Potent Acetylcholinesterase Inhibitors Research Articles

Selected herbicides screened for toxicity and analysed as inhibitors of both cholinesterases

Sets of 346 herbicides in use and 163 no longer in use were collected from open access online sources and compared in silico with cholinesterases inhibitors (ChI) and drugs in terms of physicochemical profile and estimated toxic effects on human health. The screening revealed at least one potential adverse consequence for each herbicide class assigned according to their mode of action on weeds. The classes with most toxic warnings were K1, K3/N, F1 and E. The selection of 11 commercial herbicides for in vitro biological tests on human acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), the enzymes involved in neurotoxicity and detoxification of various xenobiotics, respectively, was based mainly on the structural similarity with inhibitors of cholinesterases. Organophosphate anilofos and oxyacetanilide flufenacet were the most potent inhibitors of AChE (25 μM) and BChE (6.4 μM), respectively. Glyphosate, oxadiazon, tembotrione and terbuthylazine were poor inhibitors with an estimated IC50 above 100 μM, while for glyphosate the IC50 was above 1 mM. Generally, all of the selected herbicides inhibited with a slight preference towards BChE. Cytotoxicity assays showed that anilofos, bensulide, butamifos, piperophos and oxadiazon were cytotoxic for hepatocytes (HepG2) and neuroblastoma cell line (SH-SY5Y). Time-independent cytotoxicity accompanied with induction of reactive oxygen species indicated rapid cell death in few hours. Our results based on in silico and in vitro analyses give insight into the potential toxic outcome of herbicides in use and can be applied in the design of new molecules with a less impact on humans and the environment.

N-Methylneolitsine as a new and potent acetylcholinesterase inhibitor of Cissampelos pareira Linn. aerial parts: bioassay-guided isolation and quantitative densitometric analysis

The rising geriatric population is expected to increase the demand for drugs treating neurodegenerative diseases. The present work is aimed to discover acetylcholinesterase (AChE) inhibitors from Cissampelos pareira Linn. aerial parts (Family: Menispermaceae). Bioassay-guided isolation, AChE inhibition study and estimation of the therapeutic marker in different parts of raw herbs were conducted. The structure of the compound (1) was elucidated as N-methylneolitsine by using NMR (1D and 2D) and ESI-MS/MS spectral data, which is a new natural analogue of neolitsine. It showed good AChE inhibition with an IC50 value of 12.32 µg/mL. It was densitometrically estimated to be 0.074 − 0.33% in aerial parts of C. pareira, collected from various locations. The alkaloid reported here could be potentially useful for the treatment of various neurodegenerative diseases and the aerial part of C. pareira could be used as a promising ingredient for various preparations treating neurodegenerative diseases.

Design, synthesis and evaluation of benzo[cd]indol-2(1H)-one-donepezil hybrids as cholinesterase inhibitors and living cell imaging agents

A novel series of benzo[cd]indol-2(1H)-one-donepezil (BIO-DPZ) hybrids (5a-m, 6a-k) was designed, synthesized and evaluated as cholinesterase inhibitors and living cell imaging agents. These compounds were potent inhibitors of both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Compound 6a exhibited the strongest inhibitory activity against AChE with an IC50 value of 0.16 μM. Compound 6i had the strongest inhibition of BuChE with an IC50 value of 5.37 μM. Kinetic and molecular modeling studies showed that 6a bound both catalytic active site and peripheral anionic site of AChE. Compounds 6a and 6i both showed lower SH-SY5Y, HepG2 and HL-7702 cytotoxicity than the mitoxantrone. Promisingly, the most active compound, 6a, was successfully used in living SH-SY5Y cell imaging and had predictable lipophilicity and blood-brain-barrier permeation properties. These hybrids should undergo further systematic study in the treatment of Alzheimer's disease.

Effect of organic solvents on acetylcholinesterase inhibition and enzyme kinetics.

