinalis flowers introduced into Siberia allowed us to select the Greenheart Orange variety due to the superior content of flavonoids (46.87 mg/g) and the highest inhibitory activity against acetylcholinesterase (IC50 63.52 µg/mL). Flavonoids, isorhamnetin and quercetin derivatives were revealed as potential inhibitors with the application of high-performance liquid chromatography (HPLC) activity-based profiling. Investigation of the inhibitory activity of isorhamnetin glycosides demonstrated the maximal potency for isorhamnetin-3-O-(2′′,6′′-di-acetyl)-glucoside (IC50 51.26 μM) and minimal potency for typhaneoside (isorhamnetin-3-O-(2′′,6′′-di-rhamnosyl)-glucoside; IC50 94.92 µM). Among quercetin derivatives, the most active compound was quercetin-3-O-(2′′,6′′-di-acetyl)-glucoside (IC50 36.47 µM), and the least active component was manghaslin (quercetin-3-O-(2′′,6′′-di-rhamnosyl)-glucoside; IC50 94.92 µM). Some structure-activity relationships were discussed. Analysis of commercial marigold formulations revealed a reduced flavonoid content (from 7.18–19.85 mg/g) compared with introduced varieties. Liquid extract was the most enriched preparation, characterized by 3.10 mg/mL of total flavonoid content, and infusion was the least enriched formulation (0.41 mg/mL). The presented results suggest that isorhamnetin and quercetin and its glycosides can be considered as potential anti-acetylcholinesterase agents. PMID:28767066

[Treatment pattern of Alzheimer's disease with cholinesterase inhibitors (TRAIN study)].

PubMed

Gil-Néciga, E; Gobartt, A L

To describe the relation between the level of cognitive impairment in Alzheimer's disease and the use of cholinesterase inhibitors (ChEIs) in neurology, geriatric and psychiatric units, and to establish the clinical profile of these patients. An epidemiological, multi-centre, cross-sectional study was conducted. Subjects included in the study were consecutive outpatients diagnosed with Alzheimer's disease, in accordance with the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders, and who had been treated with rivastigmine, donepezil or galantamine, either on its own or in association with memantine in the last six months. The recruitment period lasted three months. In a single visit, researchers determined the medication that was used, the dose, the mini-mental test, the overall clinical impression-overall improvement and the overall clinical impression-severity of the disease. A total of 1940 patients were selected from neurology, psychiatric and geriatric services all over the country. Possible differences in the habits of different specialists as regards prescribing were analysed, together with the relation between cognitive impairment and the type of medication employed. The mean age of the patients was 77 +/- 6.6 years, 62% of whom were females; the mean score on the mini-mental test was 17.4 +/- 5.5. The mini-mental score was similar in patients treated with rivastigmine (18.02 +/- 5.23), donepezil (17.08 +/- 5.54) or galantamine (17.34 +/- 5.38). In patients who were treated with memantine in association with a ChEI, the mini-mental score was significantly lower (11.44 +/- 5.68) (p < 0.0001). The doses of the different ChEIs used by the specialists were similar. A higher percentage of patients had maximum doses of donepezil (81%) than in the cases of rivastigmine (43%) and galantamine (67%). The different specialists involved (neurologists, geriatricians and psychiatrists) displayed similar habits regarding the utilisation of Ch

Novel polyacetylene derivatives and their inhibitory activities on acetylcholinesterase obtained from Panax ginseng roots.

PubMed

Murata, Kazuya; Iida, Daiki; Ueno, Yoshihiro; Samukawa, Keiichi; Ishizaka, Toshihiko; Kotake, Takeshi; Matsuda, Hideaki

2017-01-01

In our research program to identify cholinesterase and β-secretase inhibitors, we investigated Ginseng (root of Panax ginseng), a crude drug described as a multifunctional drug in the ancient Chinese herbal book Shennong Ben Cao Jing. Results from hexane and methanol extracts showed moderate inhibitory activities. This suggests that ginseng roots may be effective for the prevention of and therapy for dementia. We then focused on hexane extracts of raw ginseng root and dried ginseng root since the determination of hexane extract constituents has not been studied extensively. Activity-guided fractionation and purification led to the isolation of 4 polyacetylene compounds; homopanaxynol, homopanaxydol, (9Z)-heptadeca-1, 9-diene-4,6-diyn-3-one, and (8E)-octadeca-1,8-diene-4,6-diyn-3,10-diol. The chemical structures of these compounds, including stereochemistry, were determined. This is the first study to identify the structure of homopanaxynol and homopanaxydol. Moreover, the modes of action of some compounds were characterized as competitive inhibitors. This study showed, for the first time, that polyacetylene compounds possess acetylcholinesterase inhibitory activities.

Properties of bovine erythrocyte acetylcholinesterase solubilized by phosphatidylinositol-specific phospholipase C1.

PubMed

Taguchi, R; Ikezawa, H

1987-10-01

The properties of acetylcholinesterase solubilized from bovine erythrocyte membrane by phosphatidylinositol (PI)-specific phospholipase C of Bacillus thuringiensis or with a detergent, Lubrol-PX, were studied. The activity of Lubrol-PX-solubilized acetylcholinesterase was broadly distributed in the fractions having Ve/Vo = 1.0-2.0 in gel filtration on a Sepharose 6B column. The intermediary fractions (Ve/Vo = 1.3-1.7) were collected as "the middle active Sepharose 6B eluate" and characterized on the basis of enzymology and protein chemistry. When this eluate was treated with PI-specific phospholipase C, the major activity peak was obtained in the later fractions with Ve/Vo = 1.75-2.0 on the same column chromatography. Lubrol-solubilized and phospholipase C-treated acetylcholinesterase preparations were different in the thermostability, the elution profiles of chromatography on Mono Q, butyl-Toyopearl and phenyl-Sepharose columns, and the affinity to phospholipid micelles. On treatment with PI-specific phospholipase C, Lubrol-solubilized acetylcholinesterase became more thermostable. The phospholipase C-treated enzyme was eluted at lower NaCl concentration from the Mono Q column than the Lubrol-solubilized enzyme. The most important difference was observed in the hydrophobicity of these two enzyme preparations. The Lubrol-solubilized enzyme shows high affinity to phospholipid micelles and hydrophobic adsorbents such as butyl-Toyopearl and phenyl-Sepharose. However, this hydrophobicity was lost when acetylcholinesterase was solubilized from bovine erythrocyte membrane by PI-specific phospholipase C. The presence of myo-inositol was confirmed in the purified preparation of acetylcholinesterase by gas chromatography (GC)-mass spectrometry (MS).(ABSTRACT TRUNCATED AT 250 WORDS)

Associations of centrally acting ACE inhibitors with cognitive decline and survival in Alzheimer’s disease

PubMed Central

Fazal, Karim; Khondoker, Mizanur; Howard, Robert; Stewart, Robert

2017-01-01

Background Cognitive improvement has been reported in patients receiving centrally acting angiotensin-converting enzyme inhibitors (C-ACEIs). Aims To compare cognitive decline and survival after diagnosis of Alzheimer’s disease between people receiving C-ACEIs, non-centrally acting angiotensin-converting enzyme inhibitors (NC-ACEIs), and neither. Method Routine Mini-Mental State Examination (MMSE) scores were extracted in 5260 patients receiving acetylcholinesterase inhibitors and analysed against C-/NC-ACEI exposure at the time of Alzheimer’s disease diagnosis. Results In the 9 months after Alzheimer’s disease diagnosis, MMSE scores significantly increased by 0.72 and 0.19 points per year in patients on C-ACEIs and neither respectively, but deteriorated by 0.61 points per year in those on NC-ACEIs. There were no significant group differences in score trajectories from 9 to 36 months and no differences in survival. Conclusions In people with Alzheimer’s disease receiving acetylcholinesterase inhibitors, those also taking C-ACEIs had stronger initial improvement in cognitive function, but there was no evidence of longer-lasting influence on dementia progression. Declaration of interest R.S. has received research funding from Pfizer, Lundbeck, Roche, Janssen and GlaxoSmithKline. Copyright and usage © The Royal College of Psychiatrists 2017. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) license. PMID:28713585

Novel multipotent tacrine-dihydropyridine hybrids with improved acetylcholinesterase inhibitory and neuroprotective activities as potential drugs for the treatment of Alzheimer's disease.

PubMed

Marco-Contelles, José; León, Rafael; de Los Ríos, Cristóbal; Guglietta, Antonio; Terencio, José; López, Manuela G; García, Antonio G; Villarroya, Mercedes

2006-12-28

In this work we describe the synthesis and biological evaluation of the tacrine-1,4-dihydropyridine (DHP) hybrids (3-11). These multipotent molecules are the result of the juxtaposition of an acetylcholinesterase inhibitor (AChEI) such as tacrine (1) and a 1,4-DHP such as nimodipine (2). Compounds 3-11 are very selective and potent AChEIs and show an excellent neuroprotective profile and a moderate Ca2+ channel blockade effect. Consequently, these molecules are new potential drugs for the treatment of Alzheimer's disease.

A novel fluorine-18 β-fluoroethoxy organophosphate positron emission tomography imaging tracer targeted to central nervous system acetylcholinesterase.

PubMed

James, Shelly L; Ahmed, S Kaleem; Murphy, Stephanie; Braden, Michael R; Belabassi, Yamina; VanBrocklin, Henry F; Thompson, Charles M; Gerdes, John M

2014-07-16

Radiosynthesis of a fluorine-18 labeled organophosphate (OP) inhibitor of acetylcholinesterase (AChE) and subsequent positron emission tomography (PET) imaging using the tracer in the rat central nervous system are reported. The tracer structure, which contains a novel β-fluoroethoxy phosphoester moiety, was designed as an insecticide-chemical nerve agent hybrid to optimize handling and the desired target reactivity. Radiosynthesis of the β-fluoroethoxy tracer is described that utilizes a [(18)F]prosthetic group coupling approach. The imaging utility of the [(18)F]tracer is demonstrated in vivo within rats by the evaluation of its brain penetration and cerebral distribution qualities in the absence and presence of a challenge agent. The tracer effectively penetrates brain and localizes to cerebral regions known to correlate with the expression of the AChE target. Brain pharmacokinetic properties of the tracer are consistent with the formation of an OP-adducted acetylcholinesterase containing the fluoroethoxy tracer group. Based on the initial favorable in vivo qualities found in rat, additional [(18)F]tracer studies are ongoing to exploit the technology to dynamically probe organophosphate mechanisms of action in mammalian live tissues.

Use of antidementia drugs and risk of pneumonia in older persons with Alzheimer's disease.

PubMed

Lampela, Pasi; Tolppanen, Anna-Maija; Tanskanen, Antti; Tiihonen, Jari; Lavikainen, Piia; Hartikainen, Sirpa; Taipale, Heidi

2017-05-01

Persons with Alzheimer's disease are at an increased risk of pneumonia, but the comparative risks during specific antidementia treatments are not known. We compared the risk of pneumonia in the use of donepezil, rivastigmine (oral, transdermal), galantamine and memantine. We used data from a nationwide cohort of community-dwelling individuals diagnosed with Alzheimer's disease during 2005-2011 in Finland, who initiated monotherapy with acetylcholinesterase inhibitor or memantine (n = 65,481). The risk of hospitalization or death due to pneumonia was investigated with Cox proportional hazard models. The risk of pneumonia was higher in persons using rivastigmine patch (n = 9709) (adjusted hazard ratio (HR) 1.15, 95% confidence interval (CI) 1.04-1.27) and memantine (n = 11,024) (HR 1.59, 95% CI 1.48-1.71) compared with donepezil users (n = 26,416) whereas oral rivastigmine (n = 7384) (HR 1.08, 95% CI 0.98-1.19) and galantamine (n = 10,948) (HR 0.91, 95% CI 0.83-1.00) were not associated with an increased risk. These results did not change when adjusting for comorbid conditions, use of psychotropic drugs or with inverse probability of treatment weighting. The increased risk of pneumonia in this fragile group of aged persons should be taken into account. Memantine is associated with the highest risk in the comparison of antidementia drugs. KEY Message Pneumonia risk is increased in persons with Alzheimer's disease who use memantine or rivastigmine patches.

Pyridostigmine bromide protection against acetylcholinesterase inhibition by pesticides.

PubMed

Henderson, John D; Glucksman, Gabriela; Leong, Bryan; Tigyi, Andras; Ankirskaia, Anna; Siddique, Imteaz; Lam, Helen; DePeters, Ed; Wilson, Barry W

2012-01-01

Pyridostigmine bromide (PB) has been used to protect soldiers from the toxic effects of soman, a chemical warfare agent. Recent research shows that pyridostigmine bromide protects a significant percentage of acetylcholinesterase in isolated human intercostal muscle. Findings presented here indicate that red blood cell acetylcholinesterase is similarly protected by pyridostigmine bromide from the action of diisopropyl fluorophosphate and several organophosphate pesticides including chlorpyrifos-oxon, diazinon-oxon, and paraoxon, but not malaoxon, using the bovine red blood cell as a subject. These findings suggest that pretreatment with PB may protect growers, farmworkers, first responders, and the public, in general, from the effects of selected pesticides. Copyright © 2011 Wiley Periodicals, Inc.

Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart.

PubMed

Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

2016-02-02

A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4-9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. © 2016 Authors.

Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart

PubMed Central

Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

2016-01-01

A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4–9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. PMID:26839417

Mechanism-Based Analysis of Acetylcholinesterase Inhibitory Potency of Organophosphates, Carbamates, and Their Analogs

EPA Science Inventory

Acetylcholinesterase (AChE) is a key enzyme in the nervous system of animals, terminating impulse transmission by rapid hydrolysis of the neurotransmitter acetylcholine. Organophosphate (OP) and carbamate esters can inhibit acetylcholinesterase (AChE) by binding covalently to a s...

Insect-specific irreversible inhibitors of acetylcholinesterase in pests including the bed bug, the eastern yellowjacket, German and American cockroaches, and the confused flour beetle.

PubMed

Polsinelli, Gregory A; Singh, Sanjay K; Mishra, Rajesh K; Suranyi, Robert; Ragsdale, David W; Pang, Yuan-Ping; Brimijoin, Stephen

2010-09-06

Insecticides directed against acetylcholinesterase (AChE) are facing increased resistance among target species as well as increasing concerns for human toxicity. The result has been a resurgence of disease vectors, insects destructive to agriculture, and residential pests. We previously reported a free cysteine (Cys) residue at the entrance to the AChE active site in some insects but not higher vertebrates. We also reported Cys-targeting methanethiosulfonate molecules (AMTSn), which, under conditions that spared human AChE, caused total irreversible inhibition of aphid AChE, 95% inhibition of AChE from the malaria vector mosquito (Anopheles gambia), and >80% inhibition of activity from the yellow fever mosquito (Aedes aegypti) and northern house mosquito (Culex pipiens). We now find the same compounds inhibit AChE from cockroaches (Blattella germanica and Periplaneta americana), the flour beetle (Tribolium confusum), the multi-colored Asian ladybird beetle (Harmonia axyridis), the bed bug (Cimex lectularius), and a wasp (Vespula maculifrons), with IC(50) values of approximately 1-11muM. Our results support further study of Cys-targeting inhibitors as conceptually novel insecticides that may be free of resistance in a range of insect pests and disease vectors and, compared with current compounds, should demonstrate much lower toxicity to mammals, birds, and fish. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Altered expression of acetylcholinesterase gene in rice results in enhancement or suppression of shoot gravitropism.

PubMed

Yamamoto, Kosuke; Sakamoto, Hikaru; Momonoki, Yoshie S

2016-01-01

Acetylcholinesterase (AChE), an acetylcholine-hydrolyzing enzyme, exists widely in plants, although its role in plant signal transduction is still unclear. We have hypothesized that the plant AChE regulates asymmetric distribution of hormones and substrates due to gravity stimulus, based on indirect pharmacological experiments using an AChE inhibitor. As a direct evidence for this hypothesis, our recent study has shown that AChE overexpression causes an enhanced gravitropic response in rice seedlings and suggested that the function of the rice AChE relates to the promotion of shoot gravitropism in the seedlings. Here, we report that AChE suppression inhibited shoot gravitropism in rice seedlings, as supportive evidence demonstrating the role of AChE as a positive regulator of shoot gravitropic response in plants.

Novel acetylcholinesterase inhibitors from Zijuan tea and biosynthetic pathway of caffeoylated catechin in tea plant.

PubMed

Wang, Wei; Fu, Xi-Wen; Dai, Xin-Long; Hua, Fang; Chu, Gang-Xiu; Chu, Ming-Jie; Hu, Feng-Lin; Ling, Tie-Jun; Gao, Li-Ping; Xie, Zhong-Wen; Wan, Xiao-Chun; Bao, Guan-Hu

2017-12-15

Zijuan tea is a special cultivar of Yunnan broad-leaf tea (Camellia sinensis var. assamica) with purple buds, leaves, and stems. Phytochemical study on this tea led to the discovery of three hydroxycinnamoylated catechins (HCCs) (1-3), seven other catechins (4-10), three proanthocyanidins (11-13), five flavones and flavone glycosides (14-18), two alkaloids (19, 20), one steroid (21), and one phenylpropanoid glycoside (22). The isolation and structural elucidation of the caffeoylated catechin (1) by means of spectroscopic techniques were described. We also provide the first evidence that 1 is synthesized via a two-step pathway in tea plant. The three HCCs (1-3) were investigated on their bioactivity through molecular modeling simulation and biochemical experiments. Our results show that they bind acetylcholinesterase (AChE) tightly and have strong AChE inhibitory activity with IC 50 value at 2.49, 11.41, 62.26μM, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Generating genius: how an Alzheimer's drug became considered a 'cognitive enhancer' for healthy individuals.

PubMed

Wade, Lucie; Forlini, Cynthia; Racine, Eric

2014-05-12

Donepezil, an acetylcholinesterase inhibitor used in the treatment of Alzheimer's disease, has been widely cited in media and bioethics literature on cognitive enhancement (CE) as having the potential to improve the cognitive ability of healthy individuals. In both literatures, this claim has been repeatedly supported by the results of a small study published by Yesavage et al. in 2002 on non-demented pilots (30-70 years old). The factors contributing to this specific interpretation of this study's results are unclear. We examined print media and interdisciplinary bioethics coverage of this small study, aiming to provide insight into how evidence from research may be shaped within different discourses, potentially influencing important policy, ethics, and clinical decisions. Systematic qualitative content analysis was used to examine how this study was reported in 27 media and 22 bioethics articles. Articles were analyzed for content related to: (1) headlines and titles; (2) colloquialisms; and, (3) accuracy of reporting of the characteristics and results of the study. In media and bioethics articles referencing this small study, strong claims were made about donepezil as a CE drug. The majority of headlines, titles, and colloquialisms used enhancement language and the majority of these suggest that donepezil could be used to enhance intellectual ability. Further, both literatures moved between reporting the results of the primary study and magnifying the perceived connection between these results and the CE debate that was alluded to in the primary study. Specific descriptions of the results overwhelmingly reported an improvement in performance on a flight simulator, while more general statements claimed donepezil enhanced cognitive performance. Further, a high level of reporting accuracy was found regarding study characteristics of the original study, but variable levels of accuracy surrounded the presentation of complex characteristics (i.e., methods) or

Generating genius: how an Alzheimer’s drug became considered a ‘cognitive enhancer’ for healthy individuals

PubMed Central

2014-01-01

Background Donepezil, an acetylcholinesterase inhibitor used in the treatment of Alzheimer’s disease, has been widely cited in media and bioethics literature on cognitive enhancement (CE) as having the potential to improve the cognitive ability of healthy individuals. In both literatures, this claim has been repeatedly supported by the results of a small study published by Yesavage et al. in 2002 on non-demented pilots (30–70 years old). The factors contributing to this specific interpretation of this study’s results are unclear. Methods We examined print media and interdisciplinary bioethics coverage of this small study, aiming to provide insight into how evidence from research may be shaped within different discourses, potentially influencing important policy, ethics, and clinical decisions. Systematic qualitative content analysis was used to examine how this study was reported in 27 media and 22 bioethics articles. Articles were analyzed for content related to: (1) headlines and titles; (2) colloquialisms; and, (3) accuracy of reporting of the characteristics and results of the study. Results In media and bioethics articles referencing this small study, strong claims were made about donepezil as a CE drug. The majority of headlines, titles, and colloquialisms used enhancement language and the majority of these suggest that donepezil could be used to enhance intellectual ability. Further, both literatures moved between reporting the results of the primary study and magnifying the perceived connection between these results and the CE debate that was alluded to in the primary study. Specific descriptions of the results overwhelmingly reported an improvement in performance on a flight simulator, while more general statements claimed donepezil enhanced cognitive performance. Further, a high level of reporting accuracy was found regarding study characteristics of the original study, but variable levels of accuracy surrounded the presentation of complex

Acetylcholinesterase biosensor based on single-walled carbon nanotubes--Co phtalocyanine for organophosphorus pesticides detection.

PubMed

Ivanov, A N; Younusov, R R; Evtugyn, G A; Arduini, F; Moscone, D; Palleschi, G

2011-07-15

A simple and reliable technique has been developed for the construction of an amperometric acetylcholinesterase biosensor based on screen-printed carbon electrodes. For the first time, one-step modification using single-walled carbon nanotubes and Co phtalocyanine has been proposed to decrease the working potential and to increase the signal of thiocholine oxidation. The biosensor developed made it possible to detect 5-50 ppb of paraoxon and 2-50 ppb of malaoxon with detection limits of 3 and 2 ppb, respectively (incubation 15 min). The biosensor showed high reproducibility when measurements of the substrate and inhibitor were performed (R.S.D. about 1% and 2.5%, respectively). The reliability of the inhibition measurements was confirmed by testing spiked samples of sparkling and tape waters. Copyright © 2011 Elsevier B.V. All rights reserved.

The non-competitive acetylcholinesterase inhibitor APS12-2 is a potent antagonist of skeletal muscle nicotinic acetylcholine receptors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grandič, Marjana; Aráoz, Romulo; Molgó, Jordi

APS12-2, a non-competitive acetylcholinesterase inhibitor, is one of the synthetic analogs of polymeric alkylpyridinium salts (poly-APS) isolated from the marine sponge Reniera sarai. In the present work the effects of APS12-2 were studied on isolated mouse phrenic nerve–hemidiaphragm muscle preparations, using twitch tension measurements and electrophysiological recordings. APS12-2 in a concentration-dependent manner blocked nerve-evoked isometric muscle contraction (IC{sub 50} = 0.74 μM), without affecting directly-elicited twitch tension up to 2.72 μM. The compound (0.007–3.40 μM) decreased the amplitude of miniature endplate potentials until a complete block by concentrations higher than 0.68 μM, without affecting their frequency. Full size endplate potentials,more » recorded after blocking voltage-gated muscle sodium channels, were inhibited by APS12-2 in a concentration-dependent manner (IC{sub 50} = 0.36 μM) without significant change in the resting membrane potential of the muscle fibers up to 3.40 μM. The compound also blocked acetylcholine-evoked inward currents in Xenopus oocytes in which Torpedo (α1{sub 2}β1γδ) muscle-type nicotinic acetylcholine receptors (nAChRs) have been incorporated (IC{sub 50} = 0.0005 μM), indicating a higher affinity of the compound for Torpedo (α1{sub 2}β1γδ) than for the mouse (α1{sub 2}β1γε) nAChR. Our data show for the first time that APS12-2 blocks neuromuscular transmission by a non-depolarizing mechanism through an action on postsynaptic nAChRs of the skeletal neuromuscular junction. -- Highlights: ► APS12-2 produces concentration-dependent inhibition of nerve-evoked muscle contraction in vitro. ► APS12-2 blocks MEPPs and EPPs at the neuromuscular junction. APS12-2 blocks ACh-activated current in Xenopus oocytes incorporated with Torpedo nAChRs.« less

Standardized extract of Lactuca sativa Linn. and its fractions abrogates scopolamine-induced amnesia in mice: A possible cholinergic and antioxidant mechanism.

PubMed

Malik, Jai; Kaur, Jagpreet; Choudhary, Sunayna

2018-06-01

The present study was designed to evaluate the efficacy of Lactuca sativa (LS) Linn. (Asteraceae) against scopolamine-induced amnesia and to validate its traditional claim as memory enhancer. Ethanol extract of fresh LS leaves (LSEE), standardized on the basis of quercetin content, was successively partitioned using various solvents viz., hexane, ethyl acetate, and n-butanol in increasing order of polarity. LSEE (50, 100, and 200 mg/kg) and its various fractions (at a dose equivalent to dose of LSEE exhibiting maximum activity), administered orally for 14 days, were evaluated for their memory enhancing effect against scopolamine-induced (1 mg/kg, i.p.) amnesia in 3-4 months old male Laca mice (n = 6 in each group). The memory enhancing effect was evaluated using behavioural (elevated plus maze, novel object recognition and Morris water maze tests) and biochemical parameters (acetylcholinesterase activity, malonaldehyde, superoxide dismutase, nitrite, catalase, and reduced gultathione content). The results of the test substances were compared with both scopolamine and donepezil that was used as a standard memory enhancer and acetylcholinesterase inhibitor. Scopolamine elicit marked deterioration of memory and alteration in biochemical parameters in comparison to the control group. LSEE and its n-butanol and aqueous fractions significantly (P < 0.05) attenuated the scopolamine-induced amnesia that was evident in all the behavioural and biochemical test parameters. LSEE (200 mg/kg) and n-butanol fraction (15 mg/kg) exhibited maximum anti-amnesic effect among various tested dose levels. The results exhibited that LS prophylaxis attenuated scopolamine-induced memory impairment through its acetylcholinesterase inhibitory and antioxidant activity validating its traditional claim.

Kinetics of Huperzine A Dissociation from Acetylcholinesterase via Multiple Unbinding Pathways.

PubMed

Rydzewski, J; Jakubowski, R; Nowak, W; Grubmüller, H

2018-06-12

The dissociation of huperzine A (hupA) from Torpedo californica acetylcholinesterase ( TcAChE) was investigated by 4 μs unbiased and biased all-atom molecular dynamics (MD) simulations in explicit solvent. We performed our study using memetic sampling (MS) for the determination of reaction pathways (RPs), metadynamics to calculate free energy, and maximum-likelihood estimation (MLE) to recover kinetic rates from unbiased MD simulations. Our simulations suggest that the dissociation of hupA occurs mainly via two RPs: a front door along the axis of the active-site gorge (pwf) and through a new transient side door (pws), i.e., formed by the Ω-loop (residues 67-94 of TcAChE). An analysis of the inhibitor unbinding along the RPs suggests that pws is opened transiently after hupA and the Ω-loop reach a low free-energy transition state characterized by the orientation of the pyridone group of the inhibitor directed toward the Ω-loop plane. Unlike pws, pwf does not require large structural changes in TcAChE to be accessible. The estimated free energies and rates agree well with available experimental data. The dissociation rates along the unbinding pathways are similar, suggesting that the dissociation of hupA along pws is likely to be relevant. This indicates that perturbations to hupA- TcAChE interactions could potentially induce pathway hopping. In summary, our results characterize the slow-onset inhibition of TcAChE by hupA, which may provide the structural and energetic bases for the rational design of the next-generation slow-onset inhibitors with optimized pharmacokinetic properties for the treatment of Alzheimer's disease.

Novel structural hybrids of pyrazolobenzothiazines with benzimidazoles as cholinesterase inhibitors.

