Potent Acetylcholinesterase Inhibitors Research Articles

Duguetia furfuracea (A.ST. Hil.) Saff.: Neuroprotective Effect on Chemically Induced Amnesia, Anxiolytic Effects and Preclinical Safety Evaluation in Mice

Duguetia furfuracea, “araticum-seco”, is known to contain several bioactive compounds that can mitigate oxidative stress and act on the central nervous system (CNS). This effect is partly attributed to its potent antioxidant and acetylcholinesterase (AChE) inhibitors. In this study, the effects were explored of the methanolic extract (MEDF) and alkaloid fraction (AFDF) of D. furfuracea (leaves) on cognitive behaviors in male mice with scopolamine (Scop)-induced cognitive impairment and biochemical parameters. Additionally, anxiolytic behavior, subacute toxicity, molecular docking and antioxidant activity were reported. MEDF (30, 100 or 300 mg/kg) or AFDF (30 mg/kg) were orally administered for 16 days and Scop (intraperitoneally, i.p.) between days 11 and 16. The anxiolytic behavior (open field test and marble burying) in healthy mice, and the Scop-induced memory impairment (object recognition test and Morris water maze (MWM)) were assessed, and the biochemical parameters (malondialdehyde (MDA) and AChE levels) were measured after euthanasia. The subacute toxicological impact of MEDF was assessed in female Swiss mice for 28 days. MEDF and AFDF were available for the DPPH, ABTS and β-carotene/linoleic acid models. The results revealed that MEDF and AFDF exhibit anxiolytic effects and significantly alleviated Sco-induced memory impairment, inhibited AChE in the cortex (40%) and MDA (51.51%) levels. Reticuline was reported in AFDF and molecular coupling with AChE involves link-type hydrogen bonds and van der Waals interactions. MEDF exhibited antioxidant capacity (DPPH, IC50 = 18.10 ± 1.70 µg/mL; ABTS, IC50 = 10.41 ± 1.69 µg/mL). MEDF did not reveal signs of toxicity. In conclusion, D. furfuracea shows promise in mitigating scopolamine-induced memory deficits, potentially because it inhibits AChE activity, reduces MDA levels, and enhances antioxidant activities.

Exploring the diverse acetylcholinesterase inhibitory potential of girinimbine: insights from in vitro assays, molecular docking, and simulation studies.

The search for new treatments for Alzheimer's disease (AD) has led to the exploration of plant-based drugs as potential options. Acetylcholinesterase (AChE) inhibitors are widely used as anti-AD medications. This study aimed to investigate the inhibitory mechanism of girinimbine, a constituent of Murraya koenigii, on AChE. AChE inhibition was assessed by in vitro experiments using the modified Ellman method, as well as in silico molecular docking and molecular dynamic simulation. The results were compared to those of the well-known anti-AChE agents tacrine and propidium iodide. Girinimbine, propidium, and tacrine at concentrations of 3.8X10-5M, 1.1x10-5M, and 6.1x10-7M showed percentages of inhibition percentages of 35.6%, 28.2%, and 76.6%, respectively. The docking and molecular dynamics simulation analyses indicated that girinimbine exhibited a higher binding affinity to AChE compared to propidium and tacrine. This finding was further confirmed by the docking, root mean square deviation (RMSD), root mean square fluctuation (RMSF), and radius of rotation analyses. In conclusion, M. koenigii girinimbine shows promise as an acetylcholinesterase inhibitor for Alzheimer's disease. Further research, including in vivo studies and clinical trials, is needed to explore its potential as a plant-based drug candidate for AD treatment.

Combining de novo molecular design with semiempirical protein-ligand binding free energy calculation.

