A novel series of seventeen carbazole-acrylamide-pyridinium-N-phenylacetamide hybrids (12a-q) was designed and synthesized as dual inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) for potential Alzheimer's disease therapy. Their inhibitory activity was evaluated against both enzymes using tacrine and galantamine as reference standards. Tacrine exhibited IC50 values of 58.34 nM against AChE and 160.50 nM against BChE, while galantamine showed 124.72 nM and 216.23 nM, respectively. The synthesized derivatives demonstrated IC50 values ranging from 6.41 to 74.93 nM against AChE and from 38.05 to 191.96 nM against BChE. All compounds were more potent than galantamine, and most outperformed tacrine as well. Compound 12i was the most potent AChE inhibitor (IC50 = 6.41 nM), showing 9.1-fold and 19.5-fold higher potency than tacrine and galantamine, respectively. Compound 12g was the strongest BChE inhibitor (IC50 = 38.05 nM), with 4.2-fold and 5.7-fold higher activity than tacrine and galantamine. Kinetic analysis revealed that all of the most potent compounds act as competitive inhibitors. Cytotoxicity evaluation revealed that compounds 12i and 12g exhibited lower toxicity toward HEK293 cells than sorafenib, with favorable selectivity toward SH-SY5Y cells. These results establish the carbazole-acrylamide-pyridinium scaffold as a promising lead for developing safer cholinesterase inhibitors for Alzheimer's disease.

Alzheimer's disease (AD) is a progressive and multifactorial neurodegenerative disorder characterized by cholinergic dysfunction, amyloid-β (Aβ) aggregation, tau hyperphosphorylation, oxidative stress, mitochondrial impairment, metal dyshomeostasis, and chronic neuroinflammation, collectively leading to irreversible cognitive decline and neuronal degeneration. Despite decades of intensive research, currently approved therapeutic agents, including cholinesterase inhibitors (ChEI) and NMDA receptor antagonists, provide only symptomatic relief and do not substantially alter disease progression. Among the clinically available ChEI, rivastigmine (RIV) has attracted considerable attention owing to its dual inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), pseudo-irreversible mode of action, and established clinical efficacy in AD management. In recent years, RIV has emerged as a highly promising pharmacophoric scaffold for the development of multifunctional hybrid molecules designed according to the multi-target-directed ligand (MTDL) strategy to modulate multiple pathological pathways involved in AD simultaneously. This review comprehensively summarizes and critically analyzes advances reported from 2020 to 2026 in the design, synthesis, biological evaluation, and therapeutic potential of RIV-based hybrid molecules and scaffold modifications for AD treatment. The review places particular emphasis on the rational hybridization of RIV with diverse bioactive pharmacophores, including tryptamine, coumarin, flavonoids, melatonin, tacrine, ferulic acid, cannabidiol, benzimidazole, piperidine, aryloxacetic acid, and antioxidant motifs, to generate multifunctional agents with enhanced pharmacological profiles. The reviewed hybrids demonstrated remarkable multifunctional properties, including potent inhibition of AChE and BChE, suppression of Aβ aggregation, antioxidant and metal-chelating activities, anti-inflammatory effects, modulation of monoamine oxidases, neuroprotection, mitochondrial stabilization, and improved blood-brain barrier permeability. Several derivatives exhibited significantly greater potency and broader neuroprotective profiles than RIV itself, highlighting the therapeutic value of molecular hybridization approaches in AD drug discovery.