PubMed

Aslam, Sana; Zaib, Sumera; Ahmad, Matloob; Gardiner, John M; Ahmad, Aqeel; Hameed, Abdul; Furtmann, Norbert; Gütschow, Michael; Bajorath, Jürgen; Iqbal, Jamshed

2014-05-06

Two series of novel pyrazolobenzothiazine-based hybrid compounds were efficiently synthesized starting from saccharin sodium salt. Pyrazolo[4,3-c][1,2]benzothiazine scaffolds were N-arylated by using p-fluorobenzaldehyde, followed by the incorporation of a benzimidazole or similar ring systems by treatment with arylenediamines. These phenylene-connected hybrid compounds were investigated as potential inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Compounds 12d and 12k were the most potent AChE inhibitors with IC50 values of 11 and 13 nM, respectively, while 6j (IC50 = 17 nM) proved to be the most active inhibitor against BuChE with remarkable selectivity for BuChE over AChE. Molecular docking studies were also performed on human AChE and BuChE to suggest possible binding modes in which the inhibitor's extended structure is accommodated along the active site gorge of both enzymes. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Curcumin administration suppress acetylcholinesterase gene expression in cadmium treated rats.

PubMed

Akinyemi, Ayodele Jacob; Oboh, Ganiyu; Fadaka, Adewale Oluwaseun; Olatunji, Babawale Peter; Akomolafe, Seun

2017-09-01

Curcumin, the main polyphenolic component of turmeric (Curcuma longa) rhizomes have been reported to exert anticholinesterase potential with limited information on how they regulate acetylcholinesterase (AChE) gene expression. Hence, this study sought to evaluate the effect of curcumin on cerebral cortex acetylcholinesterase (AChE) activity and their mRNA gene expression level in cadmium (Cd)-treated rats. Furthermore, in vitro effect of different concentrations of curcumin (1-5μg/mL) on rat cerebral cortex AChE activity was assessed. Animals were divided into six groups (n=6): group 1 serve as control (without Cd) and receive saline/vehicle, group 2 receive saline plus curcumin at 25mg/kg, group 3 receive saline plus curcumin 50mg/kg, group 4 receive Cd plus vehicle, group 5 receive Cd plus curcumin at 25mg/kg and group 6 receive Cd plus curcumin at 50mg/kg. Rats received Cd (2.5mg/kg) and curcumin (25 and 50mg/kg, respectively) by oral gavage for 7days. Acetylcholinesterase activity was measured by Ellman's method and AChE expression was carried out by a quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) assay. We observed that acute administration of Cd increased acetylcholinesterase activity and in addition caused a significant (P<0.05) increase in AChE mRNA levels in whole cerebral cortex when compared to control group. However, co-treatment with curcumin inhibited AChE activity and alters AChE mRNA levels when compared to Cd-treated group. In addition, curcumin inhibits rat cerebral cortex AChE activity in vitro. In conclusion, curcumin exhibit anti-acetylcholinesterase activity and suppressed AChE mRNA gene expression level in Cd exposed rats, thus providing some biochemical and molecular evidence on the therapeutic effect of this turmeric-derived compound in treating neurological disorders including Alzheimer's disease. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecular Dynamics of Mouse Acetylcholinesterase Complexed with Huperzine A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tara, Sylvia; Helms, Volkhard H.; Straatsma, TP

1999-03-16

Two molecular dynamics simulations were performed for a modeled complex of mouse acetylcholinesterase liganded with huperzine A (HupA). Analysis of these simulations shows that HupA shifts in the active site toward Tyr 337 and Phe 338, and that several residues in the active site area reach out to make hydrogen bonds with the inhibitor. Rapid fluctuations of the gorge width are observed, ranging from widths that allow substrate access to the active site, to pinched structures that do not allow access of molecules as small as water. Additional openings or channels to the active site are found. One opening ismore » formed in the side wall of the active site gorge by residues Val 73, Asp 74, Thr 83, Glu 84, and Asn 87. Another opening is formed at the base of the gorge by residues Trp 86, Val 132, Glu 202, Gly 448, and Ile 451. Both of these openings have been observed separately in the Torpedo californica form of the enzyme. These channels could allow transport of waters and ions to and from the bulk solution.« less

Chitooligosaccharides suppress the level of protein expression and acetylcholinesterase activity induced by Abeta25-35 in PC12 cells.

PubMed

Lee, Sang-Hoon; Park, Jin-Sook; Kim, Se-Kwon; Ahn, Chang-Bum; Je, Jae-Young

2009-02-01

Clinical applications of acetylcholinesterase (AChE) inhibitors are widespread in Alzheimer's sufferers in order to activate central cholinergic system and alleviate cognitive deficits by inhibiting the hydrolysis of acetylcholine. In this study, six kinds of chitooligosaccharides (COSs) with different molecular weight and degree of deacetylation were examined for their inhibitory effects against AChE. The 90-COSs exhibited potent AChE inhibitory activities compared to 50-COSs, while 90-MMWCOS (1000-5000 Da) in the 90-COSs showed the highest activity. Cell culture experiment revealed that 90-MMWCOS suppressed the level of AChE protein expression and AChE activity induced by Abeta(25-35) in PC12 cell lines.

Altered expression of acetylcholinesterase gene in rice results in enhancement or suppression of shoot gravitropism

PubMed Central

Yamamoto, Kosuke; Sakamoto, Hikaru; Momonoki, Yoshie S.

2016-01-01

ABSTRACT Acetylcholinesterase (AChE), an acetylcholine-hydrolyzing enzyme, exists widely in plants, although its role in plant signal transduction is still unclear. We have hypothesized that the plant AChE regulates asymmetric distribution of hormones and substrates due to gravity stimulus, based on indirect pharmacological experiments using an AChE inhibitor. As a direct evidence for this hypothesis, our recent study has shown that AChE overexpression causes an enhanced gravitropic response in rice seedlings and suggested that the function of the rice AChE relates to the promotion of shoot gravitropism in the seedlings. Here, we report that AChE suppression inhibited shoot gravitropism in rice seedlings, as supportive evidence demonstrating the role of AChE as a positive regulator of shoot gravitropic response in plants. PMID:26979939

Acetylcholinesterase inhibitor treatment alleviated cognitive impairment caused by delayed encephalopathy due to carbon monoxide poisoning: Two case reports and a review of the literature.

PubMed

Yanagiha, Kumi; Ishii, Kazuhiro; Tamaoka, Akira

2017-02-01

Delayed encephalopathy due to carbon monoxide (CO) poisoning can even occur in patients with mild symptoms of acute CO poisoning. Some cases taking conventional hyperbaric oxygen (HBO) therapy or steroid-pulse therapy may be insufficient, and AchEI may be effective. We report two cases of delayed encephalopathy after acute CO poisoning involving two women aged 69 (Case 1) and 60 years (Case 2) whose cognitive function improved with acetylcholinesterase inhibitor (AchEI) treatment. Delayed encephalopathy occurred 25 and 35 days after acute CO poisoning in Case 1 and Case 2, respectively. Both patients demonstrated cognitive impairment, apathy, and hypokinesia on admission. Although hyperbaric oxygen therapy did not yield any significant improvements, cognitive dysfunction improved substantially. This was evidenced by an improved Mini-Mental State Examination score ffom 9 to 28 points in Case 1 and an improved Hasegawa's dementia rating scale score from 4 to 25 points in Case 2 after administration of an AchEI. In Case 1, we administered galantamine hydrobromide, which was related with improved white matter lesions initially detected on brain magnetic resonance imaging. However, in Case 2 white matter lesions persisted despite AchEI treatment. AchEI treatment may result in improved cognitive and frontal lobe function by increasing low acetylcholine concentrations in the hippocampus and frontal lobe caused by decreased nicotinic acetylcholine receptor levels in delayed encephalopathy after CO poisoning. Physicians should consider AchEIs for patients demonstrating delayed encephalopathy due to CO poisoning.

[The effect of donepezil in comparison with conventional treatment on cognitive functioning and the performance of the patient in a prospective cohort of patients with Alzheimer's disease treated in routine clinical practice in Spain].

PubMed

López-Pousa, S; Bermejo-Pareja, F; Frank, A; Hernández, F; León, T; Rejas-Gutiérrez, J

2010-11-16

Our aim was to perform a secondary analysis of a 12-month-long, non-blind, multi-centre prospective cost-of-illness study. The analysis assessed the effect of donepezil on cognitive functioning and the performance of patients with possible or probable Alzheimer's disease, compared to that of other drugs for dementia. A sample of 700 patients took part in the study (76.8 ± 6.6 years of age, 67.3% females): 600 (31.4% drug-naive) received donepezil and 100 (9% drug-naive) were given other drugs for dementia. The mean variations corrected by the baseline values and the centre of the total scores on the Folstein minimental test, the clinical dementia rating and Blessed dementia rating scales at 12 months were significantly lower in patients treated with donepezil: -1.23 ± 3.41 versus -2.26 ± 3.07 (p = 0.006), 0.20 ± 0.68 versus 0.39 ± 1.03 (p = 0.014) and 1.28 ± 3.31 versus 2.04 ± 2.84 (p = 0.027), respectively. This secondary analysis shows that the deterioration in the cognitive functioning and performance of patients with the passage of time is slower with donepezil than with other drugs for dementia in routine medical practice. Since these results were observed in a post hoc analysis, formal prospective clinical trials should be conducted to confirm these findings.

Acetylcholinesterase inhibitory and antioxidant activities of novel symmetric sulfamides derived from phenethylamines.

PubMed

Aksu, Kadir; Topal, Fevzi; Gulcin, İlhami; Tümer, Ferhan; Göksu, Süleyman

2015-06-01

The antioxidant and acetylcholinesterase inhibitory properties of novel symmetric sulfamides derived from phenethylamines were evaluated. Phenethylamines 8-11 were reacted with SO2Cl2 in the presence of Et3N to afford sulfamides in good yields. The synthesized sulfamides were converted to their phenolic derivatives with BBr3. We elucidated the antioxidant activity of novel symmetric sulfamides by using different bioanalytical assays. For this purpose, the radical scavenging activities of the novel symmetric sulfamides were assessed by DPPH(•), ABTS(•+), DMPD(•+), and O2(•-) radical scavenging tests. In addition, the reducing abilities of the novel symmetric sulfamides were evaluated by Fe(3+)-Fe(2+) reducing, Cu(2+)-Cu(+) reducing, and [Fe(3+)-(TPTZ)2](3+)-[Fe(2+)-(TPTZ)2](2+) reducing activity tests. Also, the Fe(2+) chelating activity by the pipyrdyl reagent and the acetylcholinesterase inhibitory activities of the novel symmetric sulfamides were studied. Especially, the novel phenolic and symmetric sulfamides 16-19 showed high antioxidant and acetylcholinesterase inhibitory properties. On the other hand, IC50 values were calculated for the DPPH(•), ABTS(•+), DMPD(•+), and O2(•-) scavenging, the metal chelating, and the acetylcholinesterase inhibition effects of the novel symmetric sulfamides. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Central cholinergic challenging of migraine by testing second-generation anticholinesterase drugs.

PubMed

Nicolodi, M; Galeotti, N; Ghelardini, C; Bartolini, A; Sicuteri, F

2002-01-01

The antinociceptive activity of donepezil, a novel cholinesterase inhibitor, was investigated in the mouse hot plate test. Donepezil (5 to 10 mg kg(-1) i.p.) induced a dose-dependent antinociception that reached its maximum effect 15 minutes after injection. Donepezil antinociception was prevented by the antimuscarinic drug scopolamine. At analgesic doses, donepezil did not alter gross animal behavior. These results indicate that donepezil is endowed by muscarinic antinociceptive properties, suggesting this compound as a potential therapeutic approach for the treatment of painful pathologies. Therefore, we investigated donepezil's effect in migraine. Donepezil (5 mg per os, evening assumption) was effective as a prophylatic agent in patients suffering from migraine with or without aura by reducing the number of hours with pain, the number of attacks, and the severity of the pain attack. The efficacy of donepezil was compared with that of the beta-blocker propranolol (40 mg bid per os), showing higher activity. Response rates of a large-sized open study devoid of entry criteria regarding migraine subtypes suggest the drug as an excellent prophylactic compound for migraine in general practice. Clinical results also indicate that the activation of the cholinergic system can represent a novel prophylactic approach to migraine.

Site-activated chelators derived from anti-Parkinson drug rasagiline as a potential safer and more effective approach to the treatment of Alzheimer's disease.

PubMed

Zheng, Hailin; Fridkin, Mati; Youdim, Moussa B H

2010-12-01

chelators can modulate β-amyloid accumulation, protect against tau hyperphosphorylation, and block metal-related oxidative stress, and thereby hold considerable promise as effective anti-AD drugs. At present, a growing interest is focusing on increasing the efficacy and targeting of chelators through drug design. To this end, we have developed a new class of multifunctional prochelators from three FDA- approved drugs rasagiline, rivastigmine, and donepezil or tacrine. HLA20 A was designed by merging the important pharmacophores of rasagiline, rivastigmine, and donepezil into our newly developed multifunctional chelator HLA20. M30D was constructed using the key pharmacophoric moieties from rasagiline, rivastigmine, and tacrine. Experiments showed that both compounds possess potent anti-acetylcholinesterase (AChE) activity in vitro with weak inhibition of butyrylcholinesterase (BuChE), and without significant metal-binding activity. M30D was found also to be a highly potent MAO A inhibitor with moderate inhibition of MAO B in vitro. Both HLA20 and M30D can be activated by inhibition of AChE to release active chelators HLA20 and M30, respectively. HLA20 and M30 have been shown to be able to modulate amyloid precursor protein regulation and beta-amyloid reduction, suppress oxidative stress, and passivate excess metal ions (Fe, Cu, and Zn). Compared with the activated chelator HLA20 or M30, both HLA20A and M30D exhibited lower cytotoxicity in SH-SY5Y neuroblastoma cells, substantiating the prochelator strategy for minimizing toxicity associated with poor targeted chelators.

Rivastigmine improves isolation rearing-induced prepulse inhibition deficits via muscarinic acetylcholine receptors in mice.

PubMed

Higashino, Kosuke; Ago, Yukio; Umeki, Takahiro; Hasebe, Shigeru; Onaka, Yusuke; Hashimoto, Hitoshi; Takuma, Kazuhiro; Matsuda, Toshio

2016-02-01

The acetylcholinesterase inhibitors donepezil, galantamine, and rivastigmine are used for the treatment of Alzheimer's disease. We previously demonstrated that donepezil and galantamine differentially affect isolation rearing-induced prepulse inhibition (PPI) deficits and that this might be due to differential effects on brain muscarinic acetylcholine (mACh) receptor function in mice. We examined the effects of rivastigmine on isolation rearing-induced PPI deficits, brain ACh levels, and mACh receptor function in mice. Acoustic startle responses were measured in a startle chamber. Microdialysis was performed, and the levels of dopamine and ACh in the prefrontal cortex were measured. Rivastigmine (0.3 mg/kg) improved PPI deficits, and this improvement was antagonized by the mACh receptor antagonist telenzepine but not by the nicotinic ACh receptor antagonist mecamylamine. Rivastigmine increased extracellular ACh levels by approximately 2-3-fold, less than the increase produced by galantamine. Rivastigmine enhanced the effect of the mACh receptor agonist N-desmethylclozapine on prefrontal dopamine release, a marker of mACh receptor function, and this increase was blocked by telenzepine. In contrast, galantamine did not affect N-desmethylclozapine-induced dopamine release. Furthermore, rivastigmine did not affect cortical dopamine release induced by the serotonin1A receptor agonist osemozotan, suggesting that the effect of rivastigmine has specificity for mACh receptors. Taken together with our previous finding that marked increases in ACh levels are required for the PPI deficit improvement induced by galantamine, our present results suggest that rivastigmine improves isolation rearing-induced PPI deficits by increasing ACh levels and by concomitantly enhancing mACh receptor function.

Association of the HNK-1 epitope with the detergent-soluble G4 isoform of acetylcholinesterase from human neuroblastoma cells.

PubMed

Johnson, G; Moore, S W

2001-07-01

The HNK-1 carbohydrate epitope is expressed in neural and natural killer cells and is a mediator of cell adhesion. It is well documented that acetylcholinesterase has a secondary function in cell adhesion and differentiation. The presence of HNK-1 on isoforms of Torpedo and Electrophorus acetylcholinesterase, as well as isoforms from the bovine central nervous system has been described. In this paper, we have investigated the association of the epitope with acetylcholinesterase from human neuroblastoma cells. Acetylcholinesterase was extracted, with or without detergent, purified on immunoaffinity columns and the isoforms separated by sucrose density gradient sedimentation. Secreted acetylcholinesterase, from spent serum-free culture medium, was similarly treated. The presence of the HNK-1 epitope was determined by ELISA using the anti-HNK-1 and Elec 39 monoclonal antibodies. The epitope was found to be associated with the detergent-soluble G4 isoform, but not with the hydrophilic G1 nor the secreted hydrophilic G4 isoforms. Likewise, no HNK-1 was observed associated with human erythrocyte acetylcholinesterase. These results indicate that acetylcholinesterase-G4, anchored in the extracellular membrane, is capable of mediating cell-substrate adhesion through HNK-1.

Phenolic composition, antioxidant and anti-acetylcholinesterase activities of the Tunisian Scabiosa arenaria.

PubMed

Besbes Hlila, Malek; Omri, Amel; Ben Jannet, Hichem; Lamari, Ali; Aouni, Mahjoub; Selmi, Boulbaba

2013-05-01

There is a need for the discovery of novel natural antioxidants and acetylcholinesterase inhibitors (AChEIs) that are safe and effective at a global level. This is the first study on antioxidant and anti-acethylcholinesterase activity of Scabiosa arenaria Forssk (Dipsacaceae). The antioxidant potential and anti-acetylcholinesterase (AChE) activity of S. arenaria were investigated. The crude, ethyl acetate (EtOAc), butanol (n-BuOH) and water extracts prepared from flowers, fruits and stems and leaves of S. arenaria were tested to determine their total polyphenol content (TPC), total flavonoid content (TFC), total condensed tannin content (CTC) and their antioxidant activity by using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), reducing power and β-carotene bleaching inhibition activity. Anti-AChE activity was also determined. EtOAc and n-BuOH fractions of fruits had both the highest (TPC) (269.09 mg gallic acid equivalents/g dry weight). The crude extract of stems and leaves had the highest TFC (10.9 mg quercetin equivalent/g dry weight). The n-BuOH fraction of stems and leaves had the highest CTC (489.75 mg catechin equivalents/g dry weight). The EtOAc fraction of flowers exhibit a higher activity in each antioxidant system with a special attention for DPPH assay (IC50 = 0.017 mg/mL) and reducing power (EC50 = 0.02 mg/mL). The EtOAc and n-BuOH fractions of stems and leaves showed strong inhibition of AChE (IC50 = 0.016 and 0.029 mg/mL, respectively). These results suggest the potential of S. arenaria as a possible source of novel compounds and as an alternative antioxidant and AChEIs.

Targeting copper(II)-induced oxidative stress and the acetylcholinesterase system in Alzheimer's disease using multifunctional tacrine-coumarin hybrid molecules.

PubMed

Hamulakova, Slavka; Poprac, Patrik; Jomova, Klaudia; Brezova, Vlasta; Lauro, Peter; Drostinova, Lenka; Jun, Daniel; Sepsova, Vendula; Hrabinova, Martina; Soukup, Ondrej; Kristian, Pavol; Gazova, Zuzana; Bednarikova, Zuzana; Kuca, Kamil; Valko, Marian

2016-08-01

Alzheimer's disease is a multifactorial disease that is characterized mainly by Amyloid-β (A-β) deposits, cholinergic deficit and extensive metal (copper, iron)-induced oxidative stress. In this work we present details of the synthesis, antioxidant and copper-chelating properties, DNA protection study, cholinergic activity and amyloid-antiaggregation properties of new multifunctional tacrine-7-hydroxycoumarin hybrids. The mode of interaction between copper(II) and hybrids and interestingly, the reduction of Cu(II) to Cu(I) species (for complexes Cu-5e-g) were confirmed by EPR measurements. EPR spin trapping on the model Fenton reaction, using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trap, demonstrated a significantly suppressed formation of hydroxyl radicals for the Cu-5e complex in comparison with free copper(II). This suggests that compound 5e upon coordination to free copper ion prevents the Cu(II)-catalyzed decomposition of hydrogen peroxide, which in turn may alleviate oxidative stress-induced damage. Protective activity of hybrids 5c and 5e against DNA damage in a Fenton system (copper catalyzed) was found to be in excellent agreement with the EPR spin trapping study. Compound 5g was the most effective in the inhibition of acetylcholinesterase (hAChE, IC50=38nM) and compound 5b was the most potent inhibitor of butyrylcholinesterase (hBuChE, IC50=63nM). Compound 5c was the strongest inhibitor of A-β1-40 aggregation, although a significant inhibition (>50%) was detected for compounds 5b, 5d, 5e and 5g. Collectively, these results suggest that the design and investigation of multifunctional agents containing along with the acetylcholinesterase inhibitory segment also an antioxidant moiety capable of alleviating metal (copper)-induced oxidative stress, may be of importance in the treatment of Alzheimer's disease. Copyright © 2016 Elsevier Inc. All rights reserved.

Acetylcholinesterases of blood-feeding flies and ticks.

PubMed

Temeyer, Kevin B; Tuckow, Alexander P; Brake, Danett K; Li, Andrew Y; Pérez de León, Adalberto A

2013-03-25

Acetylcholinesterase (AChE) is the biochemical target of organophosphate (OP) and carbamate pesticides for invertebrates, vertebrate nerve agents, and AChE inhibitors used to reduce effects of Alzheimer's disease. Organophosphate pesticides (OPs) are widely used to control blood-feeding arthropods, including biting flies and ticks. However, resistance to OPs in pests affecting animal and human health has compromised control efficacy. OP resistance often results from mutations producing an OP-insensitive AChE. Our studies have demonstrated production of OP-insensitive AChEs in biting flies and ticks. Complementary DNA (cDNA) sequences encoding AChEs were obtained for the horn fly, stable fly, sand fly, and the southern cattle tick. The availability of cDNA sequences enables the identification of mutations, expression and characterization of recombinant proteins, gene silencing for functional studies, as well as in vitro screening of novel inhibitors. The southern cattle tick expresses at least three different genes encoding AChE in their synganglion, i.e. brain. Gene amplification for each of the three known cattle tick AChE genes and expression of multiple alleles for each gene may reduce fitness cost associated with OP-resistance. AChE hydrolyzes the neurotransmitter, acetylcholine, but may have additional roles in physiology and development. The three cattle tick AChEs possess significantly different biochemical properties, and are expressed in neural and non-neural tissues, which suggest separation of structure and function. The remarkable complexity of AChEs in ticks suggested by combining genomic data from Ixodes scapularis with our genetic and biochemical data from Rhipicephalus microplus is suggestive of previously unknown gene duplication and diversification. Comparative studies between invertebrate and vertebrate AChEs could enhance our understanding of structure-activity relationships. Research with ticks as a model system offers the opportunity to

Bridged Bicyclic Oximes as Acetylcholinesterase Reactivators

DTIC Science & Technology

1988-04-03

with acetylcholine as substrate, is based on coupling away the choline produced from the esterase reaction with choline kinase, which catalyzes the...transfer of the y-phosphate from ATP to choline , producing ADP, and then removed with the pyruvate kinase-lactate dehydrogenase couple, and disappearance...nitrobenzoic acid absorbs strongly at 412 nm. Choline kinase and acetylcholinesterase were purchased from Sigma as the lyophilized powders. Each enzyme

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

PubMed

Rodríguez, Yeray A; Gutiérrez, Margarita; Ramírez, David; Alzate-Morales, Jans; Bernal, Cristian C; Güiza, Fausto M; Romero Bohórquez, Arnold R

2016-10-01

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. © 2016 The Authors Chemical Biology & Drug Design Published by John Wiley & Sons Ltd.

Antioxidant and anti-acetylcholinesterase activities of extracts from Rapistrum rugosum in Tunisia

PubMed Central

Amel, Omri Hichri; Malek, Besbes Hlila; Hichem, Ben Jannet; Ali, Lamari; Mahjoub, Aouni; Boulbaba, Selmi

2013-01-01

Objective To investigate the antioxidant potential and anti-acetylcholinesterase activity of Rapistrum rugosum extracts. Methods The crude, ethyl acetate, butanol and water extracts prepared from flowers, roots, stems and leaves of Rapistrum rugosum were tested at 1 mg/mL to determine their total polyphenol content, total flavonoid content and total condensed tannin content. Their antioxidant activity was assessed at different concentrations (0.0312, 0.0625, 0.1250, 0.25, 0.50 and 1.00 mg/mL) by using DPPH, ABTS, reducing power and β-carotene bleAChIng inhibition activity. Anti-acetylcholinesterase activity was also determined. Results The extract of leaves and stems had the highest total phenolic content [(110.45±0.03) mg gallic acid equivalent/g dry weight]. The ethyl acetate extract of flowers had the highest total flavonoid content [(24.62±0.13) mg quercetin equivalent/g dry weight]. The butanolic fraction of flowers had the highest total condensed tannin content [(317.85±0.01) mg catechin equivalent/g dry weight]. The crude extracts of flowers exhibited an interesting antioxidant activity for DPPH assay (93.00±0.01)% at 1 mg/mL. The greatest acetylcholinesterase inhibitory activity (IC50=1.60 mg/mL) was exhibited by the crude extracts from the flowers. Conclusions The results demonstrated that Rapistrum rugosum contains active constituents which possess antioxidant and anti-acetylcholinesterase activities.

Cyperus rotundus extract inhibits acetylcholinesterase activity from animal and plants as well as inhibits germination and seedling growth in wheat and tomato.

PubMed

Sharma, Rashmi; Gupta, Rajendra

2007-05-30

Cyperus rotundus (nutgrass) is the world's worst invasive weed through tubers. Its success in dominating natural habitats depends on its ability to prevent herbivory, and to kill or suppress other plants growing in its vicinity. The present study was done to investigate whether chemicals in nutgrass target neuronal and non-neuronal acetylcholinesterases to affect surrounding animals and plants respectively. Methanolic extract of tubers of nutgrass strongly inhibited activity of AChE from electric eel, wheat and tomato. It also inhibited seed germination and seedling growth in wheat and tomato. Our results suggest that inhibitor of AChE in nutgrass possibly acts as agent of plant's war against (a) herbivore animals, and (b) other plants trying to grow in the same habitat. An antiAChE from nutgrass has been purified by employing chromatography and crystallization. The structural determination of the purified inhibitor is in progress.

Understanding Alzheimer's

MedlinePlus

... donepezil), and Cognex (tacrine). They are known as cholinesterase inhibitors. Scientists believe they prevent the breakdown of acetylcholine, ... the brain produces less and less acetylcholine; therefore, cholinesterase inhibitors may eventually lose their effect. Treatment for Moderate ...

Quantitative structure-activity relationships for organophosphates binding to acetylcholinesterase.

PubMed

Ruark, Christopher D; Hack, C Eric; Robinson, Peter J; Anderson, Paul E; Gearhart, Jeffery M

2013-02-01

Organophosphates are a group of pesticides and chemical warfare nerve agents that inhibit acetylcholinesterase, the enzyme responsible for hydrolysis of the excitatory neurotransmitter acetylcholine. Numerous structural variants exist for this chemical class, and data regarding their toxicity can be difficult to obtain in a timely fashion. At the same time, their use as pesticides and military weapons is widespread, which presents a major concern and challenge in evaluating human toxicity. To address this concern, a quantitative structure-activity relationship (QSAR) was developed to predict pentavalent organophosphate oxon human acetylcholinesterase bimolecular rate constants. A database of 278 three-dimensional structures and their bimolecular rates was developed from 15 peer-reviewed publications. A database of simplified molecular input line entry notations and their respective acetylcholinesterase bimolecular rate constants are listed in Supplementary Material, Table I. The database was quite diverse, spanning 7 log units of activity. In order to describe their structure, 675 molecular descriptors were calculated using AMPAC 8.0 and CODESSA 2.7.10. Orthogonal projection to latent structures regression, bootstrap leave-random-many-out cross-validation and y-randomization were used to develop an externally validated consensus QSAR model. The domain of applicability was assessed by the William's plot. Six external compounds were outside the warning leverage indicating potential model extrapolation. A number of compounds had residuals >2 or <-2, indicating potential outliers or activity cliffs. The results show that the HOMO-LUMO energy gap contributed most significantly to the binding affinity. A mean training R (2) of 0.80, a mean test set R (2) of 0.76 and a consensus external test set R (2) of 0.66 were achieved using the QSAR. The training and external test set RMSE values were found to be 0.76 and 0.88. The results suggest that this QSAR model can be used in

Synthesis and acetylcholinesterase/butyrylcholinesterase inhibition activity of new tacrine-like analogues.