Semi-empirical quantum chemistry methods estimate the binding free energies of protein-ligand complexes. We present an integrated approach combining the GFN2-xTB method with de novo design for the generation and evaluation of potential inhibitors of acetylcholinesterase (AChE). We employed chemical language model-based molecule generation to explore the synthetically accessible chemical space around the natural product Huperzine A, a potent AChE inhibitor. Four distinct molecular libraries were created using structure- and ligand-based molecular de novo design with SMILES and SELFIES representations, respectively. These libraries were computationally evaluated for synthesizability, novelty, and predicted biological activity. The candidate molecules were subjected to molecular docking to identify hypothetical binding poses, which were further refined using Gibbs free energy calculations. The structurally novel top-ranked molecule was chemically synthesized and biologically tested, demonstrating moderate micromolar activity against AChE. Our findings highlight the potential and certain limitations of integrating deep learning-based molecular generation with semi-empirical quantum chemistry-based activity prediction for structure-based drug design.

Evaluation of isatin-1,3,5-triazine-benzylamine hybrids as multi-target directed ligands against Alzheimer's disease

In this study a new series of isatin-1,3,5-triazine-benzylamine hybrids (6a-k) were designed, synthesized and evaluated for in vitro anti-Alzheimer's disease(AD) properties. These molecules were tested for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes inhibition and biometal chelation effect. Results revealed these molecules to be very potent AChE inhibitors with IC50 values in the range of 0.86-36.30 nM. BChE inhibition potencies were also good and IC50 values for active compounds were from 0.66 to 3.88 μM. Molecule 6c had the highest activity against both enzymes and further studies showed that it kinetically inhibited AChE and BChE with non-competitive and competitive mechanisms, respectively. This compound could effectively inhibit amyloid beta self/Cu2+ induced aggregation in 10μM. These compounds could significantly chelate to Cu2+ as an important biometal involved in AD andin silico simulations demonstrated that these molecules had key interactions with both ChE enzymes. It was concluded that these compounds had high potency to be used in future evaluations as anti-AD lead compounds.

In Silico and In Vitro Evaluation of Quinoline Derivatives as Potential Inhibitors of AChE, BACE1, and GSK3β for Neurodegenerative Diseases Treatment.

Neurodegenerative diseases are characterized by the structural and functional loss of neurons, affecting populations worldwide. Enzymes like acetylcholinesterase (AChE), beta-site APP cleaving enzyme-1 (BACE1), and glycogen synthase kinase 3-beta (GSK3β), contribute to their development. This study explores in silico and in vitro assays of quinoline analogues as potential inhibitors of these enzymes. In silico analyses highlighted derivative SQ6 as the most potent inhibitor for all proteins. In vitro assays confirmed that the quinoline derivatives had a modulating action on the three targets. SQ6 showed a significant AChE inhibition of 94.6%. Regarding the inhibition of GSK3β and BACE1, derivatives SQ6-SQ9, with the quinoline linked to the sulfonamide nitrogen, showed inhibition values above 40%. SQ7 and SQ9 were not considered cytotoxic for cell proliferation in human glioblastoma, and SQ6 did not show cytotoxicity at 7.8 and 3.9 µg mL-1. In murine fibroblasts, SQ6 presented a result similar to that observed for cell proliferation in human glioblastoma, while SQ7 and SQ9 were non-cytotoxic below 62.5 µg mL-1. These findings underscore compound SQ6 as the first potential multitarget enzyme inhibitor for treating neurodegenerative diseases.

Synthesis and Acetylcholinesterase Inhibitory Activity of Novel Trilaciclib Analogs.

Trilaciclib is a CDK4/6 inhibitor, used to treat the bone marrow damage in chemotherapy patients. A series of thirteen novel structural trilaciclib analogs was obtained to evaluate their activity against acetylcholinesterase. An effective method for the synthesis of 4,7-substituted 8,9-dihydropyrazino[1',2':1,5]pyrrolo[2,3-d]pyrimidine derivatives from a new methyl 4-chloro-7H-pyrrolo[2,3-d]pyrimidine-6-carboxylate was developed. Most of the synthesized pyrazino[1',2':1,5]pyrrolo[2,3-d]pyrimidine derivatives inhibited acetylcholinesterase in the micromolar range. The obtained data can be used for designing more potent acetylcholinesterase inhibitors with the pyrazino[1',2':1,5]pyrrolo[2,3-d]pyrimidine scaffold.

