Isoforms hCA Research Articles

Potent carbonic anhydrase I, II, IX and XII inhibition activity of novel primary benzenesulfonamides incorporating bis-ureido moieties

A novel series of twelve aromatic bis-ureido-substituted benzenesulfonamides was synthesised by conjugation of aromatic aminobenzenesulfonamides with aromatic bis-isocyanates. The obtained bis-ureido-substituted derivatives were tested against four selected human carbonic anhydrase isoforms (hCA I, hCA II, hCA IX and hCA XII). Most of the new compounds showed an effective inhibitory profile against isoforms hCA IX and hCA XII, also having some selectivity with respect to hCA I and hCA II. The inhibition constants of these compounds against isoforms hCA IX and XII were in the range of 6.73–835 and 5.02–429 nM, respectively. Since hCA IX and hCA XII are important drug targets for anti-cancer/anti-metastatic drugs, these effective inhibitors reported here may be considered of interest for cancer related studies in which these enzymes are involved.

2-((1H-Benzo[d]imidazol-2-yl)amino)benzo[d]thiazole-6-sulphonamides: a class of carbonic anhydrase II and VII-selective inhibitors

A small library of substituted cyclic guanidine incorporated benzothiazole-6-sulphonamides was synthesized. All obtained compounds were investigated for their inhibitory activity against the key brain-associated human carbonic anhydrase isoform hCA VII (a promising target for the treatment of neuropathic pain) and three isoforms expressed in brain and other tissues, hCA I, II, and IV. Sulphaguanidine derivatives 9a–d were inactive on the all investigated isoforms while the primary sulphonamide containing guanidines 6a–c and 7a–c were inactive towards hCA IV but displayed inhibiting properties on hCA I, II, and VII with KIs values in the low nanomolar to micromolar ranges. The results indicated that isoforms hCA II and VII were potently and selectively inhibited by these compounds, whereas the cytosolic hCA I was less sensitive to inhibition. The derivatives reported in this study might be useful for design of more potent and selective inhibitors of hCA II and VII.

4-(5-Amino-pyrazol-1-yl)benzenesulfonamide derivatives as novel multi-target anti-inflammatory agents endowed with inhibitory activity against COX-2, 5-LOX and carbonic anhydrase: Design, synthesis, and biological assessments

In the current medical era, the single target inhibition paradigm of drug discovery has given way to the multi-target design concept. As the most intricate pathological process, inflammation gives rise to a variety of diseases. There are several drawbacks to the single target anti-inflammatory drugs currently available. Herein, we present the design and synthesis of a novel series of 4-(5-amino-pyrazol-1-yl)benzenesulfonamide derivatives (7a-j) with COX-2, 5-LOX and carbonic anhydrase (CA) inhibitory activities as potential multi-target anti-inflammatory agents. The pharmacophoric 4-(pyrazol-1-yl)benzenesulfonamide moiety in Celecoxib was used as the core scaffold and different substituted phenyl and 2-thienyl tails were grafted via a hydrazone linker to enhance inhibitory activity against hCA IX and XII isoforms, yielding target pyrazoles 7a-j. All reported pyrazoles were evaluated for their inhibitory activity against COX-1, COX-2, and 5-LOX. Pyrazoles 7a, 7b, and 7j showed the best inhibitory activities against the COX-2 isozyme (IC50 = 49, 60 and 60 nM, respectively) and against 5-LOX (IC50 = 2.4, 1.9, and 2.5 μM, respectively) with excellent SI indices (COX-1/COX-2) of 212.24, 208.33, and 158.33, respectively. In addition, the inhibitory activities of pyrazoles 7a-j were evaluated against four different hCA isoforms I, II, IX, and XII. Both transmembrane hCA IX and XII isoforms were potently inhibited by pyrazoles 7a-j with KI values in the nanomolar range; 13.0–82.1 nM and 5.8–62.0 nM, respectively. Furthermore, pyrazoles 7a and 7b with the highest COX-2 activity and selectivity indices were evaluated in vivo for their analgesic, anti-inflammatory, and ulcerogenic activities. The serum level of the inflammatory mediators was then measured in order to confirm the anti-inflammatory activities of pyrazoles 7a and 7b.

