ABSTRACT
Alzheimer's disease is the most prevalent neurodegenerative disorder characterized by significant memory loss and cognitive impairments. Studies have shown that the expression level and activity of the butyrylcholinesterase enzyme increases significantly in the late stages of Alzheimer's disease, so butyrylcholinesterase can be considered as a promising therapeutic target for potential Alzheimer's treatments. In the present study, a novel series of 2,4-disubstituted quinazoline derivatives (6a-j) were synthesized and evaluated for their inhibitory activities against acetylcholinesterase (AChE) and butyrylcholinestrase (BuChE) enzymes, as well as for their antioxidant activities. The biological evaluation revealed that compounds 6f, 6h, and 6j showed potent inhibitory activities against eqBuChE, with IC50 values of 0.52, 6.74, and 3.65 µM, respectively. These potent compounds showed high selectivity for eqBuChE over eelAChE. The kinetic study demonstrated a mixed-type inhibition pattern for both enzymes, which revealed that the potent compounds might be able to bind to both the catalytic active site and peripheral anionic site of eelAChE and eqBuChE. In addition, molecular docking studies and molecular dynamic simulations indicated that potent compounds have favorable interactions with the active sites of BuChE. The antioxidant screening showed that compounds 6b, 6c, and 6j displayed superior scavenging capabilities compared to the other compounds. The obtained results suggest that compounds 6f, 6h, and 6j are promising lead compounds for the further development of new potent and selective BuChE inhibitors.
Subject(s)
Antioxidants , Butyrylcholinesterase , Cholinesterase Inhibitors , Molecular Docking Simulation , Molecular Dynamics Simulation , Quinazolines , Cholinesterase Inhibitors/pharmacology , Cholinesterase Inhibitors/chemical synthesis , Cholinesterase Inhibitors/chemistry , Butyrylcholinesterase/metabolism , Butyrylcholinesterase/chemistry , Antioxidants/pharmacology , Antioxidants/chemistry , Antioxidants/chemical synthesis , Quinazolines/pharmacology , Quinazolines/chemistry , Quinazolines/chemical synthesis , Acetylcholinesterase/metabolism , Acetylcholinesterase/chemistry , Humans , Structure-Activity Relationship , Catalytic Domain , Animals , Kinetics , ElectrophorusABSTRACT
In this study, Antarctic Latrunculia sponge-derived discorhabdin G was considered a hit for developing potential lead compounds acting as cholinesterase inhibitors. The hypothesis on the pharmacophore moiety suggested through molecular docking allowed us to simplify the structure of the metabolite. ADME prediction and drug-likeness consideration provided valuable support in selecting 5-methyl-2H-benzo[h]imidazo[1,5,4-de]quinoxalin-7(3H)-one as a candidate molecule. It was synthesized in a four-step sequence starting from 2,3-dichloronaphthalene-1,4-dione and evaluated as an inhibitor of electric eel acetylcholinesterase (eeAChE), human recombinant AChE (hAChE), and horse serum butyrylcholinesterase (BChE), together with other analogs obtained by the same synthesis. The candidate molecule showed a slightly lower inhibitory potential against eeAChE but better inhibitory activity against hAChE than discorhabdin G, with a higher selectivity for AChEs than for BChE. It acted as a reversible competitive inhibitor, as previously observed for the natural alkaloid. The findings from the in vitro assay were relatively consistent with the data available from the AutoDock Vina and Protein-Ligand ANTSystem (PLANTS) calculations.
Subject(s)
Acetylcholinesterase , Alkaloids , Butyrylcholinesterase , Cholinesterase Inhibitors , Electrophorus , Molecular Docking Simulation , Cholinesterase Inhibitors/pharmacology , Cholinesterase Inhibitors/chemistry , Animals , Acetylcholinesterase/metabolism , Alkaloids/pharmacology , Alkaloids/chemistry , Butyrylcholinesterase/metabolism , Humans , Porifera/chemistry , Structure-Activity Relationship , HorsesABSTRACT
Alzheimer's disease (AD) is a neurodegenerative disorder and the leading cause of dementia worldwide. It is characterized by a progressive decline in cholinergic neurotransmission. During the development of AD, acetylcholinesterase (AChE) binds to ß-amyloid peptides to form amyloid fibrils, which aggregate into plaque deposits. Meanwhile, tau proteins are hyperphosphorylated, forming neurofibrillary tangles (NFTs) that aggregate into inclusions. These complexes are cytotoxic for the brain, causing impairment of memory, attention, and cognition. AChE inhibitors are the main treatment for AD, but their effect is only palliative. This study aimed to design and synthesize novel benzofuran derivatives and evaluate their inhibition of AChE inâ vitro and in silico. Results: The seven synthesized benzofuran derivatives inhibited AChE inâ vitro. Benzofurans hydroxy ester 4, amino ester 5, and amido ester (±)-7 had the lowest inhibition constant (Ki) values and displayed good affinity for EeAChE in molecular docking. Six derivatives showed competitive inhibition, while the best compound (5: Ki=36.53â µM) exhibited uncompetitive inhibition. The amino, hydroxyl, amide, and ester groups of the ligands favored interaction with the enzyme by hydrogen bonds. Conclusion: Three benzofurans were promising AChE inhibitors with excellent Ki values. In future research on their their application to AD, 5 will be considered as the base structure.
