Potent Cholinesterase Inhibitor Research Articles

In vitro Cholinesterase Inhibitory Activities of Piper betle Stem and their Correlation with In silico Docking Studies of its Phytoconstituents

Background: Worldwide, millions of people are affected by neurodegenerative diseases. Even though treatment may help to reduce some of the mental or physical symptoms connected with neurodegenerative diseases, there is at present no way to slow disease development and no recognized cure. Objective: The current study was carried out to explore the cholinesterase (ChE) inhibitory properties of the stem of Piper betle and correlate them with in silico docking results of its phytoconstituents. Methods: The dried Piper betle stem was used to be extracted with purified water by using the maceration technique. The resultant was assessed for ChE inhibitory activity using Ellman’s method. The inhibitory profile of the aqueous extract of Piper betle (AEPB) stem was compared with rivastigmine, which is a standard cholinesterase inhibitor. The phytoconstituents of AEPB were procured from various literature studies. In silico docking studies were carried out with the help of AutoDock 4.2 software. Results: AEPB considerably inhibited AChE and BuChE with the inhibition constant values of 0.437 ± 0.62 μg/ml and 0.371 ± 0.62 μg/ml, respectively, in a dose-dependent manner. In computational evaluation, the selected phytoconstituents exhibited excellent binding interactions prevailing with cholinesterase targets than the standard rivastigmine. Conclusion: Based on the in vitro and in silico evaluations, Piperol A showed notable concentrationdependent inhibition of AChE and BuChE. These in vitro analyses and molecular docking studies will be helpful for the development of potent ChE inhibitors for the management of Alzheimer’s disease.

Novel multifunctional tacrine-donepezil hybrids against Alzheimer's disease: Design synthesis and bioactivity studies.

A series of tacrine-donepezil hybrids were synthesized as potential multifunctional anti-Alzheimer's disease (AD) compounds. For this purpose, tacrine and the benzylpiperidine moiety of donepezil were fused with a hydrazone group to achieve a small library of tacrine-donepezil hybrids. In agreement with the design, all compounds showed inhibitory activity toward both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with IC50 values in the low micromolar range. Kinetic studies on the most potent cholinesterase (ChE) inhibitors within the series showed a mixed-type inhibition mechanism on both enzymes. Also, the docking studies indicated that the compounds inhibit ChEs by dual binding site (DBS) interactions. Notably, tacrine-donepezil hybrids also exhibited significant neuroprotection against H2O2-induced cell death in a differentiated human neuroblastoma (SH-SY5Y) cell line at concentrations close to their IC50 values on ChEs and showed high to medium blood-brain barrier (BBB) permeability on human cerebral microvascular endothelial cells (HBEC-5i). Besides, the compounds do not cause remarkable toxicity in a human hepatocellular carcinoma cell line (HepG2) and SH-SY5Y cells. Additionally, the compounds were predicted to also have good bioavailability. Among the tested compounds, H4, H16, H17, and H24 stand out with their biological profile. Taken together, the proposed novel tacrine-donepezil scaffold represents a promising starting point for the development of novel anti-ChE multifunctional agents against AD.

Synthesis, biological activity, X-ray crystallographic, DFT calculations and molecular dynamics simulation studies of 2-phenylthiazole-1,3,5-triazine derivatives as potential cholinesterase inhibitors

Seven 2-phenylthiazole-1,3,5-triazine derivatives were synthesized and estimated for cholinesterase inhibitory activity. All target compounds were characterized by 1H NMR, 13C NMR, FT-IR, and HRMS, and their purity was tested by HPLC to be above 99%. The in vitro enzyme inhibitory activity assays determined that the majority of compounds exhibited moderate to good inhibitory effects on acetylcholinesterase or butyrylcholinesterase and compound 6g displayed the best acetylcholinesterase (IC50 = 0.26 μM) and butyrylcholinesterase inhibitory activity (IC50 = 0.78 μM). The structures of compounds 6a and 6g was further investigated by single-crystal X-ray diffraction, and the Hirshfeld surfaces, crystal voids, and molecular energy framework analysis were further discussed to study the molecular conformations, crystal packing modes, intermolecular interactions, and their energies. What's more, the density functional theory calculations including frontier molecular orbitals, global reactivity descriptors, and molecular electrostatic potential were carried out to reveal the chemical reactivity and stability of 6a and 6g molecules. Molecular docking study indicated that compound 6g could not only interact with acetylcholinesterase but also with butyrylcholinesterase. Molecular dynamics simulations study showed that compound 6g could bind to acetylcholinesterase stably. In addition, ADMET properties prediction implied the drug-like properties and safety of seven compounds. Considering these results, several of the target compounds could work as novel cholinesterase inhibitors, and compound 6g may possess the potential to become a lead compound to develop novel anti-Alzheimer drugs.

