Diosmetin derivatives as multifunctional anti-AD ligands: Design, synthesis, and biological evaluation.

With the increasing aging population, rational design of drugs for Alzheimer's disease (AD) treatment has become an important research area. Based on the multifunctional design strategy, four diosmetin derivatives (1-4) were designed, synthesized, and characterized by 1H NMR, 13C NMR, and MS. Docking study was firstly applied to substantiate the design strategies and then the biological activities including cholinesterase inhibition, metal chelation, antioxidation and ß-amyloid (Aß) aggregation inhibition in vitro were evaluated. The results showed that 1-4 had good acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibition, metal chelation (selective chelation of Cu2+ ions), antioxidation, self-induced, Cu2+-induced, and AChE-induced Aß aggregation inhibition activities, and suitable blood-brain barrier (BBB) permeability. Especially, compound 3 had the strongest inhibitory effect on AChE (10-8 M magnitude) and BuChE (10-7 M magnitude) and showed the best inhibition on AChE-induced Aß aggregation with 66.14% inhibition ratio. Furthermore, compound 3 could also reduce intracellular reactive oxygen species (ROS) levels in Caenorhabditis elegans and had lower cytotoxicity. In summary, 3 might be considered as a potential multifunctional anti-AD ligand.

Disentangling the formation, mechanism, and evolvement of the covalent methanesulfonyl fluoride acetylcholinesterase adduct: Insights into an aged-like inactive complex susceptible to reactivation by a combination of nucleophiles.

Chemical warfare nerve agents and pesticides, known as organophosphorus compounds inactivate cholinesterases (ChEs) by phosphorylating the serine hydroxyl group located at the active site of ChEs. Over the course of time, phosphorylation is followed by loss of an organophosphate-leaving group and the bond with ChEs becomes irreversible, a process known as aging. Differently, structurally related irreversible catalytic poisons bearing sulfur instead of phosphorus convert ChEs in its aged form only by covalently binding to the key catalytic serine. Kinetic and crystallographic studies of the interaction between Torpedo californica acetylcholinesterase (TcAChE) and a small organosulfonate, methanesulfonyl fluoride (MSF), indeed revealed irreversibly methylsulfonylated serine 200, to be isosteric with the bound aged sarin/soman analogues. The potent bulky reversible inhibitor 7-bis-tacrine (BTA) adopts, in the active site of the crystal structure of the MSF-enzyme adduct, a location and an orientation that closely resemble the one being found in the crystal structure of the BTA-enzyme complex. Remarkably, the presence of BTA accelerates the rate of methanesulfonylation by a factor of two. This unexpected result can be explained on the basis of two facts: i) the steric hindrance exerted by BTA to MSF in accessing the active site and ii) the acceleration of the MSF-enzyme adduct formation as a consequence of the lowering of the rotational and translational degrees of freedom in the proximity of the catalytic serine. It is well known that pralidoxime (2-Pyridine Aldoxime Methyl chloride, 2-PAM) alone or in the presence of the substrate acetylcholine cannot reactivate the active site serine of the TcAChE-MSF adduct. We show that the simultaneous presence of 2-PAM and the additional neutral oxime, 2-[(hydroxyimino)methyl]-l-methylimidazol (2-HAM), triggers the reactivation process of TcAChE within the hour timescale. Overall, our results pave the way toward the likely use of a cocktail of distinctive oximes as a promising recipe for an effective and fast reactivation of aged cholinesterases.

Variability of Isoquinoline Alkaloid Profiles and Anticholinesterase Activities with Binding-Mode Predictions of Glaucium flavum Population.