The most widespread signalling system in the brain is the cholinergic system, which plays a central role in the progress of Alzheimer's diseases (AD). Current AD treatment primarily targets the neuronal acetylcholinesterase (AChE) enzyme. The finding of AChE activity may play a vital role in optimizing assays for drug discovery of new AChE inhibiting agents. During in-vitro assay of AChE activity, the use of various organic solvents is imperative. Therefore, evaluating the effect of different organic solvents on enzyme activity and enzyme kinetics is essential. Organic solvents' AChE inhibitory potential (including enzyme kinetics: Vmax, Km and Kcat) was evaluated using a substrate velocity curve by using the non-linear reversion Michaelis-Menten kinetic function. DMSO was found to have the most potent AChE inhibitory effect, followed by acetonitrile and ethanol. The kinetic study revealed DMSO as a mixed inhibitory effect (competitive/non-competitive manner), ethanol as non-competitive, and acetonitrile as a competitive inhibitor of the AChE enzyme. Methanol has shown a negligible impact on enzyme inhibition and kinetics, suggesting its suitability for the AChE assay. We assume that our study results will help design the experimental protocols and support analyzing investigational outcomes while screening and biological evaluation of new molecules using methanol as solvent/cosolvent.

Synthesis, acetylcholinesterase and butyrylcholinesterase inhibitory potential and molecular docking study of thiazole bearing thiourea analogues

We have synthesized fourteen thiazole bearing thiourea derivatives (1-14), characterized through different techniques i.e., NMR, HR-EIMS and tested against acetylcholinesterase and butyrylcholinesterase inhibitory potentials. All analogues showed inhibitory potential having varied IC50 values ranged from 2.10 ± 0.02 to 109.40 ± 0.04 µM (for AChE) and 3.10 ± 0.01 to 102.20 ± 0.04 µM (for BuChE) as compared to standard drug Eserine (IC50 = 0.85 ± 0.0001 & 0.04 ± 0.0001 µM respectively). Among the series, analogues 6, 11, 7 and 12 displayed excellent inhibitory potential against acetylcholinesterase. Analogue 14 (IC50 = 3.10 ± 0.01 µM) was found to be most potent against butyrylcholinesterase. Structure activity relationship (SAR) was established depend upon nature, position and number of substituent/s attached to the phenyl ring of basic nucleus. Molecular docking study was carried out to check the binding interaction of most potent analogues with the active site of enzyme.

Comparative Study of Antioxidant, Antidiabetic, Cytotoxic Potentials, and Phytochemicals of Fenugreek (Trigonella foenum-graecum) and Ginger (Zingiber officinale)

Trigonella foenum-graecum and Zingiber officinale are used as traditional medicinal plants for the treatment of infectious and inflammatory diseases. However, a comparative analysis and bioactivities of T. foenum-graecum and Z. officinale lack some necessary information for therapeutic purposes. This study was designed to evaluate the biochemical characterizations and biological efficacy of T. foenum-graecum and Z. officinale as antioxidant, antidiabetic, antiamnesic, and cytotoxic agents. Antioxidant activity was determined by DPPH free radical scavenging assay. Antidiabetic potentials were evaluated by glycation, alpha-amylase, and acetylcholinesterase inhibition assays. We performed biochemical characterization through analyses of high-performance liquid chromatography (HPLC) and FTIR (Fourier transform infrared spectroscopy). Results revealed that total phenolic contents (TPCs) (g GAE/100 g) of T. foenum-graecum and Z. officinale were 5.74 ± 0.81 g and 6.15 ± 0.06 g, respectively, and total flavonoid contents (TFCs) varied from 1.51 ± 0.58 g CE/100 g to 17.54 ± 0.58. DPPH scavenging potentials of T. foenum-graecum and Z. officinale extract were 50.27% and 88.82%, respectively. Antiglycation potentials of T. foenum-graecum and Z. officinale showed a maximum activity at 16–29% and 96%. Alpha-amylase and alpha-glucosidase inhibition ranged from 9.43–24.95 and 10.52–27.89 and 54.97%, respectively. All the test samples of T. foenum-graecum and Z. officinale showed acetylcholinesterase inhibition potential at 0.37–46.88%. HPLC analysis of T. foenum-graecum revealed the presence of quercetin, gallic acid, caffeic acid, vanillic acid, syringic acid, and cumeric acid, while Z. officinale revealed the quercetin, gallic acid, vanillic acid, benzoic acid, chlorogenic acid, p.Coumaric acid, ferulic acid, and cinnamic acid. FTIR analysis revealed the presence of aldehydes, ketones, aromatic compounds, amines, and carbonyl groups in T. foenum-graecum, while alcohol, alkane, alkene, ketone, amine, and ether are bioactives present in the methanolic extract of Z. officinale. It was concluded that a comparative analysis of T. foenum-graecum and Z. officinale showed that Z. officinale showed higher therapeutic effects.