Insight into antioxidant-like activity and computational exploration of identified bioactive compounds in Talinum triangulare (Jacq.) aqueous extract as potential cholinesterase inhibitors

BackgroundRecent reports have highlighted the significance of plant bioactive components in drug development targeting neurodegenerative disorders such as Alzheimer’s disease (AD). Thus, the current study assessed antioxidant activity and enzyme inhibitory activity of the aqueous extract of Talinum triangulare leave (AETt) as well as molecular docking/simulation of the identified phytonutrients against human cholinesterase activities.MethodsIn vitro assays were carried out to assess the 2,2- azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) cation radicals and cholinesterase inhibitory activities of AETt using standard protocols. High performance liquid chromatography coupled with diode-array detection (HPLC–DAD) was employed to identify compounds in AETt. Also, for computational analysis, identified bioactive compounds from AETt were docked using Schrodinger's GLIDE against human cholinesterase obtained from the protein data bank (https://www.rcsb.org/).ResultsThe results revealed that AETt exhibited a significant concentration-dependent inhibition against ABTS cation radicals (IC50 = 308.26 ± 4.36 µg/ml) with butylated hydroxytoluene (BHT) as the reference. Similarly, AETt demonstrated a significant inhibition against acetylcholinesterase (AChE, IC50 = 326.49 ± 2.01 µg/ml) and butyrylcholinesterase (BChE, IC50 = 219.86 ± 4.13 µg/ml) activities with galanthamine as the control. Molecular docking and simulation analyses revealed rutin and quercetin as potential hits from AETt, having showed strong binding energies for both the AChE and BChE. In addition, these findings were substantiated by analyses, including radius of gyration, root mean square fluctuation, root mean square deviation, as well as mode similarity and principal component analyses.ConclusionOverall, this study offers valuable insights into the interactions and dynamics of protein–ligand complexes, offering a basis for further drug development targeting these proteins in AD.

Design, synthesis, in-vitro biological profiling and molecular docking of some novel oxazolones and imidazolones exhibiting good inhibitory potential against acetylcholine esterase

Heterocyclic compounds with oxazole and imidazole rings in their structure have disclosed momentous biological aptitudes. Taking into account their superlative attributes, the present study was designed to introduce a new synthetic scheme to make new derivatives with tremendous futuristic pharmacological potentialities. Series of Oxazolones were synthesized by using substituted benzaldehyde with benzyl halides to produce respective benzaldehyde derivatives 1 (a–d) which further reacted with hippuric acid to yield oxazolones 2 (a–e). Newly synthesized oxazolones then reacted with 4-chloroaniline to yield corresponding imidazolones 3 (a–e). All the compounds were characterized by using FTIR and NMR spectroscopic techniques. Docking studies of Compounds were conducted using AutoDock Vina and analyzed with PYMOL. All synthesized oxazolone and imidazolone derivatives exhibited antioxidant potential, demonstrated by their IC50 values compared to ascorbic acid standard. Oxazolone derivatives (2a–2e) exhibited good acetyl cholinesterase inhibitory potential whereas Imidazolone series did not show significant inhibition as shown by their IC50 values compared to donepezil as a standard. Docking studies of all compounds against acetylcholinesterase demonstrated favorable binding affinity, indicating their potential for further in-vivo studies. It is notable that novel compounds of both oxazolones and Imidazolone series exhibited antioxidant potential with maximum percentage inhibition of 75.9 (IC50 12.9 ± 0.0573 µM/mL) by compound 2d while compound 2a showed AChE inhibitory potential with maximum %age inhibition of 75.49 (IC50 7.8 ± 0.0218 µM/mL). Communicated by Ramaswamy H. Sarma

GC-MS ANALYSIS, CHOLINESTERASE INHIBITORY AND ANTIOXIDANT POTENTIALS OF ZAPOTECA PORTORICENSIS (JACQ.) H.M. HERN (FABACEAE) ROOT EXTRACTS

