Novel biphenyl bis-sulfonamides as acetyl and butyrylcholinesterase inhibitors: Synthesis,biological evaluation and molecular modeling studies

A series of new biphenyl bis-sulfonamide derivatives 2a–3p were synthesized in good to excellent yield (76–98%). The inhibitory potential of the synthesized compounds on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) was investigated. Most of the screened compounds showed modest in vitro inhibition for both AChE and BChE. Compared to the reference compound eserine (IC₅₀ 0.04 ± 0.0001 μM for AChE) and (IC₅₀ 0.85 ± 0.0001 μM for BChE), the IC₅₀ values of these compounds were ranged from 2.27 ± 0.01 to 123.11 ± 0.04 μM for AChE and 7.74 ± 0.07 to <400 μM for BuChE. Among the tested compounds, 3p was found to be the most potent against AChE (IC₅₀ 2.27 ± 0.01 μM), whereas 3g exhibited the highest inhibition for BChE (IC₅₀ 7.74 ± 0.07 μM). Structure–activity relationship (SAR) of these compounds was developed and elaborated with the help of molecular docking studies.     

Indole alkaloids of Psychotria as multifunctional cholinesterases and monoamine oxidases inhibitors

Thirteen Psychotria alkaloids were evaluated regarding their interactions with acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and monoamine oxidases A and B (MAO-A and MAO-B), which are enzymatic targets related with neurodegenerative diseases. Two quaternary β-carboline alkaloids, prunifoleine and 14-oxoprunifoleine, inhibited AChE, BChE and MAO-A with IC₅₀ values corresponding to 10 and 3.39 μM for AChE, 100 and 11 μM for BChE, and 7.41 and 6.92 μM for MAO-A, respectively. Both compounds seem to behave as noncompetitive AChE inhibitors and time-dependent MAO-A inhibitors. In addition, the monoterpene indole alkaloids (MIAs) angustine, vallesiachotamine lactone, E-vallesiachotamine and Z-vallesiachotamine inhibited BChE and MAO-A with IC₅₀ values ranging from 3.47 to 14 μM for BChE inhibition and from 0.85 to 2.14 μM for MAO-A inhibition. Among the tested MIAs, angustine is able to inhibit MAO-A in a reversible and competitive way while the three vallesiachotamine-like alkaloids display a time-dependent inhibition on this target. Docking calculations were performed in order to understand the binding mode between the most active ligands and the selected targets. Taken together, our findings established molecular details of AChE, BChE and MAO-A inhibition by quaternary β-carboline alkaloids and MIAs from Psychotria, suggesting these secondary metabolites are scaffolds for the development of multifunctional compounds against neurodegeneration.     

Synthesis of readily available fluorophenylalanine derivatives and investigation of their biological activity

A series of thirty novel N-acetylated fluorophenylalanine-based aromatic amides and esters was synthesized using N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide or phosphorus trichloride in pyridine. They were characterized by spectral methods and screened against various microbes (Mycobacterium tuberculosis, non-tuberculous mycobacteria, other bacteria, fungi), for their inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) and cytotoxicity. All amino acids derivatives revealed a moderate inhibition of both cholinesterases with IC₅₀ values for AChE and BChE of 57.88–130.75 µM and 8.25–289.0 µM, respectively. Some derivatives were comparable or superior to rivastigmine, an established drug. Phenyl 2-acetamido-3-(4-fluorophenyl)propanoate was identified as the selective and most potent inhibitor of BChE. The esterification and amidation of parent acids led to an improved BChE inhibition. The esters are better inhibitors of BChE than the amides. The introduction of NO₂ and CH₃ groups into aniline ring and CF₃ moiety in phenol is translated into lower IC₅₀ values. Seven compounds showed selectivity index higher than 10 for at least one cholinesterase. Especially the esters exhibited a mild activity against Gram-positive bacteria, mycobacteria and several fungal strains with minimum inhibitory concentrations starting from 125 µM. The highest susceptibility was recorded for Trichophyton mentagrophytes fungus.     