In this study, phytochemical and biological activity studies supported by docking were carried out on a species of the genus Glaucium, a repository of isoquinoline alkaloids. The GC-MS (Gas Chromatography-Mass Spectrometry) method is used to characterize the isoquinoline alkaloids of Glaucium flavum Crantz. (Papaveraceae). G. flavum was collected from seven different regions of Türkiye (Antalya, Urla-Izmir, Mordogan-Izmir, Mugla, Assos-Canakkale, Karabiga-Canakkale, Giresun) and totally 17 compounds were detected by GC-MS. Glaucine was found to be the major constituent in the sample collected from Mugla, whereas isocorydine was recorded to be the principal alkaloid in other samples. Further fractionation studies on G. flavum collected from Antalya province in Southwestern Türkiye, yielded five major alkaloids (isocorydine 1, dihydrosanguinarine 2, glaucine 3, dehydroglaucine 4, protopine 5) which were characterized by spectroscopic methods. Anticholinesterase activities of the extracts and isolated alkaloids were also tested by in vitro Ellman method. The isolated compounds were also analyzed by a molecular docking technique to determine the binding orientations in the gorge of the active site of acetylcholinesterase (AChE) and a homology model of butyrylcholinesterase (BuChE). This is the first comparative investigation of the phytochemical composition and biodiversity of Glaucium flavum species growing in Türkiye.

Research Progress on Natural Plant Molecules in Regulating the Blood-Brain Barrier in Alzheimer's Disease.

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder. With the aging population and the continuous development of risk factors associated with AD, it will impose a significant burden on individuals, families, and society. Currently, commonly used therapeutic drugs such as Cholinesterase inhibitors, N-methyl-D-aspartate antagonists, and multiple AD pathology removal drugs have been shown to have beneficial effects on certain pathological conditions of AD. However, their clinical efficacy is minimal and they are associated with certain adverse reactions. Furthermore, the underlying pathological mechanism of AD remains unclear, posing a challenge for drug development. In contrast, natural plant molecules, widely available, offer multiple targeting pathways and demonstrate inherent advantages in modifying the typical pathologic features of AD by influencing the blood-brain barrier (BBB). We provide a comprehensive review of recent in vivo and in vitro studies on natural plant molecules that impact the BBB in the treatment of AD. Additionally, we analyze their specific mechanisms to offer novel insights for the development of safe and effective targeted drugs as well as guidance for experimental research and the clinical application of drugs for the prevention and treatment of AD.

Pralidoxime-like reactivator with increased lipophilicity - Molecular modeling and in vitro study.

Acetylcholinesterase (AChE, EC 3.1.1.7) reactivators (2-PAM, trimedoxime, obidoxime, asoxime) have become an integral part of antidotal treatment in cases of nerve agent and organophosphorus (OP) pesticide poisonings. They are often referred to as specific antidotes due to their ability to restore AChE function when it has been covalently inhibited by an OP compound. Currently available commercial reactivators exhibit limited ability to penetrate the blood-brain barrier, where reactivation of inhibited AChE is crucial. Consequently, there have been numerous efforts to discover more brain-penetrating AChE reactivators. In this study, we examined a derivative of 2-PAM designed to possess increased lipophilicity. This enhanced lipophilicity was achieved through the incorporation of a benzyl group into its molecular structure. Initially, a molecular modeling study was conducted, followed by a comparison of its reactivation efficacy with that of 2-PAM against 10 different AChE inhibitors in vitro. Unfortunately, this relatively significant structural modification of 2-PAM resulted in a decrease in its reactivation potency. Consequently, this derivative cannot be considered as a broad-spectrum AChE reactivator.

Discovery of novel multifunctional ligands targeting GABA transporters, butyrylcholinesterase, ß-secretase, and amyloid ß aggregation as potential treatment of Alzheimer's disease.

Alzheimer's disease (AD) is a global health problem in the medical sector that will increase over time. The limited treatment of AD leads to the search for a new clinical candidate. Considering the multifactorial nature of AD, a strategy targeting number of regulatory proteins involved in the development of the disease is an effective approach. Here, we present a discovery of new multi-target-directed ligands (MTDLs), purposely designed as GABA transporter (GAT) inhibitors, that successfully provide the inhibitory activity against butyrylcholinesterase (BuChE), ß-secretase (BACE1), amyloid ß aggregation and calcium channel blockade activity. The selected GAT inhibitors, 19c and 22a - N-benzylamide derivatives of 4-aminobutyric acid, displayed the most prominent multifunctional profile. Compound 19c (mGAT1 IC50 = 10 µM, mGAT4 IC50 = 12 µM and BuChE IC50 = 559 nM) possessed the highest hBACE1 and Aß40 aggregation inhibitory activity (IC50 = 1.57 µM and 99 % at 10 µM, respectively). Additionally, it showed a decrease in both the elongation and nucleation constants of the amyloid aggregation process. In contrast compound 22a represented the highest activity and a mixed-type of eqBuChE inhibition (IC50 = 173 nM) with hBACE1 (IC50 = 9.42 µM), Aß aggregation (79 % at 10 µM) and mGATs (mGAT1 IC50 = 30 µM, mGAT4 IC50 = 25 µM) inhibitory activity. Performed molecular docking studies described the mode of interactions with GATs and enzymatic targets. In ADMET in vitro studies both compounds showed acceptable metabolic stability and low neurotoxicity. Successfully, compounds 19c and 22a at the dose of 30 mg/kg possessed statistically significant antiamnesic properties in a mouse model of amnesia caused by scopolamine and assessed in the novel object recognition (NOR) task or the passive avoidance (PA) task.

