The green synthesis and molecular docking of novel N-substituted rhodanines as effective inhibitors for carbonic anhydrase and acetylcholinesterase enzymes

Recently, inhibition effects of enzymes such as acetylcholinesterase (AChE) and carbonic anhydrase (CA) has appeared as a promising approach for pharmacological intervention in a variety of disorders such as epilepsy, Alzheimer’s disease and obesity. For this purpose, novel N-substituted rhodanine derivatives (RhAs) were synthesized by a green synthetic approach over one-pot reaction. Following synthesis the novel compounds, RhAs derivatives were tested against AChE and cytosolic carbonic anhydrase I, and II (hCAs I, and II) isoforms. As a result of this study, inhibition constant (Ki) were found in the range of 66.35 ± 8.35 to 141.92 ± 12.63 nM for AChE, 43.55 ± 14.20 to 89.44 ± 24.77 nM for hCA I, and 16.97 ± 1.42 to 64.57 ± 13.27 nM for hCA II, respectively. Binding energies were calculated with docking studies as −5.969, −5.981, and −9.121 kcal/mol for hCA I, hCA II, and AChE, respectively.     

Synthesis,biological evaluation and molecular docking of novel pyrazole derivatives as potent carbonic anhydrase and acetylcholinesterase inhibitors

A series of substituted pyrazole compounds (1–8 and 9a, b) were synthesized and their structure was characterized by IR, NMR, and Mass analysis. These obtained novel pyrazole derivatives (1–8 and 9a, b) were emerged as effective inhibitors of the cytosolic carbonic anhydrase I and II isoforms (hCA I and II) and acetylcholinesterase (AChE) enzymes with K_i values in the range of 1.03 ± 0.23–22.65 ± 5.36 µM for hCA I, 1.82 ± 0.30–27.94 ± 4.74 µM for hCA II, and 48.94 ± 9.63–116.05 ± 14.95 µM for AChE, respectively. Docking studies were performed for the most active compounds, 2 and 5, and binding mode between the compounds and the receptors were determined.     

Synthesis,biological evaluation and in silico studies of novel N-substituted phthalazine sulfonamide compounds as potent carbonic anhydrase and acetylcholinesterase inhibitors

The synthesis, characterization and biological evaluation of a series of novel N-substituted phthalazine sulfonamide (5a-l) are disclosed. Phthalazines which are nitrogen-containing heterocyclic compounds are biologically preferential scaffolds, endowed with versatile pharmacological activity, such as anti-inflammatory, cardiotonic vasorelaxant, anticonvulsant, antihypertensive, antibacterial, anti-cancer action. The compounds were investigated for the inhibition against the cytosolic hCA I, II and AChE. Most screened sulfonamides showed high potency in inhibiting hCA II, widely involved in glaucoma, epilepsy, edema, and other pathologies (K_is in the ranging from 6.32 ± 0.06 to 128.93 ± 23.11 nM). hCA I was inhibited with K_is in the range of 6.80 ± 0.10–85.91 ± 7.57 nM, whereas AChE in the range of 60.79 ± 3.51–249.55 ± 7.89 nM. ADME prediction study of the designed N-substituted phthalazine sulfonamides showed that they are not only with carbonic anhydrase and acetylcholinesterase inhibitory activities but also with appropriate pharmacokinetic, physicochemical parameters and drug-likeness properties. Also, in silico docking studies were investigated the binding modes of selected compounds, to hCA I, II, and AChE.     

New thiopyrimidine-benzenesulfonamide conjugates as selective carbonic anhydrase II inhibitors: synthesis,in vitro biological evaluation,and molecular docking studies

In the present work, a new series of thiopyrimidine-benzenesulfonamide conjugates was designed, synthesized and tested as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. Our design strategy was based on the molecular hybridization of the benzenesulfonamide moiety as a zinc binding group (ZBG), an alkylated thiopyrimidine moiety as a spacer and (un)substituted phenyl moieties with various electronic and hydrophobic environments as a tail. The designed and synthesized compounds were evaluated against four human (h) CA isoforms hCA I, hCA II, hCA IX and hCA XII. Series 6 showed promising activity and selectivity toward the cytosolic isoforms hCA I and hCA II versus the membrane bound isoforms hCA IX and hCA XII. Compounds 6e and 6f showed K_i of 0.04 µM against hCA II with a selectivity of 15.8- to 980-fold towards hCA II over hCA I, hCA IX, hCA XII isoforms. Molecular docking in the hCA II active site attributed the promising inhibitory activity of series 6 to the interaction of their sulfonamide moiety with the active site Zn²⁺ ion as well as its hydrogen bonding with the key amino acids Thr199 and Thr200. Through hydrophobic interaction, the benzenesulfonamide and the thiopyrimidine moieties interact with the hydrophobic side chains of the amino acids Val121/Leu198 and Ile91/Phe131, respectively. These results indicated that the designed and synthesized series is an interesting scaffold that can be further optimized for the development of selective antiglaucoma drugs.     