Synthesis,biological evaluation and docking studies of 2,3-dihydroquinazolin-4(1H)-one derivatives as inhibitors of cholinesterases

In search of potent inhibitors of cholinesterases, we have synthesized and evaluate a number of 2,3-dihydroquinazolin-4(1H)-one derivatives. The synthetic approach provided an efficient synthesis of the target molecules with excellent yield. All the tested compounds showed activity against both the enzymes in micromolar range. In many case, the inhibition of both enzymes are higher than or comparable to the standard drug galatamine. With the selectivity index of 2.3 for AChE, compound 5f can be considered as a potential lead compound with a feature of dual AChE/BChE inhibition with IC₅₀ = 1.6 ± 0.10 μM (AChE) and 3.7 ± 0.18 μM (BChE). Binding modes of the synthesized compounds were explored by using GOLD (Genetic Optimization for Ligand Docking) suit v5.4.1. The computed binding modes of these compounds in the active site of AChE and BChE provide an insight into the mechanism of inhibition of these two enzyme.     

Synthesis,characterization, and molecular docking analysis of novel benzimidazole derivatives as cholinesterase inhibitors

Two series of novel acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors containing benzimidazole core structure were synthesized by a four-step reaction pathway starting from 4-fluoro-3-nitrobenzoic acid as the basic compound. The structure of the novel benzimidazoles was characterized and confirmed by the elemental and mass spectral analyses as well as ¹H NMR spectroscopic data. Of the 34 novel synthesized compounds, three benzimidazoles revealed AChE inhibition with IC₅₀ < 10 μM. The highest inhibitory activity (IC₅₀ = 5.12 μM for AChE and IC₅₀ = 8.63 μM for BChE) corresponds to the compound 5IIc (ethyl 1-(3-(1H-imidazol-1-yl)propyl)-2-(4-nitrophenyl)-1H-benzo[d]imidazole-5-carboxylate). The relationship between lipophilicity and the chemical structures as well as their limited structure–activity relationship was discussed.     

Syntheses of coumarin–tacrine hybrids as dual-site acetylcholinesterase inhibitors and their activity against butylcholinesterase,Aβ aggregation,and β-secretase

Exploring small-molecule acetylcholinesterase (AChE) inhibitors to slow the breakdown of acetylcholine (Ach) represents the mainstream direction for Alzheimer’s disease (AD) therapy. As the first acetylcholinesterase inhibitor approved for the clinical treatment of AD, tacrine has been widely used as a pharmacophore to design hybrid compounds in order to combine its potent AChE inhibition with other multi-target profiles. In present study, a series of novel tacrine–coumarin hybrids were designed, synthesized and evaluated as potent dual-site AChE inhibitors. Moreover, compound 1g was identified as the most potent candidate with about 2-fold higher potency (K_i = 16.7 nM) against human AChE and about 2-fold lower potency (K_i = 16.1 nM) against BChE than tacrine (K_i = 35.7 nM for AChE, K_i = 8.7 nM for BChE), respectively. In addition, some of the tacrine–coumarin hybrids showed simultaneous inhibitory effects against both Aβ aggregation and β-secretase. We therefore conclude that tacrine–coumarin hybrid is an interesting multifunctional lead for the AD drug discovery.     

Synthesis,cholinesterase inhibition and molecular modelling studies of coumarin linked thiourea derivatives

Alzheimer’s disease is among the most widespread neurodegenerative disorder. Cholinesterases (ChEs) play an indispensable role in the control of cholinergic transmission and thus the acetylcholine level in the brain is enhanced by inhibition of ChEs. Coumarin linked thiourea derivatives were designed, synthesized and evaluated biologically in order to determine their inhibitory activity against acetylcholinesterases (AChE) and butyrylcholinesterases (BChE). The synthesized derivatives of coumarin linked thiourea compounds showed potential inhibitory activity against AChE and BChE. Among all the synthesized compounds, 1-(2-Oxo-2H-chromene-3-carbonyl)-3-(3-chlorophenyl)thiourea (2e) was the most potent inhibitor against AChE with an IC₅₀ value of 0.04 ± 0.01 μM, while 1-(2-Oxo-2H-chromene-3-carbonyl)-3-(2-methoxyphenyl)thiourea (2b) showed the most potent inhibitory activity with an IC₅₀ value of 0.06 ± 0.02 μM against BChE. Molecular docking simulations were performed using the homology models of both cholinesterases in order to explore the probable binding modes of inhibitors. Results showed that the novel synthesized coumarin linked thiourea derivatives are potential candidates to develop for potent and efficacious acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors.     