PubMed

Marco, J L; de los Ríos, C; Carreiras, M C; Baños, J E; Badía, A; Vivas, N M

2001-03-01

The synthesis and preliminary results for acetylcholinesterase and butyrylcholinesterase inhibition activity of a series of pyrano[2,3-b]quinolines (2, 3) and benzonaphthyridines (5, 6) derivatives are described. These molecules are tacrine-like analogues which have been prepared from readily available polyfunctionalized ethyl [6-amino-5-cyano-4H-pyrans and 6-amino-5-cyanopyridines]-3-carboxylates via Friedlander condensation with selected ketones. These compounds showed moderate acetylcholinesterase inhibition activity, the more potent (2e, 5b) being 6 times less active than tacrine. The butyrylcholinesterase activity of some of these molecules is also discussed.

Antioxidant and acetylcholinesterase inhibitory activities of ginger root (Zingiber officinale Roscoe) extract.

PubMed

Tung, Bui Thanh; Thu, Dang Kim; Thu, Nguyen Thi Kim; Hai, Nguyen Thanh

2017-05-04

Background Zingiber officinale Roscoe has been used in traditional medicine for the treatment of neurological disorder. This study aimed to investigate the phenolic contents, antioxidant, acetylcholinesterase enzyme (AChE) inhibitory activities of different fraction of Z. officinale root grown in Vietnam. Methods The roots of Z. officinale are extracted with ethanol 96 % and fractionated with n-hexane, ethyl acetate (EtOAc) and butanol (BuOH) solvents. These fractions evaluated the antioxidant activity by 1,1-Diphenyl -2-picrylhydrazyl (DPPH) assay and AChE inhibitory activity by Ellman's colorimetric method. Results Our data showed that the total phenolic content of EtOAc fraction was highest equivalents to 35.2±1.4 mg quercetin/g of fraction. Our data also demonstrated that EtOAc fraction had the strongest antioxidant activity with IC50 was 8.89±1.37 µg/mL and AChE inhibitory activity with an IC50 value of 22.85±2.37 μg/mL in a dose-dependent manner, followed by BuOH fraction and the n-hexane fraction is the weakest. Detailed kinetic analysis indicated that EtOAc fraction was mixed inhibition type with Ki (representing the affinity of the enzyme and inhibitor) was 30.61±1.43 µg/mL. Conclusions Our results suggest that the EtOAc fraction of Z. officinale may be a promising source of AChE inhibitors for Alzheimer's disease.

The protection of acetylcholinesterase inhibitor on β-amyloid-induced injury of neurite outgrowth via regulating axon guidance related genes expression in neuronal cells

PubMed Central

Shen, Jiao-Ning; Wang, Deng-Shun; Wang, Rui

2012-01-01

Cognitive deficits in AD correlate with progressive synaptic dysfunction and loss. The Rho family of small GTPases, including Rho, Rac, and Cdc42, has a central role in cellular motility and cytokinesis. Acetylcholinesterase inhibitor has been found to protect cells against a broad range of reagents-induced injuries. Present studies examined if the effect of HupA on neurite outgrowth in Aβ-treated neuronal cells executed via regulating Rho-GTPase mediated axon guidance relative gene expression. Affymetrix cDNA microarray assay followed by real-time RT-PCR and Western Blotting analysis were used to elucidate and analyze the signaling pathway involved in Aβ and HupA’s effects. The effects of Aβ and HupA on the neurite outgrowth were further confirmed via immunofluorescence staining. Aβ up-regulated the mRNA expressions of NFAT5, LIMK1, EPHA1, NTN4 and RAC2 markedly in SH-SY5Y cells. Co-incubation of Aβ and HupA reversed or decreased the changes of NFAT5, NTN4, RAC2, CDC42 and SEMA4F. HupA treated alone increased NFAT5, LIMK1, NTN4 significantly. Following qRT-PCR validation showed that the correlation of the gene expression ratio between microarray and qRT-PCR is significant. Western blot result showed that the change of CDC42 protein is consistent with the mRNA level while RAC2 is not. The morphological results confirmed that HupA improved, or partly reversed, the Aβ-induced damage of neurite outgrowth. The protective effect of HupA from Aβ induced morphological injury might be correlative to, at least partially, regulating the network of neurite outgrowth related genes. PMID:23119107

Clinical Significance of Repetitive Compound Muscle Action Potentials in Patients with Myasthenia Gravis: A Predictor for Cholinergic Side Effects of Acetylcholinesterase Inhibitors

PubMed Central

Lee, Hyo Eun; Kim, Yool-hee; Kim, Seung Min

2016-01-01

Background and Purpose Acetylcholinesterase inhibitors (AChEIs) are widely used to treat myasthenia gravis (MG). Although AChEIs are usually tolerated well, some MG patients suffer from side effects. Furthermore, a small proportion of MG patients show cholinergic hypersensitivity and cannot tolerate AChEIs. Because repetitive compound muscle action potentials (R-CMAPs) are an electrophysiologic feature of cholinergic neuromuscular hyperactivity, we investigated the clinical characteristics of MG patients with R-CMAPs to identify their clinical usefulness in therapeutic decision-making. Methods We retrospectively reviewed the clinical records and electrodiagnostic findings of MG patients who underwent electrodiagnostic studies and diagnostic neostigmine testing (NT). Results Among 71 MG patients, 9 could not tolerate oral pyridostigmine bromide (PB) and 17 experienced side effects of PB. R-CMAPs developed in 24 patients after NT. The highest daily dose of PB was lower in the patients with R-CMAPs (240 mg/day vs. 480 mg/day, p<0.001). The frequencies of PB intolerance and side effects were higher in the patients with R-CMAPs than in those without R-CMAPs [37.5% vs. 0% (p<0.001) and 45.8% vs. 12.8% (p=0.002), respectively]. The MG Foundation of America postintervention status did not differ significantly between MG patients with and without R-CMAPs, and the response to immunotherapy was also good in both groups. Conclusions Side effects of and intolerance to AChEIs are more common in MG patients with R-CMAPs than in those without R-CMAPs. AChEIs should be used carefully in MG patients with R-CMAPs. The presence of R-CMAPs after NT may be a good indicator of the risks of PB side effects and intolerance. PMID:27819419

Inhibition of acetylcholinesterase in guppies (Poecilia reticulata) by chlorpyrifos at sublethal concentrations: Methodological aspects

DOE Office of Scientific and Technical Information (OSTI.GOV)

van der Wel, H.; Welling, W.

1989-04-01

Acetylcholinesterase activity is a potential biochemical indicator of toxic stress in fish and a sensitive parameter for testing water for the presence of organophosphates. A number of methodological aspects regarding the determination of the in vivo effect of chlorpyrifos on acetylcholinesterase in guppies have been investigated. It was found that with acetylthiocholine as a substrate, the contribution of pseudocholinesterase to the total cholinesterase activity can be neglected. Protection of acetylcholinesterase of guppies exposed to chlorpyrifos from additional, artifactual in vitro enzyme inhibition during homogenization is necessary. Very low concentrations of acetone in the exposure medium, resulting from dilution of themore » stock solution of chlorpyrifos in acetone, can result in large decreases in the oxygen content of this medium. This may affect the uptake rate of the toxic compound and, thereby, cholinesterase inhibition. Very low, sublethal concentrations of chlorpyrifos result in high inhibition levels of acetylcholinesterase (80-90%) in guppies within 2 weeks of continuous exposure. Recovery of the enzyme activity occurs after the exposed animals are kept in clean medium for 4 days, but the rate of recovery is considerably lower than the rate of inhibition.« less

Cholinesterase inhibitor (Altenuene) from an endophytic fungus Alternaria alternata: optimization, purification and characterization.

PubMed

Bhagat, J; Kaur, A; Kaur, R; Yadav, A K; Sharma, V; Chadha, B S

2016-10-01

The aim of this study was to screen endophytic fungi isolated from Vinca rosea for their potential to produce acetylcholinesterase (AChE) inhibitors. Endophytic fungi isolated from V. rosea (Catharanthus roseus), were screened for AChE inhibitor production using Ellman's method. Maximum inhibition against AChE (78%) was observed in an isolate VS-10, identified to be Alternaria alternata on morphological and molecular basis. The isolate also inhibited butyrylcholinesterase (73%). Significant increase (1·3 fold) was achieved after optimization of process parameters using one variable at time approach. The inhibitor was purified using chromatographic techniques. The structure elucidation of the inhibitor was carried out using spectroscopic techniques and was identified to be 'altenuene'. The purified inhibitor possessed antioxidant potential as revealed by dot blot assay. The insecticidal potential of purified inhibitor was evaluated by feeding Spodoptora litura on diet amended with inhibitor. It evinced significant larval mortality. Endophytic A. alternata can serve as a source of dual cholinesterase inhibitor 'altenuene' with significant antioxidant and insecticidal activity. This is the first report on acetylcholinestearse inhibitory activity of altenuene. Alternaria alternata has the potential to produce a dual ChE inhibitor with antioxidant activity useful in the treatment of neurodegenerative disorders and in agriculture as biocontrol agent. © 2016 The Society for Applied Microbiology.

Studies of the acetylcholinesterase from houseflies (Musca domestica L.) resistant and susceptible to organophosphorus insecticides.

PubMed Central

Devonshire, A L

1975-01-01

Acetylcholinesterase from the heads of insecticide-resistant and -susceptible houseflies (Musca domestica L.) was studied in vitro. The enzymes could not be distinguished electrophoretically, and their behaviour on polyacrylamide-disc-gel electrophoresis was influenced by the presence of Triton X-100 in both the homogenate and the gels. In the absence of detergent, the acetylcholinesterase was heterogeneous, but behaved as a single enzyme when it was present. By analogy with studies of acetylcholinesterase from other sources, these observations were attributed to aggregation of the enzyme when not bound by membranes. The enzyme from resistant flies was more slowly inhibited than the susceptible enzyme, bimolecular rate constants (ki) differing by approx. 4-20-fold for a range of organophosphorus compounds. The kinetics of inhibition of acetylcholinesterase were consistent with the results of electrophoresis, i.e. they corresponded to those of a single enzyme in the presence of Triton X-100, but a mixture of enzymes in its absence. The susceptibility of the more sensitive components in these mixtures was determined. Images PLATE 1 PMID:1180906

Toxicological Differences Between NMDA Receptor Antagonists and Cholinesterase Inhibitors.

PubMed

Shi, Xiaodong; Lin, Xiaotian; Hu, Rui; Sun, Nan; Hao, Jingru; Gao, Can

2016-08-01

Cholinesterase inhibitors (ChEIs), represented by donepezil, rivastigmine, and galantamine, used to be the only approved class of drugs for the treatment of Alzheimer's disease. After the approval of memantine by the Food and Drug Administration (FDA), N-methyl-d-aspartic acid (NMDA) receptor antagonists have been recognized by authorities and broadly used in the treatment of Alzheimer's disease. Along with complementary mechanisms of action, NMDA antagonists and ChEIs differ not only in therapeutic effects but also in adverse reactions, which is an important consideration in clinical drug use. And the number of patients using NMDA antagonists and ChEIs concomitantly has increased, making the matter more complicated. Here we used the FDA Adverse Event Reporting System for statistical analysis , in order to compare the adverse events of memantine and ChEIs. In general, the clinical evidence confirmed the safety advantages of memantine over ChEIs, reiterating the precautions of clinical drug use and the future direction of antidementia drug development. © The Author(s) 2016.

Evaluating Fmoc-amino acids as selective inhibitors of butyrylcholinesterase

PubMed Central

Gonzalez, Jeannette; Ramirez, Jennifer

2018-01-01

Cholinesterases are involved in neuronal signal transduction, and perturbation of function has been implicated in diseases, such as Alzheimer’s and Huntington’s disease. For the two major classes of cholinesterases, such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), previous studies reported BChE activity is elevated in patients with Alzheimer’s disease, while AChE levels remain the same or decrease. Thus, the development of potent and specific inhibitors of BChE have received much attention as a potential therapeutic in the alleviation of neurodegenerative diseases. In this study, we evaluated amino acid analogs as selective inhibitors of BChE. Amino acid analogs bearing a 9-fluorenylmethyloxycarbonyl (Fmoc) group were tested, as the Fmoc group has structural resemblance to previously described inhibitors. We identified leucine, lysine, and tryptophan analogs bearing the Fmoc group as selective inhibitors of BChE. The Fmoc group contributed to inhibition, as analogs bearing a carboxybenzyl group showed ~tenfold higher values for the inhibition constant (KI value). Inclusion of a t-butoxycarbonyl on the side chain of Fmoc tryptophan led to an eightfold lower KI value compared to Fmoc tryptophan alone suggesting that modifications of the amino acid side chains may be designed to create inhibitors with higher affinity. Our results identify Fmoc-amino acids as a scaffold upon which to design BChE-specific inhibitors and provide the foundation for further experimental and computational studies to dissect the interactions that contribute to inhibitor binding. PMID:27522651

Evaluating Fmoc-amino acids as selective inhibitors of butyrylcholinesterase.

PubMed

Gonzalez, Jeannette; Ramirez, Jennifer; Schwans, Jason P

2016-12-01

Cholinesterases are involved in neuronal signal transduction, and perturbation of function has been implicated in diseases, such as Alzheimer's and Huntington's disease. For the two major classes of cholinesterases, such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), previous studies reported BChE activity is elevated in patients with Alzheimer's disease, while AChE levels remain the same or decrease. Thus, the development of potent and specific inhibitors of BChE have received much attention as a potential therapeutic in the alleviation of neurodegenerative diseases. In this study, we evaluated amino acid analogs as selective inhibitors of BChE. Amino acid analogs bearing a 9-fluorenylmethyloxycarbonyl (Fmoc) group were tested, as the Fmoc group has structural resemblance to previously described inhibitors. We identified leucine, lysine, and tryptophan analogs bearing the Fmoc group as selective inhibitors of BChE. The Fmoc group contributed to inhibition, as analogs bearing a carboxybenzyl group showed ~tenfold higher values for the inhibition constant (K I value). Inclusion of a t-butoxycarbonyl on the side chain of Fmoc tryptophan led to an eightfold lower K I value compared to Fmoc tryptophan alone suggesting that modifications of the amino acid side chains may be designed to create inhibitors with higher affinity. Our results identify Fmoc-amino acids as a scaffold upon which to design BChE-specific inhibitors and provide the foundation for further experimental and computational studies to dissect the interactions that contribute to inhibitor binding.

Novel tacrine/acridine anticholinesterase inhibitors with piperazine and thiourea linkers.

PubMed

Hamulakova, Slavka; Imrich, Jan; Janovec, Ladislav; Kristian, Pavol; Danihel, Ivan; Holas, Ondrej; Pohanka, Miroslav; Böhm, Stanislav; Kozurkova, Maria; Kuca, Kamil

2014-09-01

A new series of substituted tacrine/acridine and tacrine/tacrine dimers with aliphatic or alkylene-thiourea linkers was synthesized and the potential of these compounds as novel human acetylcholinesterase (hAChE) and human butyrylcholinesterase (hBChE) inhibitors with nanomolar inhibition activity was evaluated. The most potent AChE inhibitor was found to be homodimeric tacrine derivative 14a, which demonstrated an IC50 value of 2 nM; this value indicates an activity rate which is 250-times higher than that of tacrine 1 and 7500-times higher than 7-MEOTA 15, the compounds which were used as standards in the study. IC50 values of derivatives 1, 9, 10, 14b and 15 were compared with the dissociation constants of the enzyme-inhibitor complex, Ki1, and the enzyme-substrate-inhibitor complex, Ki2, for. A dual binding site is presumed for the synthesized compounds which possess two tacrines or tacrine and acridine as terminal moieties show evidence of dual site binding. DFT calculations of theoretical desolvation free energies, ΔΔGtheor, and docking studies elucidate these suggestions in more detail. Copyright © 2014 Elsevier B.V. All rights reserved.

Hairy-root organ cultures for the production of human acetylcholinesterase

PubMed Central

Woods, Ryan R; Geyer, Brian C; Mor, Tsafrir S

2008-01-01

Background Human cholinesterases can be used as a bioscavenger of organophosphate toxins used as pesticides and chemical warfare nerve agents. The practicality of this approach depends on the availability of the human enzymes, but because of inherent supply and regulatory constraints, a suitable production system is yet to be identified. Results As a promising alternative, we report the creation of "hairy root" organ cultures derived via Agrobacterium rhizogenes-mediated transformation from human acetylcholinesterase-expressing transgenic Nicotiana benthamiana plants. Acetylcholinesterase-expressing hairy root cultures had a slower growth rate, reached to the stationary phase faster and grew to lower maximal densities as compared to wild type control cultures. Acetylcholinesterase accumulated to levels of up to 3.3% of total soluble protein, ~3 fold higher than the expression level observed in the parental plant. The enzyme was purified to electrophoretic homogeneity. Enzymatic properties were nearly identical to those of the transgenic plant-derived enzyme as well as to those of mammalian cell culture derived enzyme. Pharmacokinetic properties of the hairy-root culture derived enzyme demonstrated a biphasic clearing profile. We demonstrate that master banking of plant material is possible by storage at 4°C for up to 5 months. Conclusion Our results support the feasibility of using plant organ cultures as a successful alternative to traditional transgenic plant and mammalian cell culture technologies. PMID:19105816

Preclinical and first-in-human evaluation of PRX-105, a PEGylated, plant-derived, recombinant human acetylcholinesterase-R

DOE Office of Scientific and Technical Information (OSTI.GOV)

Atsmon, Jacob; Sackler Faculty of Medicine, Tel Aviv University; Brill-Almon, Einat

PRX-105 is a plant-derived recombinant version of the human ‘read-through’ acetylcholinesterase splice variant (AChE-R). Its active site structure is similar to that of the synaptic variant, and it displays the same affinity towards organophosphorus (OP) compounds. As such, PRX-105 may serve as a bio-scavenger for OP pesticides and chemical warfare agents. To assess its potential use in prophylaxis and treatment of OP poisoning we conducted several preliminary tests, reported in this paper. Intravenous (IV) PRX-105 was administered to mice either before or after exposure to an OP toxin. All mice who received an IV dose of 50 nmol/kg PRX-105, 2more » min before being exposed to 1.33 × LD{sub 50} and 1.5 × LD{sub 50} of toxin and 10 min after exposure to 1.5 × LD{sub 50} survived. The pharmacokinetic and toxicity profiles of PRX-105 were evaluated in mice and mini-pigs. Following single and multiple IV doses (50 to 200 mg/kg) no deaths occurred and no significant laboratory and histopathological changes were observed. The overall elimination half-life (t{sub ½}) in mice was 994 (± 173) min. Additionally, a first-in-human study, to assess the safety, tolerability and pharmacokinetics of the compound, was conducted in healthy volunteers. The t{sub ½} in humans was substantially longer than in mice (average 26.7 h). Despite the small number of animals and human subjects who were assessed, the fact that PRX-105 exerts a protective and therapeutic effect following exposure to lethal doses of OP, its favorable safety profile and its relatively long half-life, renders it a promising candidate for treatment and prophylaxis against OP poisoning and warrants further investigation. - Highlights: • PRX-105 is a PEGylated plant-derived recombinant human acetylcholinesterase-R. • PRX-105 is a promising bio-scavenger for organophosphorous toxins at lethal doses. • PRX-105 was shown to protect animals both prophylactically and post-poisoning. • First

The protection of acetylcholinesterase inhibitor on β-amyloid-induced the injury of neurite outgrowth via regulating axon guidance related genes expression in neuronal cells.

PubMed

Shen, Jiao-Ning; Wang, Deng-Shun; Wang, Rui

2012-01-01

Cognitive deficits in AD correlate with progressive synaptic dysfunction and loss. The Rho family of small GTPases, including Rho, Rac, and Cdc42, has a central role in cellular motility and cytokinesis. Acetylcholinesterase inhibitor has been found to protect cells against a broad range of reagents-induced injuries. Present studies examined if the effect of HupA on neurite outgrowth in Aβ-treated neuronal cells executed via regulating Rho-GTPase mediated axon guidance relative gene expression. Affymetrix cDNA microarray assay followed by real-time RT-PCR and Western Blotting analysis were used to elucidate and analyze the signaling pathway involved in Aβ and HupA's effects. The effects of Aβ and HupA on the neurite outgrowth were further confirmed via immunofluorescence staining. Aβ up-regulated the mRNA expressions of NFAT5, LIMK1, EPHA1, NTN4 and RAC2 markedly in SH-SY5Y cells. Co-incubation of Aβ and HupA reversed or decreased the changes of NFAT5, NTN4, RAC2, CDC42 and SEMA4F. HupA treated alone increased NFAT5, LIMK1, NTN4 significantly. Following qRT-PCR validation showed that the correlation of the gene expression ratio between microarray and qRT-PCR is significant. Western blot result showed that the change of CDC42 protein is consistent with the mRNA level while RAC2 is not. The morphological results confirmed that HupA improved, or partly reversed, the Aβ-induced damage of neurite outgrowth. The protective effect of HupA from Aβ induced morphological injury might be correlative to, at least partially, regulating the network of neurite outgrowth related genes.

Red blood cell acetylcholinesterase activity among healthy dwellers of an agrarian region in Sri Lanka: a descriptive cross-sectional study.

PubMed

Rathish, Devarajan; Senavirathna, Indika; Jayasumana, Channa; Agampodi, Suneth

2018-06-21

Assessment of acetylcholinesterase-inhibitor insecticide (AChEII) toxicity depends on the measurement of red blood cell acetylcholinesterase (RBC-AChE) activity. Its interpretation requires baseline values which is lacking in scientific literature. We aim to find the measures of central tendency and variation for RBC-AChE activity among dwellers of Anuradhapura, where the use and abuse of AChEIIs were rampant for the last few decades. A descriptive cross-sectional study with a community-based sampling for 100 healthy non-farmers (male:female = 1:1) was done using pre-determined selection criteria. Duplicate measurements of RBC-AChE activity were performed according to the modified Ellman procedure. Pearson's correlation and regression analysis were sort for RBC-AChE activity against its possible determinants. RBC-AChE activity had a mean of 449.8 (SD 74.2) mU/μM Hb with a statistical power of 0.847. It was similar to values of "healthy controls" from previous Sri Lankan toxicological studies but was low against international reference value [586.1 (SD 65.1) mU/μM Hb]. None of the possible determinants showed a significant strength of relationship with RBC-AChE activity. The baseline RBC-AChE activity among people of Anuradhapura is low in comparison with international reference values. This arises a need to find a causative mechanism.

Sesquiterpenes and a monoterpenoid with acetylcholinesterase (AchE) inhibitory activity from Valeriana officinalis var. latiofolia in vitro and in vivo.

PubMed

Chen, Heng-Wen; He, Xuan-Hui; Yuan, Rong; Wei, Ben-Jun; Chen, Zhong; Dong, Jun-Xing; Wang, Jie

2016-04-01

Acetylcholinesterase Inhibitor (AchEI) is the most extensive in all anti-dementia drugs. The extracts and isolated compounds from the Valeriana genus have shown anti-dementia bioactivity. Four new sesquiterpenoids (1-4) and a new monoterpenoid (5) were isolated from the root of Valeriana officinalis var. latiofolia. The acetylcholinesterase (AchE) inhibitory activity of isolates was evaluated by modified Ellman method in vitro. Learning and memory ability of compound 4 on mice was evaluated by the Morris water maze. The contents of acetylcholine (Ach), acetylcholine transferase (ChAT) and AchE in mice brains were determined by colorimetry. The results showed IC50 of compound 4 was 0.161 μM in vitro. Compared with the normal group, the learning and memory ability of mice and the contents of Ach and ChAT decreased in model group mice (P<0.01), while the AchE increased (P<0.01). Compared with the model group, Ach and ChAT in the positive control group, the high-dose group and the medium-dose group increased (P<0.01), while the AchE decreased (P<0.01). Compound 4 can improve the learning and memory abilities of APPswe/PSΔE9 double-transgenic mice, and the mechanism may be related to the regulation of the relative enzyme in the cholinergic system. Copyright © 2016 Elsevier B.V. All rights reserved.

Nicotinic alpha 7 receptor agonists EVP-6124 and BMS-933043, attenuate scopolamine-induced deficits in visuo-spatial paired associates learning.

PubMed

Weed, Michael R; Polino, Joseph; Signor, Laura; Bookbinder, Mark; Keavy, Deborah; Benitex, Yulia; Morgan, Daniel G; King, Dalton; Macor, John E; Zaczek, Robert; Olson, Richard; Bristow, Linda J

2017-01-01

Agonists at the nicotinic acetylcholine alpha 7 receptor (nAChR α7) subtype have the potential to treat cognitive deficits in patients with Alzheimer's disease (AD) or schizophrenia. Visuo-spatial paired associates learning (vsPAL) is a task that has been shown to reliably predict conversion from mild cognitive impairment to AD in humans and can also be performed by nonhuman primates. Reversal of scopolamine-induced impairment of vsPAL performance may represent a translational approach for the development of nAChR α7 agonists. The present study investigated the effect of treatment with the acetylcholinesterase inhibitor, donepezil, or three nAChR α7 agonists, BMS-933043, EVP-6124 and RG3487, on vsPAL performance in scopolamine-treated cynomolgus monkeys. Scopolamine administration impaired vsPAL performance accuracy in a dose- and difficulty- dependent manner. The impairment of eventual accuracy, a measure of visuo-spatial learning during the task, was significantly ameliorated by treatment with donepezil (0.3 mg/kg, i.m.), EVP-6124 (0.01 mg/kg, i.m.) or BMS-933043 (0.03, 0.1 and 0.3 mg/kg, i.m.). Both nAChR α7 agonists showed inverted-U shaped dose-effect relationships with EVP-6124 effective at a single dose only whereas BMS-933043 was effective across at least a 10 fold dose/exposure range. RG3487 was not efficacious in this paradigm at the dose range examined (0.03-1 mg/kg, i.m.). These results are the first demonstration that the nAChR α7 agonists, EVP-6124 and BMS-933043, can ameliorate scopolamine-induced cognitive deficits in nonhuman primates performing the vsPAL task.

Novel hits for acetylcholinesterase inhibition derived by docking-based screening on ZINC database.

PubMed

Doytchinova, Irini; Atanasova, Mariyana; Valkova, Iva; Stavrakov, Georgi; Philipova, Irena; Zhivkova, Zvetanka; Zheleva-Dimitrova, Dimitrina; Konstantinov, Spiro; Dimitrov, Ivan

2018-12-01

The inhibition of the enzyme acetylcholinesterase (AChE) increases the levels of the neurotransmitter acetylcholine and symptomatically improves the affected cognitive function. In the present study, we searched for novel AChE inhibitors by docking-based virtual screening of the standard lead-like set of ZINC database containing more than 6 million small molecules using GOLD software. The top 10 best-scored hits were tested in vitro for AChE affinity, neurotoxicity, GIT and BBB permeability. The main pharmacokinetic parameters like volume of distribution, free fraction in plasma, total clearance, and half-life were predicted by previously derived models. Nine of the compounds bind to the enzyme with affinities from 0.517 to 0.735 µM, eight of them are non-toxic. All hits permeate GIT and BBB and bind extensively to plasma proteins. Most of them are low-clearance compounds. In total, seven of the 10 hits are promising for further lead optimisation. These are structures with ZINC IDs: 00220177, 44455618, 66142300, 71804814, 72065926, 96007907, and 97159977.

