In-silico study of some natural plant phyto-compounds for the identification of novel potent cholinesterase inhibitors against Alzheimer's Disease

The main aim of this study is to identify inhibitory binding potent of the available commercially alkaloids, against the crystal structure of acetylcholinesterase (AChE) protein by in silico studies. The inhibitory data of the compounds should be compared with the internal ligand as well as standard AChE inhibitor Aricept (which is used for the treatment of all stages of Alzheimer’s disease). AutoDock 4.0 is used for the docking study, conformational orientation site analysis, and, with the help of docking, we have calculated parameters like binding energy and inhibition constant. Docking's study showed that Glabridin, Isorosmanol, Quercetin, Honokiol, Eckol, Sargaquinoic acid, and Ginsedosides revealed strong binding affinity with the enzyme. Moreover, The ADMET profiling and physicochemical properties of the selected compounds are evaluated using the Molinspiration and Data warrior software. By showing a strong binding affinity value, positive bioactivity score, and good pharmacokinetic properties, the top compound was determined. After evaluation with all parameters, the compound Glabridin and Ginsedosides show the most potent inhibitory effect towards the acetylcholinesterase, so this compound could be used as a novel is required to treat Alzheimer's disease.

Synthesis and preliminary biological evaluation of new phthalazinone derivatives with PARP-1 and cholinesterase inhibitory activities

The inhibition of Poly (ADP-ribose) polymerases-1 (PARP-1) has a potentially therapeutical value for AD. In order to search for a new agent based on multitarget-directed ligands (MTDLs) strategy, a series of 21 novel compounds incorporated the respective pharmacophores of two marketed drugs, namely 4-benzyl phthalazinone moiety of PARP-1 inhibitor Olaparib and N-benzylpiperidine moiety of AChE inhibitor Donepezil, into one molecule was synthesized. The inhibitory activities of all the synthesized compounds against the enzymes PARP-1, AChE and BChE were evaluated. Among them, 30 exhibited the most potent inhibitory effect on PARP-1 enzyme (8.18±2.81 nM) and moderate BChE inhibitory activity (1.63±0.52µM), while its AChE inhibitory activity (13.48±2.15µM) was weaker than Donepezil (0.04±0.01µM). Further molecular docking studies revealed that four hydrogen bonds were formed between 30 and PARP-1 which were similar with the interactions between Olaparib and PARP-1. 30 interacted with the critical residues His438 and Trp82 of huBChE through hydrogen bond and hydrophobic interaction which were necessary for huBChE inhibitory potency. Our research gave a clue to search for new agents based on PARP-1 and cholinesterase dual-inhibited activities to treat Alzheimer's disease.

A novel in vitro assay model developed to measure both extracellular and intracellular acetylcholine levels for screening cholinergic agents

Background Cholinergic neurons utilize choline (Ch) to synthetize acetylcholine (ACh) and contain a high-affinity Ch transporter, Ch acetyltransferase (ChAT), ACh receptors, and acetylcholinesterase (AChE). As the depletion or malfunction of each component of the cholinergic system has been reported in patients with dementia, many studies have sought to evaluate whether treatment candidates affect each of the cholinergic components. The associated changes in the cholinergic components may be reflected by intra- or extra-cellular ACh levels, with an increase in extracellular ACh levels occurring following AChE inhibition. We hypothesized that increases in intracellular ACh levels can be more sensitively detected than those in extracellular ACh levels, thereby capturing subtle effects in the cholinergic components other than AChE. The objective of this study was to test this hypothesis. Methods We developed an in vitro model to measure both extracellular and intracellular ACh levels using the human cholinergic neuroblastoma cell line, LA-N-2, which have been reported to express Ch transporter, ChAT, muscarinic ACh receptor (mAChR), and AChE. With this model, we evaluated several drug compounds and food constituents reported to improve cholinergic function through various mechanisms. In addition, we conducted western blotting to identify the subtype of mAChR that is expressed on the cell line. Results Our cell-based assay system was capable of detecting increases in extracellular ACh levels induced by an AChE inhibitor at relatively high doses, as well as increases in intracellular ACh levels following the administration of lower AChE-inhibitor doses and an mAChR agonist. Moreover, increases in intracellular ACh levels were observed even after treatment with food constituents that have different mechanisms of action, such as Ch provision and ChAT activation. In addition, we revealed that LA-N-2 cells expressed mAChR M2. Conclusion The findings support our hypothesis and indicate that the developed assay model can broadly screen compounds from drugs to food ingredients, with varying strengths and mechanisms of action, to develop treatments for ACh-relevant phenomena, including dementia and aging-related cognitive decline.