Synthesis,molecular docking analysis and carbonic anhydrase I-II inhibitory evaluation of new sulfonamide derivatives

New sulfonamide-hydrazone derivatives (3a-3n) were synthesized to evaluate their inhibitory effects on purified human carbonic anhydrase (hCA) I and II. The inhibition profiles of the synthesized compounds on hCA I-II isoenzyme were investigated by comparing their IC₅₀ and K_i values. Acetazolamide (5-acetamido-1,3,4-thiadiazole-2-sulfonamide, AZA) has also been used as a standard inhibitor. The compound 3e demonstrated the best hCA I inhibitory effect with a K_i value of 0.1676 ± 0.017 µM. Besides, the compound 3m showed the best hCA II inhibitory effect with a K_i value of 0.2880 ± 0.080 µM. Cytotoxicity of the compounds 3e and 3m toward NIH/3T3 mouse embryonic fibroblast cell line was observed and the compounds were found to be non-cytotoxic. Molecular docking studies were performed to investigate the interaction types between active compounds and hCA enzymes. Pharmacokinetic profiles of compounds were assessed by theoretical ADME predictions. As a result of this study a novel and potent class of CA inhibitors were identified with a good activity potential.     

The first synthesis,carbonic anhydrase inhibition and anticholinergic activities of some bromophenol derivatives with S including natural products

Starting from vanillin, known four benzyl bromides with Br were synthesized. The first synthesis of natural product 3,4-dibromo-5-((methylsulfonyl)methyl)benzene-1,2-diol (2) and 3,4,6-tribromo-5-((methylsulfonyl)methyl)benzene-1,2-diol (3) and derivatives were carried out by demethylation, acetylatilation, oxidation and hydrolysis reactions of the benzyl bromides. Also, these compounds were tested against some important enzymes like acetylcholinesterase and butyrylcholinesterase enzymes, carbonic anhydrase I, and II isoenzymes. The novel bromophenols showed Ki values of in range of 53.75 ± 12.54–234.68 ± 46.76 nM against hCA I, 42.84 ± 9.36 and 200.54 ± 57.25 nM against hCA II, 0.84 ± 0.12–14.63 ± 3.06 nM against AChE and 0.93 ± 0.20–18.53 ± 5.06 nM against BChE. Induced fit docking process performed on the compounds inhibiting hCA I, hCA II, AChE, and BChE receptors. Hydroxyl group should exist at the aromatic ring of the compounds for inhibition of the enzymes. The moieties reported in this study will be useful for design of more potent and selective inhibitors against the enzymes.     

Carbohydrazones as new class of carbonic anhydrase inhibitors: Synthesis,kinetics, and ligand docking studies

Discovery and development of carbonic anhydrase inhibitors is crucial for their clinical use as antiepileptic, diurectic and antiglaucoma agents. Keeping this in mind, we have synthesized carbohydrazones 1–27 and evaluated them for their in vitro carbonic anhydrase inhibitory potential. Out of twenty-seven compounds, compounds 1 (IC₅₀ = 1.33 ± 0.01 µM), 2 (IC₅₀ = 1.85 ± 0.24 µM), 3 (IC₅₀ = 1.37 ± 0.06 µM), and 9 (IC₅₀ = 1.46 ± 0.12 µM) have showed carbonic anhydrase inhibition better than the standard drug zonisamide (IC₅₀ = 1.86 ± 0.03 µM). Moreover, compounds 4 (IC₅₀ = 2.32 ± 0.04 µM), 5 (IC₅₀ = 3.96 ± 0.35 µM), 7 (IC₅₀ = 2.33 ± 0.02 µM), and 8 (IC₅₀ = 2.67 ± 0.01 µM) showed good inhibitory activity. Cheminformatic analysis has shown that compounds 1 and 2 possess lead-like properties. In addition, kinetic and molecular docking studies were also performed to investigate the binding interaction between carbohydrazones and carbonic anhydrase enzyme. This study has identified a novel and potent class of carbonic anhydrase inhibitors with the potential to be investigated further.     