Alkaloid profiles and acetylcholinesterase inhibitory activities of Fumaria species from Bulgaria.

PubMed

Vrancheva, Radka Z; Ivanov, Ivan G; Aneva, Ina Y; Dincheva, Ivayla N; Badjakov, Ilian K; Pavlov, Atanas I

2016-01-01

GC-MS analysis of alkaloid profiles of five Fumaria species, naturally grown in Bulgaria (F. officinalis, F. thuretii, F. kralikii, F. rostellata and F. schrammii) and analysis of acetylcholinesterase inhibitory activity of alkaloid extracts were performed. Fourteen isoquinoline alkaloids were identified, with the principle ones being protopine, cryptopine, sinactine, parfumine, fumariline, fumarophycine, and fumaritine. Protopine contents, defined by HPLC analysis varied between 210.6 ± 8.8 μg/g DW (F. schrammii) and 334.5 ± 7.1 μg/g DW. (F. rostellata). While all of the investigated alkaloid extracts significantly inhibited acetylcholinesterase activity, the F. kralikii demonstrated the highest level of inhibition (IC(50) 0.13 ± 0.01 mg extract/mL).

Molecular Probe Analysis of Mammalian Brain Acetylcholinesterase

DTIC Science & Technology

1988-09-27

Project and Degrees Awarded During this Reporting Period: Judith K. Marquis, Principal Investigator Thomas Biagioni , Senior Research Technician Robert...binding sites in nerve membrane vesicles. Comp. Biochem. Physiol. 80C: 203-205 (1985). 5. Volpe, L.S., T.M. Biagioni & J.K. Marquis: In vitro modulation of...Saxena, Vol. 6(1988Y.8 11. Marquis, J.K. & T.M. Biagioni : Selective inhibition of acetylcholinesterase and butyrylcholinesterase in human plasma

Protection against β-amyloid-induced synaptic and memory impairments via altering β-amyloid assembly by bis(heptyl)-cognitin

PubMed Central

Chang, Lan; Cui, Wei; Yang, Yong; Xu, Shujun; Zhou, Wenhua; Fu, Hongjun; Hu, Shengquan; Mak, Shinghung; Hu, Juwei; Wang, Qin; Pui-Yan Ma, Victor; Chung-lit Choi, Tony; Dik-lung Ma, Edmond; Tao, Liang; Pang, Yuanping; Rowan, Michael J.; Anwyl, Roger; Han, Yifan; Wang, Qinwen

2015-01-01

β-amyloid (Aβ) oligomers have been closely implicated in the pathogenesis of Alzheimer’s disease (AD). We found, for the first time, that bis(heptyl)-cognitin, a novel dimeric acetylcholinesterase (AChE) inhibitor derived from tacrine, prevented Aβ oligomers-induced inhibition of long-term potentiation (LTP) at concentrations that did not interfere with normal LTP. Bis(heptyl)-cognitin also prevented Aβ oligomers-induced synaptotoxicity in primary hippocampal neurons. In contrast, tacrine and donepezil, typical AChE inhibitors, could not prevent synaptic impairments in these models, indicating that the modification of Aβ oligomers toxicity by bis(heptyl)-cognitin might be attributed to a mechanism other than AChE inhibition. Studies by using dot blotting, immunoblotting, circular dichroism spectroscopy, and transmission electron microscopy have shown that bis(heptyl)-cognitin altered Aβ assembly via directly inhibiting Aβ oligomers formation and reducing the amount of preformed Aβ oligomers. Molecular docking analysis further suggested that bis(heptyl)-cognitin presumably interacted with the hydrophobic pockets of Aβ, which confers stabilizing powers and assembly alteration effects on Aβ. Most importantly, bis(heptyl)-cognitin significantly reduced cognitive impairments induced by intra-hippocampal infusion of Aβ oligomers in mice. These results clearly demonstrated how dimeric agents prevent Aβ oligomers-induced synaptic and memory impairments, and offered a strong support for the beneficial therapeutic effects of bis(heptyl)-cognitin in the treatment of AD. PMID:26194093

Acetylcholinesterase inhibitory activity of Thai traditional nootropic remedy and its herbal ingredients.

PubMed

Tappayuthpijarn, Pimolvan; Itharat, Arunporn; Makchuchit, Sunita

2011-12-01

The incidence of Alzheimer disease (AD) is increasing every year in accordance with the increasing of elderly population and could pose significant health problems in the future. The use of medicinal plants as an alternative prevention or even for a possible treatment of the AD is, therefore, becoming an interesting research issue. Acetylcholinesterase (AChE) inhibitors are well-known drugs commonly used in the treatment of AD. The aim of the present study was to screen for AChE inhibitory activity of the Thai traditional nootropic recipe and its herbal ingredients. The results showed that ethanolic extracts of four out of twenty-five herbs i.e. Stephania pierrei Diels. Kaempfera parviflora Wall. ex Baker, Stephania venosa (Blume) Spreng, Piper nigrum L at 0.1 mg/mL showed % AChE inhibition of 89, 64, 59, 50; the IC50 were 6, 21, 29, 30 microg/mL respectively. The other herbs as well as combination of the whole recipe had no synergistic inhibitory effect on AChE activity. However some plants revealed antioxidant activity. More research should have be performed on this local wisdom remedy to verify the uses in scientific term.

Immobilization of acetylcholinesterase in lipid membranes deposited on self-assembled monolayers.

PubMed

Milkani, Eftim; Khaing, Aung M; Huang, Fei; Gibson, Daniel G; Gridley, Scott; Garceau, Norman; Lambert, Christopher R; McGimpsey, W Grant

2010-12-21

Human red blood cell acetylcholinesterase was incorporated into planar lipid membranes deposited on alkanethiol self-assembled monolayers (SAMs) on gold substrates. Activity of the protein in the membrane was detected with a standard photometric assay and was determined to be similar to the protein in detergent solution or incorporated in lipid vesicles. Monolayer and bilayer lipid membranes were generated by fusing liposomes to hydrophobic and hydrophilic SAMs, respectively. Liposomes were formed by the injection method using the lipid dimyristoylphosphatidylcholine (DMPC). The formation of alkanethiol SAMs and lipid monolayers on SAMs was confirmed by sessile drop goniometry, ellipsometry, and electrochemical impedance spectroscopy. In this work, we report acetylcholinesterase immobilization in lipid membranes deposited on SAMs formed on the gold surface and compare its activity to enzyme in solution.

Impaired attention in the 3xTgAD mouse model of Alzheimer's disease: rescue by donepezil (Aricept).

PubMed

Romberg, Carola; Mattson, Mark P; Mughal, Mohamed R; Bussey, Timothy J; Saksida, Lisa M

2011-03-02

Several mouse models of Alzheimer's disease (AD) with abundant β-amyloid and/or aberrantly phosphorylated tau develop memory impairments. However, multiple non-mnemonic cognitive domains such as attention and executive control are also compromised early in AD individuals. Currently, it is unclear whether mutations in the β-amyloid precursor protein (APP) and tau are sufficient to cause similar, AD-like attention deficits in mouse models of the disease. To address this question, we tested 3xTgAD mice (which express APPswe, PS1M146V, and tauP301L mutations) and wild-type control mice on a newly developed touchscreen-based 5-choice serial reaction time test of attention and response control. The 3xTgAD mice attended less accurately to short, spatially unpredictable stimuli when the attentional demand of the task was high, and also showed a general tendency to make more perseverative responses than wild-type mice. The attentional impairment of 3xTgAD mice was comparable to that of AD patients in two aspects: first, although 3xTgAD mice initially responded as accurately as wild-type mice, they subsequently failed to sustain their attention over the duration of the task; second, the ability to sustain attention was enhanced by the cholinesterase inhibitor donepezil (Aricept). These findings demonstrate that familial AD mutations not only affect memory, but also cause significant impairments in attention, a cognitive domain supported by the prefrontal cortex and its afferents. Because attention deficits are likely to affect memory encoding and other cognitive abilities, our findings have important consequences for the assessment of disease mechanisms and therapeutics in animal models of AD.

Molecular evaluation of herbal compounds as potent inhibitors of acetylcholinesterase for the treatment of Alzheimer's disease.

PubMed

Chen, Yan-Xiu; Li, Guan-Zeng; Zhang, Bin; Xia, Zhang-Yong; Zhang, Mei

2016-07-01

Alzheimer's disease (AD) is a progressive disease and the predominant cause of dementia. Common symptoms include short-term memory loss, and confusion with time and place. Individuals with AD depend on their caregivers for assistance, and may pose a burden to them. The acetylcholinesterase (AChE) enzyme is a key target in AD and inhibition of this enzyme may be a promising strategy in the drug discovery process. In the present study, an inhibitory assay was carried out against AChE using total alkaloidal plants and herbal extracts commonly available in vegetable markets. Subsequently, molecular docking simulation analyses of the bioactive compounds present in the plants were conducted, as well as a protein‑ligand interaction analysis. The stability of the docked protein‑ligand complex was assessed by 20 ns molecular dynamics simulation. The inhibitory assay demonstrated that Uncaria rhynchophylla and Portulaca oleracea were able to inhibit AChE. In addition, molecular docking simulation analyses indicated that catechin present in Uncaria rhynchophylla, and dopamine and norepinephrine present in Portulaca oleracea, had the best docking scores and interaction energy. In conclusion, catechin in Uncaria rhynchophylla, and dopamine and norepinephrine in Portulaca oleracea may be used to treat AD.

Evidence for non-acetylcholinesterase mechanisms in pesticide-induced developmental neurotoxicity#

EPA Science Inventory

Acetylcholinesterase inhibition is a well-established mode of action for adverse effects of organophosphorus and carbamate pesticides, and the use of this endpoint in regulatory considerations has been assumed to be protective of downstream cholinergic effects. It has been questi...

Detection of Anatoxin-a(s) in Environmental Samples of Cyanobacteria by Using a Biosensor with Engineered Acetylcholinesterases

PubMed Central

Devic, Eric; Li, Dunhai; Dauta, Alain; Henriksen, Peter; Codd, Geoffrey A.; Marty, Jean-Louis; Fournier, Didier

2002-01-01

Bioassays are little used to detect individual toxins in the environment because, compared to analytical methods, these assays are still limited by several problems, such as the sensitivity and specificity of detection. We tentatively solved these two drawbacks for detection of anatoxin-a(s) by engineering an acetylcholinesterase to increase its sensitivity and by using a combination of mutants to obtain increased analyte specificity. Anatoxin-a(s), a neurotoxin produced by some freshwater cyanobacteria, was detected by measuring the inhibition of acetylcholinesterase activity. By using mutated enzyme, the sensitivity of detection was brought to below the nanomole-per-liter level. However, anatoxin-a(s) is an organophosphorous compound, as are several synthetic molecules which are widely used as insecticides. The mode of action of these compounds is via inhibition of acetylcholinesterase, which makes the biotest nonspecific. The use of a four-mutant set of acetylcholinesterase variants, two mutants that are sensitive to anatoxin-a(s) and two mutants that are sensitive to the insecticides, allows specific detection of the cyanobacterial neurotoxin. PMID:12147513

The acetylcholinesterase inhibitor BW284c51 is a potent blocker of Torpedo nicotinic AchRs incorporated into the Xenopus oocyte membrane

PubMed Central

Olivera-Bravo, Silvia; Ivorra, Isabel; Morales, Andrés

2004-01-01

This work was aimed to determine if 1,5-bis(4-allyldimethylammoniumphenyl)pentan-3-one dibromide (BW284c51), the most selective acetylcholinesterase inhibitor (AchEI), affects the nicotinic acetylcholine (Ach) receptor (AchR) function. Purified Torpedo nicotinic AchRs were injected into Xenopus laevis oocytes and BW284c51 effects on Ach- and carbamylcholine (Cch)-elicited currents were assessed using the voltage-clamp technique. BW284c51 (up to 1 mM) did not evoke any change in the oocyte membrane conductance. When BW284c51 (10 pM–100 μM) and Ach were coapplied, Ach-evoked currents (IAch) were reversibly inhibited in a concentration-dependent manner (Hill coefficient, 1; IC50, 0.2–0.5 μM for 0.1–1000 μM Ach). Cch-elicited currents showed a similar inhibition by BW284c51. IAch blockade by BW284c51 showed a strong voltage dependence, being only apparent at hyperpolarising potentials. BW284c51 also enhanced IAch desensitisation. BW284c51 changed the Ach concentration-dependence curve of Torpedo AchR response from two-site to single-site kinetics, without noticeably affecting the EC50 value. The BW284c51 blocking effect was highly selective for nicotinic over muscarinic receptors. BW284c51 inhibition potency was stronger than that of tacrine, and similar to that of d-tubocurarine (d-TC). Coapplication of BW284c51 with either tacrine or d-TC revealed synergistic inhibitory effects. Our results indicate that BW284c51 antagonises nicotinic AchRs in a noncompetitive way by blocking the receptor channel, and possibly by other, yet unknown, mechanisms. Therefore, besides acting as a selective AchEI, BW284c51 constitutes a powerful and reversible blocker of nicotinic AchRs that might be used as a valuable tool for understanding their function. PMID:15644872

Self reported symptoms and inhibition of acetylcholinesterase activity among Kenyan agricultural workers.

PubMed

Ohayo-Mitoko, G J; Kromhout, H; Simwa, J M; Boleij, J S; Heederik, D

2000-03-01

This study was part of the East African pesticides project. The general objective was to assess health hazards posed by handling, storage, and use of pesticides, on agricultural estates and small farms with a view to developing strategies for prevention and control of pesticide poisoning. The aim of this paper is to describe the prevalence of symptoms in this population, to relate levels of inhibition to reported symptoms and evaluate at which levels of inhibition symptoms become increased. Complete data were available for 256 exposed subjects and 152 controls from four regions in Kenya. A structured questionnaire on symptoms experienced at the time of interview was given to all subjects and controls. Information was also obtained on sex, age, main occupation, and level of education. Symptoms reported during the high exposure period, were initially clustered in broader symptom categories from reference literature on health effects of pesticides that inhibit cholinesterase (organophosphate and carbamate). Prevalence ratios were estimated for symptoms with changes in cholinesterase activity in serum. Symptom prevalence in exposed subjects was higher during the high exposure period than the low exposure period, although these differences were not significant. Interestingly, a clear and significant change in symptoms prevalence was found in the controls with a higher prevalence in the low exposure period. Analysis of the relation between cholinesterase inhibition and symptoms showed that prevalence ratios were significantly > 1 for respiratory, eye, and central nervous system symptoms for workers with > 30% inhibition. Similar results were found for analyses with the actual level of acetylcholinesterase activity. The results suggest the presence of a relation between exposure and acetylcholinesterase inhibition, acetylcholinesterase activity, and respiratory, eye, and central nervous system symptoms. Increased symptom prevalence was found at acetylcholinesterase

Evaluation of the nature of camel retinal acetylcholinesterase: inhibition by hexamethonium.

PubMed

Alhomida, A S; Kamal, M A; al-Jafari, A A

1997-12-01

Acetylcholinesterase (AChE, EC 3.1.1.7) has been demonstrated in retinas of several species, however, the nature of the interaction of AChE with specific inhibitors are very limited in the literature and the mode of inhibition of camel retinal AChE by hexamethonium has been studied. Hexamethonium reversibly inhibited AChE in a concentration dependent manner, the IC50 value being c. 2.52 mM. The Km for the hydrolysis of acetylthiocholine iodide was found to be 0.087 mM and the Vmax was 0.63 mumol/min/mg protein. Dixon, as well as Lineweaver-Burk, plots and their secondary replots indicated that the nature of the inhibition is of the hyperbolic (partial) mixed type, which is considered to be a partial competitive and non-competitive mixture. The values of Ki(slope) and KI(intercept) from a Lineweaver-Burk plot were estimated as 0.30 mM and 0.17 mM, respectively, while Ki from a Dixon plot was estimated as 0.725 mM. The Ki was greater than KI indicating that hexamethonium has a greater affinity of binding for the active site than the peripheral site of the camel retina AChE.

Investigations into the development of catalytic activity in anti-acetylcholinesterase idiotypic and anti-idiotypic antibodies.

PubMed

Johnson, Glynis; Moore, Samuel W

2009-01-01

We have previously described anti-acetylcholinesterase antibodies that display acetylcholinesterase-like catalytic activity. No evidence of contaminating enzymes was found, and the antibodies are kinetically and apparently structurally distinct from both acetylcholinesterase (AChE) and butyrylcholinesterase. We have also mimicked the antibody catalytic sites in anti-anti-idiotypic (Ab3) antibodies. Independently from us, similar acetylcholinesterase-like antibodies have been raised as anti-idiotypic (Ab2) antibodies against a non-catalytic anti-acetylcholinesterase antibody, AE-2. In this paper, we describe an epitope analysis, using synthetic peptides in ELISA and competition ELISA, and a peptide array, of five catalytic anti-acetylcholinesterase antibodies (Ab1s), three catalytic Ab3s, as well as antibody AE-2 and a non-catalytic Ab2. The catalytic Ab1s and Ab3s recognized three Pro- and Gly-containing sequences ((40)PPMGPRRFL, (78)PGFEGTE, and (258)PPGGTGGNDTELVAC) on the AChE surface. As these sequences do not adjoin in the AChE structure, recognition would appear to be due to cross-reaction. This was confirmed by the observation that the sequences superimpose structurally. The non-catalytic antibodies, AE-2 and the Ab2, recognized AChE's peripheral anionic site (PAS), in particular, the sequence (70)YQYVD, which contains two of the site's residues. The crystal structure of the AChE tetramer (Bourne et al., 1999) shows direct interaction and high complementarity between the (257)CPPGGTGGNDTELVAC sequence and the PAS. Antibodies recognizing the sequence and the PAS may, in turn, be complementary; this may account for the apparent paradox of catalytic development in both Ab1s and Ab2s. The PAS binds, but does not hydrolyze, substrate. The catalytic Ab1s, therefore, recognize a site that may function as a substrate analog, and this, together with the presence of an Arg-Glu salt bridge in the epitope, suggests mechanisms whereby catalytic activity may have

Cholinergic Dysfunction in Fragile X Syndrome and Potential Intervention

PubMed Central

Kesler, Shelli R; Lightbody, Amy A; Reiss, Allan L

2009-01-01

Males with fragile X syndrome are at risk for significant cognitive and behavioral deficits, particularly those involving executive prefrontal systems. Disruption of the cholinergic system secondary to fragile X mental retardation protein deficiency may contribute to the cognitive-behavioral impairments associated with fragile X. We measured choline in the dorsolateral prefrontal cortex of 9 males with fragile X syndrome and 9 age-matched typically developing controls using 1H magnetic resonance spectroscopy. Right choline/creatine was significantly reduced in the fragile X group compared to controls. In controls, both left and right choline was significantly positively correlated with intelligence and age was significantly negatively correlated with left choline. There were no correlations in the fragile X group. Subjects with fragile X syndrome participating in a pilot open-label trial of donepezil, an acetylcholinesterase inhibitor, demonstrated significantly improved cognitive-behavioral function. Studies utilizing biochemical neuroimaging techniques such as these have the potential to significantly impact the design of treatment strategies for fragile X syndrome and other genetic disorders by helping identify neurochemical targets for intervention as well as serving as metrics for treatment efficacy. PMID:19215057

Phenolic Lipids Affect the Activity and Conformation of Acetylcholinesterase from Electrophorus electricus (Electric eel)

PubMed Central

Stasiuk, Maria; Janiszewska, Alicja; Kozubek, Arkadiusz

2014-01-01

Phenolic lipids were isolated from rye grains, cashew nutshell liquid (CNSL) from Anacardium occidentale, and fruit bodies of Merrulius tremellosus, and their effects on the electric eel acetylcholinesterase activity and conformation were studied. The observed effect distinctly depended on the chemical structure of the phenolic lipids that were available for interaction with the enzyme. All of the tested compounds reduced the activity of acetylcholinesterase. The degree of inhibition varied, showing a correlation with changes in the conformation of the enzyme tested by the intrinsic fluorescence of the Trp residues of the protein. PMID:24787269

Characterization of lipid-protein interactions in acetylcholinesterase lipoprotein extracted from bovine erythrocytes.

PubMed Central

Beauregard, G; Roufogalis, B D

1979-01-01

Acetylcholinesterase was released from bovine erythrocytes in hypo-osmotic sodium phosphate buffer. Initially, about 30% of the enzyme was released in a soluble lipoprotein form, and further incubation resulted in the progressive release of the enzyme in a particulate form. Solubilization of the acetylcholinesterase in the particulate fraction with Lubrol WX (2 mg/ml) resulted in the loss of all lipids except a non-exchangeable fraction identified as cardiolipin. Addition of a mixture of erythrocyte phospholipids to the soluble forms and to the Lubrol WX-solubilized enzyme resulted in the formation of particulate forms of the enzyme with increased partial specific volume and Stokes radius, and a break in the Arrhenius plot of the enzyme activity around 20 degrees C. The break in the Arrhenius plot was abolished by treatment of a soluble enzyme preparation with 1.8 M salt (NaCl) in phosphate buffer, conditions that allowed the extraction of cardiolipin from the enzyme by chloroform/methanol. Failure of the high-salt treatment to decrease the Stokes radius made it unlikely that the bound cardiolipin formed a boundary layer or annulus around the protein. It is suggested that cardiolipin is bound to the core of the dimeric protein structure, thereby controlling the acetylcholinesterase activity. PMID:475749

Synthesis and acetylcholinesterase/butyrylcholinesterase inhibition activity of 4-amino-2, 3-diaryl-5, 6, 7, 8-tetrahydrofuro(and thieno)[2, 3-b]-quinolines, and 4-amino-5, 6, 7, 8, 9-pentahydro-2, 3-diphenylcyclohepta[e]furo(and thieno)-[2, 3-b]pyridines.

PubMed

Marco, José L; De Los Ríos, Cristóbal; Carreiras, María C; Baños, Josep E; Badia, Albert; Vivas, Nuria M

2002-07-01

The acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibition activities of a series of 4-amino-2, 3-diaryl-5, 6, 7, 8-tetrahydrofuro[2, 3-b]quinolines (10-12)/4-amino-5, 6, 7, 8-tetrahydro-2, 3-diphenylthieno[2, 3-b]quinoline (14) and 4-amino-5, 6, 7, 8, 9-pentahydro-2, 3-diphenylcyclohepta[e]furo[2, 3-b]pyridine (13)/4-amino-5, 6, 7, 8, 9-pentahydro-2, 3-phenylcyclohepta[e]thieno[2, 3-b]pyridine (15) are described. These compounds are tacrine (THA) analogues which have been prepared either from readily available 2-amino-3-cyano-4, 5-diarylfurans (16-18) or from 2-amino-3-cyano-4, 5-diphenylthiophene (19), via Friedländer condensation with cyclohexanone or cycloheptanone. These compounds are competitive inhibitors for acetylcholinesterase, the more potent being compound (13) which is three-fold less active than tacrine. The butyrylcholinesterase inhibition activity is significant only in compounds 10 and133, which are ten-fold less active than tacrine. It is found that the products 11 and 12 strongly inhibit acetylcholinesterase, and show excellent selectivity regarding butyrylcholinesterase.

Bioactive Paper Sensor Based on the Acetylcholinesterase for the Rapid Detection of Organophosphate and Carbamate Pesticides

PubMed Central

Badawy, Mohamed E. I.; El-Aswad, Ahmed F.

2014-01-01

In many countries, people are becoming more concerned about pesticide residues which are present in or on food and feed products. For this reason, several methods have been developed to monitor the pesticide residue levels in food samples. In this study, a bioactive paper-based sensor was developed for detection of acetylcholinesterase (AChE) inhibitors including organophosphate and carbamate pesticides. Based on the Ellman colorimetric assay, the assay strip is composed of a paper support (1 × 10 cm), onto which a biopolymer chitosan gel immobilized in crosslinking by glutaraldehyde with AChE and 5,5′-dithiobis(2-nitrobenzoic) acid (DTNB) and uses acetylthiocholine iodide (ATChI) as an outside reagent. The assay protocol involves introducing the sample to sensing zone via dipping of a pesticide-containing solution. Following an incubation period, the paper is placed into ATChI solution to initiate enzyme catalyzed hydrolysis of the substrate, causing a yellow color change. The absence or decrease of the yellow color indicates the levels of the AChE inhibitors. The biosensor is able to detect organophosphate and carbamate pesticides with good detection limits (methomyl = 6.16 × 10−4 mM and profenofos = 0.27 mM) and rapid response times (~5 min). The results show that the paper-based biosensor is rapid, sensitive, inexpensive, portable, disposable, and easy-to-use. PMID:25484901

The NADPH oxidase inhibitor diphenyleneiodonium is also a potent inhibitor of cholinesterases and the internal Ca2+ pump

PubMed Central

Tazzeo, T; Worek, F; Janssen, LJ

2009-01-01

Background and purpose: Diphenyleneiodonium (DPI) is often used as an NADPH oxidase inhibitor, but is increasingly being found to have unrelated side effects. We investigated its effects on smooth muscle contractions and the related mechanisms. Experimental approach: We studied isometric contractions in smooth muscle strips from bovine trachea. Cholinesterase activity was measured using a spectrophotometric assay; internal Ca2+ pump activity was assessed by Ca2+ uptake into smooth muscle microsomes. Key results: Contractions to acetylcholine were markedly enhanced by DPI (10−4 M), whereas those to carbachol (CCh) were not, suggesting a possible inhibition of cholinesterase. DPI markedly suppressed contractions evoked by CCh, KCl and 5-HT, and also unmasked phasic activity in otherwise sustained responses. Direct biochemical assays confirmed that DPI was a potent inhibitor of acetylcholinesterase and butyrylcholinesterase (IC50∼8 × 10−6 M and 6 × 10−7 M, respectively), following a readily reversible, mixed non-competitive type of inhibition. The inhibitory effects of DPI on CCh contractions were not mimicked by another NADPH oxidase inhibitor (apocynin), nor the Src inhibitors PP1 or PP2, ruling out an action through the NADPH oxidase signalling pathway. Several features of the DPI-mediated suppression of agonist-evoked responses (i.e. suppression of peak magnitudes and unmasking of phasic activity) are similar to those of cyclopiazonic acid, an inhibitor of the internal Ca2+ pump. Direct measurement of microsomal Ca2+ uptake revealed that DPI modestly inhibits the internal Ca2+ pump. Conclusions and implications: DPI inhibits cholinesterase activity and the internal Ca2+ pump in tracheal smooth muscle. PMID:19788497

An Acetylcholinesterase-Based Chronoamperometric Biosensor for Fast and Reliable Assay of Nerve Agents

PubMed Central

Pohanka, Miroslav; Adam, Vojtech; Kizek, Rene

2013-01-01

The enzyme acetylcholinesterase (AChE) is an important part of cholinergic nervous system, where it stops neurotransmission by hydrolysis of the neurotransmitter acetylcholine. It is sensitive to inhibition by organophosphate and carbamate insecticides, some Alzheimer disease drugs, secondary metabolites such as aflatoxins and nerve agents used in chemical warfare. When immobilized on a sensor (physico-chemical transducer), it can be used for assay of these inhibitors. In the experiments described herein, an AChE- based electrochemical biosensor using screen printed electrode systems was prepared. The biosensor was used for assay of nerve agents such as sarin, soman, tabun and VX. The limits of detection achieved in a measuring protocol lasting ten minutes were 7.41 × 10−12 mol/L for sarin, 6.31 × 10−12 mol/L for soman, 6.17 × 10−11 mol/L for tabun, and 2.19 × 10−11 mol/L for VX, respectively. The assay was reliable, with minor interferences caused by the organic solvents ethanol, methanol, isopropanol and acetonitrile. Isopropanol was chosen as suitable medium for processing lipophilic samples. PMID:23999806

Screening of plants used in the European traditional medicine to treat memory disorders for acetylcholinesterase inhibitory activity and anti amyloidogenic activity.