Discovery of blood-brain barrier permeable and orally bioavailable caffeine-based amide derivatives as acetylcholinesterase inhibitors.

Caffeine is one of the privileged natural products that shows numerous effects on the central nervous system. Herein, thirty-one caffeine-based amide derivatives were synthesized and evaluated in vitro for their anticholinesterase activity. The introduction of the amide group to the caffeine core augmented its anticholinesterase activity from an IC50 value of 128 to 1.32 µM (derivative, 6i). The SAR study revealed that N7 substitution on caffeine core is favorable over N1, and the presence of amide 'carbonyl' as a part of the linker contributes to the biological activity. The caffeine core of 6i exhibits interactions with the peripheral anionic site, whereas the N-benzyl ring fits nicely inside the catalytic anionic site. Analog 6i inhibits AChE in a mixed-type mode (Ki 4.58 µM) and crosses the BBB in an in-vitro PAMPA assay. Compound 6i has a descent metabolic stability in MLM (>70% remaining after 30 min) and favorable oral pharmacokinetics in Swiss albino mice.

Significance of Astragaloside IV from the Roots of Astragalus mongholicus as an Acetylcholinesterase Inhibitor-From the Computational and Biomimetic Analyses to the In Vitro and In Vivo Studies of Safety.

The main aim of the study was to assess the acetylcholinesterase-inhibitory potential of triterpenoid saponins (astragalosides) found in the roots of Astragalus mongholicus. For this purpose, the TLC bioautography method was applied and then the IC50 values were calculated for astragalosides II, III and IV (5.9 µM; 4.2 µM, and 4.0 µM, respectively). Moreover, molecular dynamics simulations were carried outto assess the affinity of the tested compounds for POPC and POPG-containing lipid bilayers, which in this case are the models of the blood-brain barrier (BBB). All determined free energy profiles confirmed that astragalosides exhibit great affinity for the lipid bilayer. A good correlation was obtained when comparing the logarithm of n-octanol/water partition coefficient (logPow) lipophilicity descriptor values with the smallest values of free energy of the determined 1D profiles. The affinity for the lipid bilayers changes in the same order as the corresponding logPow values, i.e.,: I > II > III~IV. All compounds exhibit a high and also relatively similar magnitude of binding energies, varying from ca. -55 to -51 kJ/mol. Apositive correlation between the experimentally-determined IC50 values and the theoretically-predicted binding energies expressed by the correlation coefficient value equal 0.956 was observed.

Inhibition of microtubule affinity regulating kinase 4 by an acetylcholinesterase inhibitor, Huperzine A: Computational and experimental approaches.

Microtubule affinity regulating kinase 4 (MARK4), 752 amino acids long, belonging to the AMPK superfamily, plays a vital role in regulating microtubules due to its potential to phosphorylate microtubule-associated proteins (MAP's) and thus, MARK4 plays a key role in Alzheimer's disease (AD) pathology. MARK4 is a druggable target for cancer, neurodegenerative diseases, and metabolic disorders. In this study, we have evaluated the MARK4 inhibitory potential of Huperzine A (HpA), an acetylcholinesterase inhibitor (AChEI), a potential AD drug. Molecular docking revealed the key residues governing the MARK4-HpA complex formation. The structural stability and conformational dynamics of the MARK4-HpA complex was assessed by employing Molecular dynamics (MD) simulation. The results suggested that the binding of HpA with MARK4 leads to minimal structural alterations in the native conformation of MARK4, implying the stability of the MARK4-HpA complex. Isothermal titration calorimetry (ITC) studies deciphered that HpA binds to MARK4 spontaneously. Moreover, the kinase assay depicted significant inhibition of MARK by HpA (IC50 = 4.91 µM), implying it to be a potent MARK4 inhibitor that can be implicated in the treatment of MARK4-directed diseases.