Subject(s)
Acetylcholinesterase , Alzheimer Disease , Benzofurans , Cholinesterase Inhibitors , Molecular Docking Simulation , Benzofurans/chemistry , Benzofurans/chemical synthesis , Benzofurans/pharmacology , Cholinesterase Inhibitors/chemical synthesis , Cholinesterase Inhibitors/pharmacology , Cholinesterase Inhibitors/chemistry , Alzheimer Disease/drug therapy , Acetylcholinesterase/metabolism , Humans , Structure-Activity Relationship , Molecular Structure , Animals , Binding Sites , Electrophorus , Dose-Response Relationship, DrugABSTRACT
The Journal of Comparative Physiology lived up to its name in the last 100 years by including more than 1500 different taxa in almost 10,000 publications. Seventeen phyla of the animal kingdom were represented. The honeybee (Apis mellifera) is the taxon with most publications, followed by locust (Locusta migratoria), crayfishes (Cambarus spp.), and fruitfly (Drosophila melanogaster). The representation of species in this journal in the past, thus, differs much from the 13 model systems as named by the National Institutes of Health (USA). We mention major accomplishments of research on species with specific adaptations, specialist animals, for example, the quantitative description of the processes underlying the axon potential in squid (Loligo forbesii) and the isolation of the first receptor channel in the electric eel (Electrophorus electricus) and electric ray (Torpedo spp.). Future neuroethological work should make the recent genetic and technological developments available for specialist animals. There are many research questions left that may be answered with high yield in specialists and some questions that can only be answered in specialists. Moreover, the adaptations of animals that occupy specific ecological niches often lend themselves to biomimetic applications. We go into some depth in explaining our thoughts in the research of motion vision in insects, sound localization in barn owls, and electroreception in weakly electric fish.
Subject(s)
Electric Fish , Sound Localization , Strigiformes , Animals , Drosophila melanogaster , Sound Localization/physiology , Vision, Ocular , ElectrophorusABSTRACT
Few reports are available describing lesions in captive electric eels Electrophorus spp. This report describes 2 types of cutaneous proliferative lesions (i.e. hamartoma and neoplasm) in a captive electric eel. Ampullary electroreceptor hamartomas appeared grossly as 2 discrete, smooth, pink, spherical, cutaneous masses measuring 6 and 18 mm in diameter. Histologically, hamartomas were composed of predominately spindle cells that were separated into lobules by a peripheral rim of polygonal cells. Spindle cells were arranged in vague streams and occasionally whorls within a myxomatous matrix. Polygonal cells arranged in variably sized trabeculae and cords within a pre-existing fibrovascular stroma surrounded the streams of spindle cells. Admixed with the polygonal cell population were multiple mucous glands and alarm cells, similar to those seen in normal regions of epidermis. Histochemical stains confirmed similar components in the normal ampullary electroreceptor as in the hamartomas. Lymphoma was also present, appearing grossly as patchy pitting, erythematous, and thickened areas of the skin affecting the entire animal. Lymphoma was diffusely infiltrating and expanding the epidermis, oral mucosa, and branchial mucosa up to 1.5 mm in thickness. It was composed of an unencapsulated, well-demarcated, moderately cellular neoplasm composed of lymphocytes arranged in small dense sheets and clusters that separated and effaced epidermal cells. This is the first report of lymphoma in an electric eel, and the first report of ampullary electroreceptor hamartoma in any animal species.