3+2] Cycloaddition Synthesis of New Piperazine‐Linked Bis(chromene) Hybrids Possessing Pyrazole Units as Potential Acetylcholinesterase Inhibitors

Two series of piperazine-linked bis(chromene) hybrids that are attached to pyrazole units were synthesized in the current study. Both series are attached to an acyl unit at pyrazole-C3, with one series attached to an acetyl unit and the other to an ethoxycarbonyl unit. A [3+2] cycloaddition protocol was conducted to produce the target hybrids with good yields by reacting the appropriate hydrazonoyl chlorides with chromene-based bis(enaminone) in dioxane containing triethylamine at reflux for 4 h. New hybrids were tested for acetylcholinesterase inhibitory activity at concentrations of 15 and 25 μM, as well as their ability to quench 2,2-diphenylpicrylhydrazyl (DPPH) free radicals at a concentration of 25 μg/mL. In general, the inhibitory activity is related to the electronic properties of the para-substituent that is attached to the arene unit at pyrazole-N1. Furthermore, the acyl unit attached to pyrazole-C3 has a significant effect on the new hybrids' inhibitory activity. At the previous concentrations, the (3-acetylpyrazole)-linked hybrid attached to p-NO2 units demonstrated the best acetylcholinesterase inhibitory activity, with inhibition percentages of 79.7 and 90.2. Furthermore, the previous hybrid demonstrated the most effective DPPH inhibitory activity, with an inhibition percentage of 87.5.

Natural coumarins from Murraya paniculata as mixed-type inhibitors of cholinesterases: In vitro and in silico investigations.

Currently, acetylcholinesterase (AChE) inhibiting drugs in clinical use, such as tacrine, donepezil, rivastigmine, and galanthamine, are associated with serious side effects and short half-lives. In recent years, numerous phytochemicals have been identified as inhibitors of cholinesterases with potential applications in the management of Alzheimer's disease (AD). In this study three natural coumarins, 2'-O-ethylmurrangatin (1), murranganone (2), and paniculatin (3) isolated previously by our group from the leaves of Murraya paniculata, were tested against the two cholinesterases (ChE) enzymes, AChE and butyrylcholinesterase (BChE) using in vitro assay. Molecular docking was performed to highlight the structural properties that contribute to the molecular recognition pattern in the inhibition of ChE and the structural differences resulting in the selectivity of these compounds toward AChE. Classical enzyme inhibition kinetics data suggested that compounds 2 and 3 were potent inhibitors of AChE and BChE, while 1 was found inactive against both enzymes. The findings from molecular docking studies revealed the competitive and non-competitive inhibition mechanisms of compounds 2 and 3 against both enzymes. Molecular docking and simulations have revealed that hydrogen bonding, mediated by ketone and hydroxyl functionalities in various positions, significantly contributes to the binding of the inhibitor to the receptor. According to MD simulation studies, the stability of the ligand-AChE complex for the most active compound (3) is found to be comparable to that of the widely used drug Tacrine. In addition, to evaluate the drug-likeness of compounds, in silico ADME evaluation was performed, and the compounds presented good ADME profiles. Data suggested that the coumarin nucleus having diverse side chains at the C-8 position can serve as a potential inhibitor of cholinesterases and can act as a lead to develop a new semisynthetic drug for the treatment of AD.