Synthesis and in vitro evaluation of novel rhodanine derivatives as potential cholinesterase inhibitors

Based on a broad spectrum of biological activities of rhodanines, we synthesized aromatic amides and esters of 2-(4-oxo-2-thioxothiazolidin-3-yl)acetic acid (rhodanine-3-acetic acid) via carbodiimide- or PCl₃-mediated coupling. Both esters and amides were investigated for their in vitro inhibitory potency and selectivity against acetylcholinesterase (AChE) from electric eel and butyrylcholinesterase (BChE) from equine serum using Ellman’s spectrophotometric method. The derivatives exhibited mostly a moderate activity against both cholinesterases. IC₅₀ values for AChE were in a closer concentration range of 24.05–86.85 μM when compared to BChE inhibition (7.92–227.19 μM). The esters caused the more efficient inhibition of AChE than amides and parent acid. The esterification and amidation of the rhodanine-3-acetic acid increased inhibition of BChE, even up to 26 times. Derivatives of 4-nitroaniline/phenol showed the activity superior to other substituents (H, Cl, CH₃, OCH₃, CF₃). Rhodanines produced a balanced inhibition of both cholinesterases. Seven derivatives produced the more potent inhibition of AChE than rivastigmine, a clinically used drug; additional three compounds were comparable. Two amides exceeded inhibitory potency of rivastigmine towards BChE. Importantly, this is the first evidence that rhodanine-based compounds are able to inhibit BChE.     

Design,synthesis and evaluation of novel 7-aminoalkyl-substituted flavonoid derivatives with improved cholinesterase inhibitory activities

A novel series of 7-aminoalkyl-substituted flavonoid derivatives 5a–5r were designed, synthesized and evaluated as potential cholinesterase inhibitors. The results showed that most of the synthesized compounds exhibited potent acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities at the micromolar range. Compound 2-(naphthalen-1-yl)-7-(8-(pyrrolidin-1-yl)octyloxy)-4H-chromen-4-one (5q) showed the best inhibitory activity (IC₅₀, 0.64 μM for AChE and 0.42 μM for BChE) which were better than our previously reported compounds and the commercially available cholinergic agent Rivastigmine. The results from a Lineweaver–Burk plot indicated a mixed-type inhibition for compound 5q with AChE and BChE. Furthermore, molecular modeling study showed that 5q targeted both the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE. Besides, these compounds (5a–5r) did not affect PC12 and HepG2 cell viability at the concentration of 10 μM. Consequently, these flavonoid derivatives should be further investigated as multipotent agents for the treatment of Alzheimer’s disease.     

LC–MS quantification of parthenolide and cholinesterase inhibitory potential of selected Tanacetum L. (Emend. Briq.) taxa

The acetonitrile extracts of various Tanacetum L. (Emend. Briq.) taxa from Turkey as well as parthenolide, a sesquiterpene lactone found in Tanacetum species as active substance were investigated for their inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), the key enzymes in pathogenesis of Alzheimer's disease, at 100 μg mL⁻¹ using ELISA microplate assay. Most of the extracts displayed a remarkable AChE inhibition where the leaf of Tanacetum argenteum subsp. flabellifolium had the highest inhibition (96.68 ± 0.35%). The extracts had moderate inhibition toward BChE, among which the stem of Tanacetum argyrophyllum var. argyrophyllum-1 exerted the best inhibition (63.81 ± 3.64%). However, parthenolide exhibited low inhibition against both of the enzymes. Total flavonoid content of the extracts was determined spectrophotometrically. Parthenolide, a sesquiterpene lactone, was quantified in these taxa by LC–MS and the leaf of T. argenteum subsp. argenteum possessed the richest parthenolide amount (2.261 ± 0.002%), while most of the species screened were found to contain the required percentage (0.2% minimum) by European Pharmacopeia.     