Evaluation of chemical constituents in Norantea guianensis aubl. Extracts, embryotoxicity, and acetylcholinesterase inhibitory potential in Danio rerio

Norantea guianensis Aubl., commonly referred to as the parrot flower or macaw-tail vine, is a plant species found in the Brazilian Amazon, Caatinga, and Cerrado biomes. It is used in folk medicine for its anxiolytic properties, as well as its ability to alleviate headaches and reduce fever. Nevertheless, despite its therapeutic benefits, the impact on embryonic development has yet to be fully explained. The objective of this study was to evaluate chemical constituents by HPLC-DAD, UV–visible and classical phytochemistry and the LC50 of ethanolic extracts from the stem and leaves of N. guianensis in Danio rerio after 96 h and to investigate their effect on developmental morphology. The findings were then related to both Acetylcholinesterase (AChE) activity and the plant's chemical composition. Zebrafish embryos were exposed to 0, 20, 40, 60, 80 and 100 mg/L concentrations of stem and leaves extracts. Phytochemical analysis revealed that the stem extract contained predominantly phenolic compounds, tannins, and anthraquinones, while the leaf extract contained alkaloids and flavonoids. The LC50 values for the stem and leaf extracts were 64.55 mg/L and 7.16 mg/L, respectively, being the stem extract was more toxic than the leaf extract. Induced malformations and alterations in the zebrafish development in different concentrations for both extract including pericardial edema, increased heart rate, spinal malformation and equilibrium disruption. Unlike to stem extract, the leaf extract delayed larval hatching and inhibited AChE activity. The findings indicate that the leaf extract possesses higher embryotoxicity and its use should be avoided during pregnancy.

Searching for potential acetylcholinesterase inhibitors: a combined approach of multi-step similarity search, machine learning and molecular dynamics simulations.

Targeting acetylcholinesterase is one of the most important strategies for developing therapeutics against Alzheimer's disease. In this work, we have employed a new approach that combines machine learning models, a multi-step similarity search of the PubChem library and molecular dynamics simulations to investigate potential inhibitors for acetylcholinesterase. Our search strategy has been shown to significantly enrich the set of compounds with strong predicted binding affinity to acetylcholinesterase. Both machine learning prediction and binding free energy calculation, based on linear interaction energy, suggest that the compound CID54414454 would bind strongly to acetylcholinesterase and hence is a promising inhibitor.

Microwave-assisted synthesis of indoloquinoxaline derivatives as promising anti-alzheimer agents: DFT and molecular docking study

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline. One of the major pathological features of AD is the degeneration of cholinergic neurons and associated loss of acetylcholine (ACh), a key neurotransmitter involved in memory and cognition. Reduced ACh levels correlate with the severity of cognitive symptoms in AD. Thus, inhibition of acetylcholinesterase (AChE), the enzyme responsible for breaking down ACh, is a leading treatment strategy. This study aimed to synthesize and evaluate novel AChE inhibitors based on an indolo[2,3-b]quinoxaline scaffold. A series of indolo[2,3-b]quinoxaline derivatives were designed by molecular hybridization of indole and quinoxaline privileged structures. Microwave-assisted synthesis improved the efficiency of obtaining the desired compounds. In vitro screening identified several potent AChE inhibitors, with IC50 values down to 0.02 µM. The most active compounds contained electron-withdrawing groups like nitro and benzoyl moieties. DFT calculations provided insights into geometrical, thermal, and electronic properties of the compounds. FMO analysis revealed variations in HOMO and LUMO energies that impact reactivity. Molecular docking elucidated binding modes, highlighting the pi-pi, pi-H, and H-bonding interactions with key amino acids in the catalytic gorge of AChE. Overall, the indole-quinoxaline hybrids represent promising candidates for development of novel dual binding site AChE inhibitors and multifunctional anti-Alzheimer agents.