Natural Compounds Isolated from African Mistletoes (Loranthaceae) Exert Anti-Inflammatory and Acetylcholinesterase Inhibitory Potentials: In Vitro and In Silico Studies

Despite the medicinal uses of Phragmanthera capitata, Globimetula dinklagei and Tapinanthus bangwensis against memory loss, convulsions and pain, their efficacy against brain-dysfunction diseases and inflammation models has not yet been studied. Therefore, this study aims to investigate the anti-inflammatory and acetylcholinesterase (AChE) inhibitory potentials of their crude extracts and isolated natural compounds by combining in vitro and in silico experiments. Crude extracts and isolated compounds were tested in vitro for their AChE inhibitory activity by using Ellman’s method. Additionally, their anti-inflammatory activity was determined by evaluating the nitric oxide (NO) production inhibitory activity in lipopolysaccharide-stimulated RAW 264.7 macrophage cells and the 15-lipoxygenase (15-LOX) inhibitory activity by using the ferrous oxidation xylenol orange assay. Furthermore, the in silico efficacy of natural compounds was investigated against ten putative target enzymes relevant in Alzheimer’s disease (AD) pathogenesis and inflammation. It was found that the crude extracts had weak to moderate inhibitory potential against AChE, with the extract of T. bangwensis being the most active (50% inhibitory concentration (IC50) = 48.97 µg/mL). Six natural compounds, namely, 3-O-β-D-glucopyranosyl-28-hydroxy-α-amyrin (2), apigenin- 8-C-β-D-glucopyranoside (3), globimetulin B (5), globimetulin C (6), bangwaursene B (8) and 3β-acetoxy-11,12-epoxytaraxerol (9), were identified for the first time as having anti-AChE potential, among which (9) had the highest efficacy with an IC50 of 13.89 µM. Among the anti-AChE compounds, (5) was also efficient against NO production and 15-LOX, and the data are in agreement with the docking score. In summary, compounds (5) and (9) are the most prominent lead compounds that should be further tested experimentally against molecular targets of AD and inflammation.

Sub-pocket-focused designing of tacrine derivatives as potential acetylcholinesterase inhibitors

Human acetylcholinesterase (hAChE) has a potential role in the management of acetylcholine, one of the neurotransmitters that modulate the overall activity of cholinergic system, AChE inhibitors have a greater impact in the therapeutics. Though the atomic structure of hAChE has been extensively studied, the precise active site geometry upon binding to different ligands are yet to be explored. In the present study, an extensive structural analysis of our recently reported hAChE-tacrine complex has carried out and revealed the presence of two prominent sub-pockets located at the vicinity of the hAChE active site. Structural bioinformatics assisted studies designed 132 putative sub-pockets focused tacrine derivatives (SPFTDs), their molecular docking, free energy estimations revealed that they are stronger than tacrine in terms of binding affinity. Our in vitro studies also supported the in silico findings, all these SPFTDs are having better potencies than tacrine. Cytotoxic nature of these SPFTDs on HepG2 and Neuro-2a cell lines, diminishes the possibilities for future in vivo studies. However, the identification of these sub pockets and the SPFTDs paved a new way to the future drug discovery especially since AChE is one of the promising and approved drug targets in treatment of AD drug discovery.

Neuroprotective activity of novel phenanthrene derivative from Grewia tiliaefolia by in vitro and in silico studies

Medicinal plants possess range of phytochemicals accountable for their diverse biological activities. Presently, such compounds have been isolated from medicinal plants, characterized and evaluated for their pharmacological potential. In the present study, the efforts have been made to isolate the compound(s) from Grewia tiliaefolia Vahl., plant known for its ameliorative effect on brain related diseases such as anxiety, depression, cognitive disorders and Parkinson’s disease. Plant extract was subjected to isolation of compound(s) using column chromatography and isolated compound was characterized by NMR FTIR and LCMS. The isolated compound was novel with the IUPAC name of the compound is propyl 3-hydroxy-10,13-dimethyl-6,7,8,9,10,11,12,13,14,15,16,17-dodecahydro-3H-cyclopenta[a]phenanthrene-17-carboxylate, designated as A-1 and has not been reported before. A-1 was further evaluated for its antioxidant potential using in vitro antioxidant assays (2,2-diphenyl-1-picryl-hydrazyl-hydrate, DPPH assay and reducing power assay, RPA). Also, Acetylcholinesterase (AChE) inhibitory potential of A-1 and extract was analysed. Results showed that A-1 exhibited significantly higher antioxidant activity in both DPPH and RPA assay as compared to plant extract. In case of AChE inhibitory activity again, A-1 has shown significantly higher activity as compared to plant extract. In silico study was conducted to predict its action on proteins playing crucial role in neurological and neurodegenerative disorders such as gamma amino butyric acid (GABA) receptor and glutamate α amino-3-hydroxyl-5-methyl-4-isoxazolepropionic acid (Glu AMPA) receptor in epilepsy and AChE enzyme in Alzheimer’s diseases. The compound has shown interaction in following order: AChE > GABA receptor > Glu AMPA receptor. Further, molecular dynamic simulations and ADME studies of A-1 and AChE enzyme revealed that A-1 yielded good results in all parameters and hence can relieve Alzheimer’s like symptoms.

