Potent Acetylcholinesterase Research Articles

Benzenesulfonamide derivatives as potent acetylcholinesterase, α-glycosidase, and glutathione S-transferase inhibitors: biological evaluation and molecular docking studies

Sulfonamide derivatives exhibit a wide biological activity and can function as potential medical molecules in the development of a drug. Studies have reported that the compounds have an effect on many enzymes. In this study, the derivatives of amine sulfonamide (1i-11i) were prepared with reduced imine compounds (1-11) with NaBH4 in methanol. The synthesized compounds were fully characterized by spectral data and analytical. The effect of the synthesized derivatives on acetylcholinesterase (AChE), glutathione S-transferase (GST) and α-glycosidase (α-GLY) enzymes were determined. For the AChE and α-GLY, the most powerful inhibition was observed on 10 and 10i series with K I value in the range 2.26 ± 0.45–3.57 ± 0.97 and 95.73 ± 13.67–102.45 ± 11.72 µM, respectively. K I values of the series for GST were found in the range of 22.76 ± 1.23–49.29 ± 4.49. Finally, the compounds have a stronger inhibitor in lower concentrations by the attachment of functional electronegative groups such as two halogens (-Br and -CI), -OH to the benzene ring and -SO2NH2. The crystal structures of AChE, α-GLY, and GST in complex with selected derivatives 4 and 10 show the importance of the functional moieties in the binding modes within the receptors. Communicated by Ramaswamy H. Sarma

New Flavoalkaloids with Potent α-Glucosidase and Acetylcholinesterase Inhibitory Activities from Yunnan Black Tea 'Jin-Ya'.

As a subgroup of flavoalkaloids, N-ethyl-2-pyrrolidinone substituted flavan-3-ols are reported to possess various biological activities that may play important roles in the beneficial healthcare functions of tea. The HPLC and LC-MS analyses showed the existence of N-ethyl-2-pyrrolidinone substituted flavan-3-ols in 'Jin-Ya', which is a Yunnan black tea produced only from the buds of the tea plant Camellia sinensis var. assamica. Further phytochemical study on this precious black tea led to the identification of 8 flavoalkaloids, 1-8, along with 11 known flavan-3-ols (9-14) and flavonol glycosides (15-19). The new compounds, (-)-6-(5″S)-N-ethyl-2-pyrrolidinone-epiafzelechin (1), (-)-8-(5″R)-N-ethyl-2-pyrrolidinone-epiafzelechin-3-O-gallate (2a), and (-)-8-(5″S)-N-ethyl-2-pyrrolidinone-epiafzelechin-3-O-gallate (2b), were identified based on extensive spectroscopic analysis. Flavoalkaloids 2-6 showed inhibitory activity on α-glucosidase with IC50 values ranging from 2.09 to 8.47 μM, compared to those of quercetin and acarbose (IC50 = 6.87 and 228.9 μM, respectively). Moreover, compounds 2, 3, and 6 displayed an inhibitory effect on acetyl-cholinesterase with IC50 values of 14.23, 33.79, and 34.82 μM, respectively, compared to tacrine (IC50 = 0.223 μM).

Potential Acetylcholinesterase, Lipase, α-Glucosidase, and α-Amylase Inhibitory Activity, as well as Antimicrobial Activities, of Essential Oil from Lettuce Leaf Basil (Ocimum basilicum L.) Elicited with Jasmonic Acid

The aim of this study was to investigate the influence of the elicitation with jasmonic acid on the biological activities of essential oils (EOs) from lettuce leaf basil (Ocimum basilicum L.). Specifically, 0.01 µM jasmonic acid (JA1), 1 µM jasmonic acid (JA2), and 100 µM jasmonic acid (JA3) were used as elicitors. The results indicated that the elicitation increased the acetylcholinesterase, lipase, and α-amylase inhibitory activity of essential oils. A significant difference in α-glucosidase inhibition was noted only for the JA3 extract (IC50 = 0.81 µL/mL), as this activity was lower than in the control sample without elicitation (IC50 = 0.68 µL/mL). The studied basil EOs exhibited similar activity against Staphylococcus aureus (Gram-positive bacteria) and Escherichia coli (Gram-negative bacteria). Based on the value of the minimum inhibitory concentration (MIC) and the minimum bactericidal concentrations (MBC), the best antimicrobial activity was observed for JA2 and JA3.