Synthesis of novel bisindolylmethanes: New carbonic anhydrase II inhibitors,docking, and 3D pharmacophore studies

In this study, 45 bisindolylmethanes having sulfonamide moiety had been synthesized through 3 steps. In vitro assay for inhibition of carbonic anhydrase showed that some of the compounds having sulfonamide moiety are capable of inhibiting carbonic anhydrase II. Bisindoles having halogens at fifth position showed better inhibitory activity as compared to unsubstituted bisindoles. The results obtained from in vitro inhibitory activity were subjected through 3D QSAR and docking studies to identify important features contributing to the activity and further improve the structure. Pharmacophore studies suggest that bisindolylmethane moiety is contributing significantly towards the inhibition activity. Docking studies showed that compounds having nitro substituent (5g and 5i) were found to be able interact with Zn²⁺ ion, Thr199, His94, His96, and His119, which interferes with the ZnOHThr199Glu106 hydrogen bond network. Bulky nitro substituent at ortho position for compound 5g prevents the compound from interacting with other residues like Thr199 and Thr200. Methyl substituent at ortho position for Compound 5i induces less steric hindrance effect, thus allowing second oxygen atom of sulfonamide to interact with Thr199 (2.51 Å). Hydrogen bonding between NH on indole ring with Glu69 might have increased stability of ligand-receptor complex.     

Synthesis,biological evaluation,and docking studies of novel thiourea derivatives of bisindolylmethane as carbonic anhydrase II inhibitor

This article describes discovery of 29 novel bisindolylmethanes consisting of thiourea moiety, which had been synthesized through three steps. These novel bisindolylmethane derivatives evaluated for their potential inhibitory activity against carbonic anhydrase (CA) II. The results for in vitro assay of carbonic anhydrase II inhibition activity showed that some of the compounds are capable of suppressing the activity of carbonic anhydrase II. Bisindoles having halogen at fifth position showed better inhibitory activity as compared to unsubstituted bisindoles. Derivatives showing inhibition activity docked to further, understand the binding behavior of these compounds with carbonic anhydrase II. Docking studies for the active compound 3j showed that nitro substituent at para position fits into the core of the active site. The nitro substituent of compound 3j is capable of interacting with Zn ion. This interaction believed to be the main factor causing inhibition activity to take place.     

Sulfonamides containing curcumin scaffold: Synthesis,characterization, carbonic anhydrase inhibition and molecular docking studies

Curcumin is a multi-functional pharmacologically safe natural agent with proven cytoprotective effects to healthy human cells. In this study, a new series of sulfonamides with curcumin scaffold were synthesized, characterized and investigated for their carbonic anhydrase isoenzyme I (human) and II (bovine) isoforms. The structures of newly synthesized compounds were described by IR, ¹H NMR and ¹³C NMR spectral data. Compound 14 showed the K_i value of 0.99 µM with highest inhibitory activity among all other synthesized compounds against hCA-I enzyme. Similarly enzyme kinetic studies of compound 14, 16 and 30 against bCAII enzyme showed Ki values of 0.71, 0.67 and 0.71 µM respectively. Our biological assays results showed that most of active compounds have similar inhibitory activities compared to standard acetazolamide drug. The molecular docking predicted binding modes showed that these compounds bind with hCA-1 enzyme in similar fashion.     

Acetylcholinesterase and carbonic anhydrase inhibitory properties of novel urea and sulfamide derivatives incorporating dopaminergic 2-aminotetralin scaffolds

In the present study a series of urea and sulfamide compounds incorporating the tetralin scaffolds were synthesized and evaluated for their acetylcholinesterase (AChE), human carbonic anhydrase (CA, EC 4.2.1.1) isoenzyme I, and II (hCA I and hCA II) inhibitory properties. The urea and their sulfamide analogs were synthesized from the reactions of 2-aminotetralins with N,N-dimethylcarbamoyl chloride and N,N-dimethylsulfamoyl chloride, followed by conversion to the corresponding phenols via O-demethylation with BBr₃. The novel urea and sulfamide derivatives were tested for inhibition of hCA I, II and AChE enzymes. These derivatives exhibited excellent inhibitory effects, in the low nanomolar range, with K_i values of 2.61–3.69 nM against hCA I, 1.64–2.80 nM against hCA II, and in the range of 0.45–1.74 nM against AChE. In silico techniques such as, atomistic molecular dynamics (MD) and molecular docking simulations, were used to understand the scenario of the inhibition mechanism upon approaching of the ligands into the active site of the target enzymes. In light of the experimental and computational results, crucial amino acids playing a role in the stabilization of the enzyme–inhibitor adducts were identified.     