Subject(s)
Hamartoma , Lymphoma , Neoplasms , Animals , Electrophorus , Hamartoma/veterinary , Neoplasms/veterinary , Lymphoma/veterinaryABSTRACT
Background: Electric eels (Electrophorus sp.) are known for their ability to produce electric organ discharge (EOD) reaching voltages of up to 860 V. Given that gene transfer via intense electrical pulses is a well-established technique in genetic engineering, we hypothesized that electric eels could potentially function as a gene transfer mechanism in their aquatic environment. Methods: To investigate this hypothesis, we immersed zebrafish larvae in water containing DNA encoding the green fluorescent protein (GFP) and exposed them to electric eel's EOD. Results and Discussion: Some embryos exhibited a mosaic expression of green fluorescence, in contrast to the control group without electrical stimulation, which showed little distinct fluorescence. This suggests that electric eel EOD has the potential to function as an electroporator for the transfer of DNA into eukaryotic cells. While electric eel EOD is primarily associated with behaviors related to sensing, predation, and defense, it may incidentally serve as a possible mechanism for gene transfer in natural environment. This investigation represents the initial exploration of the uncharted impact of electric eel EOD, but it does not directly establish its significance within the natural environment. Further research is required to understand the ecological implications of this phenomenon.
Subject(s)
Electric Organ , Zebrafish , Animals , Electric Organ/physiology , Electrophorus/physiology , Zebrafish/genetics , DNA , Predatory Behavior/physiologyABSTRACT
A new species of Ancyracanthus, parasite of the electric eel Electrophorus varii, in the Brazilian Amazon, is described based on morphological and molecular characterization. Ancyracanthus electrophori n. sp. differs from the two congeners namely, Ancyracanthus pinnatifidus and Ancyracanthus schubarti, based on the structure of cephalic appendages, number and arrangement of caudal papillae in males, vulva very close to anus in females, eggs with smoothly mamillated shell, host taxon and geographical origin. Moreover, the new species is the first in the genus to be described with thorny cuticular rings and to be observed with the use of scanning electron microscopy (SEM). The morphology of A. pinnatifidus and A. schubarti is still poorly-known and should be revised in details; however, the separation between them and the new species was clear. Genetic characterization based on 28S rDNA and cytochrome c oxidase subunit I (cox1) mtDNA partial sequences, performed for the first time in Acyracanthus, along with phylogenetic reconstructions using both genetic markers, placed Ancyracanthus electrophori n. sp. in a suggestive basal position within Gnathostomatidae. Phylogenetic reconstructions using cox1 sequences also suggested lack of monophyly in the genera Gnathostoma and Spiroxys and, consequently, in the subfamilies Gnathostominae and Spiroxyinae. However, such results are preliminary. With the first genetic characterization and observations using SEM in Ancyracanthus, resulting in the discovery of a new species and in the expansion of the geographical occurrence of the genus to Amazonian fish, an important step towards a better understanding of these nematodes has been taken.
Subject(s)
Gymnotiformes , Nematoda , Parasites , Spirurida , Female , Male , Animals , Electrophorus , Phylogeny , BrazilABSTRACT
Acetylcholinesterase (AChE) is the object of many studies due to the fact that it plays an important role in the vital activity of organisms. In particular, when new AChE inhibitors are developed, much attention is paid to the specificity of their action. One of the approaches used to study the specificity is to compare AChE taken from various organisms. In this work, crystallographic data are used to investigate the active sites of AChE (ASAs) in the free (uncomplexed) state for the following five organisms: Homo sapiens (HS), Mus musculus (MM), Torpedo californica (TC), Electrophorus electricus (EE), and Drosophila melanogaster (DM). The structural fractal analysis (SFA) proposed by us earlier is used as a research method. This method is based on the calculation and comparison of the fractal dimensions of molecular structures. SFA demonstrates that there are no significant structural differences between the active sites of human AChE and other AChEs. However, differences are found for the MM/EE pair. Further analysis of individual AARs has revealed two different areas of active sites. Ser203, Trp236, Phe338, and Tyr341 are found to belong to a variable region, and the remaining AARs belong to a conservative region of the ASAs. The fraction of "variability" is low, 0.8%.