PubMed

Lobbens, Eva S B; Vissing, Karina J; Jorgensen, Lene; van de Weert, Marco; Jäger, Anna K

2017-03-22

Plants used in the traditional medicine of Europe to treat memory dysfunction and/or to enhance memory were investigated for activity against the underlying mechanisms of Alzheimer's disease. To investigate 35 ethanolic extracts of plants, selected using an ethnopharmacological approach, for anti-amyloidogenic activity as well as an ability to inhibit the enzymatic activity of acetylcholinesterase. The anti-amyloidogenic activity of the extracts against amyloid beta was investigated by Thioflavin T fibrillation assays and the ability to inhibit the enzymatic activity of acetylcholinesterase was evaluated monitoring the hydrolysis of acetylthiocholine RESULTS: Under the experimental conditions investigated, extracts of two plants, Carum carvi and Olea sylvestris, inhibited amyloid beta fibrillation considerably, eight plant extracts inhibited amyloid beta fibrillation to some extent, 16 plant extracts had no effect on amyloid beta fibrillation and nine extracts accelerated fibrillation of amyloid beta. Furthermore, five plant extracts from Corydalis species inhibited the enzymatic activity of acetylcholinesterase considerably, one plant extract inhibited the enzymatic activity of acetylcholinesterase to some extent and 29 plant extract had no effect on the enzymatic activity of acetylcholinesterase. An optimal extract in this study would possess acetylcholinesterase inhibitory activity as well as anti-amyloidogenic activity in order to address multiple facets of Alzheimer's disease, until the molecular origin of the disease is unraveled. Unfortunately no such extract was found. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Upregulation of α7 Nicotinic Receptors by Acetylcholinesterase C-Terminal Peptides

PubMed Central

Bond, Cherie E.; Zimmermann, Martina; Greenfield, Susan A.

2009-01-01

Background The alpha-7 nicotinic acetylcholine receptor (α7-nAChR) is well known as a potent calcium ionophore that, in the brain, has been implicated in excitotoxicity and hence in the underlying mechanisms of neurodegenerative disorders such as Alzheimer's disease. Previous research implied that the activity of this receptor may be modified by exposure to a peptide fragment derived from the C-terminal region of the enzyme acetylcholinesterase. This investigation was undertaken to determine if the functional changes observed could be attributed to peptide binding interaction with the α7-nAChR, or peptide modulation of receptor expression. Methodology/Principal Findings This study provides evidence that two peptides derived from the C-terminus of acetylcholinesterase, not only selectively displace specific bungarotoxin binding at the α7-nAChR, but also alter receptor binding properties for its familiar ligands, including the alternative endogenous agonist choline. Of more long-term significance, these peptides also induce upregulation of α7-nAChR mRNA and protein expression, as well as enhancing receptor trafficking to the plasma membrane. Conclusions/Significance The results reported here demonstrate a hitherto unknown relationship between the α7-nAChR and the non-enzymatic functions of acetylcholinesterase, mediated independently by its C-terminal domain. Such an interaction may prove valuable as a pharmacological tool, prompting new approaches for understanding, and combating, the process of neurodegeneration. PMID:19287501

Design, synthesis and evaluation of novel tacrine-coumarin hybrids as multifunctional cholinesterase inhibitors against Alzheimer's disease.

PubMed

Xie, Sai-Sai; Wang, Xiao-Bing; Li, Jiang-Yan; Yang, Lei; Kong, Ling-Yi

2013-06-01

A series of tacrine-coumarin hybrids (8a-t) were designed, synthesized and evaluated as multifunctional cholinesterase (ChE) inhibitors against Alzheimer's disease (AD). The screening results showed that most of them exhibited a significant ability to inhibit ChE and self-induced β-amyloid (Aβ) aggregation, and to act as metal chelators. Especially, 8f displayed the greatest ability to inhibit acetylcholinesterase (AChE, IC50 = 0.092 μM) and Aβ aggregation (67.8%, 20 μM). It was also a good butyrylcholinesterase inhibitor (BuChE, IC50 = 0.234 μM) and metal chelator. Besides, kinetic and molecular modeling studies indicated that 8f was a mixed-type inhibitor, binding simultaneously to active, peripheral and mid-gorge sites of AChE. These results suggested that 8f might be an excellent multifunctional agent for AD treatment. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

N-Benzoyl-D-phenylalanine attenuates brain acetylcholinesterase in neonatal streptozotocin-diabetic rats.

PubMed

Ashokkumar, Natarajan; Pari, Leelavinothan; Ramkumar, Kunga Mohan

2006-09-01

The effect of hyperglycaemia due to experimental diabetes in male Wistar rats causes a decrease in the level of acetylcholinesterase (AChE) with significant increase in lipid peroxidative markers: thiobarbituric acid-reactive substances (TBARS) and hydroperoxides in brains of experimental animals. The decreased activity of both salt soluble and detergent soluble acetylcholinesterase observed in diabetes may be attributed to lack of insulin which causes specific alterations in the level of neurotransmitter, thus causing brain dysfunction. Administration of non-sulfonylurea drug N-benzoyl-D-phenylalanine (NBDP) could protect against direct action of lipid peroxidation on brain AChE and in this way it might be useful in the prevention of cholinergic neural dysfunction, which is one of the major complications in diabetes.

Inhibition of acetylcholinesterase by two genistein derivatives: kinetic analysis, molecular docking and molecular dynamics simulation.

PubMed

Fang, Jiansong; Wu, Ping; Yang, Ranyao; Gao, Li; Li, Chao; Wang, Dongmei; Wu, Song; Liu, Ai-Lin; Du, Guan-Hua

2014-12-01

In this study two genistein derivatives (G1 and G2) are reported as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), and differences in the inhibition of AChE are described. Although they differ in structure by a single methyl group, the inhibitory effect of G1 (IC50=264 nmol/L) on AChE was 80 times stronger than that of G2 (IC50=21,210 nmol/L). Enzyme-kinetic analysis, molecular docking and molecular dynamics (MD) simulations were conducted to better understand the molecular basis for this difference. The results obtained by kinetic analysis demonstrated that G1 can interact with both the catalytic active site and peripheral anionic site of AChE. The predicted binding free energies of two complexes calculated by the molecular mechanics/generalized born surface area (MM/GBSA) method were consistent with the experimental data. The analysis of the individual energy terms suggested that a difference between the net electrostatic contributions (ΔE ele+ΔG GB) was responsible for the binding affinities of these two inhibitors. Additionally, analysis of the molecular mechanics and MM/GBSA free energy decomposition revealed that the difference between G1 and G2 originated from interactions with Tyr124, Glu292, Val294 and Phe338 of AChE. In conclusion, the results reveal significant differences at the molecular level in the mechanism of inhibition of AChE by these structurally related compounds.

Conformational energy landscape of the acyl pocket loop in acetylcholinesterase: a Monte Carlo-generalized Born model study.

PubMed

Carlacci, Louis; Millard, Charles B; Olson, Mark A

2004-10-01

The X-ray crystal structure of the reaction product of acetylcholinesterase (AChE) with the inhibitor diisopropylphosphorofluoridate (DFP) showed significant structural displacement in a loop segment of residues 287-290. To understand this conformational selection, a Monte Carlo (MC) simulation study was performed of the energy landscape for the loop segment. A computational strategy was applied by using a combined simulated annealing and room temperature Metropolis sampling approach with solvent polarization modeled by a generalized Born (GB) approximation. Results from thermal annealing reveal a landscape topology of broader basin opening and greater distribution of energies for the displaced loop conformation, while the ensemble average of conformations at 298 K favored a shift in populations toward the native by a free-energy difference in good agreement with the estimated experimental value. Residue motions along a reaction profile of loop conformational reorganization are proposed where Arg-289 is critical in determining electrostatic effects of solvent interaction versus Coulombic charging.

Preparation, in vitro screening and molecular modelling of symmetrical 4-tert-butylpyridinium cholinesterase inhibitors--analogues of SAD-128.

PubMed

Musilek, Kamil; Roder, Jan; Komloova, Marketa; Holas, Ondrej; Hrabinova, Martina; Pohanka, Miroslav; Dohnal, Vlastimil; Opletalova, Veronika; Kuca, Kamil; Jung, Young-Sik

2011-01-01

Carbamate inhibitors (e.g., pyridostimine bromide) are used as a pre-exposure treatment for the prevention of organophosphorus poisoning. They work by blocking acetylcholinesterase's (AChE) native function and thus protect AChE against irreversible inhibition by organophosphorus compounds. However, carbamate inhibitors are known for many undesirable side-effects related to the carbamylation of AChE. In this Letter, 19 analogues of SAD-128 were prepared and evaluated as cholinesterase inhibitors. The screening results showed promising inhibitory ability of four compounds better to used standards (pralidoxime, obidoxime, BW284c51, ethopropazine, SAD-128). Four most promising compounds were selected for further molecular docking studies. The SAR was stated from obtained data. The former receptor studies were reported and discussed. The further in vivo studies were recommended in the view of OP pre-exposure treatment. Copyright © 2010 Elsevier Ltd. All rights reserved.

Discontinuation, Efficacy, and Safety of Cholinesterase Inhibitors for Alzheimer’s Disease: a Meta-Analysis and Meta-Regression of 43 Randomized Clinical Trials Enrolling 16 106 Patients

PubMed Central

Blanco-Silvente, Lídia; Saez, Marc; Barceló, Maria Antònia; Garre-Olmo, Josep; Vilalta-Franch, Joan; Capellà, Dolors

2017-01-01

Abstract Background: We investigated the effect of cholinesterase inhibitors on all-cause discontinuation, efficacy and safety, and the effects of study design-, intervention-, and patient-related covariates on the risk-benefit of cholinesterase inhibitors for Alzheimer’s disease. Methods: A systematic review and meta-analysis of randomized placebo-controlled clinical trials comparing cholinesterase inhibitors and placebo was performed. The effect of covariates on study outcomes was analysed by means of meta-regression using a Bayesian framework. Results: Forty-three randomized placebo-controlled clinical trials involving 16106 patients were included. All-cause discontinuation was higher with cholinesterase inhibitors (OR = 1.66), as was discontinuation due to adverse events (OR=1.75). Cholinesterase inhibitors improved cognitive function (standardized mean difference = 0.38), global symptomatology (standardized mean difference=0.28) and functional capacity (standardized mean difference=0.16) but not neuropsychiatric symptoms. Rivastigmine was associated with a poorer outcome on all-cause discontinuation (Diff OR = 1.66) and donepezil with a higher efficacy on global change (Diff standardized mean difference = 0.41). The proportion of patients with serious adverse events decreased with age (Diff OR = -0.09). Mortality was lower with cholinesterase inhibitors than with placebo (OR = 0.65). Conclusion: While cholinesterase inhibitors show a poor risk-benefit relationship as indicated by mild symptom improvement and a higher than placebo all-cause discontinuation, a reduction of mortality was suggested. Intervention- and patient-related factors modify the effect of cholinesterase inhibitors in patients with Alzheimer’s disease. PMID:28201726

Quantitative distributions of different cholinesterases and inhibition of acetylcholinesterase by metidathion and paraquat in alimentary canal of common carp.

PubMed

Láng, G; Kufcsák, O; Szegletes, T; Nemcsók, J

1997-07-01

1. The cholinesterases play an important role in the innervation of organs. The ratio of solubilized to membrane-bound cholinesterase and the quantitative distributions of acetylcholinesterase and butyrylcholinesterase were measured in different segments of the gut of carp (Cyprinus carpio) connected with different types of nerve-muscle synapses in different parts of the alimentary tract. 2. The inhibition of acetylcholinesterase (EC 3.1.1.7.) by the herbicide paraquat and the insecticide metidathion was measured in different parts of the gut of carp. 3. Metidathion and paraquat significantly decreased the activity of acetylcholinesterase in different segments of the alimentary tract of common carp, in a concentration-dependent manner.

Nicotinic alpha 7 receptor agonists EVP-6124 and BMS-933043, attenuate scopolamine-induced deficits in visuo-spatial paired associates learning

PubMed Central

Polino, Joseph; Signor, Laura; Bookbinder, Mark; Keavy, Deborah; Benitex, Yulia; Morgan, Daniel G.; King, Dalton; Macor, John E.; Zaczek, Robert; Olson, Richard; Bristow, Linda J.

2017-01-01

Agonists at the nicotinic acetylcholine alpha 7 receptor (nAChR α7) subtype have the potential to treat cognitive deficits in patients with Alzheimer’s disease (AD) or schizophrenia. Visuo-spatial paired associates learning (vsPAL) is a task that has been shown to reliably predict conversion from mild cognitive impairment to AD in humans and can also be performed by nonhuman primates. Reversal of scopolamine-induced impairment of vsPAL performance may represent a translational approach for the development of nAChR α7 agonists. The present study investigated the effect of treatment with the acetylcholinesterase inhibitor, donepezil, or three nAChR α7 agonists, BMS-933043, EVP-6124 and RG3487, on vsPAL performance in scopolamine-treated cynomolgus monkeys. Scopolamine administration impaired vsPAL performance accuracy in a dose- and difficulty- dependent manner. The impairment of eventual accuracy, a measure of visuo-spatial learning during the task, was significantly ameliorated by treatment with donepezil (0.3 mg/kg, i.m.), EVP-6124 (0.01 mg/kg, i.m.) or BMS-933043 (0.03, 0.1 and 0.3 mg/kg, i.m.). Both nAChR α7 agonists showed inverted-U shaped dose-effect relationships with EVP-6124 effective at a single dose only whereas BMS-933043 was effective across at least a 10 fold dose/exposure range. RG3487 was not efficacious in this paradigm at the dose range examined (0.03–1 mg/kg, i.m.). These results are the first demonstration that the nAChR α7 agonists, EVP-6124 and BMS-933043, can ameliorate scopolamine-induced cognitive deficits in nonhuman primates performing the vsPAL task. PMID:29261656

Evaluation of the sensitivity of the novel α4β2* nicotinic acetylcholine receptor PET radioligand 18F-(-)-NCFHEB to increases in synaptic acetylcholine levels in rhesus monkeys.

PubMed

Gallezot, Jean-Dominique; Esterlis, Irina; Bois, Frederic; Zheng, Ming-Qiang; Lin, Shu-Fei; Kloczynski, Tracy; Krystal, John H; Huang, Yiyun; Sabri, Osama; Carson, Richard E; Cosgrove, Kelly P

2014-11-01

18F-(-)-NCFHEB (also known as 18F-(-)-Flubatine) is a new radioligand to image α4β2* nicotinic acetylcholine receptors in vivo with positron emission tomography (PET), with faster kinetics than previous radioligands such as 18F-2-F-A85380. The goal of this study was to assess the sensitivity of 18F-(-)-NCFHEB-PET to increases in synaptic acetylcholine concentration induced by acetylcholinesterase inhibitors. Two rhesus monkeys were scanned four times each on a Focus 220 scanner: first at baseline, then during two bolus plus infusions of physostigmine (0.06-0.28 mg/kg), and finally following a bolus injection of donepezil (0.25 mg/kg). The arterial input function and the plasma free fraction fP were measured. 18F-(-)-NCFHEB volume of distribution VT was estimated using the multilinear analysis MA1 and then normalized by plasma free fraction fP . 18F-(-)-NCFHEB fP was 0.89±0.04. At baseline, 18F-(-)-NCFHEB VT /fP ranged from 7.9±1.3 mL plasma/cm3 tissue in the cerebellum to 34.3±8.4 mL plasma/cm3 tissue in the thalamus. Physostigmine induced a dose-dependent reduction of 18F-(-)-NCFHEB VT /fP of 34±9% in the putamen, 32±8% in the thalamus, 25±8% in the cortex, and 23±10% in the hippocampus. With donepezil, 18F-(-)-NCFHEB VT /fP was reduced by 24±2%, 14+3% and 14±5%, 10±6% in the same regions. 18F-(-)-NCFHEB can be used to detect changes in synaptic acetylcholine concentration and is a promising tracer to study acetylcholine dynamics with shorter scan durations than previous radioligands. © 2014 Wiley Periodicals, Inc.

Chagas disease: modulation of the inflammatory response by acetylcholinesterase in hematological cells and brain tissue.

PubMed

Silva, Aniélen D; Bottari, Nathieli B; do Carmo, Guilherme M; Baldissera, Matheus D; Souza, Carine F; Machado, Vanessa S; Morsch, Vera M; Schetinger, Maria Rosa C; Mendes, Ricardo E; Monteiro, Silvia G; Da Silva, Aleksandro S

2018-01-01

Chagas disease is an acute or chronic illness that causes severe inflammatory response, and consequently, it may activate the inflammatory cholinergic pathway, which is regulated by cholinesterases, including the acetylcholinesterase. This enzyme is responsible for the regulation of acetylcholine levels, an anti-inflammatory molecule linked to the inflammatory response during parasitic diseases. Thus, the aim of this study was to investigate whether Trypanosoma cruzi infection can alter the activity of acetylcholinesterase and acetylcholine levels in mice, and whether these alterations are linked to the inflammatory cholinergic signaling pathway. Twenty-four mice were divided into two groups: uninfected (control group, n = 12) and infected by T. cruzi, Y strain (n = 12). The animals developed acute disease with a peak of parasitemia on day 7 post-infection (PI). Blood, lymphocytes, and brain were analyzed on days 6 and 12 post-infection. In the brain, acetylcholine and nitric oxide levels, myeloperoxidase activity, and histopathology were analyzed. In total blood and brain, acetylcholinesterase activity decreased at both times. On the other hand, acetylcholinesterase activity in lymphocytes increased on day 6 PI compared with the control group. Infection by T. cruzi increased acetylcholine and nitric oxide levels and histopathological damage in the brain of mice associated to increased myeloperoxidase activity. Therefore, an intense inflammatory response in mice with acute Chagas disease in the central nervous system caused an anti-inflammatory response by the activation of the cholinergic inflammatory pathway.

Free energy landscape for the binding process of Huperzine A to acetylcholinesterase

PubMed Central

Bai, Fang; Xu, Yechun; Chen, Jing; Liu, Qiufeng; Gu, Junfeng; Wang, Xicheng; Ma, Jianpeng; Li, Honglin; Onuchic, José N.; Jiang, Hualiang

2013-01-01

Drug-target residence time (t = 1/koff, where koff is the dissociation rate constant) has become an important index in discovering better- or best-in-class drugs. However, little effort has been dedicated to developing computational methods that can accurately predict this kinetic parameter or related parameters, koff and activation free energy of dissociation (). In this paper, energy landscape theory that has been developed to understand protein folding and function is extended to develop a generally applicable computational framework that is able to construct a complete ligand-target binding free energy landscape. This enables both the binding affinity and the binding kinetics to be accurately estimated. We applied this method to simulate the binding event of the anti-Alzheimer’s disease drug (−)−Huperzine A to its target acetylcholinesterase (AChE). The computational results are in excellent agreement with our concurrent experimental measurements. All of the predicted values of binding free energy and activation free energies of association and dissociation deviate from the experimental data only by less than 1 kcal/mol. The method also provides atomic resolution information for the (−)−Huperzine A binding pathway, which may be useful in designing more potent AChE inhibitors. We expect this methodology to be widely applicable to drug discovery and development. PMID:23440190

Free energy landscape for the binding process of Huperzine A to acetylcholinesterase.

PubMed

Bai, Fang; Xu, Yechun; Chen, Jing; Liu, Qiufeng; Gu, Junfeng; Wang, Xicheng; Ma, Jianpeng; Li, Honglin; Onuchic, José N; Jiang, Hualiang

2013-03-12

Drug-target residence time (t = 1/k(off), where k(off) is the dissociation rate constant) has become an important index in discovering better- or best-in-class drugs. However, little effort has been dedicated to developing computational methods that can accurately predict this kinetic parameter or related parameters, k(off) and activation free energy of dissociation (ΔG(off)≠). In this paper, energy landscape theory that has been developed to understand protein folding and function is extended to develop a generally applicable computational framework that is able to construct a complete ligand-target binding free energy landscape. This enables both the binding affinity and the binding kinetics to be accurately estimated. We applied this method to simulate the binding event of the anti-Alzheimer's disease drug (-)-Huperzine A to its target acetylcholinesterase (AChE). The computational results are in excellent agreement with our concurrent experimental measurements. All of the predicted values of binding free energy and activation free energies of association and dissociation deviate from the experimental data only by less than 1 kcal/mol. The method also provides atomic resolution information for the (-)-Huperzine A binding pathway, which may be useful in designing more potent AChE inhibitors. We expect this methodology to be widely applicable to drug discovery and development.

Acetylcholinesterase Inhibition and Information Processing in the Auditory Cortex

DTIC Science & Technology

1986-04-30

9,24,29,30), or for causing auditory hallucinations (2,23,31,32). Thus, compounds which alter cho- linergic transmission, in particular anticholinesterases...the upper auditory system. Thus, attending to and understanding verbal messages in humans, irrespective of the particular voice which speaks them, may...00, AD ACETYLCHOLINESTERASE INHIBITION AND INFORMATION PROCESSING IN THE AUDITORY CORTEX ANNUAL SUMMARY REPORT DTIC ELECTENORMAN M

Detoxification of Acetylcholinesterase Inhibitors.

DTIC Science & Technology

1987-02-19

IIB:HB-o Mvse three machanisms can be distinguished by appropriate labelling experiments in oxygen-18 H.O. If mechanism C is operating, hydrolysis...enzyue reveals that there is a single break at pa 6.2 relative to both Vmax and Vfax/Km. This would appear to represent the titration of the basic residue

Self reported symptoms and inhibition of acetylcholinesterase activity among Kenyan agricultural workers

PubMed Central

Ohayo-Mitoko, G.; Kromhout, H.; Simwa, J.; Boleij, J.; Heederik, D.

2000-01-01

OBJECTIVES—This study was part of the East African pesticides project. The general objective was to assess health hazards posed by handling, storage, and use of pesticides, on agricultural estates and small farms with a view to developing strategies for prevention and control of pesticide poisoning. The aim of this paper is to describe the prevalence of symptoms in this population, to relate levels of inhibition to reported symptoms and evaluate at which levels of inhibition symptoms become increased.
METHODS—Complete data were available for 256 exposed subjects and 152 controls from four regions in Kenya. A structured questionnaire on symptoms experienced at the time of interview was given to all subjects and controls. Information was also obtained on sex, age, main occupation, and level of education. Symptoms reported during the high exposure period, were initially clustered in broader symptom categories from reference literature on health effects of pesticides that inhibit cholinesterase (organophosphate and carbamate). Prevalence ratios were estimated for symptoms with changes in cholinesterase activity in serum.
RESULTS—Symptom prevalence in exposed subjects was higher during the high exposure period than the low exposure period, although these differences were not significant. Interestingly, a clear and significant change in symptoms prevalence was found in the controls with a higher prevalence in the low exposure period. Analysis of the relation between cholinesterase inhibition and symptoms showed that prevalence ratios were significantly >1 for respiratory, eye, and central nervous system symptoms for workers with >30% inhibition. Similar results were found for analyses with the actual level of acetylcholinesterase activity.
CONCLUSION—The results suggest the presence of a relation between exposure and acetylcholinesterase inhibition, acetylcholinesterase activity, and respiratory, eye, and central nervous system symptoms. Increased symptom

Natural cholinesterase inhibitors from Myristica cinnamomea King.

PubMed

Abdul Wahab, Siti Mariam; Sivasothy, Yasodha; Liew, Sook Yee; Litaudon, Marc; Mohamad, Jamaludin; Awang, Khalijah

2016-08-01

A new acylphenol, malabaricone E (1) together with the known malabaricones A-C (2-4), maingayones A and B (5 and 6) and maingayic acid B (7) were isolated from the ethyl acetate extract of the fruits of Myristica cinnamomea King. Their structures were determined by 1D and 2D NMR techniques and LCMS-IT-TOF analysis. Compounds 3 (1.84±0.19 and 1.76±0.21μM, respectively) and 4 (1.94±0.27 and 2.80±0.49μM, respectively) were identified as dual inhibitors, with almost equal acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes inhibiting potentials. The Lineweaver-Burk plots of compounds 3 and 4 indicated that they were mixed-mode inhibitors. Based on the molecular docking studies, compounds 3 and 4 interacted with the peripheral anionic site (PAS), the catalytic triad and the oxyanion hole of the AChE. As for the BChE, while compound 3 interacted with the PAS, the catalytic triad and the oxyanion hole, compound 4 only interacted with the catalytic triad and the oxyanion hole. Copyright © 2016 Elsevier Ltd. All rights reserved.

Prenylated xanthones from mangosteen as promising cholinesterase inhibitors and their molecular docking studies.

PubMed

Khaw, K Y; Choi, S B; Tan, S C; Wahab, H A; Chan, K L; Murugaiyah, V

2014-09-25

Garcinia mangostana is a well-known tropical plant found mostly in South East Asia. The present study investigated acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of G. mangostana extract and its chemical constituents using Ellman's colorimetric method. Cholinesterase inhibitory-guided approach led to identification of six bioactive prenylated xanthones showing moderate to potent cholinesterases inhibition with IC50 values of lower than 20.5 μM. The most potent inhibitor of AChE was garcinone C while γ-mangostin was the most potent inhibitor of BChE with IC50 values of 1.24 and 1.78 μM, respectively. Among the xanthones, mangostanol, 3-isomangostin, garcinone C and α-mangostin are AChE selective inhibitors, 8-deoxygartanin is a BChE selective inhibitor while γ-mangostin is a dual inhibitor. Preliminary structure-activity relationship suggests the importance of the C-8 prenyl and C-7 hydroxy groups for good AChE and BChE inhibitory activities. The enzyme kinetic studies indicate that both α-mangostin and garcinone C are mixed-mode inhibitors, while γ-mangostin is a non-competitive inhibitor of AChE. In contrast, both γ-mangostin and garcinone C are uncompetitive inhibitors, while α-mangostin is a mixed-mode inhibitor of BChE. Molecular docking studies revealed that α-mangostin, γ-mangostin and garcinone C interacts differently with the five important regions of AChE and BChE. The nature of protein-ligand interactions is mainly hydrophobic and hydrogen bonding. These bioactive prenylated xanthones are worthy for further investigations. Copyright © 2014 Elsevier GmbH. All rights reserved.

Overexpression of acetylcholinesterase gene in rice results in enhancement of shoot gravitropism.

PubMed

Yamamoto, Kosuke; Shida, Satoshi; Honda, Yoshihiro; Shono, Mariko; Miyake, Hiroshi; Oguri, Suguru; Sakamoto, Hikaru; Momonoki, Yoshie S

2015-09-25

Acetylcholine (ACh), a known neurotransmitter in animals and acetylcholinesterase (AChE) exists widely in plants, although its role in plant signal transduction is unclear. We previously reported AChE in Zea mays L. might be related to gravitropism based on pharmacological study using an AChE inhibitor. Here we clearly demonstrate plant AChE play an important role as a positive regulator in the gravity response of plants based on a genetic study. First, the gene encoding a second component of the ACh-mediated signal transduction system, AChE was cloned from rice, Oryza sativa L. ssp. Japonica cv. Nipponbare. The rice AChE shared high homology with maize, siratro and Salicornia AChEs. Similar to animal and other plant AChEs, the rice AChE hydrolyzed acetylthiocholine and propionylthiocholine, but not butyrylthiocholine. Thus, the rice AChE might be characterized as an AChE (E.C.3.1.1.7). Similar to maize and siratro AChEs, the rice AChE exhibited low sensitivity to the AChE inhibitor, neostigmine bromide, compared with the electric eel AChE. Next, the functionality of rice AChE was proved by overexpression in rice plants. The rice AChE was localized in extracellular spaces of rice plants. Further, the rice AChE mRNA and its activity were mainly detected during early developmental stages (2 d-10 d after sowing). Finally, by comparing AChE up-regulated plants with wild-type, we found that AChE overexpression causes an enhanced gravitropic response. This result clearly suggests that the function of the rice AChE relate to positive regulation of gravitropic response in rice seedlings. Copyright © 2015 Elsevier Inc. All rights reserved.