Discovery of new potent inhibitors for carbonic anhydrase IX by structure-based virtual screening

Through structure-based virtual screening, some dozen of benzene sulfonamides with novel scaffolds are identified as potent inhibitors against carbonic anhydrase (CA) IX with IC₅₀ values ranging from 2.86 to 588.34 nM. Among them, compounds 1 and 9 show high selectivity against tumor-target CA IX over CA II (the selectivity ratios are 21.3 and 136.6, respectively). The possible binding poses of hit compounds are also explored and the selectivity is elucidated by molecular docking simulations. The hit compounds discovered in this work would provide novel scaffolds for further hit-to-lead optimization.     

Pyrazolylbenzo[d]imidazoles as new potent and selective inhibitors of carbonic anhydrase isoforms hCA IX and XII

Novel pyrazolylbenzo[d]imidazole derivatives (2a–2f) were designed, synthesized and evaluated against four human carbonic anhydrase isoforms belonging to α family comprising of two cytosolic isoforms hCA I and II as well as two transmembrane tumor associated isoforms hCA IX and XII. Starting from these derivatives that showed high potency but low selectivity in favor of tumor associated isoforms hCA IX and XII, we investigated the impact of removing the sulfonamide group. Thus, analogs 3a–3f without sulfonamide moiety were synthesized and biological assay revealed a good activity as well as an excellent selectivity as inhibitors for tumor associated hCA IX and hCA XII and the same was analyzed by molecular docking studies.     

Synthesis and carbonic anhydrase inhibitory properties of novel coumarin derivatives

A newly series of water-soluble 1-alkyl-3-(4-methyl-7, 8-dihydroxy-2H-chromen-2-one) benzimidazolium chloride salts (3a-j) were synthesized and their inhibitory effects on the activity of purified human carbonic anhydrase (hCA) I and II were evaluated. hCA I and II from human erythrocytes were purified by a simple one step procedure by using Sepharose 4B-L-tyrosine-sulphanilamide affinity column. The result showed that all the synthesized compounds were inhibited the CA isoenzymes activity. Among them, 3g and 3j were found to be most active (IC₅₀ = 22.09 µM and 20.33 µM) for hCA I and hCA II, respectively.     

Synthesis and bioactivities of pyrazoline benzensulfonamides as carbonic anhydrase and acetylcholinesterase inhibitors with low cytotoxicity

4-(3-Substitutedphenyl-5-polymethoxyphenyl-4,5-dihydro-1H-pyrazol-1-yl)benzenesulfonamides (9–16) were synthesized and their chemical structures were elucidated by ¹H NMR, ¹³C NMR, and HRMS. The compounds designed include pyrazoline and sulfonamide pharmacophores in a single molecule by hibrit molecule approach which is a useful technique in medicinal chemistry in designing new compounds with potent activity for the desired several bioactivities. Inhibition potency of the sulfonamides were evaluated against human CA isoenzymes (hCA I and hCA II) and acetylcholinesterase (AChE) enzyme and also their cytotoxicities were investigated towards oral squamous cancer cell carcinoma (OSCC) cell lines (Ca9-22, HSC-2, HSC-3, and HSC-4) and non-tumor cells (HGF, HPLF, and HPC). Cytosolic hCA I and hCA II isoenzymes were inhibited by the sulfonamide derivatives (9–16) and Ki values were found in the range of 27.9 ± 3.2–74.3 ± 28.9 nM and 27.4 ± 1.4–54.5 ± 11.6 nM, respectively. AChE enzyme was strongly inhibited by the sulfonamide derivatives with Ki values in the range of 37.7 ± 14.4–89.2 ± 30.2 nM The CC₅₀ values of the compounds were found between 15 and 200 µM towards OSCC malign cell lines. Their tumor selectivities were also calculated with two ways. Compound’s selectivities towards cancer cell line were found generally low, except compounds bearing 3,4-dimethoxyphenyl 14 (TS1 = 1.3, TS2 = 1.4) and 10 (TS2 = 1.4). All sulfonamide derivatives studied here can be considered as good candidates to develop novel CAs or AChE inhibitor candidates based on the enzyme inhibition potencies with their low cytotoxicity and tumor selectivity.     

