Inhibition pattern of sulfamide-related compounds in binding to carbonic anhydrase isoforms I,II, VII,XII and XIV

A set of sulfamides and sulfamates were synthesized and tested against several isoforms of carbonic anhydrase: CA I, CA II, CA VII, CA XII and CA XIV. The biological assays showed a broad range of inhibitory activity, and interesting results were found for several compounds in terms of activity (K_i <1 μm) and selectivity: some aromatic sulfamides are active against CA I, CA II and/or CA VII; while they are less active in CA XII and CA XIV. On the other hand, bulky sulfamides are selective to CA VII. To understand the origin of the different inhibitory activity against each isozyme we used molecular modeling techniques such as docking and molecular dynamic simulations.     

Carbonic anhydrase inhibitors. Phenacetyl-, pyridylacetyl- and thienylacetyl-substituted aromatic sulfonamides act as potent and selective isoform VII inhibitors

A series of aromatic/heterocyclic sulfonamides incorporating phenyl(alkyl), halogenosubstituted-phenyl- or 1,3,4-thiadiazole-sulfonamide moieties and thienylacetamido; phenacetamido- and pyridinylacetamido tails were prepared and assayed as inhibitors of cytosolic human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms hCA I, II and VII. The new compounds showed moderate inhibition of the two ubiquitous isoforms I and II (K_Is of 50–390 nM) and excellent inhibitory activity against the brain associated hCA VII (K_Is in the range of 4.7–8.5 nM). Isoform VII highly selective inhibitors are being detected for the first time, with selectivity ratios for inhibiting CA VII over CA II of 11–75, and for inhibiting CA VII over CA I of 10–49, which may be useful for understanding the role of CA VII in epileptogenesis and other physiologic processes.     

N-aryl-N’-ureido-O-sulfamates: Potent and selective inhibitors of the human Carbonic Anhydrase VII isoform with neuropathic pain relieving properties

Herein we report for the first time an efficient synthetic procedure for the preparation of N-aryl-N’-ureido-O-sulfamates (AUSs) as a new class of Carbonic Anhydrase Inhibitors (CAIs). The compounds were tested for the inhibition of several human (h) Carbonic Anhydrase (CA; EC 4.2.1.1) isoforms. Interesting inhibition activity and high selectivity against CA VII and XII versus CA I and II, with K_Is in the low nanomolar range, were observed. Molecular modeling studies allowed us to decipher the structural features underpinning the selective inhibitory profile of AUSs towards isoforms CAs VII and XII. A selection of sulfamates showed promising neuropathic pain modulating effects in an in vivo animal model of oxaliplatin induced pain.     

Synthesis of novel acridine and bis acridine sulfonamides with effective inhibitory activity against the cytosolic carbonic anhydrase isoforms II and VII

4-Amino-N-(4-sulfamoylphenyl)benzamide was synthesized by reduction of 4-nitro-N-(4-sulfamoylphenyl)benzamide and used to synthesize novel acridine sulfonamide compounds, by a coupling reaction with cyclic-1,3-diketones and aromatic aldehydes. The new compounds were investigated as inhibitors of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1), and more precisely the cytosolic isoforms hCA I, II and VII. hCA I was inhibited in the micromolar range by the new compounds (K_Is of 0.16–9.64 μM) whereas hCA II and VII showed higher affinity for these compounds, with K_Is in the range of 15–96 nM for hCA II, and of 4–498 nM for hCA VII. The structure–activity relationships for the inhibition of these isoforms with the acridine–sulfonamides reported here were also elucidated.     

Novel sulfamides as potential carbonic anhydrase isoenzymes inhibitors

Sulfamides represent an important class of biologically active compounds. A series of novel sulfamides were synthesized from 1-aminoindanes, 1-aminotetralin, 2-aminoindanes and 2-aminotetralin via the reactions of free amines, benzyl alcohol and chlorosulfonyl isocyanate (CSI) followed by hydrogenolysis of the obtained sulfamoylcarbamates. Carbonic anhydrase (CA, EC 4.2.1.1) inhibitory effects of the new sulfamides have been investigated. The human (h) isozymes hCA I and hCA II have been investigated in this study by using an esterase assay with 4-nitrophenyl acetate as substrate. The new sulfamides showed inhibition constants in the micro–submicromolar range, with one compound (N-(indane-1-yl)sulfamide) showing a K_i of 0.45 μM against hCA I and of 1.07 μM against hCA II.     