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder characterized by cholinergic dysfunction and oxidative stress, making the development of multi-target-directed ligands (MTDLs) an attractive therapeutic strategy. Herein, we designed and synthesized a novel series of pyrimidinone-based acyl hydrazones 6a-g bearing substituted aryl or heteroaryl (furan) moieties. The synthesized compounds were evaluated for their in vitro acetylcholinesterase (AChE) inhibitory and antioxidant activities. The synthesized pyrimidinone-based acyl hydrazones (6a-g) exhibited promising acetylcholinesterase (AChE) inhibitory activity. Compound 6 g emerged as the most potent inhibitor, with an IC50 value of 4.79 μM, corresponding to approximately 55.7-fold greater potency than tacrine hydrochloride (IC50 = 266 μM) under standardized parallel assay conditions. Compounds 6a, 6b, and 6f also demonstrated potent AChE inhibition, with IC50 values ranging from 15.9 to 128.65 μM, whereas the remaining derivatives exhibited moderate to weak inhibitory activity. The synthesized compounds also displayed promising antioxidant activity in DPPH and nitric oxide (NO) radical scavenging assays. Notably, 6g exhibit potent DPPH and nitric oxide radical scavenging activity, surpassing standard antioxidant (ascorbic acid) by approximately 35-fold and 9-fold, respectively. Molecular docking studies supported the experimental results by revealing favorable binding modes of the most active compounds within the AChE active site, while suggesting potential computationally predicted interactions with BuChE, 5-LOX, and COX-2. Furthermore, in silico drug-likeness and ADME analyses provided baseline pharmacokinetic profiles, guiding rational structural optimization strategies to enhance blood-brain barrier permeability. These findings identify pyrimidinone-based acyl hydrazones as promising multifunctional lead compounds for the development of novel therapeutic agents against Alzheimer's neurocognitive disorder.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline, memory impairment, and neuronal loss, primarily associated with β-amyloid plaque deposition, tau hyperphosphorylation, and cholinergic dysfunction. Since the disruption of cholinergic neurotransmission is a key pathological feature of AD, the cholinesterase (ChE) inhibitors targeting acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) remain the mainstay of symptomatic treatment by enhancing synaptic acetylcholine levels. However, the currently approved small molecules, including tacrine, donepezil, rivastigmine, and galantamine, are limited by their modest efficacy, poor selectivity, and adverse effects, necessitating the development of improved therapeutic agents. Among emerging scaffolds, isatin (1H-indole-2,3-dione) has attracted considerable research attention owing to its structural versatility, synthetic accessibility, and favorable pharmacological properties. Recent studies have reported diverse isatin-based derivatives, including hydrazones, Schiff bases, thiosemicarbazones, spirooxindoles, and molecular hybrids, exhibiting potent AChE and BChE inhibitory activities, often in the submicromolar or nanomolar ranges. Structure-activity relationship studies have revealed the critical influence of electronic effects, linker optimization, N-substitution, and molecular hybridization on inhibitory potency and selectivity. This review summarizes the most promising isatin-based cholinesterase inhibitors reported from 2020 to the present, highlighting their biological activities, structure-activity relationships, and potential for the development of next-generation anti-Alzheimer therapeutics.

Liver fibrosis is a significant public health issue that necessitates an ongoing urge for efficient novel treatments. Our newly synthesized fused azine derivative compounds (1a, 1b, 2a, and 2b) were used in this study based on our promising results achieved by our team in previous studies on tacrine derivatives. This study investigated these compounds' hepatoprotective effect on mice with paracetamol (APAP) induced liver fibrosis and clarified their possible mechanisms. The administration of these compounds successfully reduced APAP-induced hepatic fibrosis through decreasing serum liver enzymes, as well as the hepatic pathological deterioration. Moreover, they increased hepatic antioxidants and countered oxidative stress caused by APAP. Furthermore, by lowering inflammatory cytokine levels and raising anti-inflammatory marker levels, these compounds effectively ameliorated the inflammatory response. Additionally, they decreased APAP induced levels of apoptosis-signal-regulating kinase-1 (ASK-1) and c-Jun-N-terminal kinase (JNK1). Additionally, they reduced caspase-3 and BCL2-associated X-protein (Bax) levels and promoted Nrf2 signaling pathway activation. Notably, the in-silico computer-assisted simulation docking results were consistent with the experimental measurements.

Alzheimer's disease (AD) is a progressive neurodegenerative disease, and cholinergic dysfunction is considered one of the fundamental pathological factors of this disease. Guided by the clinically used acetylcholinesterase (AChE) inhibitor donepezil, we explored trimetazidine dihydrochloride as an accessible starting scaffold to generate donepezil-like features and to develop new anti-AD candidates. Accordingly, 20 novel hydrazone derivatives were designed and synthesized based on trimetazidine dihydrochloride, and their structures were confirmed by spectroscopic methods. The compounds were evaluated for in vitro inhibition of AChE and butyrylcholinesterase (BChE) using donepezil and tacrine as reference inhibitors, respectively. Several derivatives displayed pronounced AChE inhibition, whereas most compounds showed weak or negligible activity toward BChE, indicating a generally favorable AChE-selective profile. Among the series, compounds 3p, 3q and 3r exhibited selective inhibitory activity against AChE comparable to donepezil, with IC50 values of 0.030 ± 0.001 μM, 0.085 ± 0.003 μM and 0.034 ± 0.001 μM, respectively. To rationalize the observed activity trends, molecular docking studies were performed, suggesting that the most active ligands adopt donepezil-like binding modes spanning the catalytic and peripheral anionic sites and are further stabilized by π-π/π-cation contacts and hydrogen-bonding interactions within the active gorge. Overall, these findings identify trimetazidine-derived hydrazide-hydrazones as a promising chemotype for the development of selective AChE inhibitors and provide a basis for further optimization and advanced biological validation.