Design, Synthesis and Bioevaluation of Two Series of 3-[(1-Benzyl-1H-1,2,3-triazol-4-yl)methyl]quinazolin-4(3H)-ones and N-(1-Benzylpiperidin-4-yl)quinazolin-4-amines.

Two series of 3-[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]quinazolin-4(3H)-ones and N-(1-benzylpiperidin-4-yl)quinazolin-4-amines were designed initially as potential acetylcholine esterase inhibitors. Biological evaluation demonstrated that N-(1-benzylpiperidin-4-yl)quinazolin-4-amines significantly inhibited AChE activity. Especially, two compounds of them were found to be the most potent with relative AChE inhibition percentages of 87 % in comparison to donepezil. The docking studies with AChE showed similar interactions between donepezil and four derivatives. N-(1-Benzylpiperidin-4-yl)quinazolin-4-amines also exhibited significant DPPH scavenging effects. The two series of compound also exerted moderate to good cytotoxicity against three human cancer cell lines, including SW620 (human colon cancer), PC-3 (prostate cancer), and NCI-H23 (lung cancer), with 3-[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]quinazolin-4(3H)-one being the most cytotoxic agent. 3-[(1-Benzyl-1H-1,2,3-triazol-4-yl)methyl]quinazolin-4(3H)-one significantly induced early apoptosis and arrested the SW620 cells at G2/M phase. From this study, two compounds of N-(1-benzylpiperidin-4-yl)quinazolin-4-amines could serve as new leads for further design and AChE inhibitors, while 3-[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]quinazolin-4(3H)-one could serve as a new lead for the design and development of more potent anticancer agents.

Structure-Based Design and Molecular Dynamics Simulations of Pentapeptide AEYTR as a Potential Acetylcholinesterase Inhibitor

Structure-based virtual screening protocol to identify potent acetylcholinesterase inhibitors was retrospectively validated. The protocol could be employed to examine the potential of designed compounds as novel acetylcholinesterase inhibitors. In a research project designing short peptides as acetylcholinesterase inhibitors, peptide AEYTR emerged as one of the potential inhibitors. This article presents the design of AEYTR assisted by the validated protocol and guided by literature reviews followed by molecular dynamics studies to examine the interactions of the pentapeptide in the binding pocket of the acetylcholinesterase enzyme. The molecular dynamics simulations were performed using YASARA Structure in Google Cloud Platform. The peptide AEYTR was identified in silico as a potent acetylcholinesterase inhibitor with the average free energy of binding (DG) of -19.138 kcal/mol.

Novel Class of Chalcone Oxime Ethers as Potent Monoamine Oxidase-B and Acetylcholinesterase Inhibitors.