The age-related neurodegenerative illness known as Alzheimer's disease (AD) is typified by the unavoidable decline in cognitive function. Existing drugs has limitations, therefore there is an urgent need for new neurotherapeutic agents. There has been a lot of excitement in recent years about finding therapeutic herbs that can restore cognitive impairment due to their lower side effects. The aim of the study is to evaluate the cholinesterase inhibitory and antioxidant potentials of Zapoteca portoricensis (Jacq.) H.M. Hern root extracts and also identify the bioactive molecules present. Ellman colorimetric assay was used to evaluate the cholinesterase inhibitory potentials of various extracts at 1 mg/mL. The antioxidant potentials of extracts were evaluated using in-vitro chemical analysis. GC-MS was used to identify bioactive molecules from most active extract. One-way ANOVA at α0.05 was adopted. Ethyl acetate extract showed the highest acetylcholinesterase (IC50 = 0.149±0.00 mg/mL) and butyrylcholinesterase (IC50 = 0.393±0.02 mg/mL) inhibitory potential as compared to eserine for AChE (IC50 = 0.051±0.01 mg/mL) and for BuChE (IC50 = 0.049±0.00 mg/mL). Ethyl acetate extract also demonstrated its potential to chelate metals (IC50 = 0.106±0.02 mg/mL) as compared to EDTA (IC50 = 0.086±0.00 mg/mL). The DPPH radical scavenging potential was higher in ethyl acetate extract (IC50 = 0.082±0.05 mg/mL) when compared to vitamin C (IC50 = 0.008±0.00 mg/mL). The total antioxidant capacity of extracts revealed that ethyl acetate extract also has the highest concentration (125.5±14.3 mg/g AAE/g of extract (R2=0.9276)). The GC-MS analysis of ethyl acetate extract revealed the presence of 62 compounds which includes n-Hexadecanoic acid (RT 14.81, Area % 10.03), 9,12-Octadecadienoic acid (Z,Z)- (RT 15.97, Area % 10.03), cis-9-Hexadecenal (RT 16.01, Area % 8.36). The ethyl acetate extract from the root of Zapoteca portoricensis has the aptitude to prolong the half-life of acetylcholine by its ability to inhibit cholinesterase enzyme.

GC-MS ANALYSIS, CHOLINESTERASE INHIBITORY AND ANTIOXIDANT POTENTIALS OF ZAPOTECA PORTORICENSIS (JACQ.) H.M. HERN (FABACEAE) ROOT EXTRACTS

The age-related neurodegenerative illness known as Alzheimer's disease (AD) is typified by the unavoidable decline in cognitive function. Existing drugs has limitations, therefore there is an urgent need for new neurotherapeutic agents. There has been a lot of excitement in recent years about finding therapeutic herbs that can restore cognitive impairment due to their lower side effects. The aim of the study is to evaluate the cholinesterase inhibitory and antioxidant potentials of Zapoteca portoricensis (Jacq.) H.M. Hern root extracts and also identify the bioactive molecules present. Ellman colorimetric assay was used to evaluate the cholinesterase inhibitory potentials of various extracts at 1 mg/mL. The antioxidant potentials of extracts were evaluated using in-vitro chemical analysis. GC-MS was used to identify bioactive molecules from most active extract. One-way ANOVA at α0.05 was adopted. Ethyl acetate extract showed the highest acetylcholinesterase (IC50 = 0.149±0.00 mg/mL) and butyrylcholinesterase (IC50 = 0.393±0.02 mg/mL) inhibitory potential as compared to eserine for AChE (IC50 = 0.051±0.01 mg/mL) and for BuChE (IC50 = 0.049±0.00 mg/mL). Ethyl acetate extract also demonstrated its potential to chelate metals (IC50 = 0.106±0.02 mg/mL) as compared to EDTA (IC50 = 0.086±0.00 mg/mL). The DPPH radical scavenging potential was higher in ethyl acetate extract (IC50 = 0.082±0.05 mg/mL) when compared to vitamin C (IC50 = 0.008±0.00 mg/mL). The total antioxidant capacity of extracts revealed that ethyl acetate extract also has the highest concentration (125.5±14.3 mg/g AAE/g of extract (R2=0.9276)). The GC-MS analysis of ethyl acetate extract revealed the presence of 62 compounds which includes n-Hexadecanoic acid (RT 14.81, Area % 10.03), 9,12-Octadecadienoic acid (Z,Z)- (RT 15.97, Area % 10.03), cis-9-Hexadecenal (RT 16.01, Area % 8.36). The ethyl acetate extract from the root of Zapoteca portoricensis has the aptitude to prolong the half-life of acetylcholine by its ability to inhibit cholinesterase enzyme. Keywords: Fabaceae, Zapoteca portoricensis, Cholinesterase inhibition, Antioxidant, GC-MS

Experimental and pharmacoinformatic approaches unveil the neuropharmacological and analgesic potential of chloroform fraction of Roktoshirinchi (Achyranthes ferruginea Roxb.)