Preparation, in vitro screening and molecular modelling of symmetrical bis-quinolinium cholinesterase inhibitors--implications for early myasthenia gravis treatment.

PubMed

Komloova, Marketa; Musilek, Kamil; Horova, Anna; Holas, Ondrej; Dohnal, Vlastimil; Gunn-Moore, Frank; Kuca, Kamil

2011-04-15

This paper describes the preparation and in vitro evaluation of 18 newly prepared bis-quinolinium inhibitors on human recombinant acetylcholinesterase (AChE) and human plasmatic butyrylcholinesterase (BChE). Their inhibitory (IC(50)) and was compared to the chosen standards ambenonium dichloride, edrophonium chloride, BW284c51 and ethopropazine hydrochloride. One novel compound was found to be a promising inhibitor of hAChE (in nM range) and was better than edrophonium chloride or BW284c51, but was worse than ambenonium chloride. This compound also showed selectivity towards hAChE and it was confirmed as a non-competitive inhibitor of hAChE by kinetic analysis. A molecular modelling study further confirmed its binding to the peripheral active site of hAChE via apparent π-π or π-cationic interactions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effect of Calea serrata Less. n-hexane extract on acetylcholinesterase of larvae ticks and brain Wistar rats.

PubMed

Ribeiro, Vera Lucia Sardá; Vanzella, Cláudia; Moysés, Felipe dos Santos; Santos, Jaqueline Campiol Dos; Martins, João Ricardo Souza; von Poser, Gilsane Lino; Siqueira, Ionara Rodrigues

2012-10-26

Acetylcholinesterase (AChE), an enzyme that hydrolyses acetylcholine (ACh) at cholinergic synapses, is a target for pesticides and its inhibition by organophosphates leads to paralysis and death of arthropods. It has been demonstrated that the n-hexane extract of Calea serrata had acaricidal activity against larvae of Rhipicephalus (Boophilus) microplus and Rhipicephalus sanguineus. The aim of the present study was to understand the mechanism of the acaricidal action of C. serrata n-hexane extract are specifically to investigate the in vitro anticholinesterase activity on larvae of R. microplus and in brain structures of male Wistar rats. The n-hexane extract significantly inhibited in vitro acetylcholinesterase activity in R. microplus larvae and rat brain structures. The results confirm that inhibition of acetylcholinesterase is a possible mechanism of action of hexane extract at C. serrata. Copyright © 2012 Elsevier B.V. All rights reserved.

Synthesis and in vitro acetylcholinesterase and butyrylcholinesterase inhibitory potential of hydrazide based Schiff bases.

PubMed

Rahim, Fazal; Ullah, Hayat; Taha, Muhammad; Wadood, Abdul; Javed, Muhammad Tariq; Rehman, Wajid; Nawaz, Mohsan; Ashraf, Muhammad; Ali, Muhammad; Sajid, Muhammad; Ali, Farman; Khan, Muhammad Naseem; Khan, Khalid Mohammed

2016-10-01

To discover multifunctional agents for the treatment of Alzheimer's disease, a series of hydrazide based Schiff bases were designed and synthesized based on multitarget-directed strategy. We have synthesized twenty-eight analogs of hydrazide based Schiff bases, characterized by various spectroscopic techniques and evaluated in vitro for acetylcholinesterase and butyrylcholinesterase inhibition. All compounds showed varied degree of acetylcholinesterase and butyrylcholinesterase inhibition when compared with standard Eserine. Among the series, compounds 10, 3 and 24 having IC50 values 4.12±0.01, 8.12±0.01 and 8.41±0.06μM respectively showed potent acetylcholinesterase inhibition when compared with Eserine (IC50=0.85±0.0001μM). Three compounds 13, 24 and 3 having IC50 values 6.51±0.01, 9.22±0.07 and 37.82±0.14μM respectively showed potent butyrylcholinesterase inhibition by comparing with eserine (IC50=0.04±0.0001μM). The remaining compounds also exhibited moderate to weak inhibitory potential. Structure activity relationship has been established. Through molecular docking studies the binding interaction was confirmed. Copyright © 2016 Elsevier Inc. All rights reserved.

Acetylcholinesterase as a Biomarker in Environmental and Occupational Medicine: New Insights and Future Perspectives

PubMed Central

Caricato, Roberto; Calisi, Antonio; Giordano, Maria Elena; Schettino, Trifone

2013-01-01

Acetylcholinesterase (AChE) is a key enzyme in the nervous system. It terminates nerve impulses by catalysing the hydrolysis of neurotransmitter acetylcholine. As a specific molecular target of organophosphate and carbamate pesticides, acetylcholinesterase activity and its inhibition has been early recognized to be a human biological marker of pesticide poisoning. Measurement of AChE inhibition has been increasingly used in the last two decades as a biomarker of effect on nervous system following exposure to organophosphate and carbamate pesticides in occupational and environmental medicine. The success of this biomarker arises from the fact that it meets a number of characteristics necessary for the successful application of a biological response as biomarker in human biomonitoring: the response is easy to measure, it shows a dose-dependent behavior to pollutant exposure, it is sensitive, and it exhibits a link to health adverse effects. The aim of this work is to review and discuss the recent findings about acetylcholinesterase, including its sensitivity to other pollutants and the expression of different splice variants. These insights open new perspective for the future use of this biomarker in environmental and occupational human health monitoring. PMID:23936791

Exploration of the Energy Landscape of Acetylcholinesterase by Molecular Dynamics Simulation.

NASA Astrophysics Data System (ADS)

McCammon, J. Andrew

2002-03-01

Proteins have rough energy landscapes. Often more states than just the ground state are occupied and have biological functions. It is essential to study these conformational substates and the dynamical transitions among them. Acetylcholinesterase (AChE) is an important enzyme that has biological functions including the termination of synaptic transmission signals. X-ray structures show that it has an active site that is accessible only via a long and narrow channel from its surface. Therefore the fact that acetylcholine and larger ligands can reach the active site is believed to reflect the protein's structural fluctuation. We carried out long molecular dynamics simulations to investigate the dynamics of AChE and its relation to biological function, and compared our results with experiments. The results reveal several "doors" that open intermittantly between the active site and the surface. Instead of having simple exponential decay correlation functions, the time series of these channels reveal complex, fractal gating between conformations. We also compared the AChE dynamics data with those from an AchE-fasciculin complex. (Fasciculin is a small protein that is a natural inhibitor of AChE.) The results show remarkable effects of the protein-protein interaction, including allosteric and dynamical inhibition by fasciculin besides direct steric blocking. More information and images can be found at http://mccammon.ucsd.edu

New perspectives for multi-level regulations of neuronal acetylcholinesterase by dioxins.

PubMed

Xie, Heidi Q; Xu, Tuan; Chen, Yangsheng; Li, Yunping; Xia, Yingjie; Xu, Sherry L; Wang, Lingyun; Tsim, Karl W K; Zhao, Bin

2016-11-25

Acetylcholinesterase (AChE; EC 3.1.1.7) is a vital functional enzyme in cholinergic neurotransmission which can rapidly hydrolyze neurotransmitter, acetylcholine, in the central and peripheral nervous systems. Emerging evidence showed that in addition to classical environmental AChE inhibitors, e.g. organophosphate and carbamate pesticides, dioxins are a new type of xenobiotic causing impairment of AChE. Dioxin can transcriptionally or post-transcriptionally suppress AChE expression in human neuroblastoma cells or mouse immune cells via the aryl hydrocarbon receptor (AhR) pathway, respectively. Dioxins can affect gene expression through other mechanisms, such as cross-talk with other signaling cascades and epigenetic modulations. Therefore, in this review, by summarizing the known mechanisms of AChE regulation and dioxin-induced gene alteration, potential signaling cascades and epigenetic mechanisms are proposed for dioxin-mediated AChE regulation. Mitogen activated protein (MAP) kinase, 3', 5'-cyclic adenosine monophosphate (cAMP) and calcium-related singaling pathways, as well as potential epigenetic mechanisms, such as DNA methylation, and post-transcriptional regulation via microRNAs, including hsa-miR-132, hsa-miR-212 and hsa-miR-25-3p are discussed here. These proposed mechanisms may be invaluable not only to promote comprehensive understanding of the action mechanisms for dioxin, but to illustrate the molecular basis of dioxin-induced health impacts. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Computer Image Analysis of Histochemically-Labeled Acetylcholinesterase.

DTIC Science & Technology

1984-11-30

image analysis on conjunction with histochemical techniques to describe the distribution of acetylcholinesterase (AChE) activity in nervous and muscular tissue in rats treated with organophosphates (OPs). The objective of the first year of work on this remaining 2 years. We began by adopting a version of the AChE staining method as modified by Hanker, which consistent with the optical properties of our video system. We wrote computer programs for provide a numeric quantity which represents the degree of staining in a tissue section. The staining was calibrated by

Taspine: bioactivity-guided isolation and molecular ligand-target insight of a potent acetylcholinesterase inhibitor from Magnolia x soulangiana.

PubMed

Rollinger, Judith M; Schuster, Daniela; Baier, Elisabeth; Ellmerer, Ernst P; Langer, Thierry; Stuppner, Hermann

2006-09-01

A bioactivity-guided approach was taken to identify the acetylcholinesterase (AChE, EC 3.1.1.7) inhibitory agent in a Magnolia x soulangiana extract using a microplate enzyme assay with Ellman's reagent. This permitted the isolation of the alkaloids taspine (1) and (-)-asimilobine (2), which were detected for the first time in this species. Compound 1 showed a significantly higher effect on AChE than the positive control galanthamine and selectively inhibited the enzyme in a long-lasting and concentration-dependent fashion with an IC(50) value of 0.33 +/- 0.07 muM. Extensive molecular docking studies were performed with human and Torpedo californica-AChE employing Gold software to rationalize the binding interaction. The results suggested ligand 1 to bind in an alternative binding orientation when compared to galanthamine. While this is located in close vicinity to the catalytic amino acid triad, the 1-AChE complex was found to be stabilized by (i) sandwich-like pi-stacking interactions between the planar aromatic ligand (1) and the Trp84 and Phe330 of the enzyme, (ii) an esteratic site anchoring with the amino side chain, and (iii) a hydrogen-bonding network.

7-Methoxytacrine-adamantylamine heterodimers as cholinesterase inhibitors in Alzheimer's disease treatment--synthesis, biological evaluation and molecular modeling studies.

PubMed

Spilovska, Katarina; Korabecny, Jan; Kral, Jan; Horova, Anna; Musilek, Kamil; Soukup, Ondrej; Drtinova, Lucie; Gazova, Zuzana; Siposova, Katarina; Kuca, Kamil

2013-02-20

A structural series of 7-MEOTA-adamantylamine thioureas was designed, synthesized and evaluated as inhibitors of human acetylcholinesterase (hAChE) and human butyrylcholinesterase (hBChE). The compounds were prepared based on the multi-target-directed ligand strategy with different linker lengths (n = 2-8) joining the well-known NMDA antagonist adamantine and the hAChE inhibitor 7-methoxytacrine (7-MEOTA). Based on in silico studies, these inhibitors proved dual binding site character capable of simultaneous interaction with the peripheral anionic site (PAS) of hAChE and the catalytic active site (CAS). Clearly, these structural derivatives exhibited very good inhibitory activity towards hBChE resulting in more selective inhibitors of this enzyme. The most potent cholinesterase inhibitor was found to be thiourea analogue 14 (with an IC₅₀ value of 0.47 µM for hAChE and an IC₅₀ value of 0.11 µM for hBChE, respectively). Molecule 14 is a suitable novel lead compound for further evaluation proving that the strategy of dual binding site inhibitors might be a promising direction for development of novel AD drugs.

Circadian Rhythms of Heart Rate and Locomotion After Treatment With Low-Dose Acetylcholinesterase Inhibitors

DTIC Science & Technology

2006-01-01

with pyridostigmine bromide (PB), a carbamate AChE by air conditioned vans and air-freight to the Laboratory inhibitor that does not cross the blood ...15. SUBJECT TERMS Nerve agents, sarin, pyridostigmine bromide, cerebral glucose utilization, cerebrovascular circulation, low dose cholinesterase ...March 2006" Accepted 12 May 2006 ABSTRACT: This study tested the hypothesis that repeated exposure to low levels of sarin, pyridostigmine bromide (PB

Molecular Characterization of Monoclonal Antibodies that Inhibit Acetylcholinesterase by Targeting the Peripheral Site and Backdoor Region

PubMed Central

Essono, Sosthène; Mondielli, Grégoire; Lamourette, Patricia; Boquet, Didier; Grassi, Jacques; Marchot, Pascale

2013-01-01

The inhibition properties and target sites of monoclonal antibodies (mAbs) Elec403, Elec408 and Elec410, generated against Electrophorus electricus acetylcholinesterase (AChE), have been defined previously using biochemical and mutagenesis approaches. Elec403 and Elec410, which bind competitively with each other and with the peptidic toxin inhibitor fasciculin, are directed toward distinctive albeit overlapping epitopes located at the AChE peripheral anionic site, which surrounds the entrance of the active site gorge. Elec408, which is not competitive with the other two mAbs nor fasciculin, targets a second epitope located in the backdoor region, distant from the gorge entrance. To characterize the molecular determinants dictating their binding site specificity, we cloned and sequenced the mAbs; generated antigen-binding fragments (Fab) retaining the parental inhibition properties; and explored their structure-function relationships using complementary x-ray crystallography, homology modeling and flexible docking approaches. Hypermutation of one Elec403 complementarity-determining region suggests occurrence of antigen-driven selection towards recognition of the AChE peripheral site. Comparative analysis of the 1.9Å-resolution structure of Fab408 and of theoretical models of its Fab403 and Fab410 congeners evidences distinctive surface topographies and anisotropic repartitions of charges, consistent with their respective target sites and inhibition properties. Finally, a validated, data-driven docking model of the Fab403-AChE complex suggests a mode of binding at the PAS that fully correlates with the functional data. This comprehensive study documents the molecular peculiarities of Fab403 and Fab410, as the largest peptidic inhibitors directed towards the peripheral site, and those of Fab408, as the first inhibitor directed toward the backdoor region of an AChE and a unique template for the design of new, specific modulators of AChE catalysis. PMID:24146971

Electronic structure calculations toward new potentially AChE inhibitors

NASA Astrophysics Data System (ADS)

de Paula, A. A. N.; Martins, J. B. L.; Gargano, R.; dos Santos, M. L.; Romeiro, L. A. S.

2007-10-01

The main purpose of this study was the use of natural non-isoprenoid phenolic lipid of cashew nut shell liquid from Anacardium occidentale as lead material for generating new potentially candidates of acetylcholinesterase inhibitors. Therefore, we studied the electronic structure of 15 molecules derivatives from the cardanol using the following groups: methyl, acetyl, N, N-dimethylcarbamoyl, N, N-dimethylamine, N, N-diethylamine, piperidine, pyrrolidine, and N-benzylamine. The calculations were performed at RHF level using 6-31G, 6-31G(d), 6-31+G(d) and 6-311G(d,p) basis functions. Among the proposed compounds we found that the structures with substitution by acetyl, N, N-dimethylcarbamoyl, N, N-dimethylamine, and pyrrolidine groups were better correlated to rivastigmine indicating possible activity.

Discontinuation, Efficacy, and Safety of Cholinesterase Inhibitors for Alzheimer's Disease: a Meta-Analysis and Meta-Regression of 43 Randomized Clinical Trials Enrolling 16 106 Patients.

PubMed

Blanco-Silvente, Lídia; Castells, Xavier; Saez, Marc; Barceló, Maria Antònia; Garre-Olmo, Josep; Vilalta-Franch, Joan; Capellà, Dolors

2017-07-01

We investigated the effect of cholinesterase inhibitors on all-cause discontinuation, efficacy and safety, and the effects of study design-, intervention-, and patient-related covariates on the risk-benefit of cholinesterase inhibitors for Alzheimer's disease. A systematic review and meta-analysis of randomized placebo-controlled clinical trials comparing cholinesterase inhibitors and placebo was performed. The effect of covariates on study outcomes was analysed by means of meta-regression using a Bayesian framework. Forty-three randomized placebo-controlled clinical trials involving 16106 patients were included. All-cause discontinuation was higher with cholinesterase inhibitors (OR = 1.66), as was discontinuation due to adverse events (OR=1.75). Cholinesterase inhibitors improved cognitive function (standardized mean difference = 0.38), global symptomatology (standardized mean difference=0.28) and functional capacity (standardized mean difference=0.16) but not neuropsychiatric symptoms. Rivastigmine was associated with a poorer outcome on all-cause discontinuation (Diff OR = 1.66) and donepezil with a higher efficacy on global change (Diff standardized mean difference = 0.41). The proportion of patients with serious adverse events decreased with age (Diff OR = -0.09). Mortality was lower with cholinesterase inhibitors than with placebo (OR = 0.65). While cholinesterase inhibitors show a poor risk-benefit relationship as indicated by mild symptom improvement and a higher than placebo all-cause discontinuation, a reduction of mortality was suggested. Intervention- and patient-related factors modify the effect of cholinesterase inhibitors in patients with Alzheimer's disease. © The Author 2017. Published by Oxford University Press on behalf of CINP.

The interactions of azure B, a metabolite of methylene blue, with acetylcholinesterase and butyrylcholinesterase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petzer, Anél, E-mail: 12264954@nwu.ac.za; Harvey, Brian H.; Petzer, Jacobus P.

Methylene blue (MB) is reported to possess diverse pharmacological actions and is attracting increasing attention for the treatment of neurodegenerative disorders such as Alzheimer's disease. Among the pharmacological actions of MB, is the significant inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). These activities may, at least in part, underlie MB's beneficial effects in Alzheimer's disease. MB is metabolized to yield N-demethylated products of which azure B, the monodemethyl metabolite, is the predominant species. Azure B has been shown to be pharmacologically active and also possesses a variety of biological actions. Azure B therefore may contribute to the pharmacological profile ofmore » MB. Based on these considerations, the present study investigates the possibility that azure B may, similar to MB, act as an inhibitor of human AChE and BuChE. The results document that azure B inhibits AChE and BuChE with IC{sub 50} values of 0.486 μM and 1.99 μM, respectively. The results further show that azure B inhibits AChE and BuChE reversibly, and that the modes of inhibition are most likely competitive. Although the AChE and BuChE inhibitory activities of azure B are twofold and fivefold, respectively, less potent than those recorded for MB [IC{sub 50}(AChE) = 0.214 μM; IC{sub 50}(BuChE) = 0.389 μM] under identical conditions, azure B may be a contributor to MB's in vivo activation of the cholinergic system and beneficial effects in Alzheimer's disease. - Highlights: • Methylene blue (MB) is a known inhibitor of AChE and BuChE. • Azure B, the major metabolite of MB, also is an inhibitor of AChE and BuChE. • Azure B may be a contributor to MB's in vivo activation of the cholinergic system. • Azure B may contribute to MB's potential in Alzheimer's disease therapy.« less

Systemic Administration of the Potential Countermeasure Huperzine Reversibly Inhibits Central and Peripheral Acetylcholinesterase Activity Without Adverse Cognitive-Behavioral Effects

DTIC Science & Technology

2010-01-01

reversibly inhibits 5a. CONTRACT NUMBER central and peripheral acetylcholinesterase activity without adverse cognitive–behavioral effects 5b. GRANT...huperzine reversibly inhibits central and peripheral acetylcholinesterase activity without adverse cognitive–behavioral effects Todd M. Myers a,⁎, Wei Sun b...HUP to enter the brain is also evidenced by studies that use well-documented centrally active anticholinergics to induce cognitive impairments that are

Study of efficacy of reactivator HI 6 in reactivation of immobilized acetylcholinesterase, inhibited by organophosphorus chemical warfare agents of the "G" series.

PubMed

Hoskovcová, Monika; Halámek, Emil; Kobliha, Zbynĕk

2009-01-01

Reactivation with bis quaternary aldoxime HI-6, chemical formula 1-(2-hydroxyamino-methylpyridinium)-3-(4-carbamoylpyridinium)-2-oxapropane dichloride of immobilized enzyme acetylcholinesterase inhibited by nerve agent type "G" was studied. This aldoxime is effective in reactivation of sarin-inhibited acetylcholinesterase. Substantially lower reactivation potency was observed with cyclosarin-inhibited enzyme and almost no effect was found for that acetylcholinesterase is the enzyme complex. HI 6 is completely ineffective towards the soman-inhibited enzyme: After a 2-minute inhibition of the enzyme with soman no ability to define reactivator the inhibited enzymes and complexes.

In vitro acetylcholinesterase activity of peptide derivatives isolated from two species of Leguminosae.

PubMed

Alves, Clayton Q; Lima, Luciano S; David, Jorge M; Lima, Marcos V B; David, Juceni P; Lima, Fernanda W M; Pedroza, Kelly C M C; Queiroz, Luciano P

2013-07-01

Cratylia mollis Martius ex Benth. and Cenostigma macrophyllum Tul. (Leguminosae) are both endemic Brazilian plants and they are used by the natives as medicinal plants, and the leaves of C. mollis are also employed as forage for cattle during the dry season of region. Isolation of the compounds responsible for the acetylcholinesterase (AChE) inhibition from the CHCl3 active extract. Two peptidic compounds were isolated by chromatographic techniques from the CHCl3 extract of the leaves of C. mollis and C. macrophyllum. They were identified by spectrometric data analysis (MS and NMR) and they were subjected to AChE inhibition employing Ellman's test. The peptides were identified as N-benzoylphenylalaninoyl-phenlyalaninolacetate (aurentiamide acetate) (1) and N-benzoylphenylalaninyl-N-benzoylphenylalaninate (2). Both peptides 1 and 2 exhibit AChE inhibition, with IC50 values equal to 111.34 µM and 137.6 µM, respectively. Compound 1 (aurentiamide acetate) has rarely been isolated from the Leguminosae family, and N-benzoylphenylalaninyl-N-benzoylphenylalaninate (2) is a compound that has never previously been isolated from this family. Compound 1 is shown to be a potent inhibitor of AChE, with IC50 values similar to the physostigmine control (141.51 µM).

Taspine: Bioactivity-Guided Isolation and Molecular Ligand–Target Insight of a Potent Acetylcholinesterase Inhibitor from Magnolia x soulangiana

PubMed Central

Rollinger, Judith M.; Schuster, Daniela; Baier, Elisabeth; Ellmerer, Ernst P.; Langer, Thierry; Stuppner, Hermann

2012-01-01

A bioactivity-guided approach was taken to identify the acetylcholinesterase (AChE, EC 3.1.1.7) inhibitory agent in a Magnolia x soulangiana extract using a microplate enzyme assay with Ellman’s reagent. This permitted the isolation of the alkaloids taspine (1) and (−)-asimilobine (2), which were detected for the first time in this species. Compound 1 showed a significantly higher effect on AChE than the positive control galanthamine and selectively inhibited the enzyme in a long-lasting and concentration-dependent fashion with an IC50 value of 0.33 ± 0.07 μM. Extensive molecular docking studies were performed with human and Torpedo californica-AChE employing Gold software to rationalize the binding interaction. The results suggested ligand 1 to bind in an alternative binding orientation when compared to galanthamine. While this is located in close vicinity to the catalytic amino acid triad, the 1–AChE complex was found to be stabilized by (i) sandwich-like π-stacking interactions between the planar aromatic ligand (1) and the Trp84 and Phe330 of the enzyme, (ii) an esteratic site anchoring with the amino side chain, and (iii) a hydrogen-bonding network. PMID:16989531

Natural AChE Inhibitors from Plants and their Contribution to Alzheimer’s Disease Therapy

PubMed Central

Murray, Ana Paula; Faraoni, María Belén; Castro, María Julia; Alza, Natalia Paola; Cavallaro, Valeria

2013-01-01

As acetylcholinesterase (AChE) inhibitors are an important therapeutic strategy in Alzheimer’s disease, efforts are being made in search of new molecules with anti-AChE activity. The fact that naturally-occurring compounds from plants are considered to be a potential source of new inhibitors has led to the discovery of an important number of secondary metabolites and plant extracts with the ability of inhibiting the enzyme AChE, which, according to the cholinergic hypothesis, increases the levels of the neurotransmitter acetylcholine in the brain, thus improving cholinergic functions in patients with Alzheimer’s disease and alleviating the symptoms of this neurological disorder. This review summarizes a total of 128 studies which correspond to the most relevant research work published during 2006-2012 (1st semester) on plant-derived compounds, plant extracts and essential oils found to elicit AChE inhibition. PMID:24381530

Buprofezin inhibits acetylcholinesterase activity in B-biotype Bemisia tabaci.

PubMed

Cottage, Emma L A; Gunning, Robin V

2006-01-01

B-biotype Bemisia tabaci is a severe insect pest worldwide in many ornamental, agricultural, and horticultural industries. Control of this insect is hampered by resistance to many acetylcholinesterase (AChE)-inhibiting insecticides, such as organophosphates and carbamates. Consequently, insect growth regulators such as buprofezin, which act by inhibiting chitin synthesis, are being investigated for use against B-biotype B. tabaci in Australia. This study discusses the effects of buprofezin on B. tabaciAChE.

Silibinin inhibits acetylcholinesterase activity and amyloid β peptide aggregation: a dual-target drug for the treatment of Alzheimer's disease.

PubMed

Duan, Songwei; Guan, Xiaoyin; Lin, Runxuan; Liu, Xincheng; Yan, Ying; Lin, Ruibang; Zhang, Tianqi; Chen, Xueman; Huang, Jiaqi; Sun, Xicui; Li, Qingqing; Fang, Shaoliang; Xu, Jun; Yao, Zhibin; Gu, Huaiyu

2015-05-01

Alzheimer's disease (AD) is characterized by amyloid β (Aβ) peptide aggregation and cholinergic neurodegeneration. Therefore, in this paper, we examined silibinin, a flavonoid extracted from Silybum marianum, to determine its potential as a dual inhibitor of acetylcholinesterase (AChE) and Aβ peptide aggregation for AD treatment. To achieve this, we used molecular docking and molecular dynamics simulations to examine the affinity of silibinin with Aβ and AChE in silico. Next, we used circular dichroism and transmission electron microscopy to study the anti-Aβ aggregation capability of silibinin in vitro. Moreover, a Morris Water Maze test, enzyme-linked immunosorbent assay, immunohistochemistry, 5-bromo-2-deoxyuridine double labeling, and a gene gun experiment were performed on silibinin-treated APP/PS1 transgenic mice. In molecular dynamics simulations, silibinin interacted with Aβ and AChE to form different stable complexes. After the administration of silibinin, AChE activity and Aβ aggregations were down-regulated, and the quantity of AChE also decreased. In addition, silibinin-treated APP/PS1 transgenic mice had greater scores in the Morris Water Maze. Moreover, silibinin could increase the number of newly generated microglia, astrocytes, neurons, and neuronal precursor cells. Taken together, these data suggest that silibinin could act as a dual inhibitor of AChE and Aβ peptide aggregation, therefore suggesting a therapeutic strategy for AD treatment. Copyright © 2015 Elsevier Inc. All rights reserved.

Taste-masked and affordable donepezil hydrochloride orally disintegrating tablet as promising solution for non-compliance in Alzheimer's disease patients.