2-amino-6-ethoxy-4-arylpyridine-3,5-dicarbonitrile Scaffolds as potential acetylcholinesterase and butyrylcholinesterase inhibitors

Inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes are of prime importance for treating Alzheimerʼs disease (AD). Apart from many organic scaffolds, pyridine-based compounds have previously been reported as potential α-glucosidase inhibitors. The current study reports a series of pyridine-based synthetic molecules for their acetylcholinesterase AChE and butyrylcholinesterase BChE inhibitory potential assessed via in vitro, kinetics, and in silico studies. For this purpose, 2-amino-6-ethoxy-4-arylpyridine-3,5-dicarbonitrile analogs 1–23 were synthesized by using a two-step reaction scheme. In the first step, different aryl aldehydes were treated with malononitrile to afford the 2-benzylidenemalononitrile in the presence of catalyst ammonium acetate. In the next step, 2-benzylidenemalononitrile intermediates were reacted again with malononitrile, catalyzed by potassium hydroxide, to synthesize a range of functionalized pyridine scaffolds in good yields. Compounds were subjected to in vitro screening against AChE and BChE enzymes. Several derivatives, including 2, 3, 11, 14–16, 19, 20, and 22, showed many folds of increased inhibitory potential and binding affinity in the ranges of Ki = 1.62 ± 0.13 nM to 15.84 ± 0.10 nM for AChE and Ki = 1.35 ± 0.31 nM to 13.52 ± 0.61 nM for BChE, as compared to the standard tacrine Ki = 53.31 ± 11.32 nM for AChE, and Ki = 58.16 ± 7.24 nM for BChE. Further, molecular docking studies deduced key interactions between the ligands (compounds) and the active pocket of enzymes. The current research study has identified several potential AChE and BChE inhibitors that may serve as lead candidates after targeted advanced research for exploring anti-Alzheimer agents.

Synthesis and biological evaluation of novel aminoquinolines with an n-octyl linker: Impact of halogen substituents on C(7) or a terminal amino group on anticholinesterase and BACE1 activity

Alzheimer’s disease is age-related multifactorial neurodegenerative disease manifested by gradual loss of memory, cognitive decline and changes in personality. Due to rapid and continuous growth of its prevalence, the treatment of Alzheimer’s disease calls for development of new and efficacies drugs, especially those that could be able to simultaneously act on more than one of possible targets of action. Aminoquinolines have proven to be a highly promising structural scaffold in the design of such a drug as cholinesterases and β-secretase 1 inhibitors. In this study, we synthesised twenty-two new 4-aminoquinolines with different halogen atom and its position in the terminal N-benzyl group or with a trifluoromethyl or a chlorine as C(7)-substituents on the quinoline moiety. All compounds were evaluated as multi-target-directedligands by determining their inhibition potency towards human acetylcholinesterase, butyrylcholinesterase and β-secretase 1. All of the tested derivatives were very potent inhibitors of human acetylcholinesterase and butyrylcholinesterase with inhibition constants (Ki) in the nM to low μM range. Most were estimated to be able to cross the blood–brain barrier by passive transport and were nontoxic toward cells that represented the main models of individual organs.

Sturgeon (Acipenser schrenckii) spinal cord peptides: Antioxidative and acetylcholinesterase inhibitory efficacy and mechanisms