Synthetic developments of <italic>Lycopodium</italic> alkaloids

<p indent="0mm"><italic>Lycopodium</italic> alkaloids are numerous and complexed in structures. They are potent inhibitors of acetylcholinesterase (AChE). The efficient synthesis of these natural products is one of the research hotspots of organic synthetic chemists. In this review, we summarized some representative achievements in collective synthesis of <italic>Lycopodium</italic> alkaloids in recent five years.

Gamma irradiation mediated production improvement of some myco-fabricated nanoparticles and exploring their wound healing, anti-inflammatory and acetylcholinesterase inhibitory potentials

In the current scenario, scaling up the microbial production of nanoparticles with diverse biological applications is an emerging prospect for NPs’ sustainable industry. Thus, this paper was conducted to develop a suitable applicative process for the myco-fabrication of cobalt-ferrite (CoFeNPs), selenium (SeNPs), and zinc oxide (ZnONPs) nanoparticles. A strain improvement program using gamma irradiation mutagenesis was applied to improve the NPs-producing ability of the fungal strains. The achieved yields of CoFeNPs, SeNPs, and ZnONPs were intensified by a 14.47, 7.85, and 22.25-fold increase from the initial yield following gamma irradiation and isolation of stable mutant strains. The myco-fabricated CoFeNPs, SeNPs, and ZnONPs were then exploited to study their wound healing, and anti-inflammatory. In addition, the acetylcholinesterase inhibition activities of the myco-fabricated NPs were evaluated and analyzed by molecular docking. The obtained results confirmed the promising wound healing, anti-inflammatory, and acetylcholinesterase inhibition potentials of the three types of NPs. Additionally, data from analyzing the interaction of NPs with acetylcholinesterase enzyme by molecular docking were in conformation with the experimental data.

Efficient Combination of Complex Chromatography, Molecular Docking and Enzyme Kinetics for Exploration of Acetylcholinesterase Inhibitors from Poria cocos.

Poria cocos (P. cocos) is a traditional Chinese medicinal product with the same origin as medicine and food. It has diuretic, anti-inflammatory and liver protection properties, and has been widely used in a Chinese medicine in the treatment of Alzheimer's disease (AD). This study was conducted to explore the activity screening, isolation of acetylcholinesterase inhibitors (AChEIs), and in vitro inhibiting effect of P. cocos. The aim was to develop a new extraction process optimization method based on the Matlab genetic algorithm combined with a traditional orthogonal experiment. Moreover, bio-affinity ultrafiltration combined with molecular docking was used to screen and evaluate the activity of the AChEIs, which were subsequently isolated and purified using high-speed counter-current chromatography (HSCCC) and semi-preparative high-performance liquid chromatography (semi-preparative HPLC). The change in acetylcholinesterase (AChE) activity was tested using an enzymatic reaction kinetics experiment to reflect the inhibitory effect of active compounds on AChE and explore its mechanism of action. Five potential AChEIs were screened via bio-affinity ultrafiltration. Molecular docking results showed that they had good binding affinity for the active site of AChE. Meanwhile, the five active compounds had reversible inhibitory effects on AChE: Polyporenic acid C and Tumulosic acid were non-competitive inhibitors; 3-Epidehydrotumulosic acid was a mixed inhibitor; and Pachymic acid and Dehydrotrametenolic acid were competitive inhibitors. This study provided a basis for the comprehensive utilization of P. cocos and drug development for the treatment of AD.