Previously synthesized novel chalcone oxime ethers (COEs) were evaluated for inhibitory activities against monoamine oxidases (MAOs) and acetylcholinesterase (AChE). Twenty-two of the 24 COEs synthesized, except COE-17 and COE-24, had potent and/or significant selective inhibitory effects on MAO-B. COE-6 potently inhibited MAO-B with an IC50 value of 0.018 µM, which was 105, 2.3, and 1.1 times more potent than clorgyline, lazabemide, and pargyline (reference drugs), respectively. COE-7, and COE-22 were also active against MAO-B, both had an IC50 value of 0.028 µM, which was 67 and 1.5 times lower than those of clorgyline and lazabemide, respectively. Most of the COEs exhibited weak inhibitory effects on MAO-A and AChE. COE-13 most potently inhibited MAO-A (IC50 = 0.88 µM) and also significantly inhibited MAO-B (IC50 = 0.13 µM), and it could be considered as a potential nonselective MAO inhibitor. COE-19 and COE-22 inhibited AChE with IC50 values of 5.35 and 4.39 µM, respectively. The selectivity index (SI) of COE-22 for MAO-B was higher than that of COE-6 (SI = 778.6 vs. 222.2), but the IC50 value (0.028 µM) was slightly lower than that of COE-6 (0.018 µM). In reversibility experiments, inhibitions of MAO-B by COE-6 and COE-22 were recovered to the levels of reference reversible inhibitors and both competitively inhibited MAO-B, with Ki values of 0.0075 and 0.010 µM, respectively. Our results show that COE-6 and COE-22 are potent, selective MAO-B inhibitors, and COE-22 is a candidate of dual-targeting molecule for MAO-B and AChE.

Three-Component Access to Functionalized Spiropyrrolidine Heterocyclic Scaffolds and Their Cholinesterase Inhibitory Activity.

A novel one-pot [3+2]-cycloaddition reaction of (E)-3-arylidene-1-phenyl-succinimides, cyclic 1,2-diketones (isatin, 5-chloro-isatin and acenaphtenequinone), and diverse α-aminoacids such as 2-phenylglycine or sarcosine is reported. The reaction provides succinimide-substituted dispiropyrrolidine derivatives with high regio- and diastereoselectivities under mild reaction conditions. The stereochemistry of these N-heterocycles has been confirmed by four X-ray diffraction studies. Several synthetized compounds show higher inhibition on acetylcholinesterase (AChE) than butyrylcholinesterase (BChE). Of the 17 synthesized compounds tested, five exhibit good AChE inhibition with IC50 of 11.42 to 22.21 µM. A molecular docking study has also been undertaken for compound 4n possessing the most potent AChE inhibitory activity, disclosing its binding to the peripheral anionic site of AChE enzymes.

Sulfonamides incorporating ketene N,S-acetal bioisosteres as potent carbonic anhydrase and acetylcholinesterase inhibitors.

In this study, 15 novel compounds in a series of sulfonamide-based ketenes (7a-o) were synthesized and characterized using Fourier-transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and mass spectrometry. All compounds were tested for their ability to inhibit the human carbonic anhydrase (hCA) isoforms I and II, and acetylcholinesterase (AChE). The halogen-appended compounds, 7g, 7o, and 7i, exhibited the highest hCA I/II and AChE inhibition, with the KI values in the low nanomolar range (KI = 9.01 ± 0.08, 7.41 ± 0.03, and 7.37 ± 0.31 nM, respectively), as compared with their corresponding parent 2-[2,2-dicyano-1-(phenylamino)vinylthio]-N-(4-sulfamoylphenyl)acetamide analogs 7a-o. Besides, derivatives 7c and 7e selectively inhibited the isoform hCA I, whereas compounds 7m and 7n selectively inhibited isoform hCA II. These findings indicated that all compounds can inhibit metabolic dysfunctions, such as edema, epilepsy, glaucoma, and Alzheimer's disease, by specifically targeting both the hCA isoforms and AChE expression. Herein, also the interactions between ligands and receptors were highlighted through in silico molecular docking studies. The molecular mechanics-generalized Born surface area method was utilized to compute the binding free energy and the energy contribution of the critical residues in the active site was estimated. All these results would help us to perfectly understand the relationship between activity and structural characteristics of derivatives and to further improve newly and highly effective analogs targeting hCA and AChE.