Synthesis and cholinesterase inhibition of cativic acid derivatives

Alzheimer’s disease (AD) is a neurodegenerative disorder associated with memory impairment and cognitive deficit. Most of the drugs currently available for the treatment of AD are acetylcholinesterase (AChE) inhibitors. In a preliminary study, significant AChE inhibition was observed for the ethanolic extract of Grindelia ventanensis (IC₅₀ = 0.79 mg/mL). This result prompted us to isolate the active constituent, a normal labdane diterpenoid identified as 17-hydroxycativic acid (1), through a bioassay guided fractionation. Taking into account that 1 showed moderate inhibition of AChE (IC₅₀ = 21.1 μM), selectivity over butyrylcholinesterase (BChE) (IC₅₀ = 171.1 μM) and that it was easily obtained from the plant extract in a very good yield (0.15% w/w), we decided to prepare semisynthetic derivatives of this natural diterpenoid through simple structural modifications. A set of twenty new cativic acid derivatives (3–6) was prepared from 1 through transformations on the carboxylic group at C-15, introducing a C2–C6 linker and a tertiary amine group. They were tested for their inhibitory activity against AChE and BChE and some structure–activity relationships were outlined. The most active derivative was compound 3c, with an IC₅₀ value of 3.2 μM for AChE. Enzyme kinetic studies and docking modeling revealed that this inhibitor targeted both the catalytic active site and the peripheral anionic site of this enzyme. Furthermore, 3c showed significant inhibition of AChE activity in SH-SY5Y human neuroblastoma cells, and was non-cytotoxic.     

Pyridine sulfonamide as a small key organic molecule for the potential treatment of type-II diabetes mellitus and Alzheimer’s disease: In vitro studies against yeast α-glucosidase,acetylcholinesterase and butyrylcholinesterase

This paper presents the efficient high yield synthesis of novel pyridine 2,4,6-tricarbohydrazide derivatives (4a–4i) along with their α-glucosidase, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition activities. The enzymes inhibition results showed the potential of synthesized compounds in controlling both type-II diabetes mellitus and Alzheimer’s disease. In vitro biological investigations revealed that most of compounds were more active against yeast α-glucosidase than the reference compound acarbose (IC₅₀ 38.25 ± 0.12 μM). Among the tested series the compound 4c bearing 4-flouro benzyl group was noted to be the most active (IC₅₀ 25.6 ± 0.2 μM) against α-glucosidase, and it displayed weak inhibition activities against AChE and BChE. Compound 4a exhibited the most desired results against all three enzymes, as it was significantly active against all the three enzymes; α-glucosidase (IC₅₀ 32.2 ± 0.3 μM), AChE (IC₅₀ 50.2 ± 0.8 μM) and BChE (IC₅₀ 43.8 ± 0.8 μM). Due to the most favorable activity of 4a against the tested enzymes, for molecular modeling studies this compound was selected to investigate its pattern of interaction with α-glucosidase and AChE targets.     

Ionic liquid mediated synthesis of mono- and bis-spirooxindole-hexahydropyrrolidines as cholinesterase inhibitors and their molecular docking studies

One pot, three-component reaction of 1-acryloyl-3,5-bisarylmethylidenepiperidin-4-ones with isatin and sarcosine in molar ratios of 1:1:1 and 1:2:2 furnished to mono- and bis-spiropyrrolidine heterocyclic hybrids comprising functionalized piperidine, pyrrolidine and oxindole structural motifs. Both mono and bis-spiropyrrolidines displayed good inhibitory activity against acetylcholinesterase (AChE) with IC₅₀ values of 2.36–9.43 μM. For butyrylcholinesterase (BChE), mono-cycloadducts in series 8 with IC₅₀ values of lower than 10 μM displayed better inhibitory activities than their bis-cycloadduct analogs in series 9 with IC₅₀ values of 7.44–19.12 μM. The cycloadducts 9j and 8e were found to be the most potent AChE and BChE inhibitors with IC₅₀ values of 2.35 and 3.21 μM, respectively. Compound 9j was found to be competitive inhibitor of AChE while compound 8e was a mixed-mode inhibitor of BChE with calculated K_i values of 2.01 and 6.76 μM, respectively. Molecular docking on Torpedo californica AChE and human BChE showed good correlation between IC₅₀ values and free binding energy values of the synthesized compounds docked into the active site of the enzymes.     