Synthesis characterization and evaluation of novel triazole based analogs as a acetylcholinesterase and α-glucosidase inhibitors

A series of novel triazole analogs (10a-k) bearing piperidine were synthesized in an aprotic solvent on the most effective pharmacophore with acetylcholinesterase (AChE) and α-glucosidase inhibitory activity. Triazole analogs (10a-k) were obtained in excellent yields (75–90 %) and characterized by EI-MS, IR, 13C NMR and 1H NMR. The newly synthesized triazole analogs (10a-k) showed potent AChE inhibitory activity in the range of Ki = 0.0155 ± 1.25 µM to 0.557 ± 0.50 µM, IC50 = 0.031 ± 0.85 to 0.537 ± 0.76 µM than Eserine (0.04 ± 0.001 µM) having strong electron-withdrawing fluorine group on the pyridine ring was recorded as a most potent inhibitor of AChE while (%) inhibition against α-glucosidase was ranging between 52.36 ± 1.67 to 85.35 ± 1.39. The kinetic study predicted that triazole analogs (10a-k) followed the un-competitive and mixed type of inhibition against AChE. In silico molecular docking was performed at the active site of the AChE co-crystal structure (PDB ID:1NEN). The results of molecular docking corelate will with the experimental findings.

Conjugates of Tacrine and Salicylic Acid Derivatives as New Promising Multitarget Agents for Alzheimer's Disease.

A series of previously synthesized conjugates of tacrine and salicylamide was extended by varying the structure of the salicylamide fragment and using salicylic aldehyde to synthesize salicylimine derivatives. The hybrids exhibited broad-spectrum biological activity. All new conjugates were potent inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with selectivity toward BChE. The structure of the salicylamide moiety exerted little effect on anticholinesterase activity, but AChE inhibition increased with spacer elongation. The most active conjugates were salicylimine derivatives: IC50 values of the lead compound 10c were 0.0826 µM (AChE) and 0.0156 µM (BChE), with weak inhibition of the off-target carboxylesterase. The hybrids were mixed-type reversible inhibitors of both cholinesterases and displayed dual binding to the catalytic and peripheral anionic sites of AChE in molecular docking, which, along with experimental results on propidium iodide displacement, suggested their potential to block AChE-induced β-amyloid aggregation. All conjugates inhibited Aβ42 self-aggregation in the thioflavin test, and inhibition increased with spacer elongation. Salicylimine 10c and salicylamide 5c with (CH2)8 spacers were the lead compounds for inhibiting Aβ42 self-aggregation, which was corroborated by molecular docking to Aβ42. ABTS•+-scavenging activity was highest for salicylamides 5a-c, intermediate for salicylimines 10a-c, low for F-containing salicylamides 7, and non-existent for methoxybenzoylamides 6 and difluoromethoxybenzoylamides 8. In the FRAP antioxidant (AO) assay, the test compounds displayed little or no activity. Quantum chemical analysis and molecular dynamics (MD) simulations with QM/MM potentials explained the AO structure-activity relationships. All conjugates were effective chelators of Cu2+, Fe2+, and Zn2+, with molar compound/metal (Cu2+) ratios of 2:1 (5b) and ~1:1 (10b). Conjugates exerted comparable or lower cytotoxicity than tacrine on mouse hepatocytes and had favorable predicted intestinal absorption and blood-brain barrier permeability. The overall results indicate that the synthesized conjugates are promising new multifunctional agents for the potential treatment of AD.

Novel Inhibitors of Acetyl- and Butyrylcholinesterase Derived from Benzohydrazides: Synthesis, Evaluation and Docking Study.