Arylaminopropanone Derivatives as Potential Cholinesterase Inhibitors: Synthesis, Docking Study and Biological Evaluation

Neurodegenerative diseases in which the decrease of the acetylcholine is observed are growing worldwide. In the present study, a series of new arylaminopropanone derivatives with N-phenylcarbamate moiety (1–16) were prepared as potential acetylcholinesterase and butyrylcholinesterase inhibitors. In vitro enzyme assays were performed; the results are expressed as a percentage of inhibition and the IC50 values. The inhibitory activities were compared with reference drugs galantamine and rivastigmine showing piperidine derivatives (1–3) as the most potent. A possible mechanism of action for these compounds was determined from a molecular modelling study by using combined techniques of docking, molecular dynamics simulations and quantum mechanics calculations.

Efficient palladium‐catalyzed C‐S cross‐coupling reaction of benzo‐2,1,3‐thiadiazole at C‐5‐position: A potential class of AChE inhibitors

Functionalization of 2,1,3‐benzothiadiazole (BTD) with thiols at C‐5 position remains low explored. Moreover, the arylthiol‐substitutions at this position are also unexplored and can not be found by a SN2 or SN1 reaction. In this sense, herein we present a new palladium‐catalyzed methodology for a wide variety of unpublished 5‐arylsulfanyl‐benzo‐2,1,3‐thiadiazole derivatives synthesis with moderate to high yields using a low catalytic loading of Pd(L‐Pro)2 as low‐coast, and efficient catalyst in low reaction time. Besides, we concluded that the pKa of thiol species has an important role in this catalysis, mainly in the CMD like catalytic cyclo process, which strongly interferes in the reaction yields. Furthermore, arylsulfanyl‐benzo‐2,1,3‐thiadiazoles derivatives have been assessed (in vitro) as potential acetylcholinesterase inhibitors.

Synthesis, biological evaluation, theoretical investigations, docking study and ADME parameters of some 1,4-bisphenylhydrazone derivatives as potent antioxidant agents and acetylcholinesterase inhibitors.

Five 1,4-bisphenylhydrazone derivatives (1-5) were successfully synthesized and evaluated for their antioxidant and acetylcholinesterase inhibitory activities. The antioxidant activity has been carried out using DPPH, ABTS, CUPRAC and superoxide radical scavenging methods. All the compounds showed a very good antioxidant activity compared to that of the standards used. Compound 1 was found to be the best antioxidant agent with IC50 values lower or comparable to that of the standards. The acetylcholinesterase inhibitory activity has been evaluated using a modified Ellman's assay. The obtained results indicate that compound 2 is the best acetylcholinesterase inhibitor with a low IC50 value comparable to that of the galantamine. In addition, DFT calculations have been performed to determine in which mechanism the synthesized hydrazones follow to scavenge free radicals. Molecular docking study was performed for compound 2, and its interaction modes with the enzyme acetylcholinesterase were determined. As a result, a strong interaction between this compound and the active site of AChE enzyme was revealed. Finally, ADME properties of the synthesized compounds were also studied and showed good drug-like properties.

Design, synthesis and evaluation of new chromone-derived aminophosphonates as potential acetylcholinesterase inhibitor.

A series of novel N-substituted α-aminophosphonates-bearing chromone moiety were synthesized and evaluated for acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) activities and antioxidant properties. Porcine pancreatic lipase was employed as a catalyst. Inhibitory activity against AChE ranged between 0.103 and 5.781µM, whereas for BuChE, activities ranged between 8.619 and 18.789µM. The results show that among the various synthesized compounds, strongest AChE inhibition was found for the compound containing aliphatic amine analogs, while in case of BuChE, aromatic amines showed better activity as compared to aliphatic amines. Compound 4j was found to be the most potent inhibitor of AChE with an IC50 value of 0.103 ± 0.24μM and inhibited AChE through mixed-type inhibition. Compound 4j was twofolds more potent than tacrine, 35-folds potent than galantamine and 50-folds potent than rivastigmine. Also, docking study revealed that compound 4j binds to both the peripheral anionic site and catalytic anionic site of AChE and BuChE. The antioxidant activities of synthesized compounds were performed against 2,2-diphenyl-1-picrylhydrazyl and hydrogen peroxide scavenging. DNA nicking activity of selected compounds also suggested that the compounds do not harm plasmid DNA pBR322. Compound 4j also showed significant DNA damage protection activity. Novel N-substituted α-aminophosphonates bearing chromone moiety were synthesized and evaluated for anti-acetylcholinesterase, anti-butyrylcholinesterase, antioxidant and DNA damage activities.