PubMed

Liew, Kai Bin; Tan, Yvonne Tze Fung; Peh, Kok Khiang

2015-04-01

Manufacturing process and superdisintegrants used in orally disintegrating tablet (ODT) formulation are often time discussed. However, the effect of suitable filler for ODT formulation is not explored thoroughly. The aim of this study was to develop a novel taste masked and affordable donepezil hydrochloride ODT with fast disintegration time and stable to improve medication compliance of Alzheimer's disease patient. The ODT was manufactured using simple wet-granulation method. Crospovidone XL-10 was used as superdisintegrant and optimization was done by comparing the effect of three grades of lactose monohydrate compound as filler: Starlac®, Flowlac® and Tablettose®. Formulations containing higher amount of colloidal silicon dioxide showed increase in hardness, weight, disintegration time and wetting time after stability study. Formulation E which containing 50% of Starlac® was found with shortest in vitro disintegration time (21.7 ± 1.67 s), in vivo disintegration time (24.0 ± 1.05 s) and in vitro disintegration time in artificial salvia (22.5 ± 1.67 s). Physical stability studies at 40 °C/75% RH for 6 months, Fourier transform infrared spectroscopy analysis and X-ray diffraction results showed that the formulation was stable. The drug-released profile showed that 80% of donepezil hydrochloride was released within 1 min. A single-dose, fasting, four-period, seven-treatment, double-blinded study involving 16 healthy human volunteers was performed to evaluate the palatability of ODT. Formulation VII containing 10 mg of ammonium glycyrrhizinate was able to mask the bitter taste of the drug. The product has the potential to be commercialized and it might serve as solution for non-compliance among the Alzheimer's disease patients.

ELECTRON MICROSCOPIC LOCALIZATION OF ACETYLCHOLINESTERASE AND NONSPECIFIC CHOLINESTERASE AT THE NEUROMUSCULAR JUNCTION BY THE GOLD-THIOCHOLINE AND GOLD-THIOLACETIC ACID METHODS

PubMed Central

Davis, Richard; Koelle, George B.

1967-01-01

By means of the gold-thiocholine (AuThCh) and gold-thiolacetic acid (AuThAc) methods, it has been demonstrated electron microscopically that acetylcholinesterase (AChE) is located at the prejunctional axoplasmic membrane and the postjunctional sarcoplasmic membrane, including the full lengths of its invaginations, at the motor end plate of mouse intercostal muscle. Nonspecific cholinesterase (ChE) is present in relatively low concentrations at the same sites, and in greater concentrations in the teloglial Schwann sheath cells. Significant amounts of reaction product appeared in the junctional cleft only after prolonged incubation with both methods. The identification of AChE and ChE was confirmed by the use of appropriate concentrations of several selective inhibitors. In confirmation of previous studies by light microscopy, the AuThCh method is more specific for AChE and ChE, whereas the AuThAc method allows greater accuracy of localization. PMID:6033530

A marine sponge associated strain of Bacillus subtilis and other marine bacteria can produce anticholinesterase compounds.

PubMed

Pandey, Sony; Sree, Ayinampudi; Sethi, Dipti Priya; Kumar, Chityal Ganesh; Kakollu, Sudha; Chowdhury, Lipsa; Dash, Soumya Suchismita

2014-02-15

Acetylcholinesterase (AChE) inhibitors or anticholinesterases reduce the activity of enzyme acetylcholinesterase that degrades the neurotransmitter acetylcholine in the brain. The inhibitors have a significant pharmacological role in neurodegenerative diseases like Alzheimer's and Parkinson's etc. Although plants have been a significant source of these compounds, there are very few sporadic reports of microorganisms producing such inhibitors. Anticholinesterase activity in bacterial associates of marine soft corals and sponges were not previously reported. We screened 887 marine bacteria for the presence of acetylcholinesterase inhibitors, in a microplate based assay, and found that 140 (15.8%) of them inhibit the electric eel enzyme, acetylcholinesterase. Majority of the active isolates were bacterial associates of soft corals followed by sediment isolates while most of the potent inhibitors belonged to the bacterial associates of marine sponges. Maximum inhibition (54%) was exhibited by a bacterial strain M18SP4P (ii), isolated from the marine sponge Fasciospongia cavernosa. Based on phenotypic characterization and 16S rDNA sequencing, the strain was identified as Bacillus subtilis - revealing yet another activity in a strain of the model organism that is considered to be a cell factory. TLC bioautography of the methanol extract of this culture, showed the presence of two major components having this activity, when compared to Galanthamine, the positive control. From the results of our study, we conclude that acetylcholinesterase inhibitors are quite prevalent in marine bacteria, particularly the bacterial associates of marine invertebrates. Several potential AChE inhibitors in marine bacteria are waiting to be discovered to provide easily manipulable natural sources for the mass production of these therapeutic compounds.

Acetylcholinesterase activity in soleus muscle intrafusal and extrafusal fibres in tail suspended rats.

PubMed

Tang, Bin; Fan, Xiao-li; Wu, Su-di

2002-10-01

Objective. To explore the mechanisms involved in muscle atrophy and conversion of the fiber types induced by simulated weightlessness. Method. Weightlessness was simulated by tail suspension of female rats. Intrafusal and extrafusal fibers of soleus muscles in the rat were examined histochemically for their activity of acetylcholinesterase (AChE) and succinic dehydrogenase (SDH) in 7 d, 14 d, 21 d tail-suspended groups and control groups. Result. Staining for succinic dehydrogenase showed that simulated weightlessness caused obvious atrophy and change in fiber type composition in soleus muscle, with decrease of the proportion of type I fiber and increase of type II fiber. Acetylcholinesterase activities of intrafusal and extrafusal fibers were both decreased significantly after 21 d tail suspension. Conclusion. Simulated weightlessness could induce decrease of AChE activity in neuromuscular junctions, which might be linked with decrease in motor neuron activity.

Design, synthesis and biological evaluation of 3,4-dihydro-2(1H)-quinoline-O-alkylamine derivatives as new multipotent cholinesterase/monoamine oxidase inhibitors for the treatment of Alzheimer's disease.

PubMed

Sang, Zhipei; Pan, Wanli; Wang, Keren; Ma, Qinge; Yu, Lintao; Liu, Wenmin

2017-06-15

A new family of multitarget molecules able to interact with acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), as well as with monoamino oxidase (MAO) A and B, has been synthesized. Novel 3,4-dihydro-2(1H)-quinoline-O-alkylamine derivatives have been designed using a conjunctive approach that combines the JMC49 and donepezil. The most promising compound TM-33 showed potent and balance inhibitory activities toward ChE and MAO (eeAChE, eqBuChE, hMAO-A and hMAO-B with IC 50 values of 0.56μM, 2.3μM, 0.3μM and 1.4μM, respectively) but low selectivity. Both kinetic analysis of AChE inhibition and molecular modeling study suggested that TM-33 binds simultaneously to the catalytic active site and peripheral anionic site of AChE. Furthermore, our investigation proved that TM-33 could cross the blood-brain barrier (BBB) in vitro, and abided by Lipinski's rule of five. The results suggest that compound TM-33, an interesting multi-targeted active molecule, offers an attractive starting point for further lead optimization in the drug-discovery process against Alzheimer's disease. Copyright © 2017 Elsevier Ltd. All rights reserved.

"Nonspecific" cholinesterase and acetylcholinesterase in rat tissues: molecular forms, structural and catalytic properties, and significance of the two enzyme systems.

PubMed Central

Vigny, M; Gisiger, V; Massoulié, J

1978-01-01

"Nonspecific" cholinesterase (acylcholine acylhydrolase; EC 3.1.1.8) from various rat tissues has been found to exist in several stable molecular forms that appear as exact counterparts of molecular forms of acetylcholinesterase (acetylcholine hydrolase; EC 3.1.1.7). The sedimentation pattern of cholinesterase was similar to that of acetylcholinesterase with a small but significant shift between the sedimentation coefficients of the corresponding forms. Extraction yields in different media also demonstrated a close parallelism between the two enzyme systems. Other properties, such as thermal stability and catalytic characteristics, indicated both differences and similarities. In spite of the structural resemblance implied by their physicochemical properties, cholinesterase did not crossreact with antibodies against acetylcholinesterase. The nature of the relationships revealed by these studies and their bearing on the physiological significance of cholinesterases are discussed. PMID:78492

Identification and characterization of novel benzil (diphenylethane-1,2-dione) analogues as inhibitors of mammalian carboxylesterases.

PubMed

Wadkins, Randy M; Hyatt, Janice L; Wei, Xin; Yoon, Kyoung Jin P; Wierdl, Monika; Edwards, Carol C; Morton, Christopher L; Obenauer, John C; Damodaran, Komath; Beroza, Paul; Danks, Mary K; Potter, Philip M

2005-04-21

Carboxylesterases (CE) are ubiquitous enzymes responsible for the metabolism of xenobiotics. Because the structural and amino acid homology among esterases of different classes, the identification of selective inhibitors of these proteins has proved problematic. Using Telik's target-related affinity profiling (TRAP) technology, we have identified a class of compounds based on benzil (1,2-diphenylethane-1,2-dione) that are potent CE inhibitors, with K(i) values in the low nanomolar range. Benzil and 30 analogues demonstrated selective inhibition of CEs, with no inhibitory activity toward human acetylcholinesterase or butyrylcholinesterase. Analysis of structurally related compounds indicated that the ethane-1,2-dione moiety was essential for enzyme inhibition and that potency was dependent on the presence of, and substitution within, the benzene ring. 3D-QSAR analyses of these benzil analogues for three different mammalian CEs demonstrated excellent correlations of observed versus predicted K(i) (r(2) > 0.91), with cross-validation coefficients (q(2)) of 0.9. Overall, these results suggest that selective inhibitors of CEs with potential for use in clinical applications can be designed.

First molecular genotyping of insensitive acetylcholinesterase associated with malathion resistance in Culex quinquefasciatus Say populations in Malaysia.

PubMed

Low, Van Lun; Chen, Chee Dhang; Lim, Phaik Eem; Lee, Han Lim; Lim, Yvonne Ai Lian; Tan, Tiong Kai; Sofian-Azirun, Mohd

2013-12-01

Given that there is limited available information on the insensitive acetylcholinesterase in insect species in Malaysia, the present study aims to detect the presence of G119S mutation in the acetylcholinesterase gene of Culex quinquefasciatus from 14 residential areas across 13 states and a federal territory in Malaysia. The ace-1 sequence and PCR-RFLP test revealed the presence of glycine-serine ace-1 mutation in the wild populations of Cx. quinquefasciatus. Both direct sequencing and PCR-RFLP methods demonstrated similar results and revealed the presence of a heterozygous genotype at a very low frequency (18 out of 140 individuals), while a homozygous resistant genotype was not detected across any study site in Malaysia. In addition, statistical analysis also revealed that malathion resistance is associated with the frequency of ace-1(R) in Cx. quinquefasciatus populations. This study has demonstrated the first field-evolved instance of G119S mutation in Malaysian populations. Molecular identification of insensitive acetylcholinesterase provides significant insights into the evolution and adaptation of the Malaysian Cx. quinquefasciatus populations. © 2013 Society of Chemical Industry.

Acetylcholinesterase-R increases germ cell apoptosis but enhances sperm motility

PubMed Central

Mor, I; Sklan, EH; Podoly, E; Pick, M; Kirschner, M; Yogev, L; Bar-Sheshet Itach, S; Schreiber, L; Geyer, B; Mor, T; Grisaru, D; Soreq, H

2008-01-01

Abstract Changes in protein subdomains through alternative splicing often modify protein-protein interactions, altering biological processes. A relevant example is that of the stress-induced up-regulation of the acetylcholinesterase (AChE-R) splice variant, a common response in various tissues. In germ cells of male transgenic TgR mice, AChE-R excess associates with reduced sperm differentiation and sperm counts. To explore the mechanism(s) by which AChE-R up-regulation affects spermatogenesis, we identified AChE-R's protein partners through a yeast two-hybrid screen. In meiotic spermatocytes from TgR mice, we detected AChE-R interaction with the scaffold protein RACK1 and elevated apoptosis. This correlated with reduced scavenging by RACK1 of the pro-apoptotic TAp73, an outcome compatible with the increased apoptosis. In contrast, at later stages in sperm development, AChE-R's interaction with the glycolytic enzyme enolase-α elevates enolase activity. In transfected cells, enforced AChE-R excess increased glucose uptake and adenosine tri-phosphate (ATP) levels. Correspondingly, TgR sperm cells display elevated ATP levels, mitochondrial hyperactivity and increased motility. In human donors' sperm, we found direct association of sperm motility with AChE-R expression. Interchanging interactions with RACK1 and enolase-α may hence enable AChE-R to affect both sperm differentiation and function by participating in independent cellular pathways. PMID:18194455

The binding sites of inhibitory monoclonal antibodies on acetylcholinesterase. Identification of a novel regulatory site at the putative "back door".

PubMed

Simon, S; Le Goff, A; Frobert, Y; Grassi, J; Massoulié, J

1999-09-24

We investigated the target sites of three inhibitory monoclonal antibodies on Electrophorus acetylcholinesterase (AChE). Previous studies showed that Elec-403 and Elec-410 are directed to overlapping but distinct epitopes in the peripheral site, at the entrance of the catalytic gorge, whereas Elec-408 binds to a different region. Using Electrophorus/rat AChE chimeras, we identified surface residues that differed between sensitive and insensitive AChEs: the replacement of a single Electrophorus residue by its rat homolog was able to abolish binding and inhibition, for each antibody. Reciprocally, binding and inhibition by Elec-403 and by Elec-410 could be conferred to rat AChE by the reverse mutation. Elec-410 appears to bind to one side of the active gorge, whereas Elec-403 covers its opening, explaining why the AChE-Elec-410 complex reacts faster than the AChE-Elec-403 or AChE-fasciculin complexes with two active site inhibitors, m-(N,N, N-trimethyltammonio)trifluoro-acetophenone and echothiophate. Elec-408 binds to the region of the putative "back door," distant from the peripheral site, and does not interfere with the access of inhibitors to the active site. The binding of an antibody to this novel regulatory site may inhibit the enzyme by blocking the back door or by inducing a conformational distortion within the active site.

Natural monomeric form of fetal bovine serum acetylcholinesterase lacks the C-terminal tetramerization domain.

PubMed

Saxena, Ashima; Hur, Regina S; Luo, Chunyuan; Doctor, Bhupendra P

2003-12-30

Acetylcholinesterase isolated from fetal bovine serum (FBS AChE) was previously characterized as a globular tetrameric form. Analysis of purified preparations of FBS AChE by gel permeation chromatography revealed the presence of a stable, catalytically active, monomeric form of this enzyme. The two forms could be distinguished from each other based on their molecular weight, hydrodynamic properties, kinetic properties, thermal stability, and the type of glycans they carry. No differences between the two forms were observed for the binding of classical inhibitors such as edrophonium and propidium or inhibitors that are current or potential drugs for the treatment of Alzheimer's disease such as (-) huperzine A and E2020; tacrine inhibited the monomeric form 2-3-fold more potently than the tetrameric form. Sequencing of peptides obtained from an in-gel tryptic digest of the monomer and tetramer by tandem mass spectrometry indicated that the tetramer consists of 583 amino acid residues corresponding to the mature form of the enzyme, whereas the monomer consists of 543-547 amino acid residues. The subunit molecular weight of the protein component of the monomer (major species) was determined to be 59 414 Da and that of the tetramer as 64 239 Da. The N-terminal of the monomer and the tetramer was Glu, suggesting that the monomer is not a result of truncation at the N-terminal. The only differences detected were at the C-terminus. The tetramer yielded the expected C-terminus, CSDL, whereas the C-terminus of the monomer yielded a mixture of peptides, of which LLSATDTLD was the most abundant. These results suggest that monomeric FBS AChE is trimmed at the C-terminus, and the results are consistent with the involvement of C-terminal amino acids in the assembly of monomers into tetramers.

Treatment of Visual Hallucinations in Schizophrenia by Acetylcholinesterase Inhibitors: a case report

PubMed Central

Abad, Nazir Hashemi; Doulatabad, Najafi Shala; Mohammadi, Ali

2011-01-01

Schizophrenia and various neurological disorders have some signs and symptoms. Visual hallucinations are one of such disorders. The related studies in some diseases for example Parkinson Disease and Lewy Body Dementia indicate that Acetylcholine (Ach) plays a significant role in neuropsychiatric manifestation and its association with visual hallucination; therefore, visual hallucinations occur due to the depletion of Ach. Drug therapies such as Cholinesterase inhibitors (ChEIs) for increasing Ach level may be beneficial in treating visual hallucination. AchEI's have been used in the treatment of visual hallucinations in Dementia and Parkinson's Disease. We thought that a similar Ach depletion may cause visual hallucinations in patients with schizophrenia and may provide a target for drug treatment. We had a patient with schizophrenia whose psychotic symptoms responded to the treatment plan, but her visual hallucination did not. However, the patient's visual hallucination successfully responded to Rivastigmine (AchEI). This case illustrates the use of an AchEI in the treatment of refractory visual hallucinations in a patient with schizophrenia. PMID:22952543

Ibogaine and the inhibition of acetylcholinesterase.

PubMed

Alper, Kenneth; Reith, Maarten E A; Sershen, Henry

2012-02-15

Ibogaine is a psychoactive monoterpine indole alkaloid extracted from the root bark of Tabernanthe iboga Baill. that is used globally in medical and nonmedical settings to treat drug and alcohol addiction, and is of interest as an ethnopharmacological prototype for experimental investigation and pharmaceutical development. The question of whether ibogaine inhibits acetylcholinesterase (AChE) is of pharmacological and toxicological significance. AChE activity was evaluated utilizing reaction with Ellman's reagent with physostigmine as a control. Ibogaine inhibited AChE with an IC(50) of 520±40 μM. Ibogaine's inhibition of AChE is physiologically negligible, and does not appear to account for observations of functional effects in animals and humans that might otherwise suggest the possible involvement of pathways linked to muscarinic acetylcholine transmission. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Management, Diagnostic and Prognostic Significance of Acetylcholinesterase as a Biomarker of the Toxic Effects of Pesticides in People Occupationally Exposed.

PubMed

Lutovac, Mitar; Popova, Olga V; Jovanovic, Zoran; Berisa, Hatidza; Kristina, Radoman; Ketin, Sonja; Bojic, Marko

2017-12-15

The paper presents research on the most common causes of exposure that leads to disorders of cholinesterase activity, as well as an overview of the results of cholinesterase activity with the poisoned people. In a group of 35 acute poisoned patients by organophosphate compounds has led to inhibition of AchE. A total number of examined workers are 175 in the chemical industry and agricultural production in the area of Rasina District-Serbia. The results showed that among workers who are constantly exposed to pesticides, acetylcholinesterase is within the reference value. Having examined the medical records of these workers, it is noted that, at 72%, there is a slight fall of AchE activity, each year. The workers who had been exposed to pesticides at the time of testing had acetylcholinesterase regarding reference value, but 52% of them had a few years ago significantly reduced the value of the activity of acetylcholinesterase, which was treated and then transferred to other jobs. The 48% of these workers had acetylcholinesterase regarding benchmarks or were transferred to other jobs, for a variety of other health problems. Using each pesticide should only deal with people who are well versed in the way of its use, as well as the way of protecting them from poisoning.

Cerebral Acetylcholine and Choline Contents and Turnover Following Low-Dose Acetylcholinesterase Inhibitor Treatment in Rats

DTIC Science & Technology

2006-05-01

JH, Jr., Romano JA, King JM (1990) Age-related differences in soman toxicity and in blood and brain regional cholinesterase activity . Brain Res.Bull...of OP AChE inhibitors when given in anticipation of exposure to toxic nerve agents. The mechanism of this protection seems to be the pre- occupation of...has indicated effects on blood AChE activity during and shortly after treatment and delayed effects, 2 to 16 weeks post-treatment, on exploratory

A case of successful treatment with donepezil of olfactory hallucination in parkinson disease.

PubMed

Osada, Osamu; Iwasaki, Akira

2017-01-31

We report a 74-year-old female patient with Parkinson disease (PD). Around 2010, she developed depression and bradykinesia and was diagnosed as PD. In July 2014, she came to our hospital, of which she lived in the neighborhood. In the last part of December 2014, she felt uneasy about her fecal smell and saw a psychiatrist in the first part of January 2015. Quetiapine (25 mg/day) was added. In the last part of January, she complained of fecal smell everywhere and could not take a meal. No-one else could detect the smell. A diagnosis of olfactory hallucination was made. The next day after increasing to 75mg/day, however, she was admitted to our hospital because of refusing to take medicine. After introducing donepezil, olfactory hallucination subsided and her appetite was improved. Brain MRI showed atrophy of the bilateral temporal lobes and N-isopropyl-p-(iodine-123)-iodoamphetamine single photon emission computed tomography ( 123 I-IMP-SPECT) revealed hypoperfusion in the bilateral mesial temporal lobes. We suppose that cholinergic denervation in the mesial temporal lobes is an important determinant of her olfactory hallucination.

Optimization of sol-gel medium for entrapment of acetylcholinesterase enzyme in biosensor for pesticide detection

NASA Astrophysics Data System (ADS)

Wijayanti, S. D.; Rahayu, F. S.; Widyaningsih, T. D.

2018-03-01

Pesticides are chemical substances used to kill and control pests or diseases that can damage crops. The use of pesticides should be done precisely because the accumulation of chemicals contained in pesticides can cause various health effects. Therefore, detection of pesticide residues on plants is important to reduce the risk of poisoning due to pesticide residues. Some of the conventional methods that have been done to detect pesticide residues have weaknesses among expensive tools, takes a long time, and are generally performed by trained laboratory technicians. Biosensors are analytical devices that can measure the quantitative or semi-quantitative targets of analyte by utilizing a bioreceptor such as enzyme. Several studies have shown that enzyme-based acetylcholinesterase-based biosensors can be used to detect pesticide residues in vegetable samples. The objective of this research was to get a proper silica based sol-gel formulation with molar ratio of H2O:TEOS and NaOH concentration as immobilization medium of acetylcholinesterase enzyme for biosensor application. Response Surface Methodology (RSM) was used in order to determine the interaction between the parameters studied and resulting responses which were amount and activity of acetylcholinesterase enzyme. Based on the research, the best result for immobilized enzyme activity was shown by molar ratio (H2O: TEOS) 1: 8 and 4 mM NaOH treatment.

Effect of local acetylcholinesterase inhibition on sweat rate in humans

NASA Technical Reports Server (NTRS)

Shibasaki, M.; Crandall, C. G.

2001-01-01

ACh is the neurotransmitter responsible for increasing sweat rate (SR) in humans. Because ACh is rapidly hydrolyzed by acetylcholinesterase (AChE), it is possible that AChE contributes to the modulation of SR. Thus the primary purpose of this project was to identify whether AChE around human sweat glands is capable of modulating SR during local application of various concentrations of ACh in vivo, as well as during a heat stress. In seven subjects, two microdialysis probes were placed in the intradermal space of the forearm. One probe was perfused with the AChE inhibitor neostigmine (10 microM); the adjacent membrane was perfused with the vehicle (Ringer solution). SR over both membranes was monitored via capacitance hygrometry during microdialysis administration of various concentrations of ACh (1 x 10(-7)-2 M) and during whole body heating. SR was significantly greater at the neostigmine-treated site than at the control site during administration of lower concentrations of ACh (1 x 10(-7)-1 x 10(-3) M, P < 0.05), but not during administration of higher concentrations of ACh (1 x 10(-2)-2 M, P > 0.05). Moreover, the core temperature threshold for the onset of sweating at the neostigmine-treated site was significantly reduced relative to that at the control site. However, no differences in SR were observed between sites after 35 min of whole body heating. These results suggest that AChE is capable of modulating SR when ACh concentrations are low to moderate (i.e., when sudomotor activity is low) but is less effective in governing SR after SR has increased substantially.

Acetylcholinesterase in blood vessels of the guinea-pig ovary during different phases of the reproductive cycle.

PubMed

Silver, A

1977-05-01

The distribution of acetylcholinesterase-containing blood vessels in the ovary has been investigated histochemically during the reproductive cycle of the guinea-pig. Whole mounts as well as frozen sections have been studied. Stained vessels were found in the stroma throughout the oestrous cycle and pregnancy. In the corpus luteum the vascular reaction varied at different stages of the oestrous cycle; while never very pronounced, it was more marked in lactating than in non-lactating animals. A feregnancy advanced an increasing number of vessels were strongly stained. At the end of pregnancy, stained vessels were less prominent. Acetylcholinesterase appeared to be localized prinicipally in the vessels themselves (possibly in muscle cells) rather than in associated nerves. Experiments in which ovaries were injected, via their arterial or venous supply, with starch or coloured gelatine suggested that most stained vessels were arterioles but a reaction also occurred in some vessels which were probably arteries and others which could have been the postulated arterio-venous shunts. Capillaries were unstained; whether the veins were also totally unreactive could not be established. The significance of the changes in acetylcholinesterase staining in varying functional states remains obscure; they may or may not reflect the emergence of certain types of vessel at different stages.

Two Bombyx mori acetylcholinesterase genes influence motor control and development in different ways

USDA-ARS?s Scientific Manuscript database

Among its other biological roles, acetylcholinesterase (AChE, EC 3.1.1.7), encoded by two ace genes in most insects, catalyses the breakdown of acetylcholine, thereby terminating synaptic transmission. ace1 encodes the synaptic enzyme and ace2 has other essential actions in many insect species, such...

Management, Diagnostic and Prognostic Significance of Acetylcholinesterase as a Biomarker of the Toxic Effects of Pesticides in People Occupationally Exposed

PubMed Central

Lutovac, Mitar; Popova, Olga V.; Jovanovic, Zoran; Berisa, Hatidza; Kristina, Radoman; Ketin, Sonja; Bojic, Marko

2017-01-01

AIM: The paper presents research on the most common causes of exposure that leads to disorders of cholinesterase activity, as well as an overview of the results of cholinesterase activity with the poisoned people. MATERIAL AND METHODS: In a group of 35 acute poisoned patients by organophosphate compounds has led to inhibition of AchE. A total number of examined workers are 175 in the chemical industry and agricultural production in the area of Rasina District-Serbia. RESULTS: The results showed that among workers who are constantly exposed to pesticides, acetylcholinesterase is within the reference value. Having examined the medical records of these workers, it is noted that, at 72%, there is a slight fall of AchE activity, each year. The workers who had been exposed to pesticides at the time of testing had acetylcholinesterase regarding reference value, but 52% of them had a few years ago significantly reduced the value of the activity of acetylcholinesterase, which was treated and then transferred to other jobs. The 48% of these workers had acetylcholinesterase regarding benchmarks or were transferred to other jobs, for a variety of other health problems. CONCLUSION: Using each pesticide should only deal with people who are well versed in the way of its use, as well as the way of protecting them from poisoning. PMID:29362639

Synthesis of some new 3-coumaranone and coumarin derivatives as dual inhibitors of acetyl- and butyrylcholinesterase.