Subject(s)
Acetylcholinesterase , Fractals , Acetylcholinesterase/chemistry , Animals , Catalytic Domain , Cholinesterase Inhibitors/chemistry , Cholinesterase Inhibitors/pharmacology , Drosophila melanogaster , Electrophorus/metabolism , Humans , Mice , Torpedo/metabolismABSTRACT
The inhibitory effects of bisphenol A (BPA) and bisphenol S (BPS), which are common pollutants, especially in marine and freshwater, on the electric eel acetylcholinesterase (AChE) activity were studied in vitro and in silico. Both produced full non-competitive inhibition, but the Ki value of BPA was half that of BPS. Molecular docking analyses revealed that both interact with residues W286, F297, Y337, F338 in the PAS and ABS regions in the middle and entrance of the active site gorge, and that BPS also has hydrogen bond with S203 of the catalytic triad. The surge at IC50 values of both compounds with an inflection point at pH: 8.2 suggested that Y124 and/or Y337 in the narrow gorge are primary structural factors in binding. Less effective inhibition of BPS, especially at 25-30 °C, the temperature at which enzyme activity peaks, was attributed to the conformation of the narrow gorge. Homology analyses for AChE initially revealed a significant degree of identity, particularly in the alpha/beta hydrolase domain, which also comprises the active site, with sequences from seven distinct teleost species of various environments. Finally, it was discovered for the first time that BPS, like BPA, is a significant inhibitor of AChE, and this was confirmed by in vitro and in silico analyses done at various pH and temperature levels. It was concluded that this effect might also apply to AChE of most other bony fish.
Subject(s)
Acetylcholinesterase , Cholinesterase Inhibitors , Acetylcholinesterase/metabolism , Animals , Benzhydryl Compounds , Cholinesterase Inhibitors/chemistry , Cholinesterase Inhibitors/toxicity , Electrophorus/metabolism , Molecular Docking Simulation , PhenolsABSTRACT
The management of neurological disorders such as dementia associated with Alzheimer's or Parkinson's disease includes the use of cholinesterase inhibitors. These compounds can slow down the progression of these diseases and can also be used in the treatment of glaucoma and myasthenia gravis. The majority of the cholinesterase inhibitors used in the clinic are derived from natural products and our current paper describes the use of a small marine pharmacophore to develop potent and selective cholinesterase inhibitors. Fourteen small inhibitors were designed based on recent discoveries about the inhibitory potential of a range of related marine secondary metabolites. The compounds were evaluated, in kinetic enzymatic assays, for their ability to inhibit three different cholinesterase enzymes and it was shown that compounds with a high inhibitory activity towards electric eel and human recombinant acetylcholinesterase (IC50 between 20-70 µM) could be prepared. It was also shown that this compound class was particularly active against horse serum butyrylcholinesterase, with IC50 values between 0.8-16 µM, which is an order of magnitude more potent than the clinically used positive control neostigmine. The compounds were further tested for off-target toxicity against both human umbilical vein endothelial cells and bovine and human erythrocytes and were shown to display a low mammalian cellular toxicity. Overall, the study illustrates how the brominated dipeptide marine pharmacophore can be used as a versatile natural scaffold for the design of potent, and selective cholinesterase inhibitors.
Subject(s)
Alzheimer Disease , Cholinesterase Inhibitors , Acetylcholinesterase/metabolism , Alzheimer Disease/metabolism , Animals , Butyrylcholinesterase/metabolism , Cattle , Cholinesterase Inhibitors/chemistry , Electrophorus , Endothelial Cells/metabolism , Horses , Humans , Molecular Docking Simulation , Structure-Activity RelationshipABSTRACT
Structure-based virtual screening of the Enamine database of 1.7 million compounds followed by WaterMap calculations (a molecular-dynamics-simulation-based method) was applied to identify novel acetylcholinesterase (AChE) inhibitors. The inhibitory potency of 29 selected compounds against electric eel (ee) AChE was determined using Ellman's method. Three compounds were found to be active (success rate 10 %). For the most potent compound (â¼40 % inhibition at 10â µM), 20 derivatives were discovered based on the Enamine similarity search. Finally, five compounds were found to be promising (IC50 ranged from 6.3â µM to 17.5â µM) inhibitors of AChE. The performed similarity and fragment analysis confirmed significant structural novelty for these AChE inhibitors. Toxicity/safety of selected compounds was determined in zebrafish model.
Subject(s)
Acetylcholinesterase , Cholinesterase Inhibitors , Acetylcholinesterase/chemistry , Animals , Cholinesterase Inhibitors/chemistry , Cholinesterase Inhibitors/toxicity , Electrophorus , Molecular Docking Simulation , ZebrafishABSTRACT
Based on the multitarget-directed ligands strategy, a series of 3-butyl-6-benzyloxyphthalide Mannich base derivatives were designed, synthesized and identified for Alzheimer's disease (AD). Biological activity studies demonstrated that the designed hybrids showed multitarget activities toward AD. Among them, compound 7d was the most potent agent with excellent inhibitory activities on EeAChE (IC50 = 0.087 µM), HuAChE (IC50 = 0.041 µM) and MAO-B (IC50 = 0.30 µM). Furthermore, molecular docking studies were conducted to investigate the interaction mode with enzymes. Besides, 7d also possessed good effects of Cu2+ chelation, ameliorate oxidative stress, and anti-neuroinflammation, desirable BBB permeability and eligible drug-like properties. Altogether, the multifunctional profiles of 7d prove that it deserves further investigation as a novel drug candidate for AD treatment.