Inhibition Profiles of Some Symmetric Sulfamides Derived from Phenethylamines on Human Carbonic Anhydrase I,and II Isoenzymes

In this work, the inhibitory effect of some symmetric sulfamides derived from phenethylamines were determined against human carbonic anhydrase (hCA) I, and II isoenzymes, and compared with standard compound acetazolamide. IC₅₀ values were obtained from the Enzyme activity (%)-[Symmetric sulfamides] graphs. Also, K_i values were calculated from the Lineweaver-Burk graphs. Some symmetric sulfamides compounds ( 11 – 18 ) demonstrated excellent inhibition effects against hCA I, and II isoenzymes. These compounds demonstrated effective inhibitory profiles with IC₅₀ values in ranging from 21.66–28.88 nM against hCA I, 14.44–30.13 nM against hCA II. Among these compounds, the best K_i value for hCA I (K_i: 8.34±1.60 nM) and hCA II (K_i: 16.40±1.00 nM) is compound number 11 . Besides, the IC₅₀ value of acetazolamide used as a standard was determined as hCA I, hCA II 57.75 nM, 49.50 nM, respectively. Moreover, in silico ADME-Tox study showed that all synthesized compounds ( 11 – 18 ) had good oral bioavailability in light of Jorgensen's rule of three, and of Lipinski's rule of five.     

Synthesis,biological activity and multiscale molecular modeling studies for coumaryl-carboxamide derivatives as selective carbonic anhydrase IX inhibitors

New coumaryl-carboxamide derivatives with the thiourea moiety as a linker between the alkyl chains and/or the heterocycle nucleus were synthesized and their inhibitory activity against the human carbonic anhydrase (hCA) isoforms hCA I, II, VII and IX were evaluated. While the hCA I, II and VII isoforms were not inhibited by the investigated compounds, the tumour-associated isoform hCA IX was inhibited in the high nanomolar range. 2-Oxo-N-((2-(pyrrolidin-1-yl)ethyl)carbamothioyl)-2H-chromene-3-carboxamide (e11) exhibited a selective inhibitory action against hCA IX with the K_i of 107.9?nM. In order to better understand the inhibitory profiles of studied molecules, multiscale molecular modeling approaches were used. Different molecular docking algorithms were used to investigate binding poses and predicted binding energies of studied compounds at the active sites of the CA I, II, VII and IX isoforms.     

N-β-glycosyl sulfamides are selective inhibitors of the cancer associated carbonic anhydrase isoforms IX and XII

The transmembrane isoforms of carbonic anhydrase (CA IX and XII) have been shown to be linked to carcinogenesis and their inhibition to arrest primary tumor and metastases growth. In this Letter, we present a series of peracetylated and deprotected N-β-glycosyl sulfamides that were tested for the inhibition of 4 carbonic anhydrase isoforms: the cytosolic hCA I and hCA II and transmembrane tumor-associated IX and XII. Compounds 1-4 and 6-8 selectively target cancer-associated CAs (IX and XII) with K_Is in the low nanomolar range.     

Microwave assisted synthesis of novel acridine–acetazolamide conjugates and investigation of their inhibition effects on human carbonic anhydrase isoforms hCA I,II, IV and VII

4-Amino-N-(5-sulfamoyl-1,3,4-thiadiazol-2-yl)benzamide was condensed with cyclic-1,3-diketones (dimedone and cyclohexane-1,3-dione) and aromatic aldehydes under microwave irradiation, leading to a series of acridine–acetazolamide conjugates. The new compounds were investigated as inhibitors of carbonic anhydrases (CA, EC 4.2.1.1), and more precisely cytosolic isoforms hCA I, II, VII and membrane-bound one hCA IV. All investigated isoforms were inhibited in low micromolar and nanomolar range by the new compounds. hCA IV and VII were inhibited with K_Is in the range of 29.7–708.8 nM (hCA IV), and of 1.3–90.7 nM (hCA VII). For hCA I and II the K_Is were in the range of 6.7–335.2 nM (hCA I) and of 0.5–55.4 nM (hCA II). The structure–activity relationships (SAR) for the inhibition of these isoforms with the acridine–acetazolamide conjugates reported here were delineated.     