Preclinical and randomized clinical evaluation of the p38α kinase inhibitor neflamapimod for basal forebrain cholinergic degeneration.

The endosome-associated GTPase Rab5 is a central player in the molecular mechanisms leading to degeneration of basal forebrain cholinergic neurons (BFCN), a long-standing target for drug development. As p38α is a Rab5 activator, we hypothesized that inhibition of this kinase holds potential as an approach to treat diseases associated with BFCN loss. Herein, we report that neflamapimod (oral small molecule p38α inhibitor) reduces Rab5 activity, reverses endosomal pathology, and restores the numbers and morphology of BFCNs in a mouse model that develops BFCN degeneration. We also report on the results of an exploratory (hypothesis-generating) phase 2a randomized double-blind 16-week placebo-controlled clinical trial (Clinical trial registration: NCT04001517/EudraCT #2019-001566-15) of neflamapimod in mild-to-moderate dementia with Lewy bodies (DLB), a disease in which BFCN degeneration is an important driver of disease expression. A total of 91 participants, all receiving background cholinesterase inhibitor therapy, were randomized 1:1 between neflamapimod 40 mg or matching placebo capsules (taken orally twice-daily if weight <80 kg or thrice-daily if weight >80 kg). Neflamapimod does not show an effect in the clinical study on the primary endpoint, a cognitive-test battery. On two secondary endpoints, a measure of functional mobility and a dementia rating-scale, improvements were seen that are consistent with an effect on BFCN function. Neflamapimod treatment is well-tolerated with no study drug associated treatment discontinuations. The combined preclinical and clinical observations inform on the validity of the Rab5-based pathogenic model of cholinergic degeneration and provide a foundation for confirmatory (hypothesis-testing) clinical evaluation of neflamapimod in DLB.

Development and structure-activity relationship of tacrine derivatives as highly potent CDK2/9 inhibitors for the treatment of cancer.

CDK2/9 are members of the CDKs family, which play key roles in the occurrence and development of many cancers by regulating cell cycle and transcriptional prolongation, respectively. To further optimize and discuss the structure-activity relationships (SARs), a series of tacrine-based compounds were designed and synthesized from the compound ZLWT-37, which was studied by our group previously but no detailed SARs study was conducted on CDK2/9. Among this series, compounds ZLMT-12 (35) exhibited the most potent antiproliferative activity (GI50 = 0.006 µM for HCT116) and superior CDK2/9 inhibitory properties (CDK2: IC50 = 0.011 µM, CDK9: IC50 = 0.002 µM). Meanwhile, ZLMT-12 showed a weak inhibitory effect on acetylcholinesterase (AChE, IC50 = 19.023 µM) and butyrylcholinesterase (BuChE, IC50 = 2.768 µM). In addition, ZLMT-12 can suppress colony formation and migration in HCT116 cells, as well as induce the apoptosis and arrest the cell cycle in the S phase and G2/M phase. In vivo investigations revealed that ZLMT-12 inhibits tumor growth in the HCT116 xenograft tumor model at a low dose of 10 mg/kg without causing hepatotoxicity. The acute toxicity test showed low toxicity with a median lethal dosage (LD50) of 104.417 mg/kg. These findings showed that ZLMT-12 might be used as a drug candidate by targeting CDK2/9.

Anti-Alzheimer's disease potential of traditional chinese medicinal herbs as inhibitors of BACE1 and AChE enzymes.