Insecticides research must explore alternative pathways to identify small compounds that satisfy the needs of farmers in both developing and developed countries. Reducing the cost of these inputs is essential to increasing agricultural production and mitigating food insecurity. In this study, a multi-stage computational screening of 407615 natural products were conducted, utilizing filters for volatility (MW < 350Da), Protein-Ligand Interaction Fingerprint (PLIF) similarity to a tacrine reference, and a commercial cost threshold of less than 8USD/g. Out of 16 finalists evaluated in vitro, two compounds demonstrated significant inhibitory activity against Acetylcholinesterase from Electrophorus electricus (52% and 77% at 250μM, respectively) and Drosophila melanogaster. Kinetic analysis of one novel compound, the most potent lead (Ki=88.1±3.1μM), revealed a mixed-type inhibition mechanism. These results validate the identification of affordable, reversible, and volatile natural scaffolds that serve as promising optimizable fragments for the development of sustainable biopesticides.

In this study, novel pyrrolidine-based compounds bearing indole, chromone, and benzoylthiourea pharmacophores were rationally designed, synthesized, and evaluated as dual inhibitors of carbonic anhydrase I/II (hCA I, hCA II) and acetylcholinesterase (AChE). The target compounds were synthesized via imine azomethine ylide 1,3-dipolar cycloaddition and in selected cases, benzoyl isothiocyanate condensation reactions. Their structures were fully characterized using FTIR, NMR, microanalysis, and single-crystal X-ray diffraction (for 1ba). Compound 2ad (hCA I, Ki = 35.56 ± 5.10 nM, hCA II, Ki = 31.10 ± 4.84 nM) exhibited remarkable inhibitory activity against both hCA I and hCA II, outperforming the reference acetazolamide (AZA) (hCA I, Ki = 303.45 ± 10.21 nM, hCA II, Ki = 240.15 ± 8.65 nM). Compounds 1aa and 2bd demonstrated potent AChE inhibitory activity, displaying approximately 3-fold and 4-fold higher potency than tacrine (TAC), with Ki values of 47.92 ± 8.25 nM, and 35.04 ± 7.69 nM, respectively. An in silico approach, including molecular docking and ADMET analyses, was employed to elucidate the binding interactions and pharmacokinetic profiles of the synthesized compounds. Docking simulations revealed that compound 2ad showed favorable binding affinities toward hCA I and hCA II (-8.24 and -10.09 kcal/mol, respectively), while compounds 2bd and 1aa showed highly favorable binding energies toward AChE (-12.48 and -11.56 kcal/mol, respectively), forming stable interactions comparable to reference inhibitors. Furthermore, ADMET predictions indicated good oral absorption and favorable drug-likeness properties, although optimization may be required to enhance blood-brain barrier (BBB) permeability. The experimental and computational findings support the strong interaction potential of compound 2ad toward hCA II, whereas compounds 2bd and 1aa exhibit high binding affinity toward AChE, in agreement with the experimental inhibition data.

Alzheimer's disease is marked by a gradual decline in cognitive function accompanied by alterations in cholinergic signaling. Cholinergic function can be improved by targeting acetylcholinesterase (AChE). In this work, an in silico approach was applied to study a series of tacrine-based carbamate derivatives. 3D-QSAR models determined by CoMFA and CoMSIA and validated by cross-validation, external testing and Y-randomization were developed using a dataset of 27 compounds. A complementary 2D-QSAR model provided consistent results to support the proposed structure-activity relationships. The statistical parameters (Q [2] > 0.67 and R [2] > 0.93) show the influence of steric and hydrogen bond donor effects on activity. Then, four new derivatives were proposed and tested. The ADMET analysis revealed good pharmacokinetic properties and low predicted toxicity. The DFT calculations characterized the electronic properties of the designed derivatives, and the docking results showed stronger contacts within the active sites of TcAChE (2CKM) and hAChE (4EY7). The selected complexes with both AChE structures were stable in the molecular dynamics simulations for 200 ns. The binding energies and stable conformational behavior of the selected complexes were further confirmed by MM-GBSA, PCA, FEL and DCCM analyses. Overall, the results indicate that the designed derivatives could be promising candidates for AChE inhibition in Alzheimer's disease.