Ethnopharmacological relevanceAchyranthes ferruginea (A. ferruginea) Roxb. is a common plant used in traditional medicine in Asia and Africa. It has a variety of local names, including “Gulmanci” in Nigeria, “Dangar” in Pakistan, “Thola” in Ethiopia, and “Roktoshirinchi” in Bangladesh. It is edible and has several ethnomedical uses for a wide range of illnesses, including hysteria, dropsy, constipation, piles, boils, asthma, and shigellosis. However, the neuropharmacological and analgesic potential of A. ferruginea remains uninvestigated. Aim of the studyTo assess the neuropharmacological and analgesic potential of A. ferruginea through a multifaceted approach encompassing both experimental and computational models. Materials and methodsMethanol was used to extract the leaves of A. ferruginea. It was then fractionated with low to high polar solvents (n-hexane, chloroform, ethyl acetate, and water) to get different fractions, including chloroform fraction (CLF). The study selected CLF at different doses and conducted advanced chemical element and proximate analyses, as well as phytochemical profiling using GC-MS. Toxicological studies were done at 300 μg per rat per day for 14 days. Cholinesterase inhibitory potential was checked using an in-vitro colorimetric assay. Acetic acid-induced writhing (AAWT) and formalin-induced licking tests (FILT) were used to assess anti-nociceptive effects. The forced swim test (FST), tail suspension test (TST), elevated plus maze (EPM), hole board test (HBT), and light and dark box test (LDB) were among the behavioral tests used to assess depression and anxiolytic activity. Network pharmacology-based analysis was performed on selected compounds using the search tool for interacting chemicals-5 (STITCH 5), Swiss target prediction tool, and search tool for the retrieval of interacting genes and proteins (STRING) database to link their role with genes involved in neurological disorders through gene ontology and reactome analysis. ResultsQualitative chemical element analysis revealed the presence of 15 elements, including Na, K, Ca, Mg, P, and Zn. The moisture content, ash value, and organic matter were found to be 11.12, 11.03, and 88.97%, respectively. GC-MS data revealed that the CLF possesses 25 phytoconstituents. Toxicological studies suggested the CLF has no effects on normal growth, hematological and biochemical parameters, or cellular organs after 14 days at 300 μg per rat. The CLF markedly reduced the activity of both acetylcholinesterase and butyrylcholinesterase (IC50: 56.22 and 13.22 μg/mL, respectively). Promising dose-dependent analgesic activity (p < 0.05) was observed in chemically-induced pain models. The TST and FST showed a dose-dependent substantial reduction in immobility time due to the CLF. Treatment with CLF notably increased the number of open arm entries and time spent in the EPM test at doses of 200 and 400 mg/kg b.w. The CLF showed significant anxiolytic activity at 200 mg/kg b.w. in the HBT test, whereas a similar activity was observed at 400 mg/kg b.w. in the EPM test. A notable increase in the amount of time spent in the light compartment was observed in the LDB test by mice treated with CLF, suggesting an anxiolytic effect. A network pharmacology study demonstrated the relationship between the phytochemicals and a number of targets, such as PPARA, PPARG, CHRM1, and HTR2, which are connected to the shown bioactivities. ConclusionsThis study demonstrated the safety of A. ferruginea and its efficacy in attenuating cholinesterase inhibitory activity, central and peripheral pain, anxiety, and depression, warranting further exploration of its therapeutic potential.

Plant Soup Formulations Show Cholinesterase Inhibition Potential in the Prevention of Alzheimer's Disease.