Alzheimer's disease (AD) is a common neurodegenerative disease that often occurs in the elderly population. At present, most drugs for AD on the market are single-target drugs, which have achieved certain success in the treatment of AD. However, the efficacy and safety of single-target drugs have not achieved the expected results because AD is a multifactorial disease. Multi-targeted drugs act on multiple factors of the disease network to improve efficacy and reduce adverse reactions. Therefore, the search for effective dual-target or even multi-target drugs has become a new research trend. Many of results found that the dual-target inhibitors of the beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) and acetylcholinesterase (AChE) found from traditional Chinese medicine have a good inhibitory effect on AD with fewer side effects. This article reviews sixty-six compounds extracted from Chinese medicinal herbs, which have inhibitory activity on BACE1 and AChE. This provides a theoretical basis for the further development of these compounds as dual-target inhibitors for the treatment of AD.

Emetine and Indirubin- 3- monoxime interaction with human brain acetylcholinesterase: A computational and statistical analysis.

Alzheimer's disease is a chronic neurodegenerative ailment and the most familiar type of dementia in the older population with no effective cure to date. It is characterized by a decrease in memory, associated with the mutilation of cholinergic neurotransmission. Presently, acetylcholinesterase inhibitors have emerged as the most endorsed pharmacological medications for the symptomatic treatment of mild to moderate Alzheimer's disease. This study aimed to research the molecular enzymatic inhibition of human brain acetylcholinesterase by a natural compound emetine and I3M. Molecular docking studies were used to identify superior interaction between enzyme acetylcholinesterase and ligands. Furthermore, the docked acetylcholinesterase-emetine complex was validated statistically using an analysis of variance in all tested conformers. In this interaction, H-bond, hydrophobic interaction, pi-pi, and Cation-pi interactions played a vital function in predicting the accurate conformation of the ligand that binds with the active site of acetylcholinesterase. The conformer with the lowest free energy of binding was further analyzed. The binding energy for acetylcholinesterase complex with emetine and I3M was -9.72kcal/mol and -7.09kcal/mol, respectively. In the current study, the prediction was studied to establish a relationship between binding energy and intermolecular energy (coefficient of determination [R2 linear = 0.999), and intermolecular energy and Van der wall forces (R2 linear = 0.994). These results would be useful in gaining structural insight for designing novel lead compounds against acetylcholinesterase for the effective management of Alzheimer's disease.

Toxicity, pharmacokinetics, and effectiveness of the ortho-chlorinated bispyridinium oxime, K870.

Oxime reactivators are causal antidotes for organophosphate intoxication. Herein, the toxicity, pharmacokinetics, and reactivation effectiveness of o-chlorinated bispyridinium oxime K870 are reported. Oxime K870 was found to have a safe profile at a dose of 30 mg/kg in rats. It exhibited rapid absorption and renal clearance similar to those of other charged oximes after intramuscular administration. Its isoxazole-pyridinium degradation product was identified in vivo. Although it showed some improvement in brain targeting, it was nevertheless rapidly effluxed from the central nervous system. Its reactivation effectiveness was evaluated in rats and mice intoxicated with sarin, tabun, VX, and paraoxon and compared with pralidoxime and asoxime. K870 was found to be less effective in reversing tabun poisoning compared to its parent unchlorinated oxime K203. However, K870 efficiently reactivated blood acetylcholinesterase for all tested organophosphates in rats. In addition, K870 significantly protected against intoxication by all tested organophosphates in mice. For these reasons, oxime K870 seems to have a broader reactivation spectrum against multiple organophosphates. It seems important to properly modulate the oximate forming properties (pKa) to obtain more versatile oxime reactivators.

Suillin: A mixed-type acetylcholinesterase inhibitor from Suillus luteus which is used by Saraguros indigenous, southern Ecuador.