PubMed

Alipour, Masoumeh; Khoobi, Mehdi; Nadri, Hamid; Sakhteman, Amirhossein; Moradi, Alireza; Ghandi, Mehdi; Foroumadi, Alireza; Shafiee, Abbas

2013-08-01

A novel series of coumarin and 3-coumaranone derivatives encompassing the phenacyl pyridinium moiety were synthesized and evaluated for their acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activity using Ellman's method. All compounds presented inhibitory activity against both AChE and BuChE in the micromolar range. The molecular docking simulations revealed that all compounds were dual binding site inhibitors of AChE. A kinetic study was performed and the mechanism of enzyme inhibition was proved to be of mixed type. All compounds were tested for their antioxidant activity and no significant activity was observed. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of small bisquaternary cholinesterase inhibitors as drugs for pre-treatment of nerve agent poisonings

PubMed Central

Kuca, Kamil; Karasova, Jana Zdarova; Soukup, Ondrej; Kassa, Jiri; Novotna, Eva; Sepsova, Vendula; Horova, Anna; Pejchal, Jaroslav; Hrabinova, Martina; Vodakova, Eva; Jun, Daniel; Nepovimova, Eugenie; Valis, Martin; Musilek, Kamil

2018-01-01

Background Intoxication by nerve agents could be prevented by using small acetylcholinesterase inhibitors (eg, pyridostigmine) for potentially exposed personnel. However, the serious side effects of currently used drugs led to research of novel potent molecules for prophylaxis of organophosphorus intoxication. Methods The molecular design, molecular docking, chemical synthesis, in vitro methods (enzyme inhibition, cytotoxicity, and nicotinic receptors modulation), and in vivo methods (acute toxicity and prophylactic effect) were used to study bispyridinium, bisquinolinium, bisisoquinolinium, and pyridinium-quinolinium/isoquinolinium molecules presented in this study. Results The studied molecules showed non-competitive inhibitory ability towards human acetylcholinesterase in vitro that was further confirmed by molecular modelling studies. Several compounds were selected for further studies. First, their cytotoxicity, nicotinic receptors modulation, and acute toxicity (lethal dose for 50% of laboratory animals [LD50]; mice and rats) were tested to evaluate their safety with promising results. Furthermore, their blood levels were measured to select the appropriate time for prophylactic administration. Finally, the protective ratio of selected compounds against soman-induced toxicity was determined when selected compounds were found similarly potent or only slightly better to standard pyridostigmine. Conclusion The presented small bisquaternary molecules did not show overall benefit in prophylaxis of soman-induced in vivo toxicity. PMID:29563775

The action of two ethyl carbamates on acetylcholinesterase and reproductive organs of Rhipicephalus microplus.

PubMed

Prado-Ochoa, M G; Ramírez-Noguera, P; Díaz-Torres, R; Garrido-Fariña, G I; Vázquez-Valadez, V H; Velázquez-Sánchez, A M; Muñoz-Guzmán, M A; Angeles, E; Alba-Hurtado, F

2014-01-31

The effects produced by the new synthetic carbamates ethyl-(4-bromophenyl) carbamate and ethyl-(4-chlorophenyl) carbamate on the acetylcholinesterase (AChE) activity, egg structure and reproductive organs of two Rhipicephalus microplus strains were evaluated. Inhibition kinetic parameters showed that the studied carbamates are weak inhibitors and have a low affinity for R. microplus AChE. Histologically, in oocytes from carbamate-treated engorged female ticks, a loss of shape, cytoplasmic vacuoles, decreased chorion deposition, alterations in cytoplasmic granularity and irregular membranes were observed. In oocyte germinal vesicles, a loss of shape, nucleolar fragmentation and membrane alterations with degenerative signs were observed. The ovarian epithelium was vacuolated, flattened, eroded and contained pyknotic nuclei. These alterations were observed from the first day and persisted and increased in severity until day 7 post-treatment. The ovaries from carbamate-treated ticks had fewer stage IV-V oocytes and more stage I-II oocytes. Additionally, eggs produced by the treated ticks had a modified appearance, decreased size, a reduced superficial waxy layer and a loss of viability. The results of this study show that the effects of carbamates on R. microplus were independent of AChE inhibition and show that the morphological alterations in the reproductive organs were due to carbamate actions on the vitellogenesis and viability of the ovarian cells. Copyright © 2013 Elsevier B.V. All rights reserved.

Anti-inflammatory, antioxidant and anti-acetylcholinesterase activities of Bouvardia ternifolia: potential implications in Alzheimer's disease.

PubMed

García-Morales, Giovanni; Huerta-Reyes, Maira; González-Cortazar, Manasés; Zamilpa, Alejandro; Jiménez-Ferrer, Enrique; Silva-García, Raúl; Román-Ramos, Rubén; Aguilar-Rojas, Arturo

2015-07-01

Bouvardia ternifolia has been used medicinally to treat inflammation. In the present study, we investigate the anti-Alzheimer's potential effect of the hydroalcoholic extract of B. ternifolia through evaluation of anti-inflammatory and antioxidant activities, quantification of the percentage inhibition of acetylcholinesterase activity, protection effect against β-amyloid fibrillar-induce neurotoxicity, and the identification of the main constituents. Our results show that B. ternifolia extract and ethyl acetate fraction induced anti-inflammatory effects by reducing inflammation by >70 %, while antioxidant test revealed significant IC50 values for flavonoid content fraction (30.67 ± 2.09 μg/ml) and ethyl acetate fraction (42.66 ± 0.93 μg/ml). The maximum inhibition of acetylcholinesterase was exhibited by scopoletin content fraction (38.43 ± 3.94 %), while ethyl acetate fraction exerted neuroprotective effect against β-amyloid peptide (83.97 ± 5.03 %). Phytochemical analysis, showed the presence of 3-O-quercetin glucopyranoside (415 mg/g), rutin (229.9 mg/g), ursolic and oleanolic acid (54 and 20.8 mg/g respectively), 3-O-quercetin rhamnopyranoside (12.8 mg/g), chlorogenic acid (9.5 mg/g), and scopoletin (1.38 mg/g). Our findings support the use of B. ternifolia since the extract induced significant neuroprotection against β-amyloid peptide, anti-inflammatory, antioxidant and anti-acetylcholinesterase effects that could be attributed to its contents of polyphenols, coumarins, and triterpenes, and encourage further studies for development of this extract as therapeutic agent in treatment of Alzheimer's disease.

Prediction of the binding sites of huperzine A in acetylcholinesterase by docking studies

NASA Astrophysics Data System (ADS)

Pang, Yuan-Ping; Kozikowski, Alan P.

1994-12-01

We have performed docking studies with the SYSDOC program on acetylcholinesterase (AChE) to predict the binding sites in AChE of huperzine A (HA), which is a potent and selective, reversible inhibitor of AChE. The unique aspects of our docking studies include the following: (i) Molecular flexibility of the guest and the host is taken into account, which permits both to change their conformations upon binding. (ii) The binding energy is evaluated by a sum of energies of steric, electrostatic and hydrogen bonding interactions. In the energy calculation no grid approximation is used, and all hydrogen atoms of the system are treated explicitly. (iii) The energy of cation-π interactions between the guest and the host, which is important in the binding of AChE, is included in the calculated binding energy. (iv) Docking is performed in all regions of the host's binding cavity. Based on our docking studies and the pharmacological results reported for HA and its analogs, we predict that HA binds to the bottom of the binding cavity of AChE (the gorge) with its ammonium group interacting with Trp84, Phe330, Glu199 and Asp72 (catalytic site). At the the opening of the gorge with its ammonium group partially interacting with Trp279 (peripheral site). At the catalytic site, three partially overlapping subsites of HA were identified which might provide a dynamic view of binding of HA to the catalytic site.

Amelioration of intracerebroventricular streptozotocin induced cognitive dysfunction and oxidative stress by vinpocetine -- a PDE1 inhibitor.

PubMed

Deshmukh, Rahul; Sharma, Vivek; Mehan, Sidharth; Sharma, Nidhi; Bedi, K L

2009-10-12

Enhancing cyclic nucleotides signaling by inhibition of phosphodiesterases (PDEs) is known to be beneficial in disorders associated with cognitive decline. The present study was designed to investigate the effect of vinpocetine (PDE1 inhibitor) on intracerebroventricular (i.c.v.) streptozotocin induced experimental sporadic dementia of Alzheimer's type. Infusion of streptozotocin impaired learning and memory, increased oxidative-nitritive stress and induced cholinergic hypofunction in rats. Chronic treatment with vinpocetine (5, 10 and 20 mg/kg i.p.) for 21 days following first i.c.v. streptozotocin infusion significantly improved learning and memory in Morris water maze and passive avoidance paradigms. Further, vinpocetine significantly reduced the oxidative-nitritive stress, as evidenced by decrease in malondialdehyde (MDA) and nitrite levels, and restored the reduced glutathione (GSH) levels. Significant increase in acetylcholinesterase activity and lactate dehydrogenase levels was observed in the present model indicating cholinergic hypofunction and increase in neuronal cell damage. Chronic treatment with vinpocetine also reduced significantly the increase in acetylcholinesterase activity and lactate dehydrogenase levels indicating restorative capacity of vinpocetine with respect to cholinergic functions and preventing the neuronal damage. The observed beneficial effects of vinpocetine on spatial memory may be due to its ability to favorably modulate cholinergic functions, prevent neuronal cell damage and possibly through its antioxidant mechanism also.

Large-Scale First-Principles Molecular Dynamics Simulations with Electrostatic Embedding: Application to Acetylcholinesterase Catalysis

DOE PAGES

Fattebert, Jean-Luc; Lau, Edmond Y.; Bennion, Brian J.; ...

2015-10-22

Enzymes are complicated solvated systems that typically require many atoms to simulate their function with any degree of accuracy. We have recently developed numerical techniques for large scale First-Principles molecular dynamics simulations and applied them to study the enzymatic reaction catalyzed by acetylcholinesterase. We carried out Density functional theory calculations for a quantum mechanical (QM) sub- system consisting of 612 atoms with an O(N) complexity finite-difference approach. The QM sub-system is embedded inside an external potential field representing the electrostatic effect due to the environment. We obtained finite temperature sampling by First-Principles molecular dynamics for the acylation reaction of acetylcholinemore » catalyzed by acetylcholinesterase. Our calculations shows two energies barriers along the reaction coordinate for the enzyme catalyzed acylation of acetylcholine. In conclusion, the second barrier (8.5 kcal/mole) is rate-limiting for the acylation reaction and in good agreement with experiment.« less

Sugammadex to Reverse Neuromuscular Blockade in a Child with a Past History of Cardiac Transplantation

PubMed Central

Miller, Karen; Hall, Brian; Tobias, Joseph D

2017-01-01

Sugammadex is a novel agent for the reversal of neuromuscular blockade. The speed and efficacy of reversal with sugammadex are significantly faster than acetylcholinesterase inhibitors, such as neostigmine. Sugammadex also has a limited adverse profile when compared with acetylcholinesterase inhibitors, specifically in regard to the incidence of bradycardia. This adverse effect may be particularly relevant in the setting of a heart transplant recipient with a denervated heart. The authors present a case of an 8-year-old child, status postcardiac transplantation, who required anesthetic care for laparoscopy and lysis of intra-abdominal adhesions. Sugammadex was used to reverse neuromuscular blockade and avoid the potential adverse effects of neostigmine. The unique mechanism of action of sugammadex is discussed, previous reports of its use in this unique patient population are reviewed, and its potential benefits compared to traditional acetylcholinesterase inhibitors are presented. PMID:28701612

Sugammadex to reverse neuromuscular blockade in a child with a past history of cardiac transplantation.

PubMed

Miller, Karen; Hall, Brian; Tobias, Joseph D

2017-01-01

Sugammadex is a novel agent for the reversal of neuromuscular blockade. The speed and efficacy of reversal with sugammadex are significantly faster than acetylcholinesterase inhibitors, such as neostigmine. Sugammadex also has a limited adverse profile when compared with acetylcholinesterase inhibitors, specifically in regard to the incidence of bradycardia. This adverse effect may be particularly relevant in the setting of a heart transplant recipient with a denervated heart. The authors present a case of an 8-year-old child, status postcardiac transplantation, who required anesthetic care for laparoscopy and lysis of intra-abdominal adhesions. Sugammadex was used to reverse neuromuscular blockade and avoid the potential adverse effects of neostigmine. The unique mechanism of action of sugammadex is discussed, previous reports of its use in this unique patient population are reviewed, and its potential benefits compared to traditional acetylcholinesterase inhibitors are presented.

Nippostrongylus brasiliensis: infection induces upregulation of acetylcholinesterase activity on rat intestinal epithelial cells.

PubMed

Russell, W S; Henson, S M; Hussein, A S; Tippins, J R; Selkirk, M E

2000-12-01

Expression of cholines terases and muscarinic acetylcholine receptors in the jejunal mucosa has been investigated during infection of rats with the nematode parasite Nippostrongylus brasiliensis. Selective expression of m3 receptors was observed on epithelial cells from uninfected rats and animals 7 days postinfection, and saturation binding with [(3)H]quinuclidinyl benzilate indicated that receptor expression on cell membranes was unaltered by infection. Butyrylcholinesterase was highly expressed in mucosal epithelia, but acetylcholinesterase was present at low levels in uninfected animals. In contrast, discrete foci of intense acetylcholinesterase activity were observed on the basement membrane of intestinal epithelial cells in animals infected with N. brasiliensis. This was demonstrated to be due to upregulation of expression of endogenous enzyme, which peaked at Day 10 postinfection and subsequently declined to preinfection levels. It is suggested that this occurs in response to hyper-activation of the enteric nervous system as a result of infection, and may benefit the host by limiting excessive fluid secretion due to cholinergic stimulation. Copyright 2000 Academic Press.

Acetylcholinesterase inhibition and locomotor function after motor-sensory cortex impact injury.

PubMed

Holschneider, Daniel P; Guo, Yumei; Roch, Margareth; Norman, Keith M; Scremin, Oscar U

2011-09-01

Traumatic brain injury (TBI) induces transient or persistent dysfunction of gait and balance. Enhancement of cholinergic transmission has been reported to accelerate recovery of cognitive function after TBI, but the effects of this intervention on locomotor activity remain largely unexplored. The hypothesis that enhancement of cholinergic function by inhibition of acetylcholinesterase (AChE) improves locomotion following TBI was tested in Sprague-Dawley male rats after a unilateral controlled cortical impact (CCI) injury of the motor-sensory cortex. Locomotion was tested by time to fall on the constant speed and accelerating Rotarod, placement errors and time to cross while walking through a horizontal ladder, activity monitoring in the home cages, and rearing behavior. Assessments were performed the 1st and 2nd day and the 1st, 2nd, and 3rd week after TBI. The AChE inhibitor physostigmine hemisulfate (PHY) was administered continuously via osmotic minipumps implanted subcutaneously at the rates of 1.6-12.8 μmol/kg/day. All measures of locomotion were impaired by TBI and recovered to initial levels between 1 and 3 weeks post-TBI, with the exception of the maximum speed achievable on the accelerating Rotarod, as well as rearing in the open field. PHY improved performance in the accelerating Rotarod at 1.6 and 3.2 μmol/kg/day (AChE activity 95 and 78% of control, respectively), however, higher doses induced progressive deterioration. No effect or worsening of outcomes was observed at all PHY doses for home cage activity, rearing, and horizontal ladder walking. Potential benefits of cholinesterase inhibition on locomotor function have to be weighed against the evidence of the narrow range of useful doses.

O-Hydroxyl- or o-amino benzylamine-tacrine hybrids: multifunctional biometals chelators, antioxidants, and inhibitors of cholinesterase activity and amyloid-β aggregation.

PubMed

Mao, Fei; Huang, Ling; Luo, Zonghua; Liu, Anqiu; Lu, Chuanjun; Xie, Zhiyong; Li, Xingshu

2012-10-01

In an effort to identify novel multifunctional drug candidates for the treatment of Alzheimer's disease (AD), a series of hybrid molecules were synthesised by reacting N-(aminoalkyl)tacrine with salicylic aldehyde or derivatives of 2-aminobenzaldehyde. These compounds were then evaluated as multifunctional anti-Alzheimer's disease agents. All of the hybrids are potential biometal chelators, and in addition, most of them were better antioxidants and inhibitors of cholinesterases and amyloid-β (Aβ) aggregation than the lead compound tacrine. Compound 7c has the potential to be a candidate for AD therapy: it is a much better inhibitor of acetylcholinesterase (AChE) than tacrine (IC(50): 0.55 nM vs 109 nM), has good biometal chelation ability, is able to inhibit Aβ aggregation and has moderate antioxidant activity (1.22 Trolox equivalents). Copyright © 2012 Elsevier Ltd. All rights reserved.

Cholinergic Enhancement of Frontal Lobe Activity in Mild Cognitive Impairment

ERIC Educational Resources Information Center

Saykin, Andrew J.; Wishart, Heather A.; Rabin, Laura A.; Flashman, Laura A.; McHugh, Tara L.; Mamourian, Alexander C.; Santulli, Robert B.

2004-01-01

Cholinesterase inhibitors positively affect cognition in Alzheimer's disease (AD) and other conditions, but no controlled functional MRI studies have examined where their effects occur in the brain. We examined the effects of donepezil hydrochloride (Aricept[Registered sign]) on cognition and brain activity in patients with amnestic mild cognitive…

Muscarinic Receptor-Dependent Long Term Depression in the Perirhinal Cortex and Recognition Memory are Impaired in the rTg4510 Mouse Model of Tauopathy.

PubMed

Scullion, Sarah E; Barker, Gareth R I; Warburton, E Clea; Randall, Andrew D; Brown, Jonathan T

2018-02-26

Neurodegenerative diseases affecting cognitive dysfunction, such as Alzheimer's disease and fronto-temporal dementia, are often associated impairments in the visual recognition memory system. Recent evidence suggests that synaptic plasticity, in particular long term depression (LTD), in the perirhinal cortex (PRh) is a critical cellular mechanism underlying recognition memory. In this study, we have examined novel object recognition and PRh LTD in rTg4510 mice, which transgenically overexpress tau P301L . We found that 8-9 month old rTg4510 mice had significant deficits in long- but not short-term novel object recognition memory. Furthermore, we also established that PRh slices prepared from rTg4510 mice, unlike those prepared from wildtype littermates, could not support a muscarinic acetylcholine receptor-dependent form of LTD, induced by a 5 Hz stimulation protocol. In contrast, bath application of the muscarinic agonist carbachol induced a form of chemical LTD in both WT and rTg4510 slices. Finally, when rTg4510 slices were preincubated with the acetylcholinesterase inhibitor donepezil, the 5 Hz stimulation protocol was capable of inducing significant levels of LTD. These data suggest that dysfunctional cholinergic innervation of the PRh of rTg4510 mice, results in deficits in synaptic LTD which may contribute to aberrant recognition memory in this rodent model of tauopathy.

Biological Evaluation of Azomethine-dihydroquinazolinone Conjugates as Cancer and Cholinesterase Inhibitors.

PubMed

Iqbal, Jamshed; Saeed, Aamer; Shah, Syed J A; al-Rashida, Mariya; Shams-ul Mahmood

2016-01-01

In an attempt to discover novel anti-cancer agents and potent cholinesterase inhibitors, 11 azomethine-dihydroquinazolinone conjugates were evaluated against lung carcinoma cells and cholinesterases. Most of the compounds exhibited significant cytotoxicity at low micromolar concentrations and were less toxic to normal cells. After 24 h incubation period, 2i showed maximum cytotoxicity. The 4-bromine substituted compounds showed higher acetylcholinesterase (AChE) inhibitory activity than other screened compounds. The most active compound 2c, among the series, had an IC50 value 209.8 µM against AChE. The tested compounds showed less inhibition against butyrylcholinesterase. Molecular docking studies were performed in order to investigate the plausible binding modes of synthesized compounds. The compounds can be further optimized to treat cancer and Alzheimer's disease. These derivatives may open new pathways for introducing new therapies for curing cancer and senile dementia.

Novel 16-substituted bifunctional derivatives of huperzine B: multifunctional cholinesterase inhibitors

PubMed Central

Shi, Yu-fang; Zhang, Hai-yan; Wang, Wei; Fu, Yan; Xia, Yu; Tang, Xi-can; Bai, Dong-lu; He, Xu-chang

2009-01-01

Aim: To design novel bifunctional derivatives of huperzine B (HupB) based on the concept of dual binding site of acetylcholinesterase (AChE) and evaluate their pharmacological activities for seeking new drug candidates against Alzheimer's disease (AD). Methods: Novel 16-substituted bifunctional derivatives of HupB were synthesized through chemical reactions. The inhibitory activities of the derivatives toward AChE and butyrylcholinesterase (BuChE) were determined in vitro by modified Ellman's method. Cell viability was quantified by the reduction of MTT. Results: A new preparative method was developed for the generation of 16-substituted derivatives of HupB, and pharmacological trials indicated that the derivatives were multifunctional cholinesterase inhibitors targeting both AChE and BuChE. Among the derivatives tested, 9c, 9e, 9f, and 9i were 480 to 1360 times more potent as AChE inhibitors and 370 to 1560 times more potent as BuChE inhibitors than the parent HupB. Further preliminary pharmacological trials of derivatives 9c and 9i were performed, including examining the mechanism of AChE inhibition, the substrate kinetics of the enzyme inhibition, and protection against hydrogen peroxide (H2O2)-induced cytotoxicity in PC12 cells. Conclusion: Preliminary pharmacological evaluation indicated that 16-substituted derivatives of HupB, particularly 9c and 9i, would be potentially valuable new drug candidates for AD therapy, and further exploration is needed to evaluate their pharmacological and clinical efficacies. PMID:19578388

A comparison of reactivating and therapeutic efficacy of bispyridinium acetylcholinesterase reactivator KR-22934 with the oxime K203 and commonly used oximes (obidoxime, trimedoxime, HI-6) in tabun-poisoned rats and mice.

PubMed

Kassa, Jiri; Karasova, Jana Zdarova; Pavlikova, Ruzena; Musilek, Kamil; Kuca, Kamil; Bajgar, Jiri; Jung, Young-Sik

2011-03-01

The potency of bispyridinium acetylcholinesterase reactivator KR-22934 in reactivating tabun-inhibited acetylcholinesterase and reducing tabun-induced lethal toxic effects was compared with the oxime K203 and commonly used oximes. Studies determining percentage of reactivation of tabun-inhibited blood and tissue acetylcholinesterase in rats showed that the reactivating efficacy of KR-22934 was slightly higher than the reactivating efficacy of K203 and roughly corresponded to the reactivating efficacy of obidoxime and trimedoxime in blood and diaphragm. On the other hand, the oxime KR-22934 was not able to reactivate tabun-inhibited acetylcholinesterase in the brain. The therapeutic efficacy of all oximes studied approximately corresponded to their reactivating efficacy. Based on the results, one can conclude that the oxime KR-22934 is not suitable for the replacement of commonly used oximes for the antidotal treatment of tabun poisoning in spite of its potency to reactivate tabun-inhibited acetylcholinesterase in the peripheral compartment (blood, diaphragm).

Anti-acetylcholinesterase and Antioxidant Activities of Inhaled Juniper Oil on Amyloid Beta (1-42)-Induced Oxidative Stress in the Rat Hippocampus.

PubMed

Cioanca, Oana; Hancianu, Monica; Mihasan, Marius; Hritcu, Lucian

2015-05-01

Juniper volatile oil is extracted from Juniperus communis L., of the Cupressaceae family, also known as common juniper. Also, in aromatherapy the juniper volatile oil is used against anxiety, nervous tension and stress-related conditions. In the present study, we identified the effects of the juniper volatile oil on amyloid beta (1-42)-induced oxidative stress in the rat hippocampus. Rats received a single intracerebroventricular injection of amyloid beta (1-42) (400 pmol/rat) and then were exposed to juniper volatile oil (200 μl, either 1 or 3 %) for controlled 60 min period, daily, for 21 continuous days. Also, the antioxidant activity in the hippocampus was assessed using superoxide dismutase, glutathione peroxidase and catalase specific activities, the total content of the reduced glutathione, protein carbonyl and malondialdehyde levels. Additionally, the acetylcholinesterase activity in the hippocampus was assessed. The amyloid beta (1-42)-treated rats exhibited the following: increase of the acetylcholinesterase, superoxide dismutase and catalase specific activities, decrease of glutathione peroxidase specific activity and the total content of the reduced glutathione along with an elevation of malondialdehyde and protein carbonyl levels. Inhalation of the juniper volatile oil significantly decreases the acetylcholinesterase activity and exhibited antioxidant potential. These findings suggest that the juniper volatile oil may be a potential candidate for the development of therapeutic agents to manage oxidative stress associated with Alzheimer's disease through decreasing the activity of acetylcholinesterase and anti-oxidative mechanism.

Neuroinflammatory Pathobiology in Gulf War Illness: Characterization with an Animal Model

DTIC Science & Technology

2013-08-01

GFAP,IL6,CCL2, TNF, L118, Lif, IL10 Hip, Ctx Ctx Ctx CORT=corticosterone;(200mg/L) for days 7-14 P8= pyridostigmine bromide ;P8(2.5 mg/kg/day, s.c...reversible acetylcholinesterase (AChE) inhibitor pyridostigmine bromide (PB), the insect repellent DEET and, potentially, the nerve agent, sarin. These...acetylcholinesterase (AChE) inhibitor, pyridostigmine bromide (PB), the insect repellent, DEET, and, potentially, acutely to the nerve agent sarin. Previously, we

Acetylcholine-hydrolyzing activities in soluble brain fraction: Characterization with reversible and irreversible inhibitors.

PubMed

Estévez, Jorge; Selva, Verónica; Benabent, Mónica; Mangas, Iris; Sogorb, Miguel Ángel; Vilanova, Eugenio

2016-11-25

Some effects of organophosphorus compounds (OPs) esters cannot be explained through actions on currently recognized targets acetylcholinesterase or neuropathy target esterase (NTE). In soluble chicken brain fraction, three components (Eα, Eβ and Eγ) of pheny lvalerate esterase activity (PVase) were kinetically discriminated and their relationship with acetylcholine-hydrolyzing activity (cholinesterase activity) were studied in previous works. In this work, four enzymatic components (CS1, CS2, CS3 and CS4) of cholinesterase activity have been discriminated in soluble fraction, according to their sensitivity to irreversible inhibitors mipafox, paraoxon, PMSF and iso-OMPA and to reversible inhibitors ethopropazine and BW284C51. Cholinesterase component CS1 can be related to the Eα component of PVase activity and identified as butyrylcholinesterase (BuChE). No association and similarities can be stablished among the other PVase component (Eβ and Eγ) with the other cholinesterase components (CS2, CS3, CS4). The kinetic analysis has allowed us to stablish a method for discriminating the enzymatic component based on a simple test with two inhibitors. It can be used as biomarker in toxicological studies and for monitoring these cholinesterase components during isolation and molecular identification processes, which will allow OP toxicity to be understood by a multi-target approach. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Benefits of statistical molecular design, covariance analysis, and reference models in QSAR: a case study on acetylcholinesterase

NASA Astrophysics Data System (ADS)

Andersson, C. David; Hillgren, J. Mikael; Lindgren, Cecilia; Qian, Weixing; Akfur, Christine; Berg, Lotta; Ekström, Fredrik; Linusson, Anna

2015-03-01

Scientific disciplines such as medicinal- and environmental chemistry, pharmacology, and toxicology deal with the questions related to the effects small organic compounds exhort on biological targets and the compounds' physicochemical properties responsible for these effects. A common strategy in this endeavor is to establish structure-activity relationships (SARs). The aim of this work was to illustrate benefits of performing a statistical molecular design (SMD) and proper statistical analysis of the molecules' properties before SAR and quantitative structure-activity relationship (QSAR) analysis. Our SMD followed by synthesis yielded a set of inhibitors of the enzyme acetylcholinesterase (AChE) that had very few inherent dependencies between the substructures in the molecules. If such dependencies exist, they cause severe errors in SAR interpretation and predictions by QSAR-models, and leave a set of molecules less suitable for future decision-making. In our study, SAR- and QSAR models could show which molecular sub-structures and physicochemical features that were advantageous for the AChE inhibition. Finally, the QSAR model was used for the prediction of the inhibition of AChE by an external prediction set of molecules. The accuracy of these predictions was asserted by statistical significance tests and by comparisons to simple but relevant reference models.

Analogous β-Carboline Alkaloids Harmaline and Harmine Ameliorate Scopolamine-Induced Cognition Dysfunction by Attenuating Acetylcholinesterase Activity, Oxidative Stress, and Inflammation in Mice