As the cholinesterase theory is a prominent hypothesis underlying our current understanding of Alzheimer's disease (AD), the goal of this study was to compose functional vegan lunchtime soups with potential health benefits in the prevention of AD (in the context of cholinesterase inhibition). The potential of 36 edible plant raw materials in terms of acetyl- and butyrylcholinesterase inhibition was investigated using a 96-well microplate reader. The most promising ingredients were combined to obtain 18 palatable vegetable soup recipes with 6 dominant flavor, appearance, and aroma variants. To shortlist candidates for in-depth analysis and potential consideration in industrial production, our team performed a sensory analysis of the soups. The white boletus soup exhibited the highest potential for cholinesterase inhibition, further bolstered by the inclusion of other ingredients known for their elevated capacity to inhibit both AChE and BChE. Ingredients such as blackthorn (Prunus spinosa), garlic, and white potato contributed significantly to this inhibitory effect (nearly 100% of AChE inhibition). Notably, intriguing results were also observed for asparagus soup, despite the fact that the inhibitory potential of asparagus itself is negligible compared to other raw materials. The success of the asparagus soup lies in the meticulous selection of various ingredients, each contributing to its overall effectiveness. It was observed that mushroom soups scored the highest in this respect, while the team members' response to nettle soup was the least favorable. The outcomes of our study should serve as a catalyst for further exploration of this important research domain. Our current research focuses on deeper insights into the potential of comprehensive meal options. Furthermore, the synergy/antagonism/non-interaction between respective soup ingredients as well as elements of individual soups' chemical composition is a very interesting topic currently under our intensive scientific investigation.

Photochemical Transformations of Diverse Biologically Active Resveratrol Analogs in Batch and Flow Reactors.

Previous biological tests have shown that some resveratrol analogs exhibited significant antioxidative and cholinesterase inhibitory potential, as evidenced by lower IC50 values compared to the established standards, resveratrol and galantamine, respectively. Photochemical transformations were made in parallel on these compounds in the presence of porphyrin photocatalysts in batch and microreactor, showing the significant advantage of flow photochemistry concerning productivity, selectivity, and yields. In this research, the products of photocatalysis and direct irradiation (photolysis) of resveratrol analogs were compared to elucidate how the types and ratios of the products depend on the excitation energy, to reveal the effects of the substituent on the photoinduced reactions and to rationalize experimentally and computationally the nature and ratio of the obtained products. Thus, two main paths were computed in agreement with the experimental results: isomerization with the participation of triplet state intermediates to yield the experimentally detected cis-isomers and subsequent cyclization following a pathway not available for the trans-isomers. The investigation of five model compounds confirmed the advantages of the flow photoreactor in the photochemical reactions of heterocyclic resveratrol analogs.

Chemical profile, enzyme inhibitory and antioxidant activities of essential oils of an endemic Algerian species: Abies numidica. De Lannoy ex Carrière

ABSTRACT The essential oils (EOs) from needles, twigs and cones of Abies numidica, an endemic tree from Algeria, were analysed by gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and 13C nuclear magnetic resonance (13C NMR). Fifty, forty-nine, and thirty-eight components from needles, twigs and cones were identified accounting for 86.0%, 93.5% and 93.8% of the total EO, respectively. EOs were mainly composed of monoterpene hydrocarbons (46.3%-86.0%), followed by sesquiterpene hydrocarbons (2.6%-33.6-%). The antioxidant activity was determined using five tests: ABTS, β-Carotene bleaching, DPPH, FRAP and phosphomolybdenum. Cholinesterase inhibition potential of EOs was also evaluated. EO of cones was found to have the highest antioxidant activity for most of the tests performed. All EOs exhibited better antiacetylcholinesterase (AChE) than antibutyrylcholinesterase (BChE) activities at various rates. The most potent AChE inhibition was observed for twigs EO (IC50 = 2.73 g/mL), followed by needles (IC50 = 4.09 µg/mL) while cones’ EO showed least potential (IC50 = 13.64 µg/mL).

Hydrazone-sulfonate hybrids as potential cholinesterase inhibitors: design, synthesis and molecular modeling simulation.

Aim: Design and synthesis of a series of hydrazone-sulfonate hybrids, 5a-r. Methodology: The inhibitory properties of the synthesized compounds against acetylcholinesterase and butyrylcholinesterase were evaluated using donepezil as the reference standard. Results & conclusion: Compound 5e was identified as the most potent inhibitor of acetylcholinesterase (IC50=9.30μM), and compound 5i was the most potent inhibitor of butyrylcholinesterase (IC50=11.82μM). To confirm the safety of the most potent hits at the used doses, toxicological bioassays were conducted. Molecular docking was performed and the tested derivatives were found to fit well in the active sites of both enzymes. This study provides valuable insights into the potential of hydrazone-sulfonate hybrids as drug candidates.