Suillus luteus (L.) Roussel is an edible mushroom commonly known as slippery jack or "Kallampa" by indigenous people from Loja province. It is used in traditional medicine to manage gastrointestinal disorders and headaches. In addition, edible mushrooms have been used for neurodegenerative diseases; however, there is no report about the anticholinesterase effect produced by this species. The aim of this work was to isolate the main secondary metabolite of Suillus luteus and characterize its inhibitory potential against acetylcholinesterase. Fruiting bodies were extracted with ethanol (EtOH) and ethyl acetate (EtOAc). From the EtOAc, suillin, is reported as the major compound. The cholinesterase inhibitory potential of extracts and the major isolated compound was assessed by Ellman´s method and progression curves were recorded at 405 nm for 60 min. Donepezil hydroclhoride was used as a positive control. The samples were dissolved in methanol at 10 mg/mL and two more 10× dilutions were included to obtain final concentrations of 1, 0.1 and 0.01 mg/mL at the mix of reaction. IC50, Km, Vmax, and Ki were calculated for suillin. Suillin (200 mg) along with linoleic acid, ergosterol peroxide and ergosterol were isolated. The EtOH and EtOAc extracts exerted a moderate inhibitory effect (IC50 > 200 µg/mL. In adittion, suillin exerted a non-competitive mixed mechanism. against AChE with an IC50 value of 31.50 µM and Ki of 17.25 µM. To the best of our knowledge, this is the first report of the anticholinesterase effect of Suillus luteus and suillin. The kinetic parameters and the moderate potency of the compound determined in this study, encourage us to propose suillin as a promising chemopreventing agent for the treatment of neurodegenerative diseases such as Alzheimer.

Rapid screening for acetylcholinesterase inhibitors in Selaginella doederleinii Hieron by using functionalized magnetic Fe3O4 nanoparticles.

Insufficient acetylcholine (ACh) can cause cognitive and memory dysfunction, clinically known as, Alzheimer's disease (AD). Acetylcholinesterase (AChE) can hydrolyze ACh into acetic acid and inactivate choline. Therefore, inhibiting the activity of AChE would help to improve the effectiveness of AD treatment. Currently, the methods for rapid screening of AChE inhibitors are limited. This study reports the application of AChE-immobilized magnetic nanoparticles as a drug screening tool to screen AChE inhibitors for natural products. First, AChE was immobilized on a surface of amino-modified magnetic nanoparticles using covalent binding and the AChE concentration, and the pH as well as time was optimized to obtain the maximum enzyme immobilization yield (61.4 µg/mg), and the kinetic model indicated that AChE-immobilized magnetic nanoparticles and the substrate had the high affinity and specificity. Then, a ligand fishing experiment was carried out using a mixed model of tacrine (an inhibitor of AChE) and caffeic acid (a non-inhibitor of AChE) to verify the specificity of the immobilized AChE, and the conditions for ligand fishing were further optimized. Finally, the optimized immobilized AChE was combined with UPLC-MS to screen for AChE inhibitors in Selaginella doederleinii Hieron extracts. Four compounds were confirmed to be potent AChE inhibitors. Among the four compounds, amentoflavone had a stronger AChE inhibitory effect than tacrine (positive control) with an IC50 of 0.73 ± 0.009 µmol/L. The results showed that AChE-functionalized magnetic nanoparticles can be used in the discovery of target drugs from complex matrices.

Photoswitchable Pseudoirreversible Butyrylcholinesterase Inhibitors Allow Optical Control of Inhibition in Vitro and Enable Restoration of Cognition in an Alzheimer's Disease Mouse Model upon Irradiation.

To develop tools to investigate the biological functions of butyrylcholinesterase (BChE) and the mechanisms by which BChE affects Alzheimer's disease (AD), we synthesized several selective, nanomolar active, pseudoirreversible photoswitchable BChE inhibitors. The compounds were able to specifically influence different kinetic parameters of the inhibition process by light. For one compound, a 10-fold difference in the IC50-values (44.6 nM cis, 424 nM trans) in vitro was translated to an "all or nothing" response with complete recovery in a murine cognition-deficit AD model at dosages as low as 0.3 mg/kg.

Identification of sulfonamide based butyrylcholinesterase inhibitors through scaffold hopping approach.

Butyrylcholinesterase (BChE), a hydrolytic enzyme, is responsible for the termination of the action of acetylcholine besides acetylcholinesterase (AChE) in the synaptic cleft of the brain. The alteration in the enzyme level, in patients with the progression of Alzheimer's disease, makes it a therapeutic target. In the present study, we developed BChE inhibitors through scaffold hopping by exploring two previously reported compounds, i.e., 1,4-bis((4-chlorophenyl) sulfonyl)-3,6-diphenylpiperazine-2,5-dione and N-(2-chlorophenyl)-4-(phenylsulfonamido)benzamide, to afford scaffold and pharmacophore fragments, respectively. The N,2-diphenyl-2-(phenylsulfonamido)acetamide derivatives, thus designed, were synthesised and screened for the inhibition of AChE and BChE enzymes. Compounds 30 and 33 were found to be most active against BChE among the derivatives, with IC50 values of 7.331 ± 0.946 and 10.964 ± 0.936 µM, respectively. The compounds displayed a non-competitive mode of inhibition along with BBB permeability and good cell viability on SH-SY5Y cell line. The molecular docking analysis of the compounds with BChE showed interactions with Trp82, Trp231, Leu286, and His438. The molecular dynamics study revealed the stability of the protein-ligand complexes.