Discovery of new 6-ureido/amidocoumarins as highly potent and selective inhibitors for the tumour-relevant carbonic anhydrases IX and XII

A series of 6-ureido/amidocoumarins (5a–p and 7a–c) has been designed and synthesised to develop potent and isoform- selective carbonic anhydrase hCA XI and XII inhibitors. All coumarin derivatives were investigated for their CA inhibitory effect against hCA I, II, IX, and XII. Interestingly, target coumarins potently inhibited both tumour-related isoforms hCA IX (K Is: 14.7–82.4 nM) and hCA XII (K Is: 5.9–95.1 nM), whereas the cytosolic off-target hCA I and II isoforms have not inhibited by all tested coumarins up to 100 μM. These findings granted the target coumarins an excellent selectivity profile towards both hCA IX and hCA XII isoforms, supporting their development as promising anticancer candidates. Moreover, all target molecules were evaluated for their anticancer activities against HCT-116 and MCF-7 cancer cells. The 3,5-bis-trifluoromethylphenyl ureidocoumarin 5i, exerted the best anticancer activity. Overall, ureidocoumarins, particularly compound 5i, could serve as a promising prototype for the development of potent anticancer CAIs.

Synthesis, Biological and In Silico Studies of Griseofulvin and Usnic Acid Sulfonamide Derivatives as Fungal, Bacterial and Human Carbonic Anhydrase Inhibitors.

Carbonic anhydrases (CAs, EC 4.2.1.1) catalyze the essential reaction of CO2 hydration in all living organisms, being actively involved in the regulation of a plethora of patho-/physiological conditions. A series of griseofulvin and usnic acid sulfonamides were synthesized and tested as possible CA inhibitors. Since β- and γ- classes are expressed in microorganisms in addition to the α- class, showing substantial structural differences to the human isoforms they are also interesting as new antiinfective targets with a different mechanism of action for fighting the emerging problem of extensive drug resistance afflicting most countries worldwide. Griseofulvin and usnic acid sulfonamides were synthesized using methods of organic chemistry. Their inhibitory activity, assessed against the cytosolic human isoforms hCA I and hCA II, the transmembrane hCA IX as well as β- and γ-CAs from different bacterial and fungal strains, was evaluated by a stopped-flow CO2 hydrase assay. Several of the investigated derivatives showed interesting inhibition activity towards the cytosolic associate isoforms hCA I and hCA II, as well as the three γ-CAs and Malassezia globosa (MgCA) enzyme. Six compounds (1b-1d, 1h, 1i and 1j) were more potent than AAZ against hCA I while five (1d, 1h, 1i, 1j and 4a) showed better activity than AAZ against the hCA II isoform. Moreover, all compounds appeared to be very potent against MgCA with a Ki lower than that of the reference drug. Furthermore, computational procedures were used to investigate the binding mode of this class of compounds within the active site of human CAs.

Investigation of novel alkyl/benzyl (4-sulphamoylphenyl)carbamimidothioates as carbonic anhydrase inhibitors

A library of novel alkyl/benzyl (4-sulphamoylphenyl)carbamimidothioates was synthesised by selective S-alkylation of the easily accessible 4-thioureidobenzenesulphonamide. The compounds were assayed as inhibitors of four human (h) carbonic anhydrase isoforms hCA I, II, VII, and XIII, as well as three bacterial enzymes belonging to the β-CA class, MscCA from Mammaliicoccus (Staphylococcus) sciuri and StCA1 and StCA2, from Salmonella enterica (serovar Typhimurium). Most compounds investigated here exhibited moderate to low nanomolar inhibition constants against hCA I, II, and VII. The cytosolic hCA XIII was also inhibited by these compounds, but not as effective as hCA I, II, and VII. Several compounds were very effective against MscCA and StCA1. StCA2 was less inhibited compared to MscCA and StCA1. Some compounds showed considerable selectivity for inhibiting some CA isoforms. They may thus be considered as interesting starting points for the discovery and development of novel therapeutic agents belonging to this class of enzyme inhibitors.