Subject(s)
Alzheimer Disease/drug therapy , Cholinesterase Inhibitors/pharmacology , Drug Discovery , Mannich Bases/pharmacology , Monoamine Oxidase Inhibitors/pharmacology , Neuroprotective Agents/pharmacology , Acetylcholinesterase/metabolism , Alzheimer Disease/metabolism , Animals , Blood-Brain Barrier/drug effects , Blood-Brain Barrier/metabolism , Cholinesterase Inhibitors/chemical synthesis , Cholinesterase Inhibitors/chemistry , Dose-Response Relationship, Drug , Electrophorus , Humans , Mannich Bases/chemical synthesis , Mannich Bases/chemistry , Molecular Structure , Monoamine Oxidase/metabolism , Monoamine Oxidase Inhibitors/chemical synthesis , Monoamine Oxidase Inhibitors/chemistry , Neuroprotective Agents/chemical synthesis , Neuroprotective Agents/chemistry , Oxidative Stress/drug effects , Structure-Activity RelationshipABSTRACT
A sensitive assay was developed to evaluate inhibitory effects of aqueous solution on acetylcholinesterase (AChE) activity via measuring hydrolysis rates of acetylcholine (ACh) based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Upon having identified precursor ions and product ions of the ACh and its hydrolysis products choline (Ch), the separation chromatogram for these two analytes has been established using a 50 mm reverse-phase BEH Shield RP18 column. The total chromatographic separation time is 7 min; limits of detection (LODs) for ACh and Ch are 0.14 µg L-1 and 0.12 µg L-1, respectively. A simple method for inactivation of AChE and optimization of operational parameters were then sequentially performed. It was found that adjusting solution pH to 2.5 not only can terminate the enzymatic reaction but also solve band shifting and broadening caused by aqueous matrices in chromatographic separation during UPLC-MS/MS detection. Under conditions of 0.00075 U mL-1 AChE, initial concentration of ACh at 100 µg L-1 and 20 min observation time, IC50 values of the proposed assay for chlorpyrifos-oxon, diazoxon, malaoxon, methidathion oxon, omethoate and paraoxon were 3.5 nM, 16.8 nM, 2.4 nM, 6.8 nM, 270 nM and 36.9 nM, respectively. They are 4.5-51.9 times smaller than those reported in a LC-MS based method, and >120 times lower than those obtained by the traditional Ellman method. The results suggested that, the proposed assay significantly increases the sensitivity of commercial AChE. In addition, inhibition efficiencies of three surface waters, a groundwater and four commercial brands of bottled drinking water samples on AChE activity were firstly measured using this UPLC-MS/MS based method. These water samples were proved to have different inhibitory effects on AChE activity, and the inhibition efficiencies dependent on concentrations of dissolved organic carbon (DOC) but are independent of UV absorbance at 254 nm (UV254) values. These results indicate that the proposed method has advantages of high sensitivity over all other conventional methods. It may become a promising AChE inhibition assay for assessing toxicity of aqueous solution containing neurotoxicity contaminants such as organophosphorus pesticides (OPPs) at low levels, or used to evaluate potential inhibition effects of natural waters on AChE activity.