Providing antioxidants and targeting acetylcholinesterase (AChE) are key strategies in treating neurocognitive dysfunction. In this study, bioactive sturgeon (Acipenser schrenckii) spinal cord peptides (SSCPs) with antioxidant and AChE inhibitory potency were extracted and separated from sturgeon spinal cord by enzymatic hydrolysis and ultrafiltration, and targeted peptide PGGW was screened via computer simulated molecular docking. Further, the molecular dynamic interactions of the PGGW with superoxide dismutase (SOD) and AChE were analyzed, and the protective effect of PGGW on glutamate-induced PC12 cells in vitro was evaluated. The <3 kDa fraction of SSCPs displays the most potent antioxidative efficacy (1 mg/mL, DPPH•: 89.07%, ABTS+: 76.35%). Molecular dynamics simulation showed that PGGW was stable within AChE and tightly bound to residues SER203, PHE295, ILE294 and TRP236. When combined with SOD, the indole group of PGGW was stuck inside SOD, but the tail chain PGG fluctuated greatly outside. Surface plasmon resonance demonstrated that PGGW has a high binding affinity for AChE (KD = 1.4 mM) and 0.01 mg/mL PGGW provided good protection against glutamate-induced apoptosis. The findings suggest a promising strategy for drug research on neurodegenerative diseases.

Atomistic Origins of Resurrection of Aged Acetylcholinesterase by Quinone Methide Precursors.

Nerve agents are organophosphates (OPs) that act as potent inhibitors of acetylcholinesterase (AChE), the enzyme responsible for the hydrolysis of acetylcholine. After inhibition, a dealkylation reaction of the phosphorylated serine, known as the aging of AChE, can occur. When aged, reactivators of OP-inhibited AChE are no longer effective. Therefore, the realkylation of aged AChE may offer a pathway to reverse AChE aging. In this study, molecular modeling was conducted to propose new ligands as realkylators of aged AChE. We applied a methodology involving docking and quantum mechanics/molecular mechanics (QM/MM) calculations to evaluate the resurrection kinetic constants and ligand interactions with OP-aged AChE, comparing them to data found in the literature. The results obtained confirm that this method is suitable for predicting kinetic and thermodynamic parameters of ligands, which can be useful in the design and selection of new and more effective ligands for AChE realkylation.

Lead Identification Through In Silico Studies: Targeting Acetylcholinesterase Enzyme Against Alzheimer's Disease.

In this work, we aimed to acquire the best potential small molecule for Alzheimer's disease (AD) treatment using different models in Biovia Discovery Studio to identify new potential inhibitors of acetylcholinesterase (AChE) via in silico studies. The prevalence of cognitive impairment-related neurodegenerative disorders, such as AD, has been observed to escalate rapidly. However, we still know little about the underlying functions, outcome predictors, or intervention targets causing AD. The objective of the study was to optimize and identify the lead compound to target AChE against Alzheimer's disease. Different in silico studies were employed, including the pharmacophore model, virtual screening, molecular docking, de novo evolution model, and molecular dynamics. The pharmacophoric features of AChE inhibitors were determined by ligand-based pharmacophore models and 3D QSAR pharmacophore generation. Further validation of the best pharmacophore model was done using the cost analysis method, Fischer's randomization method, and test set. The molecules that harmonized the best pharmacophore model with the estimated activity < 1 nM and ADMET parameters were filtered, and 12 molecules were subjected to molecular docking studies to obtain binding energy. 3vsp_EK8_1 secured the highest binding energy of 65.60 kcal/mol. Further optimization led to a 3v_Evo_4 molecule with a better binding energy of 70.17 kcal/mol. The molecule 3v_evo_4 was subjected to 100 ns molecular simulation compared to donepezil, which showed better stability at the binding site. A lead compound, 3v_Evo_4 molecule, was identified to inhibit AChE, and it could be further studied to develop as a drug with better efficacy than the existing available drugs for treating AD.

Design, Synthesis, and Evaluation of New Pyrazolines As Small Molecule Inhibitors of Acetylcholinesterase.