Cholinesterase inhibitors with distinct pharmacological profiles may influence exploratory behavior, yet their effects on recall-related exploration in physiologically intact animals remain insufficiently characterized. The present study aimed to directly compare the effects of donepezil, a relatively selective acetylcholinesterase inhibitor, and tacrine, a cholinesterase inhibitor with broader enzymatic and pharmacological activity, on exploratory allocation during memory recall in healthy rats. Male Wistar rats were assigned to five groups (n = 8/group): control, donepezil 1 mg/kg, donepezil 3 mg/kg, tacrine 3 mg/kg, and tacrine 5 mg/kg. Treatments were administered intraperitoneally 50 min before the acquisition trial, while recall performance was evaluated 24 h later without additional treatment using a two-trial Y-maze paradigm. Time spent and entries into the familiar and novel arms, novel-to-familiar ratios, and mean time per entry were analyzed. Control animals showed no marked preference for the novel arm, whereas donepezil produced only limited, non-significant behavioral changes. Tacrine 5 mg/kg significantly increased the U/K time ratio compared with controls (p = 0.0006) and the U/K entry ratio (p = 0.001), primarily through reduced time spent in the familiar arm (p = 0.0004) and fewer familiar-arm entries (p = 0.025). Absolute time spent in, and entries into, the novel arm did not differ significantly among groups (p = 0.689 and p = 0.883, respectively). Overall, these findings suggest that tacrine, but not donepezil, modified recall-phase exploratory preference in healthy rats, predominantly by reducing persistence in the familiar arm.

Elatostema stewardii is traditionally consumed as both a vegetable and a flavoring agent; however, its phytochemical composition and functional properties remain poorly understood. This study investigated the nutritional profile, metabolite composition, and biological activities of different plant parts using an integrated approach combining untargeted metabolomics based on ultra-performance liquid chromatography-Q Exactive Orbitrap high-resolution mass spectrometry (UPLC-QE-Orbitrap-HRMS), chemometric analysis, and multiple bioassays. On a dry-weight basis, leaves and stems were rich in protein (19.0-21.1 g/100 g), dietary fiber (27.66-28.73 g/100 g), flavonoids (110-630 mg rutin equivalents/100 g), and minerals, particularly calcium in leaves (6580 mg/100 g) and potassium in stems (5460 mg/100 g). Metabolomic profiling annotated 707 metabolites, including fatty acids, flavonoids, and terpenoids. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) clearly discriminated plant parts and identified 58 differential metabolites as potential organ-specific markers. Bioactivity evaluation showed distinct plant-part-dependent effects. The primary root exhibited potent acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition (IC50 = 0.10 and 0.41 μg/mL), comparable to tacrine, along with strong antioxidant capacity comparable to l-ascorbic acid, as evidenced by DPPH (IC50 = 8.02 μg/mL), ABTS (IC50 = 10.30 μg/mL), and FRAP (0.24 μmol Fe[2+]/mL) assays. It also showed higher anti-inflammatory effects, while both primary roots and leaves displayed stronger cytotoxic potential against five human cancer cells. S-plot analysis further revealed 99 biomarkers including known bioactive compounds, such as 18α-glycyrrhetinic acid, catechin and vicenin 2. Collectively, these findings provide scientific evidence supporting the traditional dietary use of E. stewardii and highlight its potential as a promising source of functional food or nutraceutical ingredients.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cholinergic dysfunction, making acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) attractive therapeutic targets. In the present study, twelve novel phenolic Mannich base-derived hydrazones incorporating a diaryl ether scaffold were rationally designed, synthesized, and evaluated as cholinesterase inhibitors. All synthesized compounds exhibited potent nanomolar inhibition against both cholinesterases, with Ki values ranging from 24.27 to 98.56 nM for AChE and 28.68-148.41 nM for BChE. Compound 5 was identified as the most potent AChE inhibitor (Ki = 24.27 nM), whereas compound 6 showed the highest BChE inhibitory activity (Ki = 28.68 nM). Both compounds were considerably more potent than the reference inhibitors tacrine and donepezil. Enzyme kinetic studies revealed that all compounds acted as competitive inhibitors. Cytotoxicity evaluation against SH-SY5Y neuronal cells demonstrated low toxicity, with IC50 values ranging from 33.41 to 46.79 μM, indicating that effective cholinesterase inhibition occurred at concentrations far below those affecting neuronal cell viability. Molecular docking and MD simulations demonstrated stable binding of the most active compounds within the catalytic gorge of both enzymes through persistent hydrogen bonds, cation-π, and π-π interactions with key active-site residues. MM-GBSA and energy decomposition analyses further supported their favorable binding affinities. In addition, the synthesized compounds exhibited acceptable predicted pharmacokinetic properties, including favorable parameters related to blood-brain barrier permeability and oral absorption. These results identify phenolic Mannich base-derived hydrazones as promising lead compounds for the development of new cholinesterase inhibitors for the treatment of Alzheimer's disease.