Subject(s)
Cholinesterase Inhibitors/chemistry , Chromatography, High Pressure Liquid/methods , Fish Proteins/antagonists & inhibitors , Tandem Mass Spectrometry/methods , Water Pollutants/chemistry , Acetylcholine/chemistry , Acetylcholinesterase/chemistry , Animals , Drinking Water/chemistry , Electrophorus , Groundwater/chemistry , Hydrolysis , Organophosphorus Compounds/chemistry , Sensitivity and SpecificityABSTRACT
Alzheimer's disease (AD) possesses a complex pathogenetic mechanism. Nowadays, multitarget agents are considered to have potential in effectively treating AD via triggering molecules in functionally complementary pathways at the same time. Here, based on the screening (â¼1400 compounds) against neuroinflammation, an imidazolylacetophenone oxime ether (IOE) was discovered as a novel hit. In order to obtain SARs, a series of imidazolylacetophenone oxime derivatives were constructed, and their C=N bonds were confirmed as the Z configuration by single crystals. These derivatives exhibited potential multifunctional neuroprotective effects including anti-neuroinï¬ammatory, antioxidative damage, metal-chelating, inhibition of acetylcholinesterase (AChE) properties. Among these derivatives, compound 12i displayed the most potent inhibitory activity against nitric oxide (NO) production with EC50 value of 0.57 µM 12i can dose-dependently suppress the expression of iNOS and COX-2 but not change the expression of HO-1 protein. Moreover, 12i exhibited evidently neuroprotective effects on H2O2-induced PC12 cells damage and ferroptosis without cytotoxicity at 10 µM, as well as selectively metal chelating properties via chelating Cu2+. In addition, 12i showed a mixed-type inhibitory effect on AChE in vitro. The structure-activity relationships (SARs) analysis indicated that dioxolane groups on benzene ring and rigid oxime ester can improve the activity. Parallel artificial membrane permeation assay (PAMPA) also verified that 12i can overcome the blood-brain barrier (BBB). Overall, this is the ï¬rst report on imidazolylacetophenone oxime-based multifunctional neuroprotective effects, suggesting that this type of compounds might be novel multifunctional agents against AD.
Subject(s)
Acetophenones/pharmacology , Drug Discovery , Enzyme Inhibitors/pharmacology , Imidazoles/pharmacology , Neuroprotective Agents/pharmacology , Oximes/pharmacology , Acetophenones/chemical synthesis , Acetophenones/chemistry , Acetylcholinesterase/metabolism , Animals , Biphenyl Compounds/antagonists & inhibitors , Cell Line , Cyclooxygenase 2/metabolism , Dose-Response Relationship, Drug , Electrophorus , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Humans , Imidazoles/chemical synthesis , Imidazoles/chemistry , Lipopolysaccharides/antagonists & inhibitors , Lipopolysaccharides/pharmacology , Mice , Molecular Structure , Neuroprotective Agents/chemical synthesis , Neuroprotective Agents/chemistry , Nitric Oxide/antagonists & inhibitors , Nitric Oxide/biosynthesis , Oximes/chemical synthesis , Oximes/chemistry , Picrates/antagonists & inhibitors , Rats , Structure-Activity RelationshipABSTRACT
A novel series of chalcone-Vitamin E-donepezil hybrids was designed and developed based on multitarget-directed ligands (MTDLs) strategy for treating Alzheimer's disease (AD). The biological results revealed that compound 17f showed good AChE inhibitory potency (ratAChE IC50 = 0.41 µM; eeAChE IC50 = 1.88 µM). Both the kinetic analysis and docking study revealed that 17f was a mixed type AChE inhibitor. 17f was also a good antioxidant (ORAC = 3.3 eq), selective metal chelator and huMAO-B inhibitor (IC50 = 8.8 µM). Moreover, it showed remarkable inhibition of self- and Cu2+-induced Aß1-42 aggregation with a 78.0 and 93.5% percentage rate at 25 µM, respectively, and disassembled self-induced and Cu2+-induced aggregation of the accumulated Aß1-42 fibrils with 72.3 and 84.5% disaggregation rate, respectively. More importantly, 17f exhibited a good neuroprotective effect on H2O2-induced PC12 cell injury and presented good blood-brain barrier permeability in vitro. Thus, 17f was a promising multi-target-directed ligand for treating AD.