In pursuit of identifying small molecule inhibitors of acetylcholinesterase (AChE), the synthesis of new 2-pyrazolines was performed efficiently. A modified spectrophotometric method was used to examine their inhibitory effects on AChE as well as butyrylcholinesterase. Four compounds (2a, 2g, 2j, and 2l) were identified as selective AChE inhibitors. Molecular docking studies were conducted to explore their potential interactions with the active site of AChE (PDB code: 4EY7). 1-(3-Nitrophenyl)-3-(thiophen-3-yl)-5-[4-(4-morpholinyl)phenyl]-2-pyrazoline (2l) exerted significant AChE inhibitory action with an IC50 value of 0.040 μM close to donepezil (IC50 = 0.021 μM). In addition to π-π interactions with Tyr341, Tyr124, and Trp86 residues, compound 2l was also capable of forming two hydrogen bonds and a salt bridge at the active site of AChE thanks to its nitro group at the meta position of the phenyl moiety linked to the N 1 position of the pyrazoline scaffold. The higher inhibitory effect of compound 2l on AChE when compared to other compounds in this series might be explained by these additional interactions. Based on the in vitro parallel artificial membrane permeability assay, compound 2l was found to have high blood-brain barrier permeability. In vitro and in silico studies suggest that compound 2l is a potent inhibitor of AChE, which is an important target for neurodegenerative disorders, particularly Alzheimer's disease.

Phytochemical profile and pharmacological potential of Withania somnifera whole plant extracts.

Withania somnifera belongs to the family Solanaceae, commonly called ashwagandha, and is traditionally used as an astringent, hepatoprotective and antioxidant, and as a treatment for rheumatism. Therefore the current study aimed to explore the dichloromethane fraction of W. somnifera whole plant (DCFWS) and ethyl acetate fraction of W. somnifera (EAFWS) using gas chromatoghraphy-mass spectrometry (GC-MS) analysis and to find the acetylcholinesterase inhibition potential along with spasmolytic activity. The GC-MS-detected phytochemicals were 2,4-bis(1,1-dimethylethyl), hexadecanoic acid, 1-nonadecene and 11-octadecenoic acid. The DCFWS and EAFWS exhibited acetylcholinesterase inhibitory potential with significant inhibitory concentration values. The acute toxicity results of both fractions showed high toxicity, causing emesis at 0.5g and both emesis and diarrhea at 1g/kg. Both fractions exhibited significant (p ≤ 0.01) laxative activity against metronidazole (7mg/kg) and loperamide hydrochloride (4mg/kg) induced constipation. Both DCFWS (66.8 ± 3.85%) and EAFWS (58.58 ± 3.28%) significantly (p ≤ 0.05) increased charcoal movement compared with distal water (43.93 ± 4.34%). Similarly the effect of DCFWS on KCl-induced (80 mm) contraction was more significant as compared with EAFWS. It was concluded that the plant can be used in the treatment of gastrointestinal tract diseases such as constipation. Furthermore, additional work is required in the future to determine the bioactive compounds that act as therapeutic agents in W. somnifera.

Barbiturate-sulfonate hybrids as potent cholinesterase inhibitors: design, synthesis and molecular modeling studies.

Aim: Design and synthesis of a series of 5-benzylidene(thio)barbiturates 3a-r.Methodology: Evaluation of the inhibitory activity of the new chemical entities on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) using Donepezil as the standard reference.Results & Conclusion: Compound 3r emerged as the most potent AChE inhibitor (IC50=9.12μM), while compound 3q exhibited the highest inhibitory activity against BChE (IC50=19.43μM). Toxicological bioassays confirmed the absence of cytotoxicity for the most potent compounds at the tested doses. Molecular docking analysis demonstrated that the tested derivatives effectively bind to the active sites of both enzymes. Overall, this study sheds light on the potential of barbiturate-sulfonate conjugates as promising drug candidates.

In silico molecular modeling and invitro biological screening of novel benzimidazole-based piperazine derivatives as potential acetylcholinesterase and butyrylcholinesterase inhibitors.