Composition, Anticholinesterase and Antipedicular Activities of Satureja capitata L. Volatile Oil

AbstractThe emergence of resistance for antipedicular agents and the need of potent acetylcholinesterase (AChE) therapeutics for the treatment of a neurodegenerative disorder such as Alzheimer disease has led researchers to the exploration of new therapeutic alternatives such as natural volatile oils. Therefore, the current investigation aimed to identify the components of Satureja capitata L. volatile oil (VO), and examine the VO anticholinesterase, and antipedicular activities. The plant phytoconstituents were identified using Gas chromatography mass spectrometry (GC-MS) method, while the anticholinesterase activity was determined against butyryl- and acetyl-cholinesterase using Ellman’s method. In addition, antipedicular activity was established using the diffusion method. The obtained GC-MS results identified 16 compounds in S. capitata VO with the major constituents being carvacrol, γ-terpinene, and p-cymene. Anticholinesterase analysis showed a marked inhibition potential against acetyl- and butyryl-cholinesterase enzymes with half maximal inhibitory concentration (IC50) values of 28.24±0.97 μg/ml and 92.31±1.22 μg/ml, respectively in comparison with the reference compound galantamine, which has IC50 values against the same enzymes of 5.21±0.07 μg/ml and 10.33±0.37 μg/ml, respectively. In addition, the VO, at a concentration of 20%, was effective against head lice, similar to benzyl benzoate, which resulted in 100% mortality. In addition, the VO completely inhibited the emergence of lice nits after 6 and 14 days. On the basis of the obtained results, S. capitata VO is a promising natural alternative to synthetic antipedicular and anticholinesterase drugs, which can be employed in drug development, and may lead to new candidates against head lice and neurodegenerative diseases.

Pharmacokinetic Evaluation of Brain Penetrating Morpholine-3-hydroxy-2-pyridine Oxime as an Antidote for Nerve Agent Poisoning.

Nerve agents, the deadliest chemical warfare agents, are potent inhibitors of acetylcholinesterase (AChE) and cause rapid cholinergic crisis with serious symptoms of poisoning. Oxime reactivators of AChE are used in medical practice in the treatment of nerve agent poisoning, but the search for novel improved reactivators with central activity is an ongoing pursuit. For numerous oximes synthesized, in vitro reactivation is a standard approach in biological evaluation with little attention given to the pharmacokinetic properties of the compounds. This study reports a comprehensive physicochemical, pharmacokinetic, and safety profiling of five lipophilic 3-hydroxy-2-pyridine aldoximes, which were recently shown to be potent AChE reactivators with a potential to be centrally active. The oxime JR595 was singled out as highly metabolically stable in human liver microsomes, noncytotoxic oxime for SH-SY5Y neuroblastoma and 1321N1 astrocytoma cell lines, and its pharmacokinetic profile was determined after intramuscular administration in mice. JR595 was rapidly absorbed into blood after 15 min with simultaneous distribution to the brain at up to about 40% of its blood concentration; however, it was eliminated from both the brain and blood within an hour. In addition, the MDCKII-MDR1 cell line assay showed that oxime JR595 was not a P-glycoprotein efflux pump substrate. Finally, the preliminary antidotal study against multiple LD50 doses of VX and sarin in mice showed the potential of JR595 to provide desirable therapeutic outcomes with future improvements in its circulation time.

Extraction and isolation of acetylcholinesterase inhibitors from Citrus limon peel using an in vitro method.