A new arylsulfanyl-benzo-2,1,3-thiadiazoles derivative produces an anti-amnesic effect in mice by modulating acetylcholinesterase activity.

The aim of the present study was investigate the binding affinity of 5-((4-methoxyphenyl)thio)benzo[c][1,2,5]thiadiazole (MTDZ) with acetylcholinesterase (AChE). We also evaluated the effect of MTDZ against scopolamine (SCO)-induced amnesia in mice and we looked at the toxicological potential of this compound in mice. The binding affinity of MTDZ with AChE was investigated by molecular docking analyses. For an experimental model, male Swiss mice were treated daily with MTDZ (10 mg/kg, intragastrically (i.g.)) or canola oil (10 ml/kg, i.g.), and induced, 30 min later, with injection of SCO (0.4 mg/kg, intraperitoneally (i.p.)) or saline (0.9%, 5 ml/kg, i.p.) daily. From day 1 to day 10, mice were submitted to the behavioral tasks (Barnes maze, open-field, object recognition and location, Y-maze and step-down inhibitory avoidance tasks), 30 min after induction with SCO. On the tenth day, the animals were euthanized and blood was collected for the analysis of biochemical markers (creatinine, aspartate (AST), and alanine (ALT) aminotransferase). MTDZ interacts with residues of the AChE active site. SCO caused amnesia in mice by changing behavioral tasks. MTDZ treatment attenuated the behavioral changes caused by SCO. In ex vivo assay, MTDZ also protected against the alteration of AChE activity, reactive species (RS) levels, thiobarbituric acid reative species (TBARS) levels, catalase (CAT) activity in tissues, as well as in transaminase activities of plasma caused by SCO in mice. In conclusion, MTDZ presented anti-amnesic action through modulation of the cholinergic system and provided protection from kidney and liver damage caused by SCO.

Cytotoxic activity and influence on acetylcholinesterase of series dinuclear platinum(II) complexes with aromatic nitrogen-containing heterocyclic bridging ligands: Insights in the mechanisms of action.

Herein, the stability, lipophilicity, in vitro cytotoxicity, and influence on acetylcholinesterase of five dinuclear platinum(II) complexes with the general formula [{Pt(en)Cl}2(µ-L)]2+ (L is a different aromatic nitrogen-containing heterocyclic bridging ligands pyrazine (pz, Pt1), pyridazine (pydz, Pt2), quinoxaline (qx, Pt3), phthalazine (phtz, Pt4) and quinazoline (qz, Pt5), while en is bidentate coordinated ethylenediamine) were evaluated. The most active analyzed platinum complexes induced time-dependent growth inhibition of A375, HeLa, PANC-1, and MRC-5 cells. The best efficiency was achieved on HeLa and PANC-1 cells for Pt1, Pt2, and Pt3 at the highest concentration, while Pt1 was significantly more potent than cisplatin at a lower concentration. Additionally, a lower effect on normal cells was observed compared to cisplatin, which may indicate potentially fewer side effects of these complexes. Selected complexes induce reactive oxygen species and apoptosis on tumor cell lines. The most potent reversible acetylcholinesterase (AChE) inhibitors were Pt2, Pt4, and Pt5. Pt1 showed similar inhibitory potential toward AChE as cisplatin, but a different type of inhibition, which could contribute to lower neurotoxicity. Docking studies revealed that Pt2 and Pt4 were bound to the active gorge above the catalytic triad. In contrast, the other complexes were bound to the edge of the active gorge without impeding the approach to the catalytic triad. According to this, Pt1 represents a promising compound with potent anticancer properties, high selectivity, and low neurotoxicity.