Synthesis and carbonic anhydrase inhibitory properties of sulfamides structurally related to dopamine

A series of novel sulfamides incorporating the dopamine scaffold were synthesized. Reaction of amines and tert-butyl-alcohol/benzyl alcohol in the presence of chlorosulfonyl isocyanate (CSI) afforded sulfamoyl carbamates, which were converted to the title compounds by treatment with trifluoroacetic acid or by palladium-catalyzed hydrogenolysis. Inhibition of six α-carbonic anhydrases (CAs, EC 4.2.1.1), that is, CA I, CA II, CA VA, CA IX, CA XII and CA XIV, and two β-CAs from Candida glabrata (CgCA) and Mycobacterium tuberculosis (Rv3588) with these sulfamides was investigated. All CA isozymes were inhibited in the low micromolar to nanomolar range by the dopamine sulfamide analogues. K_is were in the range of 0.061–1.822 μM for CA I, 1.47–2.94 nM for CA II, 2.25–3.34 μM for CA VA, 0.041–0.37 μM for CA IX, 0.021–1.52 μM for CA XII, 0.007–0.219 μM for CA XIV, 0.35–5.31 μM for CgCA and 0.465–4.29 μM for Rv3588. The synthesized sulfamides may lead to inhibitors targeting medicinally relevant CA isoforms with potential applications as antiepileptic, antiobesity antitumor agents or anti-infective.     

Inhibition of mammalian carbonic anhydrases I-XIV with grayanotoxin III: solution and in silico studies

Abstract

Grayanotoxin III (GTX3) was investigated for inhibition of all catalytically active mammalian carbonic anhydrase (CA, EC 4.2.1.1) isoforms, i.e. CA I to CA XIV. It showed micromolar inhibition (K_Is of 8.01 and 6.13?µM) for cytosolic isoforms CA I and II, respectively. GTX3 showed a submicromolar inhibition (K_Is in the range of 0.51–2.15?µM) for the remaining cytosolic (CA III, VII and XIII), membrane-associated/transmembrane (CA IV, IX, XII and XIV), mitochondrial (CA VA and CA VB) and secreted (CA VI) isoforms. This inhibition profile is very different from that of the sulfonamide CA inhibitors (CAIs), which possess different clinical applications. A molecular docking study for GTX3 within the active sites of CA I and II assisted to the understanding of molecular mechanism of the ligand. The interesting inhibition profile, coupled with various possibilities of interacting with the enzyme active site make this family of natural compounds attractive leads for designing novel chemotypes acting as CAIs.     

Synthesis and biological evaluation of coumarin-1,3,4-oxadiazole hybrids as selective carbonic anhydrase IX and XII inhibitors

With an aim to develop novel heterocyclic hybrids as potent anticancer agents, we synthesized a series of coumarin-1,3,4-oxadiazole hybrids (7a-t) and evaluated for their inhibitory activity against the four physiologically relevant human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms CA I, CA II, CA IX and CA XII. The CA inhibition results clearly indicated that the coumarin-1,3,4-oxadiazole derivatives (7a-t) exhibited selective inhibition of the tumor associated isoforms, CA IX and CA XII over CA I and II isoforms. Among all, compound 7b, exhibited significant inhibition in lower micromolar potency against hCA XII, with a K_i of 0.16 µM and compound 7n, exhibited significant inhibition in lower micromolar potency against hCA IX, with a K_i of 2.34 µM respectively. Therefore, compound 7b and 7n could be the potential leads for development of selective anticancer agents by exhibiting a novel mechanism of action through hCA IX and XII inhibition.     