Design, synthesis, biological evaluation and crystal structure determination of dual modulators of carbonic anhydrases and estrogen receptors

Multi-target compounds have become increasingly important for the development of safer and more effective drug candidates. In this work, we devised a combined ligand-based and structure-based multi-target repurposing strategy and applied it to a series of hexahydrocyclopenta[c]quinoline compounds synthesized previously. The in silico analyses identified human Carbonic Anhydrases (hCA) and Estrogen Receptors (ER) as top scoring candidates for dual modulation. hCA isoforms IX and XII, and ER subtypes ER⍺ and/or ERβ are co-expressed in various cancer cell types, including breast and prostate cancer cells. ER⍺ is the primary target of anti-estrogen therapy in breast cancer, and the hCA IX isoform is a therapeutic target in triple-negative breast cancer. ER⍺-mediated transcriptional programs and hCA activity in cancer cells promote favorable microenvironments for cell proliferation. Interestingly, several lines of evidence indicate that the combined modulation of these two targets may provide significant therapeutic benefits. Moving from these first results, two additional hexahydrocyclopenta[c]quinoline derivatives bearing a sulfonamide zinc binding group (hCA) and a phenolic hydroxyl (ER) pharmacophoric group placed at the appropriate locations were designed and synthesized. Interestingly, these compounds were able to directly modulate the activities of both hCA and ER targets. In cell-based assays, they inhibited proliferation of breast and prostate cancer cells with micromolar potency and cell type-selective efficacy. The compounds inhibited hCA activity with nanomolar potency and isoform-selectivity. In transactivation assays, they reduced estrogen-driven ER activity with micro-molar potency. Finally, crystal structures of the synthesized ligands in complex with the two targets revealed that the compounds bind directly to the hCA active site, as well as to the ER ligand-binding domain, providing structural explanation to the observed activity and a rationale for optimization of their dual activity. To the best of our knowledge, this work describes the design, synthesis and biological characterization of the first dual modulators of hCA and ER, laying the ground for the structure-based optimization of their multi-target activity.

Exploration of 1,2,3-triazole linked benzenesulfonamide derivatives as isoform selective inhibitors of human carbonic anhydrase

A novel series of 1,2,3-triazole benzenesulfonamide substituted 1,3-dioxoisoindolin-5-carboxylate (7a-l) inhibitors of human α-carbonic anhydrase (hCA) was designed using a tail approach. The design method relies on the hybridization of a benzenesulfonamide moiety with a tail of 1,3-dioxoisoindoline-5-carboxylate and a zinc-binding group on a 1,2,3-triazole scaffold. Among the synthesized analogues, 2‑iodophenyl (7f, KI of 105.00 nM and SI of 2.98) and 2‑naphthyl (7h, KI of 32.11 nM and SI of 3.48) analogues (over off-target hCA I) and phenyl (7a, KI of 50.13 nM and SI of 2.74) and 2,6‑dimethylphenyl (7d, KI of 50.60 nM and SI of 3.35) analogues (over off-target hCA II) exhibited a remarkable selectivity for tumor isoforms hCA IX and XII, respectively. Meanwhile, analogue 7a displayed a potent inhibitory effect against the tumor-associated isoform hCA IX (KI of 18.29 nM) compared with the reference drug acetazolamide (AAZ, KI of 437.20 nM), and analogue 7h showed higher potency (KI of 9.22 nM) than AAZ (KI of 338.90 nM) against another tumor-associated isoform hCA XII. However, adding the lipophilic large naphthyl tail to the 1,3-dioxoisoindolin-5-carboxylate analogues increased both the hCA inhibitory and selective activities against the target isoform, hCA XII. Additionally, these analogues (7a-l) showed IC50 values against the human lung (A549) adenocarcinoma cancer cell line ranging from 129.71 to 352.26 μM. The results of the molecular docking study suggested that the sulfonamide moiety fits snugly into the hCAs active sites and interacts with the Zn2+ ion. At the same time, the tail extension engages in various hydrophilic and hydrophobic interactions with the nearby amino acids, which affects the potency and selectivity of the hybrids.