Chemo- and bio-informatics insight into anti-cholinesterase potentials of berries and leaves of Myrtus communis L., Myrtaceae: an in vitro/in silico study

BackgroundMyrtus communis L. (MC) has been used in Mesopotamian medicine. Here, the cholinesterase (ChE) inhibitory potential of its methyl alcohol extracts has been investigated and computationally dissected.MethodThe ChE inhibition has been measured based on usual Ellman’s colorimetric method compared to a canonical ChE inhibitor, eserine. Through a deep text mining, the structures of phytocompounds (= ligands) of MC were curated from ChemSpider, PubChem, and ZINC databases and docked into protein targets, AChE (PDB 1EVE) and BChE (PDB 1P0I) after initial in silico preparedness and binding affinity (BA; kcal/mol) reported as an endpoint. The calculation of ADMET (absorption, distribution, metabolism, excretion, and toxicity) features of phytocompounds were retrieved from SwissADME (http://www.swissadme.ch/) and admetSAR software to predict the drug-likeness or lead-likeness fitness. The Toxtree v2.5.1, software platforms (http://toxtree.sourceforge.net/) have been used to predict the class of toxicity of phytocompounds. The STITCH platform (http://stitch.embl.de) has been employed to predict ChE-chemicals interactions.ResultsThe possible inhibitory activities of AChE of extracts of leaves and berries were 37.33 and 70.00%, respectively as compared to that of eserine while inhibitory BChE activities of extracts of leaves and berries of MC were 19.00 and 50.67%, respectively as compared to that of eserine. Phytochemicals of MC had BA towards AChE ranging from -7.1 (carvacrol) to -9.9 (ellagic acid) kcal/mol. In this regard, alpha-bulnesene, (Z)-gamma-Bisabolene, and beta-bourbonene were top-listed low toxic binders of AChE, and (Z)-gamma-bisabolene was a more specific AChE binder. Alpha-cadinol, estragole, humulene epoxide II, (a)esculin, ellagic acid, patuletin, juniper camphor, linalyl anthranilate, and spathulenol were high class (Class III) toxic substances which among others, patuletin and alpha-cadinol were more specific AChE binders. Among intermediate class (Class II) toxic substances, beta-chamigrene was a more specific AChE binder while semimyrtucommulone and myrtucommulone A were more specific BChE binders.ConclusionIn sum, the AChE binders derived from MC were categorized mostly as antiinsectants (e.g., patuletin and alpha-cardinal) due to their predicted toxic classes. It seems that structural amendment and stereoselective synthesis like adding sulphonate or sulphamate groups to these phytocompounds may make them more suitable candidates for considering in preclinical investigations of Alzheimer’s disease.

Synthesis and molecular docking simulation of new benzimidazole-thiazole hybrids as cholinesterase inhibitors.

Dementia is a cognitive disturbance that is generally correlated with central nervous system diseases, especially Alzheimer's disease. The limited number of medications available is insufficient to improve the lifestyle of the patients suffering from this disease. Thus, new benzimidazole-thiazole hybrids (3-10) were designed and synthesized as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory agents. The in vitro evaluation displayed that the derivatives 4b, 4d, 5b, 6a, 7a, and 8b demonstrated dual inhibitory efficiency against both AChE with IC50 ranging from 4.55 to 8.62 µM and BChE with IC50 ranging from 3.50 to 8.32 µM. By analyzing the Lineweaver-Burk plot, an uncompetitive form of inhibition was determined for the highly active compound 4d, revealing its inhibition type. The human telomerase reverse transcriptase-immortalized retinal pigment epithelial cell linewas used to ensure the safety of the most potent cholinesterase inhibitors. Furthermore, compounds 4b, 4d, 5b, 6a, 7a, and 8b were evaluated for their neuroprotective and antioxidant properties, as well as their ability to suppress COX-2. The results demonstrated that compounds 4d, 5b, and 8b presented significant neuroprotection efficiency against H2 O2 -induced damage in SH-SY5Y cells with % cell viability of 67.42 ± 7.90%, 62.51 ± 6.71%, and 72.61 ± 8.10%, respectively, while the tested candidates did not reveal significant antioxidant activity. Otherwise, compounds 4b, 6a, 7a, and 8b displayed outstanding COX-2 inhibition effects with IC50 ranging from 0.050 to 0.080 μM relative to celecoxib (IC50 = 0.050 µM). In addition, molecular docking was carried out for the potent benzimidazole-thiazole hybrids with the active sites of both AChE (PDB ID: 4EY7) and BChE (PDB code: 1P0P). The tested candidates fit well in the active sites of both portions, with docking scores ranging from -8.65 to -6.64 kcal/mol (for AChE) and -8.71 to -7.73 kcal/mol (for BChE). In silico results show that the synthesized benzimidazole-thiazole hybrids have good physicochemical and pharmacokinetic properties with no Lipinski rule violations. The preceding results exhibited that compound 4d could be used as a new template for developing more significant cholinesterase inhibitors in the future.