In-Silico Study of Some Natural Plant Phyto-compounds for the Identification of Novel Potent Cholinesterase Inhibitors Against Alzheimer Disease

The main aim of this study is to identify inhibitory binding potent of the available commercially alkaloids, against the crystal structure of acetylcholinesterase (AChE) protein by in silico studies. The inhibitory data of the compounds should be compared with the internal ligand as well as standard AChE inhibitor Aricept (which is used for the treatment of all stages of Alzheimer’s disease). AutoDock 4.0 is used for the docking study, conformational orientation site analysis, and, with the help of docking, we have calculated parameters like binding energy and inhibition constant. Docking's study showed that Glabridin, Isorosmanol, Quercetin, Honokiol, Eckol, Sargaquinoic acid, and Ginsedosides revealed strong binding affinity with the enzyme. Moreover, The ADMET profiling and physicochemical properties of the selected compounds are evaluated using the Molinspiration and Data warrior software. By showing a strong binding affinity value, positive bioactivity score, and good pharmacokinetic properties, the top compound was determined. After evaluation with all parameters, the compound Glabridin and Ginsedosides show the most potent inhibitory effect towards the acetylcholinesterase, so this compound could be used as a novel is required to treat Alzheimer's disease.

Five-Membered-Ring-Fused Tacrines as Anti-Alzheimer’s Disease Agents

Our endeavors in the design, synthesis, and biological assessment of five-membered-ring-fused tacrines as potential therapeutic agents for Alzheimer’s disease are summarized. Particularly, we have identified racemic 4-(2-methoxyphenyl)-3-methyl-2,4,6,7,8,9-hexahydropyrazolo[4′,3′:5,6]pyrano[2,3-b]quinolin-5-amine, a pyranopyrazolotacrine, as having the best nontoxic profile at the highest concentrations used (300 μM); this allows cell viability, is less hepatotoxic than tacrine, and is a potent noncompetitive AChE inhibitor (IC50 = 1.52 ± 0.49 μM). It is able to completely inhibit the EeAChE-induced Aβ1–40 aggregation in a statistically significant manner without affecting the Aβ1–40 self-aggregation at 25 μM, and shows strong neuroprotective effects (EC50 = 0.82 ± 0.17 μM).1 Introduction2 Furo-, Thieno-, and Pyrrolotacrines3 Pyrazolo-, Oxazolo-, and Isoxazolotacrines4 Indolotacrines5 Pyrano- and Pyridopyrazolotacrines6 Conclusions and Outlook

In vivo Evaluation of a Newly Synthesized Acetylcholinesterase Inhibitor in a Transgenic Drosophila Model of Alzheimer’s Disease

Alzheimer’s disease is a neurodegenerative disease characterized by disrupted memory, learning functions, reduced life expectancy, and locomotor dysfunction, as a result of the accumulation and aggregation of amyloid peptides that cause neuronal damage in neuronal circuits. In the current study, we exploited a transgenic Drosophila melanogaster line, expressing amyloid-β peptides to investigate the efficacy of a newly synthesized acetylcholinesterase inhibitor, named XJP-1, as a potential AD therapy. Behavioral assays and confocal microscopy were used to characterize the drug effect on AD symptomatology and amyloid peptide deposition. The symptomatology induced in this particular transgenic model recapitulates the scenario observed in human AD patients, showing a shortened lifespan and reduced locomotor functions, along with a significant accumulation of amyloid plaques in the brain. XJP-1 treatment resulted in a significant improvement of AD symptoms and a reduction of amyloid plaques by diminishing the amyloid aggregation rate. In comparison with clinically effective AD drugs, our results demonstrated that XJP-1 has similar effects on AD symptomatology, but at 10 times lower drug concentration than donepezil. It also showed an earlier beneficial effect on the reduction of amyloid plaques at 10 days after drug treatment, as observed for donepezil at 20 days, while the other drugs tested have no such effect. As a novel and potent AChE inhibitor, our study demonstrates that inhibition of the enzyme AChE by XJP-1 treatment improves the amyloid-induced symptomatology in Drosophila, by reducing the number of amyloid plaques within the fruit fly CNS. Thus, compound XJP-1 has the therapeutic potential to be further investigated for the treatment of AD.