Alzheimer disease (AD) and Parkinson disease (PD) are multifactorial neurodegenerative disorders for which there is currently no therapy that prevents or slows their progress. Some drugs used to treat AD are inhibitors of acetylcholinesterase (AChE) and antagonists of N-methyl-D-aspartate receptor (NMDAr), while inhibitors of catechol-O-methyltransferase (COMT) and monoamine oxidase B (MAO-B) are used for PD. Tacrine was the first FDA (Food and Drug Administration) approved drug against AD. Although later withdrawn due to hepatotoxicity, it remains a pivotal scaffold for drug development. Herein, 1295 tacrine derivatives, meant to enhance therapeutic efficacy and safety of the parent compound, were designed through the CADMA-Chem protocol. The chemical space was screened using selection scores based on ADME properties, toxicity, and synthetic accessibility. Two derivatives with the best drug-like behavior were chosen for further investigation. Acid-base constants and reactivity descriptors were estimated for them. Our findings show that these derivatives are promising inhibitors of AChE, COMT, NMDAr, and MAO-B. Therefore, according to in silico predictions they are expected to be beneficial for AD and PD. One of the compounds investigated here is the first reported tacrine-derived compound with potential as COMT inhibitor.

Alzheimer's disease (AD) benefits from multitarget-directed ligands (MTDLs) that can enhance cholinergic transmission while attenuating monoamine-oxidase-linked oxidative stress. Here, we report a benzoxazolinone-based propionyl thiosemicarbazide series, synthesized and fully characterized by infrared (IR) spectroscopy, 1H nuclear magnetic resonance (NMR), and high-resolution mass spectra (HRMS). The compounds showed consistent submicromolar inhibitory activity across AChE, BChE, MAO-A, and MAO-B in vitro. Several AChE potencies approached the reference donepezil, and selected BChE activities were within an order of magnitude of tacrine. Notably, 4bk' (5-Me/benzyl) inhibited three targets (IC50: 0.029 ± 0.001 μM for AChE, IC50: 0.071 ± 0.003 μM for BChE, IC50: 0.048 ± 0.002 μM for MAO-B), and 4af' (5-Cl/phenyl) showed a balanced profile (IC50: 0.025 ± 0.001 μM for AChE, IC50: 0.056 ± 0.002 μM for BChE, IC50: 0.095 ± 0.003 μM for MAO-A), 4ac' (5-Cl/propyl) combined potent AChE and MAO-B inhibition (IC50: 0.035 ± 0.001 μM for AChE, IC50: 0.045 ± 0.002 μM for MAO-B), whereas 4ag' (5-Cl/4'-Cl-phenyl) was strongly MAO-B-selective (IC50: 0.041 ± 0.001 μM for MAO-B). Antioxidant capacity was pronounced for para-substituted analogues. The efficient compounds 4bk', 4af', 4ac', and 4ag' presented quite low toxicity on healthy cells (cell survival % was above %70 for 4bk', 4af', and 4ac', while it was around 64% for 4ag') even when they were applied at 100 times higher concentrations than their IC50 values, which indicates that they are safe at effective doses. Moreover, assessment of the compounds at a concentration of 10 μM demonstrated no cytotoxic effects on either healthy BV-2 microglial cells or H9c2 rat myoblastoma cells. Docking and 100 ns molecular dynamics (MD) simulations (AChE: 4EY7; MAO-B: 2V5Z) supported stable binding for dual-active representatives (RMSD ∼1.5-2.8 Å). In silico ADME (QikProp) indicated compliance with Lipinski's Rule of Five and Jorgensen's Rule of Three. Collectively, this scaffold is tunable from MAO-B-selective to balanced MTDL profiles suitable for further AD-relevant optimization.