(3,4-Dihydroxyphenyl)(2,3,4-trihydroxyphenyl)methanone and its derivatives as carbonic anhydrase isoenzymes inhibitors

In this study, we have synthesised (3,4-dihydroxyphenyl)(2,3,4-trihydroxyphenyl)methanone and a series of its derivatives (5, 13–16) and tested the ability of these compounds to inhibit two metalloenzyme human carbonic anhydrase (hCA, EC 4.2.1.1) isozymes, hCA I and hCA II. The synthesised compounds showed inhibitory effect on hCA I and hCA II isozymes. The results showed that synthesised compounds (5, 13–16) demonstrated the best inhibition activity against hCA I (IC₅₀: 3.22–54.28 μM) and hCA II (IC₅₀: 18.52–142.01 μM). The compound 14 showed the highest inhibiton effect against hCA I (IC₅₀: 3.22 μM; K_i: 1.19?±?1.4 μM). On the other hand, the compound 13 showed the highest inhibiton effect against hCA II (IC₅₀: 18.52 μM; K_i: 3.25?±?1.13 μM).     

Carbonic anhydrase inhibitors: Synthesis,molecular docking,cytotoxic and inhibition of the human carbonic anhydrase isoforms I,II, IX,XII with novel benzenesulfonamides incorporating pyrrole,pyrrolopyrimidine and fused pyrrolopyrimidine moieties

A series of novel pyrroles, pyrrolopyrimidines, pyrazolopyrrolopyrimidine, triazolopyrrolopyrimidines, tetrazolopyrrolopyrimidine, triazinopyrrolopyrimidines and pyrrolopyrimidotriazepines bearing the biologically active benzenesulfonamide moiety were synthesized by using pyrrole-o-amino-carbonitrile as key intermediate. All the synthesized compounds were evaluated for their in vitro carbonic anhydrase (CA, EC 4.2.1.1) inhibitory effects against the human (h) isoforms hCA I, II, IX and XII. Among the tested derivatives, compounds 16, 18 and 20–24 showed potent activity as inhibitors for the tumor associated transmembrane isoforms (hCA IX and XII) in the nanomolar and subnanomolar range, with high selectivity. All compounds underwent cytotoxic activity assays on human breast cancer cell line (MCF-7) showing effective activity, comparable to that of the clinically used drug doxorubicin.     

Design,synthesis, and carbonic anhydrase inhibition activity of benzenesulfonamide-linked novel pyrazoline derivatives

Carbonic anhydrases (CA, EC 4.2.1.1) are Zinc metalloenzymes and are present throughout most living organisms. Among the catalytically active isoforms are the cytosolic CA I and II, and tumor-associated CA IX and CA XII. The carbonic anhydrase (CA) inhibitory activities of newly synthesized pyrazoline-linked benzenesulfonamides 18–33 against human CA (hCA) isoforms I, II, IX, and XII were measured and compared with that of acetazolamide (AAZ), a standard inhibitor. Potent inhibitory activity against hCA I was exerted by compounds 18–25, with inhibition constant (K_I) values of 87.8–244.1 nM, which were greater than that of AAZ (K_I, 250.0 nM). Compounds 19, 21, 22, 29, 30, and 32 were proven to have inhibitory activities against hCA IX with K_I values (5.5–37.0 nM) that were more effective than or nearly equal to that of AAZ (K_I, 25.0 nM). Compounds 20–22, and 30 exerted potent inhibitory activities (K_Is, 7.1–10.1 nM) against hCA XII, in comparison with AAZ (K_I, 5.7 nM).     

Synthesis of benzensulfonamides linked to quinazoline scaffolds as novel carbonic anhydrase inhibitors

Carbonic anhydrase (CA) inhibitory activities of newly synthesized quinazoline-linked benzensulfonamides 10–29, 31, 32, 35, 36, and 45–51 against human CA (hCA) isoforms I, II, IX, and XII were measured and compared to that of acetazolamide (AAZ) as a standard inhibitor. Potent selective inhibitory activity against hCA I was exerted by compounds 14, 15, 17, 19, 20, 21, 24, 25, 28, 29, 31, 35, 45, 47, 49, and 51 with inhibition constant (K_Is) values of 39.4–354.7 nM that were nearly equivalent or even greater than that of AAZ (K_I, 250.0 nM). Compounds 15, 20, 24, 28, 29, 45 and 47 proved to have inhibitory activities against hCA II with (K_Is, 0.73–16.5 nM) that were similar or improved to that of AAZ (K_I, 12.0 nM). Compounds 13–29, 31–32, and 45–51 displayed potent hCA IX inhibitory activities (K_Is, 1.6–32.2 nM) that were more effective than or nearly equal to AAZ (K_I, 25.0 nM). Compounds 14, 15, 20, 21, 26, 45, and 47 exerted potent hCA XII inhibitory activities (K_Is, 5.2–9.2 nM), indicating similar CAI activities as compared to that of AAZ (K_I, 5.7 nM).     

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.