Efficient synthesis of novel dialkyl-3-cyanopropylphosphate derivatives and evaluation of their anticholinesterase activity

Based on the broad spectrum of biological activities associated with organophosphates, a novel type of this class of compounds was synthesized, bearing a nitrile group, from the sodium alkoxide-catalyzed reaction of dialkylphosphites with γ-ketonitriles at 80 °C under solvent-free conditions. A reaction mechanism involving a phospha-Brook type rearrangement is proposed. Eight title compounds were investigated for their in vitro inhibitory potency and selectivity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) using Ellman’s spectrophotometric method. The synthesized derivatives exhibited mostly a moderate activity against both cholinesterases. The IC₅₀ values for BChE were in a smaller concentration range (5.96–23.35 µM) compared to those for AChE inhibition (9.61–53.74 µM). The diethyl-3-cyano-1-p-tolylpropylphosphate which displayed the higher dual inhibitory potency towards both cholinesterases could be considered as a potential candidate for developing new drugs to treat Alzheimer’s disease.     

Salicylanilide diethyl phosphates as cholinesterases inhibitors

Based on the presence of dialkyl phosphate moiety, we evaluated twenty-seven salicylanilide diethyl phosphates (diethyl [2-(phenylcarbamoyl)phenyl] phosphates) for the inhibition of acetylcholinesterase (AChE) from electric eel (Electrophorus electricus L.) and butyrylcholinesterase (BChE) from equine serum. Ellman’s spectrophotometric method was used. The inhibitory activity (expressed as IC₅₀ values) was compared with that of the established drugs galantamine and rivastigmine. Salicylanilide diethyl phosphates showed significant activity against both cholinesterases with IC₅₀ values from 0.903 to 86.3 μM. IC₅₀s for BChE were comparatively lower than those obtained for AChE. All of the investigated compounds showed higher inhibition of AChE than rivastigmine, and six of them inhibited BChE more effectively than both rivastigmine and galantamine. In general, derivatives of 4-chlorosalicylic acid showed enhanced activity when compared to derivatives of 5-halogenated salicylic acids, especially against BChE. The most effective inhibitor of AChE was O-{5-chloro-2-[(3-bromophenyl)carbamoyl]phenyl} O,O-diethyl phosphate with IC₅₀ of 35.4 μM, which is also one of the most potent inhibitors of BChE. O-{5-Chloro-2-[(3,4-dichlorophenyl)carbamoyl]phenyl} O,O-diethyl phosphate exhibited in vitro the strongest inhibition of BChE (0.90 μM). Salicylanilide diethyl phosphates act as pseudo-irreversible cholinesterases inhibitors.     

Dianthus erinaceus var. erinaceus: Extraction,isolation, characterization and antimicrobial activity investigation of novel saponins

A phytochemical analysis of Dianthus erinaceus Boiss. var. erinaceus (Caryophyllaceae) has led to the isolation of two novel triterpenoid saponins, containing an oleane type skeleton, named dianosides K and L (1, 2), along with six known triterpenoid saponins (3–8). On the basis of chemical and spectrometric data, the structures of the new compounds were elucidated as 3-O-[β-d-glucopyranosyl (1 → 3)]–[β-d-glucopyranosyl (1 → 6)]-β-d-glucopyranosyl-olean-12-ene-23α,28-β–dioic acid 28-O-β-d-glucopyranosyl ester (1) and 3-O-[β-d-glucopyranosyl (1 → 3)]–[β-d-glucopyranosyl(1 → 6)]-β-d-glucopyranosyl-olean-12-ene-23α,28-β-dioic acid 28-O-α-l-mannopyranosyl (1 → 6)-β-d-glucopyranosyl ester (2). All isolated natural compounds were structurally characterized by 1D- (¹H, ¹³C, DEPT); 2D- (COSY, HMQC, HMBC) NMR and HR-ESI/MS methods. The antimicrobial activity of compounds 1 and 2 were tested against four Gram-negative, three Gram-positive bacteria and the yeast Candida albicans by the MIC method.     

The synthesis of novel sulfamides derived from β-benzylphenethylamines as acetylcholinesterase,butyrylcholinesterase and carbonic anhydrase enzymes inhibitors