The human carbonic anhydrase isoenzymes I and II inhibitory effects of some hydroperoxides,alcohols, and acetates

The carbonic anhydrases (CAs, EC 4.2.1.1) represent a superfamily of widespread enzymes, which catalyze a crucial biochemical reaction, the reversible hydration of carbon dioxide to bicarbonate and protons. Human CA isoenzymes I and II (hCA I and hCA II) are ubiquitous cytosolic isoforms. In this study, a series of hydroperoxides, alcohols, and acetates were tested for the inhibition of the cytosolic hCA I and II isoenzymes. These compounds inhibited both hCA isozymes in the low nanomolar ranges. These compounds were good hCA I inhibitors (K_is in the range of 24.93–97.99?nM) and hCA II inhibitors (K_is in the range of 26.04–68.56?nM) compared to acetazolamide as CA inhibitor (K_i: 34.50?nM for hCA I and K_i: 28.93?nM for hCA II).     

Evaluation of antimicrobial,antibiofilm and carbonic anhydrase inhibition profiles of 1,3‐bis‐chalcone derivatives

A series of 1,3‐bis‐chalcone derivatives ( 3a‐i, 6a‐i and 8 ) were synthesized and evaluated antimicrobial, antibiofilm and carbonic anhydrase inhibition activities. In this evaluation, 6f was found to be the most active compound showing the same effect as the positive control against Bacillus subtilis and Streptococcus pyogenes in terms of antimicrobial activity. Biofilm structures formed by microorganisms were damaged by compounds at the minimum inhibitory concentration value between 0.5% and 97%.1,3‐bis‐chalcones ( 3a‐i, 6a‐i and 8 ) showed good inhibitory action against human (h) carbonic anhydrase (CA) isoforms I and II. hCA I and II were effectively inhibited by these compounds, with K _i values in the range of 94.33 ± 13.26 to 787.38 ± 82.64 nM for hCA I, and of 100.37 ± 11.41 to 801.76 ± 91.11 nM for hCA II, respectively. In contrast, acetazolamide clinically used as CA inhibitor showed K _i value of 1054.38 ± 207.33 nM against hCA I, and 983.78 ± 251.08 nM against hCA II, respectively.     

A thiabendazole sulfonamide shows potent inhibitory activity against mammalian and nematode α-carbonic anhydrases

A sulfonamide derivative of the antihelmintic drug thiabendazole was prepared and investigated for inhibition of the zinc enzyme carbonic anhydrase CA (EC 4.2.1.1). Mammalian isoforms CA I–XIV and the nematode enzyme of Caenorhabditis elegans CAH-4b were included in this study. Thiabendazole-5-sulfonamide was a very effective inhibitor of CAH-4b and CA IX (K_Is of 6.4–9.5 nm) and also inhibited effectively isozymes CA I, II, IV–VII, and XII, with K_Is in the range of 17.8–73.2 nM. The high resolution X-ray crystal structure of its adduct with isozyme II evidenced the structural elements responsible for this potent inhibitory activity.     

Inhibition of tumor-associated human carbonic anhydrase isozymes IX and XII by a new class of substituted-phenylacetamido aromatic sulfonamides

Here, we investigate 28 structurally new sulfonamides and their subsequent testing for enzyme inhibition of cytosolic and tumor-associated carbonic anhydrases (CAs, EC 4.2.1.1). The compounds showed very potent inhibition of four physiologically relevant human (h) CA isoforms, namely hCA I, II, IX and XII. Interestingly, the K_I values were in the nanomolar range for the tumor-associated hCA IX and hCA XII. Docking studies have revealed details regarding the very favorable interactions between the scaffolds of this new class of inhibitors and the active sites of the investigated CA isoforms. As there are reported cases of tumors overexpressing both CA II and IX, such potent inhibitors for the two isoforms as those detected in this work, may have applications for targeting more than one CA present in tumors.     