3H-1,2-Benzoxaphosphepine 2-oxides as selective inhibitors of carbonic anhydrase IX and XII

The synthesis of 3H-1,2-benzoxaphosphepine 2-oxides and evaluation of their inhibitory activity against human carbonic anhydrase (hCA) isoforms I, II, IX, and XII are described. The target compounds were obtained via a concise synthesis from commercial salicylaldehydes and displayed low to sub-micromolar inhibition levels against the tumour-associated isoforms hCA IX and XII. All obtained benzoxaphosphepine 2-oxides possess remarkable selectivity for inhibition of hCA IX/XII over the off-target cytosolic hCA isoforms I and II, whose inhibition may lead to side effects.

Tail approach synthesis of triazolylthiazolotriazole bearing benzenesulfonamides as carbonic anhydrase inhibitors capable of inducing apoptosis.

Inhibition of human carbonic anhydrase (hCA) isoform IX with concurrent induction of apoptosis is a promising approach for targeting cancer in humans. Prompted by the scope, novel benzenesulfonamides containing the 1,2,3-triazolylthiazolotriazole tail were synthesized and screened as inhibitors of hCA isoforms I, II, IV, and IX. The tumor-associated isoform hCA IX was strongly inhibited by the sulfonamides reported here with KI values ranging from 45 nM to 1.882 μM. Overall, nine compounds showed hCA IX inhibition with KI < 250 nM. The glaucoma-associated isoform hCA II was moderately inhibited while the cytosolic isoform hCA I and membrane-bound isoform hCA IV were weakly inhibited by the synthesized sulfonamides. Compound 6Ac (KI = 3.6 nM) was found to be an almost three times more potent inhibitor of hCA II as compared to the standard drug acetazolamide (KI = 12.1 nM). The selective hCA IX inhibitors were further studied for their apoptotic efficacy in goat ovarian cells and showed better results as compared to the control. A comparative study of previously synthesized compounds and molecular docking study of representative compounds revealed some important generalizations that could prove beneficial in further investigations of isoform-selective hCA inhibitors.

Design and synthesis of some new benzoylthioureido benzenesulfonamide derivatives and their analogues as carbonic anhydrase inhibitors

The present investigation reports the design and synthesis of three series of benzoylthioureido derivatives bearing either benzenesulfonamide 7a–f, benzoic acid 8a–f or ethylbenzoate 9a–f moieties. The synthesised compounds were screened for their carbonic anhydrase inhibitory activity (CAI) against four isoforms hCA I, II, IX, and XII. Compounds 7a, 7b, 7c, and 7f exhibited a potent inhibitory activity towards hCAI (K is = 58.20, 56.30, 33.00, and 43.00 nM), respectively compared to acetazolamide (AAZ) and SLC-0111 (K is = 250.00 and 5080.00 nM). Compounds 7a, 7b, 7c, 7e, and 7f elicited selectivity over h CA II (K is = 2.50, 2.10, 56.60,39.60 and 39.00 nM) respectively, relative to AAZ and SLC-0111(K is = 12.10 and 960.00 nM). Also, compounds 7c, 7f, and 9e displayed selectivity against the tumour-associated isoform hCA IX (K is = 31.20, 30.00 and 29.00 nM) respectively, compared to AAZ and SLC-0111 (K is = 25.70 and 45.00 nM). Additionally, compounds 8a and 8f revealed a moderate to superior selectivity towards hCAXII (K is = 17.00 and 11.00 nM) relative to AAZ and SLC-0111(K is = 5.70 and 45.00 nM). Molecular docking and ADME prediction studies were performed on the most active compounds to shed light on their interaction with the hot spots of the active site of CA isoforms, in addition to prediction of their pharmacokinetic and physicochemical properties.