On the basis of previous reports, novel 2-benzoylhydrazine-1-carboxamides were designed as potential inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Inhibitors of these enzymes have many clinical applications. 2-(Substituted benzoyl)hydrazine-1-carboxamides decorated with N-methyl or tridecyl were prepared with three methods from commercially available or self-prepared hydrazides and isocyanates. For methyl derivatives, N-succinimidyl N-methylcarbamate was used or methyl isocyanate was prepared via Curtius rearrangement. Tridecyl isocyanate was synthesized again via Curtius rearrangement or from triphosgene and tridecylamine. The compounds were evaluated for the inhibition of AChE and BChE using Ellman's spectrophotometric method. Most of the derivatives showed the dual inhibition of both enzymes with IC50 values of 44-100 µM for AChE and from 22 µM for BChE. In general, the carboxamides inhibited AChE more strongly. A large number of the compounds showed better or quite comparable inhibition of cholinesterases in vitro than that of the drug rivastigmine. Molecular docking was performed to investigate the possible conformation of the compounds and their interactions with target enzymes. In both AChE and BChE, the compounds occupied the enzyme active cavity, and, especially in the case of BChE, the compounds were placed in close proximity to the catalytic triad.

A Review on Recent Approaches on Molecular Docking Studies of Novel Compounds Targeting Acetylcholinesterase in Alzheimer Disease.

Alzheimer's disease (AD), a neurodegenerative brain disorder that affects millions of people worldwide, is characterized by memory loss and cognitive decline. Low levels of acetylcholine and abnormal levels of beta-amyloid, T protein aggregation, inflammation, and oxidative stress, have been associated with AD, and therefore, research has been oriented towards the cholinergic system and primarily on acetylcholinesterase (AChE) inhibitors. In this review, we are focusing on the discovery of AChE inhibitors using computer-based modeling and simulation techniques, covering the recent literature from 2018-2022. More specifically, the review discusses the structures of novel, potent acetylcholinesterase inhibitors and their binding mode to AChE, as well as the physicochemical requirements for the design of potential AChE inhibitors.

Chemical profiling and biological activities of “green” extracts of willow species (Salix L., Salicaceae): Experimental and chemometric approaches

Willow bark extract (Salix spp., Salicaceae) has been used since ancient times as an analgesic, antipyretic and anti-inflammatory agent. In this paper, microwave-assisted extraction (MAE) was applied for the extraction of little-studied leaves and bark of six different species of the genus Salix with potential medicinal value. MAE extracts were evaluated in terms of their content of total phenolics, total flavonoids, selected phenolic constituents (salicin, chlorogenic acid, rutin, quercetin, naringenin) and antioxidant activity. Extracts with the highest content of target compounds were assessed for acetylcholinesterase inhibitory potential. Chemometric analysis was performed to identify clusters of samples based on the quantities of target phenolic compounds. Chemical composition varied among the analyzed species, as well as between leaves and bark of the same willow species. The extracts exhibited significant scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl (OH) radicals. Chemometric tools enabled selection of species and plant part (leaf or bark) with the most favorable chemical profile, which could be further explored as sources of bioactive compounds for nutraceutical and pharmaceutical purposes.

In Vitro and in Silico Insights on the Biological Activities, Phenolic Compounds Composition of Hypericum perforatum L. Hairy Root Cultures

Three Hypericum perforatum hairy root lines (HR B, HR F and HR H) along with non-transformed roots were analyzed for phenolic compounds composition and in vitro enzyme inhibitory properties. In silico molecular modeling was performed to predict the interactions of the most representative phenolic compounds in HR clones with enzymes related to depression, neurodegeneration and diabetes. Chromatographic analyses revealed that HR clones represent an efficient source of quinic acid and hydroxybenzoic acids, epicatechin and procyanidin derivatives, quercetin and kaempferol glycosides, as well numerous xanthones. In vitro antidepressant activity of HR extracts through monoamine oxidase A (MAO-A) inhibition was attributed to the production of oxygenated and prenylated xanthones. The neuroprotective potential of HR extracts was related to the accumulation of quercetin 6-C-glucoside, epicatechin, procyanidins and γ-mangostin isomers as potential inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Vanillic acid and prenylated xanthones in HR clones as promising inhibitors of tyrosinase additionally contributed to the neuroprotective activity. Five preeminent xanthones in HR (γ-mangostin, mangiferin, garcinone C, garcinone E and 1,3,7-trihydroxy-6-metoxy-8-prenyl xanthone) along with the flavonol quercetin 6-C-glucoside effectively inhibited α-amylase and α-glucosidase indicating the antidiabetic properties of HR extracts. Transgenic roots of H. perforatum can be exploited for the preparation of novel phytoproducts with multi-biological activities.