Design,synthesis and evaluation of N-substituted saccharin derivatives as selective inhibitors of tumor-associated carbonic anhydrase XII

A series of N-alkylated saccharin derivatives were synthesized and tested for the inhibition of four different isoforms of human carbonic anhydrase (CA, EC 4. 2.1.1): the transmembrane tumor-associated CA IX and XII, and the cytosolic CA I and II. Most of the reported derivatives inhibited CA XII in the nanomolar/low micromolar range, hCA IX with K_Is ranging between 11 and 390 nM, whereas they were inactive against both CA I (K_Is >50 μM) and II (K_Is ranging between 39.1 nM and 50 μM). Since CA I and II are off-targets of antitumor carbonic anhydrase inhibitors (CAIs), the obtained results represent an encouraging achievement for the development of new anticancer candidates without the common side effects of non-selective CAIs. Moreover, the lack of an explicit zinc binding function on these inhibitors opens the way towards the exploration of novel mechanisms of inhibition that could explain the high selectivity of these compounds for the inhibition of the transmembrane, tumor-associated isoforms over the cytosolic ones.     

Carbonic anhydrase inhibitors: Inhibition of the β-class enzyme from the pathogenic yeast Candida glabrata with sulfonamides,sulfamates and sulfamides

The fungal pathogen Candida glabrata encodes for a β-carbonic anhydrase (CA, EC 4.2.1.1), CgNce103, recently discovered. Only anions have been investigated as CgNce103 inhibitors up until now. Here we report the first sulfonamides inhibition study of this enzyme. Simple sulfonamides showed weak or moderate CgNce103 inhibitory properties, whereas acetazolamide, and a series of 4-substituted ureido-benzene-sulfonamides, sulfamates and sulfamides showed effective CgNce103 inhibitory properties, with K_Is in the range of 4.1–115 nM, being also ineffective as human CA II inhibitors. As there is significant resistance of C. glabrata clinical isolates to many classical antifungal agents, inhibition of the β-CA from this organism may allow an interesting means of controlling the pathogen growth, eventually leading to antifungals with a novel mechanism of action.     

The impact of hydroquinone on acetylcholine esterase and certain human carbonic anhydrase isoenzymes (hCA I,II, IX,and XII)

Abstract

Carbonic anhydrases (CAs) are widespread and the most studied members of a great family of metalloenzymes in higher vertebrates including humans. CAs were investigated for their inhibition of all of the catalytically active mammalian isozymes of the Zn²⁺-containing CA, (CA, EC 4.2.1.1). On the other hand, acetylcholinesterase (AChE. EC 3.1.1.7), a serine protease, is responsible for ACh hydrolysis and plays a fundamental role in impulse transmission by terminating the action of the neurotransmitter ACh at the cholinergic synapses and neuromuscular junction. In the present study, the inhibition effect of the hydroquinone (benzene-1,4-diol) on AChE activity was evaluated and effectively inhibited AChE with K_i of 1.22?nM. Also, hydroquinone strongly inhibited some human cytosolic CA isoenzymes (hCA I and II) and tumour-associated transmembrane isoforms (hCA IX, and XII), with K_is in the range between micromolar (415.81?μM) and nanomolar (706.79?nM). The best inhibition was observed in cytosolic CA II.     

Effects of dopaminergic compounds on carbonic anhydrase isozymes I,II, and VI

Studies on carbonic anhydrase (CA, EC 4.2.1.1) inhibitors have increased due to several therapeutic applications while there are few investigations on activators. Here we investigated CA inhibitory and activatory capacities of a series of dopaminergic compounds on human carbonic anhydrase (hCA) isozymes I, II, and VI. 2-Amino-1,2,3,4-tetrahydronaphthalene-6,7-diol hydrobromide and 2-amino-1,2,3,4-tetrahydronaphthalene-5,6-diol hydrobromide were found to show effective inhibitory action on hCA I and II whereas 2-amino-5,6-dibromoindan hydrobromide and 2-amino-5-bromoindan hydrobromide exhibited only moderate inhibition against both isoforms, being more effective inhibitors of hCA VI. K_i values of the molecules 3–6 were in the range of 41.12–363 μM against hCA I, of 0.381–470 μM against hCA II and of 0.578–1.152 μM against hCA VI, respectively. Compound 7 behaved as a CA activator with K_A values of 27.3 μM against hCA I, of 18.4 μM against hCA II and of 8.73 μM against hCA VI, respectively.