Subject(s)
Alzheimer Disease/drug therapy , Antioxidants/pharmacology , Cholinesterase Inhibitors/pharmacology , Drug Design , Monoamine Oxidase Inhibitors/pharmacology , Neuroprotective Agents/pharmacology , Acetylcholinesterase/metabolism , Alzheimer Disease/metabolism , Amyloid beta-Peptides/antagonists & inhibitors , Amyloid beta-Peptides/metabolism , Animals , Antioxidants/chemical synthesis , Antioxidants/chemistry , Chalcone/chemistry , Chalcone/pharmacology , Cholinesterase Inhibitors/chemical synthesis , Cholinesterase Inhibitors/chemistry , Dose-Response Relationship, Drug , Electrophorus , Humans , Ligands , Molecular Structure , Monoamine Oxidase/metabolism , Monoamine Oxidase Inhibitors/chemical synthesis , Monoamine Oxidase Inhibitors/chemistry , Neuroprotective Agents/chemical synthesis , Neuroprotective Agents/chemistry , PC12 Cells , Protein Aggregates/drug effects , Rats , Structure-Activity Relationship , Vitamin E/chemistry , Vitamin E/pharmacologyABSTRACT
The identification of novel compounds that can inhibit physiologically and metabolically important drug targets or enzymes has prime importance in medicinal chemistry. With this aim, a range of secnidazole esters 1-30 were synthesized under the heading of biology-oriented drug synthesis by the 1,1'-carbonyldiimidazole-mediated coupling reaction between secnidazole and varyingly benzoic acid derivatives. All compounds were screened for inhibitory activity against human carbonic anhydrase (hCA) I and II, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and α-glucosidase. The results indicate that all the synthesized compounds showed potent inhibitory activities against all targets, as compared to the standard inhibitors, revealed by IC50 values. Ki values of the secnidazole derivatives 1-30 for hCA I, hCA II, AChE, BChE, and α-glucosidase enzymes were obtained in the ranges of 47.37-190.74, 44.38-198.21, 12.14-68.37, 8.04-61.53, and 7.78-45.91 nM, respectively. To assess the enzyme-ligand interactions, the optimized most active compounds 2, 3, 8, 9, 14, 17, and 23 were subjected to molecular docking studies with modeled AChE, BChE, hCA I, hCA II, and α-glucosidase enzymes, where several important and key interactions were monitored with amino acid residues of each target enzyme.
Subject(s)
Carbonic Anhydrase Inhibitors/pharmacology , Cholinesterase Inhibitors/pharmacology , Glycoside Hydrolase Inhibitors/pharmacology , Metronidazole/analogs & derivatives , Animals , Carbonic Anhydrase Inhibitors/chemical synthesis , Carbonic Anhydrase Inhibitors/chemistry , Cholinesterase Inhibitors/chemical synthesis , Cholinesterase Inhibitors/chemistry , Electrophorus , Esters , Glycoside Hydrolase Inhibitors/chemical synthesis , Glycoside Hydrolase Inhibitors/chemistry , Horses , Humans , Inhibitory Concentration 50 , Ligands , Metronidazole/chemical synthesis , Metronidazole/chemistry , Metronidazole/pharmacology , Molecular Docking Simulation , Structure-Activity RelationshipABSTRACT
Four new and four known isoxazoline derivatives were synthesized from the reactions of benzonorbornadiene with nitrile oxides formed from the corresponding benzaldehydes. Three new and one known pyrazoline derivatives were also synthesized from the reactions of the benzonorbornadiene with nitrile imines formed from the corresponding compounds. The synthesized nitrogen-based novel heterocyclic compounds were evaluated against the human carbonic anhydrase isoenzymes I and II (hCA I and hCA II), acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) enzymes. The synthesized nitrogen-based novel heterocyclic compounds showed IC50 values in the range of 2.69-7.01 against hCA I, 2.40-4.59 against hCA II, 0.81-1.32 µM against AChE, and 20.83-1.70 µM against BChE enzymes. On the contrary, nitrogen-based novel heterocyclic compounds demonstrated Ki values between 2.93 ± 0.59-8.61 ± 1.39 against hCA I, 2.05 ± 0.62-4.97 ± 0.95 against hCA II, 0.34 ± 0.02-0.92 ± 0.17 nM against AChE, and 0.50 ± 0.04-1.20 ± 0.16 µM against BChE enzymes. The synthesized nitrogen-based novel heterocyclic compounds exhibited effective inhibition profiles against both indicated metabolic enzymes. These results may contribute to the development of new drugs particularly to treat some disorders, which are widespread in the world including glaucoma and Alzheimer's diseases.