Comparative Study of Chemical Composition and Cholinesterase Inhibition Potential of Essential Oils Isolated from Artemisia Plants from Croatia

The essential oil (EO) of Artemisia plants contains a large number of bioactive compounds that are widely used. The aim of this study was to analyse the chemical composition of EOs of six Artemisia plants collected in Croatia and to test their cholinesterase inhibitory potential. GC–MS analysis of the EO of A. absinthium showed that the dominant compounds are cis-sabinyl acetate and cis-epoxy-ocimene; in EO of A. abrotanum, it is borneol; in the EO of A. annua, they are artemisia ketone, camphor and 1,8-cineole; in the EO of A. arborescens, they are camphor and chamazulene; in the EO of A. verlotiorum, they are cis-thujone, 1,8-cineole and trans-thujone; and in the EO of A. vulgaris, they are trans-thujone and trans-epoxy-ocimene. The EO of the five studied Artemisia species from Croatia is rich in monoterpenoid compounds (1,8-cineole, artemisia ketone, cis-thujone, trans-thujone, cis-epoxy-ocimene, camphor, borneol and cis-sabinyl acetate). The EO of A. arborescens is also rich in chamazulene. The results also showed that the tested EOs have moderate cholinesterase inhibition potential, especially the EOs of A. annua, A. vulgaris and A. abrotanum. This is the first analysis of the chemical composition of the EOs of four Artemisia plants and the first analysis of cholinesterase potential for plants collected in Croatia.

Pyrimidine-morpholine hybrids as potent druggable therapeutics for Alzheimer’s disease: Synthesis, biochemical and in silico analyses

The identification of effective and druggable cholinesterase inhibitors to treat progressive neurodegenerative Alzheimer’s disorder remains a continuous drug discovery hunt. In this perspective, the present study investigates the design and discovery of pyrimidine-morpholine hybrids (5a-l) as potent cholinesterase inhibitors. Palladium-catalyzed Suzuki-Miyaura cross-coupling reaction was employed to introduce the structural diversity on the pyrimidine heterocyclic core. A range of commercially available boronic acids was successfully coupled showing a high functional group tolerance. In vitro cholinesterase inhibitory potential using Ellman’s method revealed significantly strong potency. Compound 5h bearing a meta-tolyl substituent at 2-position of pyrimidine ring emerged as a lead candidate against AChE with an inhibitory potency of 0.43 ± 0.42 µM, ∼38-fold stronger value than neostigmine (IC50 = 16.3 ± 1.12 µM). Compound 5h also showed the lead inhibition against BuChE with an IC50 value of 2.5 ± 0.04 µM. The kinetics analysis of 5h revealed the non-competitive mode of inhibition against AChE whereas computational modelling results of potent leads depicted diverse contacts with the binding site amino acid residues. Molecular dynamics simulations revealed the stability of biomolecular system, while, ADME analysis demonstrated druglikeness behaviour of potent compounds. Overall, the investigated pyrimidine-morpholine scaffold presented a remarkable potential to be developed as efficacious anti-Alzheimer’s drugs.

Solvents and detergents compatible with enzyme kinetic studies of cholinesterases

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are enzymes that serve a wide range of physiological functions including the hydrolysis of the neurotransmitter acetylcholine and several other xenobiotics. The development of inhibitors for these enzymes has been the focus for the treatment of several conditions, such as Alzheimer's disease. Novel chemical entities are evaluated as potential inhibitors of AChE and BChE using enzyme kinetics. A common issue encountered in these studies is low aqueous solubility of the possible inhibitor. Additives such as cosolvents or detergents can be included in these studies improve the aqueous solubility. Typical cosolvents include acetonitrile or dimethyl sulfoxide while typical detergents include Polysorbate 20 (Tween 20) or 3-((3-cholamidopropyl) dimethylammonio)-1-propanesulfonate (CHAPS). When solubility is not improved, these molecules are often not evaluated further. To address this issue eleven cosolvents and six detergents that could facilitate aqueous solubility were evaluated to understand how they would affect cholinesterase enzymes using Ellman's assay. These studies show that propylene glycol, acetonitrile, methanol, Tween 20, Polysorbate 80 (Tween 80), polyoxyethylene 23 lauryl ether (Brij 35) and polyoxyethylene 10 oleoyl ether (Brij 96v) have the least inhibitory effects towards cholinesterase activity. It is concluded that these cosolvents and detergents should be considered as solubilizing agents for evaluation of potential cholinesterase inhibitors with low aqueous solubility.