New series of benzimidazole incorporating piperazine moieties in single molecular framework has been reported. The structures of the synthesized derivatives were assigned by 1H-NMR, 13C-NMR, and HR-MS techniques. The hybrid derivatives were evaluated for their acetylcholinesterase and butyrylcholinesterase inhibition effect. All the synthesized analogs showed good to moderate inhibitory effect ranging from IC50 value 0.20±0.01 µM to 0.50±0.10 µM for acetylcholinesterase and from IC50 value 0.25±0.01 µM to0.70±0.10 µM for butyrylcholinesterase except one thatshowed least potency with IC50 value 1.05±0.1 µM and 1.20±0.1 µM. The differences in inhibitory potential of synthesized compounds were due to the nature and position of substitution attached to the main ring. Additionally, molecular docking study was carried out for most active inorder to explore the binding interactions established byligand (active compounds) with the active residues of targeted AChE & BuChE enzyme.

Design, Green Synthesis and in silico Studies of New Substituted Naphtho[1,2-e][1,3]Oxazines as Potential Acetylcholinesterase Inhibitors.

Alzheimer's disease (AD) is a prevalent neurodegenerative condition characterized by progressive cognitive decline and memory impairment resulting from the degeneration and death of brain neurons. Acetylcholinesterase (AChE) inhibitors as the primary pharmacotherapy for numerous neurodegenerative conditions, leveraging their capacity to modulate acetylcholine levels crucial for cognitive function. Recently, oxazine and its derivatives have brought worthy synthetic interest due to their extensive biological activities including, anti-acetylcholinesterase, anti-oxidant, anti-pyretic, anti-tubercular, anti-convulsant, anti-microbial, anti-malarial, and anti-cancer activities. In this study, a series of novel naphtho[1,2-e][1,3]oxazine derivatives has been designed and synthesized with potential of acetylcholinesterase (AChE) inhibition. The target products have been prepared by a one-pot and three-component condensation reaction of 2-naphthol, various aromatic aldehydes, and arylmethanimine in the presence of 3-methyl-1-sulfonic acid imidazolium chloride ([Msim]Cl) as an effective and recyclable ionic liquid catalyst under microwave irradiation solvent-free condition. The chemical structures of all resulting products were confirmed by spectroscopic methods (IR, 1H-NMR, 13C NMR) as well as elemental analysis. The molecular docking studies has also been performed to investigate the synthetic compounds in the the AChE active site gorge. The results showed that all these derivatives interact with the enzymes with high affinity in binding pocket. The MM-GBSA studies were performed for all synthesized derivatives and among them, compound 3-(4-Chlorophenyl)-1-phenyl-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazine 5f, showed the lowest the binding free energy (-48.04 kcal mol-1). In general, oxazine derivatives could be proposed as the strong AChE inhibitors.

Exploring new 5-Nitroimidazole Derivatives as Potent Acetylcholinesterase and Butyrylcholinesterase Enzyme Inhibitors.

Discovering new compounds capable of inhibiting physiologically and metabolically significant drug targets or enzymes is of paramount importance in biological chemistry. With this aim, new 5-nitroimidazole derivatives (1-4) were designed and synthesized, and their inhibitory activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) were discovered using acetyl (butyryl) thiocholine and Ellman's reagents for spectrophotometric assay. The inhibitory profiles of the synthesized compounds were assessed by comparing their IC50 and Ki values. Results demonstrate significant inhibitory activity of all synthesized compounds against both AChE and BuChE compared to the reference compound, donepezil. Notably, compound 4 exhibited dual inhibition of these enzymes, showing the highest activity against Electrophorus electricus AChE (EeAChE) with a Ki value of 0.024±0.009 nM and against equine BuChE (eqBuChE) with a Ki value of 0.087±0.017 nM. Furthermore, molecular modeling was conducted to study the interaction modes of the most potent compound (4) and donepezil in the active site of their related enzymes' crystal structures (PDB ID: 4EY7 and 4BDS, respectively). Additionally, drug-likeness, ADME, and toxicity profiles of the compounds and metronidazole were predicted. The above results indicated that the dual inhibition of these enzymes is considered as a promising strategy for the treatment of neurological disorder especially Alzheimer's disease.