A simple and efficient ultrafiltration-liquid chromatography-mass spectrometry-based method was developed for the rapid screening and identification of ligands from Citrus limon peel, which are suitable acetylcholinesterase inhibitors. Subsequently, the anti-Alzheimer's activity of these compounds was assessed using a PC12 cell model. Six major compounds, viz. neoeriocitrin, isonaringin, naringin, hesperidin, neohesperidin, and limonin, were identified as potent acetylcholinesterase inhibitors. A continuous and efficient online method, which involved the use of a microwave-assisted extraction device, solvent concentration tank, and centrifugal partition chromatography column, was developed for the scale-up of these compounds, and the obtained compounds presented high purity. Next, their bioactivity was evaluated using a PC12 cell model. This novel approach, which was based on ultrafiltration-liquid chromatography-mass spectrometry, microwave-assisted extraction online coupled with solvent concentration tank, and centrifugal partition chromatography along with in vitro evaluation, could represent a powerful tool for the screening and extraction of acetylcholinesterase inhibitors from complex matrices, and could be a useful platform for the large-scale production of bioactive and nutraceutical ingredients.

Aporphinoid Alkaloids Derivatives as Selective Cholinesterases Inhibitors: Biological Evaluation and Docking Study.

Alzheimer's dementia is a neurodegenerative disease that affects the elderly population and causes memory impairment and cognitive deficit. Manifestation of this disease is associated to acetylcholine decrease; thus, Cholinesterase inhibition is the main therapeutic strategy for the treatment of Alzheimer's disease. In the present study, a series of aporphinoid alkaloids were tested as potential acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors in vitro. Alkaloids liriodenine (3) and cassythicine (10) were the best inhibitors of both cholinesterases with IC50 values lower than 10 μM. In addition, these alkaloids demonstrated better inhibition of BChE than reference drug galantamine. In addition, some alkaloids showed selective inhibition. Laurotetatine clorhydrate (13) selectively inhibit AChE over BChE. On the contrary, pachyconfine (7) interacted more efficiently with BChE active site. Molecular modelling studies were performed in order to illustrate key interactions between most active compounds and the enzymes and to explain their selectivity. These studies reveal that the benzodioxole moiety exhibits strong interactions due to hydrogen bonds that form with the Glu201 (AChE) and Tyr440 (BChE) residues, which is reflected in the IC50 values.

Organocatalyzed Solvent Free and Efficient Synthesis of 2,4,5-Trisubstituted Imidazoles as Potential Acetylcholinesterase Inhibitors for Alzheimer's Disease.

The catalytic potential of pyridine-2-carboxlic acid has been evaluated for efficient, green and solvent free synthesis of 2,4,5-trisubstituted imidazole derivatives 3a-3m. The compounds 3a-3m were synthesized by one pot condensation reaction of substituted aromatic aldehydes, benzil, and ammonium acetate in good to excellent yields (74-96 %). To explore the potential of these compounds against Alzheimer's disease, their inhibitory activities against acetylcholinesterase (AChE) were evaluated. In this series of compounds, compound 3m, bearing one ethoxy and a hydroxy group on the phenyl ring on 2,4,5-trisubstituted imidazoles, proved to be a potent AChE inhibitor (102.56±0.14). Structure-activity relationship (SAR) of these compounds was developed. Molecular dockings were carried out for the compounds 3m, 3e, 3k, 3c, 3a, 3d, 3j, and 3f in order to further investigate the binding mechanism. The inhibitor molecule was molecularly docked with acetylcholinesterase to further study its binding mechanism. The amino group of the compound 3m forms an H-bond with the oxygen atom of the residue (i. e., THR121) which has a bond length of 3.051 Å.

Novel Tacrine and Hesperetin analogues: Design, Molecular docking and in silico ADME studies to identify potential Acetyl choline esterase inhibitors for Alzheimer’s disease.