In this study, a series of novel β-benzylphenethylamines and their sulfamide derivatives were synthesized starting from (Z)-2,3-diphenylacrylonitriles. Pd-C catalysed hydrogenation of diphenylacrylonitriles, reduction of propanenitriles with LiAlH₄ in the presence of AlCl₃ followed by addition of conc. HCl afforded β-benzylphenethylamine hydrochloride salts. The reactions of these amine hydrochloride salts with chlorosulfonyl isocyanate (CSI) in the presence of tert-BuOH and excess Et₃N gave sulfamoylcarbamates. Removing of Boc group from the synthesized sulfamoylcarbamates with trifluoroacetic acid (TFA) yielded novel sulfamides in good yields. These novel sulfamides derived from β-benzylphenethylamines were effective inhibitors of the cytosolic carbonic anhydrase I and II isoenzymes (hCA I and II), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with K_i values in the range of 0.278–2.260 nM for hCA I, 0.187–1.478 nM for hCA II, 0.127–2.452 nM for AChE and 0.494–1.790 nM for BChE. The inhibitory effects of the synthesized novel sulfamides derived from β-benzylphenethylamines were compared to those of acetazolamide and dorzolamide as clinical hCA I and II isoenzymes inhibitors and tacrine as a clinical AChE and BChE enzymes inhibitors. In addition to in vitro tests, molecular modeling approaches are implemented not only for prediction of the binding affinities of the compounds but also to study their inhibition mechanisms in atomic level at the catalytic domains.     

Microwave assisted synthesis,cholinesterase enzymes inhibitory activities and molecular docking studies of new pyridopyrimidine derivatives

A series of hitherto unreported pyrido-pyrimidine-2-ones/pyrimidine-2-thiones were synthesized under microwave assisted solvent free reaction conditions in excellent yields and evaluated in vitro for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes inhibitory activity. Among the pyridopyrimidine derivatives, 7e and 7l displayed 2.5- and 1.5-fold higher enzyme inhibitory activities against AChE as compared to standard drug, galanthamine, with IC₅₀ of 0.80 and 1.37 μM, respectively. Interestingly, all the compounds except 6k, 7j and 7k displayed higher inhibitory potential against BChE enzyme in comparison to standard with IC₅₀ ranging from 1.18 to 18.90 μM. Molecular modeling simulations of 7e and 7l was performed using three-dimensional structure of Torpedo californica AChE (TcAChE) and human butyrylcholinesterase (hBChE) enzymes to disclose binding interaction and orientation of these molecule into the active site gorge of respective receptors.     

Design,synthesis and evaluation of novel 4-dimethylamine flavonoid derivatives as potential multi-functional anti-Alzheimer agents

A series of 4-dimethylamine flavonoid derivatives 5a–5r were designed, synthesized and evaluated as potential multi-functional anti-Alzheimer agents. The results showed that most of the synthesized compounds exhibited high acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity at the micromolar range (IC₅₀, 1.83–33.20 μM for AChE and 0.82–11.45 μM for BChE). A Lineweaver–Burk plot indicated a mixed-type inhibition for compound 5j with AChE, and molecular modeling study showed that 5j targeted both the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE. Besides, the derivatives showed potent self-induced Aβ aggregation inhibitory activity at 20 μM with percentage from 25% to 48%. In addition, some compounds (5j–5q) showed potent oxygen radical absorbance capacity (ORAC) ranging from 1.5- to 2.6-fold of the Trolox value. These compounds should be further investigated as multi-potent agents for the treatment of Alzheimer’s disease.     

The first synthesis of 4-phenylbutenone derivative bromophenols including natural products and their inhibition profiles for carbonic anhydrase,acetylcholinesterase and butyrylcholinesterase enzymes

The first synthesis of (E)-4-(3-bromo-4,5-dihydroxyphenyl)but-3-en-2-one (1), (E)-4-(2-bromo-4,5-dihydroxyphenyl)but-3-en-2-one (2), and (E)-4-(2,3-dibromo-4,5-dihydroxyphenyl)but-3-en-2-one (3) was realized as natural bromophenols. Derivatives with mono OMe of 2 and 3 were obtained from the reactions of their derivatives with di OMe with AlCl₃. These novel 4-phenylbutenone derivatives were effective inhibitors of the cytosolic carbonic anhydrase I and II isoenzymes (hCA I and II), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with K_i values in the range of 158.07–404.16 pM for hCA I, 107.63–237.40 pM for hCA II, 14.81–33.99 pM for AChE and 5.64–19.30 pM for BChE. The inhibitory effects of the synthesized novel 4-phenylbutenone derivatives were compared to acetazolamide as a clinical hCA I and II isoenzymes inhibitor and tacrine as a clinical AChE and BChE enzymes inhibitor.