Synthesis, molecular docking, and bioactivity study of isoquinoline-sulfonamide hybrid analogues: A promising acetylcholinesterase and butyrylcholinesterase inhibitor candidate

Isoquinoline-sulfonamide hybrid analogues (1–11) were synthesised and tested for their dual cholinesterase inhibitory potentials. All analogues showed a varied degree of inhibitory potential, with IC50 values ranging between 0.30 ± 0.05 to 26.30 ± 0.20 µM (AChE) and 0.80 ± 0.01 to 37.60 ± 0.70 µM (BuChE) as compared to standard drug donepezil (IC50 = 2.16 ± 0.12 and 4.5 ± 0.11 µM respectively). In case of AChE, analogue 2 (IC50 = 0.30 ± 0.05 μM) was most potent, while in case of BuChE, analogues 2, 11, and 5 with IC50 values of 0.80 ± 0.01, 1.20 ± 0.05 and 2.50 ± 0.10 μM respectively, were found most potent. Structure-activity relationship was investigated, which is primarily depending upon nature, number, position, and electron donating/withdrawing effect on phenyl ring. A molecular docking study was carried out to determine the binding interactions of the most potent analogues with the active site of enzymes. The compounds were synthesized by simple modes of synthesis like esterification, hydrazide and finally sulfonamide formation.

Phytochemical Profile, Antioxidant Activity and Cholinesterase Inhibition Potential of Essential Oil and Extracts of Teucrium montanum from Bosnia and Herzegovina

Bioactive compounds from plants play an important role in slowing many neurodegenerative diseases, such as Alzheimer’s disease, by inhibiting cholinesterase enzymes. Studies have shown that oxidative stress is associated with the development of Alzheimer’s disease. In traditional medicine of Bosnia and Herzegovina, Teucrium montanum is used to treat numerous diseases. The chemical composition and biological activity of the essential oil (EO) and aqueous (AE) and methanol extract (ME) of this plant were studied. The chemical composition of EO was studied using GC-MS, while the composition of the extracts was studied using HPLC-DAD. Antioxidant activity was tested using the DPPH and FRAP methods. The protection of lipids and proteins from oxidation was tested using the ammonium thiocyanate and BSA oxidation methods. The ability to inhibit cholinesterases was tested by the Ellman method. The main identified EO compounds were α-cadinol, ß-selinene, δ-cadinene, epi-α-cadinol, germacrene D-4-ol, and α-pinene. The main phenolic compounds of the extracts were p-coumaric acid, ellagic acid and caffeic acid. The tested extracts showed good antioxidant radical scavenging and reducing potential and a very good ability to protect lipids and proteins from oxidation. The EO showed moderate AChE and BChE inhibition potential, while the extracts showed weak or no ability.

Multi-combined QSAR, molecular docking, molecular dynamics simulation, and ADMET of Flavonoid derivatives as potent cholinesterase inhibitors

In searching for a new and efficient therapeutic agent against Alzheimer’s disease, a Quantitative structure-activity relationship (QSAR) was derived for 45 Flavonoid derivatives recently synthesized and evaluated as cholinesterase inhibitors. The multiple linear regression method (MLR) was adopted to develop an adequate mathematical model that describes the relationship between a variety of molecular descriptors of the studied compounds and their biological activities (cholinesterase inhibitors). Golbraikh and Tropsha criteria were applied to verify the validity of the built model. The built MLR model was statistically reliable, robust, and predictive (R2 = 0.801, Q2 cv = 0.876, R2 test = 0.824). Dreiding energy and Molar Refractivity were the major factors that govern the Anti-cholinesterase activity. These results were further exploited to design a new series of Flavonoid derivatives with higher Anti-cholinesterase activities than the existing ones. Thereafter, molecular docking and molecular dynamic studies were performed to predict the binding types of the designed compounds and to investigate their stability at the active site of the Butyrylcholinestérase BuChE protein. The negative and low binding affinity calculated for all designed compounds shows that designed compound 1 has a favorable affinity for the 4TPK. Moreover, molecular dynamics simulation studies confirmed the stability of designed compound 1 in the active pocket of 4TPK over 100 ns. Finally, the ADMET analysis was incorporated to analyze the pharmacokinetics and toxicity parameters. The designed compounds were found to meet the ADMET descriptor criteria at an acceptable level having respectable intestinal permeability and water solubility and can reach the intended destinations. Communicated by Ramaswamy H. Sarma