Alzheimer’s disease is considered as most prevailing and common CNS disease found in elder population over 60 years of age. The early diagnosis of the disease prior to the occurrence of first behavioral symptom, dementia is difficult and hence the management of dementia and alleviation of other symptoms is the only available treatment for the AD. Acetyl cholinesterase inhibitors (AchE) are widely used in the treatment. In this study two series of new Tacrine(T1-T9) and Hesperetin derivatives(H1-H9) on the basis of the structural characteristics of acetyl cholinesterase (AchE) inhibitors were designed and screened to identify potential analogues as Anti-Alzheimer drug on the AchE (PDB ID:1DX4) using GLIDE employing extra-precision docking. The docking results Glide score, XPscore, docking score and binding interactions were compared with standard drug Tacrine. From the docking results it was found that T9 showed highest docking score among the designed compounds. The ADME properties also predicted using Qikprop application, from the above studies potential analogues with highest AchE inhibition and excellent pharmacokinetic properties were identified.

Tacrine-xanomeline and tacrine-iperoxo hybrid ligands: Synthesis and biological evaluation at acetylcholinesterase and M1 muscarinic acetylcholine receptors.

We synthesized a set of new hybrid derivatives (7-C8, 7-C10, 7-C12 and 8-C8, 8-C10, 8-C12), in which a polymethylene spacer chain of variable length connected the pharmacophoric moiety of xanomeline, an M1/M4-preferring orthosteric muscarinic agonist, with that of tacrine, a well-known acetylcholinesterase (AChE) inhibitor able to allosterically modulate muscarinic acetylcholine receptors (mAChRs). When tested in vitro in a colorimetric assay for their ability to inhibit AChE, the new compounds showed higher or similar potency compared to that of tacrine. Docking analyses were performed on the most potent inhibitors in the series (8-C8, 8-C10, 8-C12) to rationalize their experimental inhibitory power against AChE. Next, we evaluated the signaling cascade at M1 mAChRs by exploring the interaction of Gαq-PLC-β3 proteins through split luciferase assays and the myo-Inositol 1 phosphate (IP1) accumulation in cells. The results were compared with those obtained on the known derivatives 6-C7 and 6-C10, two quite potent AChE inhibitors in which tacrine is linked to iperoxo, an exceptionally potent muscarinic orthosteric activator. Interestingly, we found that 6-C7 and 6-C10 behaved as partial agonists of the M1 mAChR, at variance with hybrids 7-Cn and 8-Cn containing xanomeline as the orthosteric molecular fragment, which were all unable to activate the receptor subtype response.

Synthesis and evaluation of chromone-2-carboxamido-alkylamines as potent acetylcholinesterase inhibitors

Alzheimer’s disease (AD) is considered one of the greatest global public burdens. Pathophysiology of AD is proposed to be associated with reduced levels of the neurotransmitter acetylcholine (ACh). Cholinesterase enzymes, namely acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) cleave ACh via hydrolysis. Cholinesterase inhibitors (ChEIs) are the main group of drugs currently used for the treatment of AD. Novel chromone-2-carboxamido-alkylamines (7–18) were designed, synthesized, and evaluated for cholinesterase inhibitory activity. The compounds exhibited potent AChE inhibitory activities at micromolar range (IC50 0.09–9.16 µM) and demonstrated weak BChE inhibitory activities (IC50 12.09–44.56 µM). Compound 14 (IC50 0.09 ± 0.02 µM) was the most potent AChEI in this series; it showed higher activity than the clinical used drug tacrine. Enzyme kinetic study suggested that 14 was an uncompetitive inhibitor. Molecular docking study revealed that 14 was a dual-binding site inhibitor. Compound 14 did not induce any concentration-related cytotoxic effect against SH-SY5Y cells. It also showed neuroprotective effect in the cell line. Chromone-2-carboxamido-alkylamines can be promising lead compounds for development of anti-Alzheimer’s agents.