4-Cyanamidobenzenesulfonamide derivatives: a novel class of human and bacterial carbonic anhydrase inhibitors

A one-pot two-step protocol was developed for the synthesis of a series of novel 4-cyanamidobenzenesulfonamides from easily accessible methyl (4-sulfamoylphenyl)-carbamimidothioate. The new sulphonamides were investigated as inhibitors of the enzyme carbonic anhydrase (CA, EC 4.2.1.1), the human (h) cytosolic isoforms hCA I, II, VII, and XIII, as well as three bacterial enzymes belonging to the β-CA class, MscCA from Mammaliicoccus (Staphylococcus) sciuri and StCA1 and StCA2, from Salmonella enterica (serovar Typhimurium). The human isoforms were generally effectively inhibited by these compounds, with a clear structure-activity relationship privileging long aliphatic chains (C6, C7 and C18) as substituents at the cyanamide functionality. The bacterial CAs were also inhibited by these compounds, but not as effective as the hCAs. The most sensitive enzyme to these inhibitors was StCA1 (KIs of 50.7 − 91.1 nM) whereas SscCA was inhibited in the micromolar range (KIs of 0.86–9.59 µM).

Structure-guided identification of a selective sulfonamide-based inhibitor targeting the human carbonic anhydrase VA isoform.

In recent years, multistep hybrid computational protocols have attracted attention for their application in the drug discovery of enzyme inhibitors. So far, there are large collections of human carbonic anhydrase (hCA) inhibitors, but only a few of them selectively inhibit the mitochondrial isoforms hCA VA and VB as potential therapeutics in obesity treatment. Most sulfonamide-based inhibitors show poor selectivity for inhibiting isoforms of therapeutic interest over ubiquitous hCA I and hCA II. Herein, we propose a combination of ligand- and structure-based approaches to generate pharmacophore models for hCA VA inhibitors. Then, we performed a virtual screening (VS) campaign on a database of commercially available sulfonamides. Finally, the in silico screening followed by docking studies suggested several "hit compounds" that demonstrated to inhibit hCA VA at a low nanomolar concentration in a stopped-flow CO2 hydrase assay. Notably, the best candidate, 2-(3,4-dihydro-2H-quinolin-1-yl)-N-(4-sulfamoylphenyl)acetamide (code name VAME-28) proved to be a potent hCA VA inhibitor (Ki value of 54.8 nM) and a more selective agent over hCA II when compared to the reference compound topiramate.

Synthesis and anticancer activity of new benzensulfonamides incorporating s-triazines as cyclic linkers for inhibition of carbonic anhydrase IX

Limited presence of hCA IX in normal physiological tissues and their overexpression only in solid hypoxic tumors made this isoform excellent possible target for developing new anticancer agents. We reported designing and synthesis of two novel series of benzenesulfonamides derivatives as hCA IX inhibitors bearing rigid cyclic linkers (1,3,5-dihydrotriazine in series A and 1,3,5-triazine in series B) in replace of traditional linear linkers. Also, novel cyanoethenyl spacer was assembled next to the 1,3,5-triazine linker in series B. Target compounds of series (A) and (B) were screened against four hCA isoforms. Human CA IX efficiently inhibited in series (A) by compound 5a (KI = 134.8 nM). Meanwhile, in series (B) the most active inhibitor was 12i (KI = 38.8 nM). US-NCI protocol was followed to evaluate the anticancer activity of target compounds against panel of sixty cancer cell lines. Compound 12d, exposed the best activity towards breast cancer (MDA-MB-468) with GI% = 62%. The most active analogues, 12d and 12i were further screened for in vitro cytotoxic activity under hypoxic condition against breast cancer (MDA-MB-468) (IC50 = 3.99 ± 0.21 and 1.48 ± 0.08 µM, respectively) and leukemia (CCRF-CM) cell line (IC50 = 4.51 ± 0.24 and 9.83 ± 0.52 µM, respectively). In addition, 12d arrested breast cancer MDA-MB-468 cell cycle in G0-G1 and S phases and induced its apoptosis which indicated by increasing the level of cleaved caspases 3 and 9. Molecular docking was performed for selected analogues to understand their biological alterations. This study revealed that insertion of 1,3,5-triazines as cyclic linkers enhanced the significant anticancer and hCA IX inhibition activity of benzenesulfonamides.