Acetylcholinesterase inhibitory activity of extract and fractions from the root of Rauvolfia serpentina(L.) Bth.ex Kurz

Objectives Alzheimer’s disease (AD) is a degenerative brain disease characterized by confusion, behavior changes, decline in memory and cognitive skills. One of the strategies in the treatment of AD is to use acetylcholinesterase (AChE) inhibitors. The current study aims to determine the AChE inhibitory activities of the extract and fractions of the root of Rauvolfia serpentina. Methods Extraction was carried out by maceration method using ethanol, followed by liquid–liquid partition using n-hexane, ethyl acetate and n-butanol. Further fractionation was conducted by using vacuum liquid chromatography (VLC). The AChE inhibitory assays were performed by using Ellmann’s method. Phytochemical screening was carried out by TLC method. Results The ethanolic extract of R. serpentina showed inhibition against AChE enzyme with an IC50 value of 7.46 μg/mL. The extract and fractions showed higher inhibition against butyrylcholinesterase (BChE) compared to AChE. Amongst three fractions obtained, the n-butanol fraction showed the strongest inhibition with an IC50 value of 5.99 μg/mL against AChE. VLC fractionation of the n-butanol fraction yielded 13 subfractions (VLC 1–VLC 13). Four out of 13 subfractions gave more than 80% inhibition against AChE, namely subfractions 4–7, with IC50 values ranging from 4.87 to 47.22 μg/mL. The phytochemical screening of these subfractions suggested the presence of alkaloids. Conclusions The ethanolic extract, as well as fractions of R. serpentina root, are potential for AChE inhibitor. The alkaloid compound may be responsible for this activity.

A REVIEW: AQUILARIA SPECIES AS POTENTIAL OF PHARMACOLOGICAL

One of the plants that is rich in benefits is from the genus Aquilaria spp. which is known to be able to produce agarwood resin. This genus includes 47 species, of which the four main species are Aquilaria malaccensis, Aquilaria subintegra, Aquilaria crassna and Aquilaria sinensis. Aquilaria species are known to have a wide spectrum of pharmacological activity and have been reported in many studies, including activity, anticancer, anti-inflammatory, AChE inhibitor (Acetylcholinesterase), anti-proliferative, and antidiabetic. The aim of this review is to expand information on the pharmacological activity of various Aquilaria species that can support future studies in the medical field of medicine.

Acetylcholinesterase Inhibition, Molecular Docking and ADME Prediction Studies of New Dihydrofuran-Piperazine Hybrid Compounds

Novel acrylamide and methacryloyl carrying piperazine-dihydrofuran derivatives ( 3a-p ) were designed and obtained from radical cyclizations of unsaturated piperazine derivatives ( 1a-f ) with 1,3-dicarbonyl compounds ( 2a-c ) mediated by Mn(OAc) 3 . Structures of obtained compounds were confirmed with 1 H NMR (proton nuclear magnetic resonance), 13 C NMR (Carbon-13 nuclear magnetic resonance), HRMS (High resolution mass spectrometry), FTIR (Fourier-transform infrared spectroscopy and melting point analysis. Inhibitory activites of all piperazine-dihydrofuran compounds were evaluated against AChE (Acetylcholinesterase) by Ellman method and test results showed that 3a , 3c , 3j and 3l are most active AChEI’s (AChE inhibitors) of our work with IC 50 (half-maximal inhibitory concentration) values of 2.62, 5.29, 1.17 and 3.90 µM, respectively. Furthermore, ligand-protein interactions and inhibitory activity mechanisms of 3a and 3j were investigated by molecular docking. Finally, in silico molecular property and ADME (absorption, distribution, metabolism and excretion) of potential AChEI’s (AChE inhibitor) were predicted by PreADMET and Molinspiration webservers. It can be concluded that the lead compound 3j show excellent inhibiton and satisfactory druglike characteristics.

The ACE Genes in Aphelenchoides Besseyi Isolates and Their Expression Correlation to the Fenamiphos Treatment

Aphelenchoides besseyi could cause great yield loss on rice and many economically important crops. Acetylcholinesterase inhibitors were commonly used to mitigate plant parasitic nematodes. However, increasing nematicide-resistance has been reported due to the extensive use of these chemicals. The correlation between the AChE-inhibitor (fenamiphos) sensitivities and acetylcholinesterase (ace) genes in two isolates of A. besseyi (designated Rl and HSF) was established. The LD50 of fenamiphos to Rl and HSF were 572.2 ppm and 129.4 ppm, respectively, indicating that two nematode isolates had different sensitivities to fenamiphos. Three ace genes were cloned and sequenced in A. besseyi, and their homology was supported by phylogenic analysis with AChEs protein sequences from various vertebrate and invertebrate species. Molecular docking showed that the affinities of each AChEs to fenamiphos were higher in HSF isolate, indicating that there should be point mutations in Rl isolate AChEs. Treating the two isolates with 100 ppm fenamiphos for 12 h, three ace genes of HSF isolate were down-regulated but were up-regulated in Rl isolate. The results suggest that fenamiphos can transcriptionally modulate the expression of ace genes, as well as the variants in AChEs and increased expression of ace genes might be associated with fenamiphos-insensitivity in Rl isolate.