Subject(s)
Acetylcholinesterase , Butyrylcholinesterase/chemistry , Carbonic Anhydrase II , Carbonic Anhydrase I , Carbonic Anhydrase Inhibitors , Acetylcholinesterase/chemistry , Animals , Carbonic Anhydrase I/antagonists & inhibitors , Carbonic Anhydrase I/chemistry , Carbonic Anhydrase II/antagonists & inhibitors , Carbonic Anhydrase II/chemistry , Carbonic Anhydrase Inhibitors/chemical synthesis , Carbonic Anhydrase Inhibitors/chemistry , Cholinesterase Inhibitors/chemical synthesis , Cholinesterase Inhibitors/chemistry , Electrophorus , GPI-Linked Proteins/antagonists & inhibitors , GPI-Linked Proteins/chemistry , Structure-Activity RelationshipABSTRACT
Alzheimer's disease is a multifactorial neurodegenerative disorder. Since cholinergic deficit is a major factor in this disease, two molecular targets for its treatment are the acetylcholinesterase (AChE) and the nicotinic acetylcholine receptors (nAChRs). Given that caffeine is a natural compound that behaves as an AChE inhibitor and as a partial agonist of nAChRs, the aim of this work was to synthetize more potent bifunctional caffeine analogs that modulate these two molecular targets. To this end, a theophylline structure was connected to a pyrrolidine structure through a methylene chain of different lengths (3 to 7 carbon atoms) to give compounds 7-11 All caffeine derivatives inhibited the AChE, of which compound 11 showed the strongest effect. Electrophysiological studies showed that all compounds behave as agonists of the muscle and the neuronal α7 nAChR with greater potency than caffeine. To explore whether the different analogs could affect the nAChR conformational state, the nAChR conformational-sensitive probe crystal violet (CrV) was used. Compounds 9 and 10 conduced the nAChR to a different conformational state comparable with a control nAChR desensitized state. Finally, molecular docking experiments showed that all derivatives interacted with both the catalytic and anionic sites of AChE and with the orthosteric binding site of the nAChR. Thus, the new synthetized compounds can inhibit the AChE and activate muscle and α7 nAChRs with greater potency than caffeine, which suggests that they could be useful leaders for the development of new therapies for the treatment of different neurologic diseases. SIGNIFICANCE STATEMENT: In this work we synthetized caffeine derivatives which can inhibit acetylcholinesterase and activate both muscle and α7 nicotinic acetylcholine receptors (nAChRs) with higher potency than caffeine. These analogs can be divided into two groups: a non-desensitizing and a desensitizing nAChR group. From the nAChR non-desensitizing group, we propose compound 11 as the most interesting analog for further studies since it inhibits acetylcholinesterase with the highest potency and activates the nAChRs in the picomolar range without inducing receptor desensitization.
Subject(s)
Caffeine/analogs & derivatives , Caffeine/chemical synthesis , alpha7 Nicotinic Acetylcholine Receptor/agonists , alpha7 Nicotinic Acetylcholine Receptor/metabolism , Animals , Caffeine/metabolism , Caffeine/pharmacology , Electrophorus , HEK293 Cells , Humans , Molecular Docking Simulation/methods , Protein Structure, Secondary , Torpedo , alpha7 Nicotinic Acetylcholine Receptor/chemistryABSTRACT
Structure-based drug design (SBDD) is an important in silico technique, used for the identification of enzyme inhibitors. Acetylcholinesterase (AChE), obtained from Electrophorus electricus (ee), is widely used for the screening of AChE inhibitors. It shares structural homology with the AChE of human and other organisms. Till date, the three-dimensional crystal structure of enzyme from ee is not available that makes it challenging to use the SBDD approach for the identification of inhibitors. A homology model was developed for eeAChE in the present study, followed by its structural refinement through energy minimisation. The docking protocol was developed using a grid dimension of 84 × 66 × 72 and grid point spacing of 0.375 Å for eeAChE. The protocol was validated by redocking a set of co-crystallised inhibitors obtained from mouse AChE, and their interaction profiles were compared. The results indicated a poor performance of the Autodock scoring function. Hence, a batch of machine learning-based scoring functions were developed. The validation results displayed an accuracy of 81.68 ± 1.73% and 82.92 ± 3.05% for binary and multiclass classification scoring function, respectively. The regression-based scoring function produced [Formula: see text] and [Formula: see text] values of 0.94, 0.635 and 0.634, respectively.
Subject(s)
Acetylcholinesterase , Cholinesterase Inhibitors , Acetylcholinesterase/chemistry , Animals , Cholinesterase Inhibitors/chemistry , Cholinesterase Inhibitors/pharmacology , Drug Design , Electrophorus , Machine Learning , MiceABSTRACT
Triterpenoic acids (oleanolic, ursolic, betulinic, platanic and glycyrrhetinic acid) were acetylated and coupled with 1,3- or 1,4-diazabicyclo[3.2.2]nonanes to yield amides. Reaction of these amides with methyl iodide at the distal nitrogen of the bicyclic system gave the corresponding quaternary ammonium salts. These compounds were shown to act as excellent inhibitors of the enzyme butyrylcholinesterase (BChE) while being only weak inhibitors for acetylcholinesterase (AChE). Evaluation of the enzyme kinetics revealed these compounds to act as hyperbolic inhibitors for BChE while the results from molecular modeling gave an explanation for their selectivity between AChE and BChE.