Design and synthesis of some new benzoylthioureido phenyl derivatives targeting carbonic anhydrase enzymes

The present study aimed to develop potent carbonic anhydrase inhibitors (CAIs). The design of the target compounds was based on modifying the structure of the ureido-based carbonic anhydrase inhibitor SLC-0111. Six series of a substituted benzoylthioureido core were prepared featuring different zinc-binding groups; the conventional sulphamoyl group 4a–d and 12a–c, its bioisosteric carboxylic acid group 5a–d and 13a–c or the ethyl carboxylate group 6a–d and 14a–c as potential prodrugs. All compounds were assessed for their carbonic anhydrase (CA) inhibitory activity against a panel of four physiologically relevant human CA isoforms hCA I and hCA II, and hCA IX, and hCA XII. Compounds 4a, 4b, 4c, 4d, 5d, 12a, and 12c revealed significant inhibitory activity against hCA I that would highlight these compounds as promising drug candidates for the treatment of glaucoma.

Synthesis, characterization, evaluation of metabolic enzyme inhibitors and in silico studies of thymol based 2-amino thiol and sulfonic acid compounds

Eight new aminothiols (4a-g and 5) and three new sulfonic acid derivatives (6a-c) were synthesized, and their structures were characterized. Inhibitory effects of the obtained compounds on carbonic anhydrase I and II isoforms (hCA I and hCA II), butyrylcholinesterase (BChE) and acetylcholinesterase (AChE), enzymes were investigated. The newly synthesized compounds have inhibited hCA I with Kis ranging from 7.11 ± 1.46 nM (6a) to 670.52 ± 300.41 nM (4b) and, hCA II with Kis ranging from 16.83 ± 5.72 nM (6a) to 453.34 ± 208.56 nM (4c). Acetazolamide was employed as the positive control for both hCA isoforms (Ki for hCA I 198.81 ± 14.13 nM and Ki for hCA II 211.42 ± 13.10 nM), and among the new compounds obtained, it was observed that there were compounds that were active at much lower nM levels. All compounds were also evaluated for inhibition of AChE and BChE. They inhibited AChE and BChE enzymes in the range of Ki 5.24 ± 2.27 (6c) - 48.44 ± 21.82 (4g) for AChE and 4.86 ± 0.64 (6c) - 51.75 ± 12.56 (4a) for BChE, and the results were compared with the standard inhibitor Tacrine (Ki: 14.20 ± 8.83 nM toward AChE and Ki: 3.39 ± 1.91 nM for BChE). Cholinesterase (BChE and AChE) inhibitory abilities of all synthesized molecules were also performed in situ and molecular docking and molecular dynamics (MD) simulation studies. The molecular coupling scores of the compounds and the free binding energies calculated by MM/GBSA were found to be compatible. Examining the results obtained from this study shows that it may have the potential to develop new drugs to treat some global patients such as glaucoma and Alzheimer's disease (AD).

Synthesis of Sulfonamides Incorporating Piperidinyl-Hydrazidoureido and Piperidinyl-Hydrazidothioureido Moieties and Their Carbonic Anhydrase I, II, IX and XII Inhibitory Activity.

Here we report a small library of hydrazinocarbonyl-ureido and thioureido benzenesulfonamide derivatives, designed and synthesized as potent and selective human carbonic anhydrase inhibitors (hCAIs). The synthesized compounds were evaluated against isoforms hCA I, II, IX and XII using acetazolamide (AAZ) as standard inhibitor. Several urea and thiourea derivatives showed inhibitory activity at low nanomolar levels with selectivity against the cytosolic hCA II isoform, as well as the transmembrane, tumor-associated enzymes hCA IX and XII. The thiourea derivatives showed enhanced potency as compared to urea analogues. Additionally, eight compounds 5g, 5m, 5o, 5q, 6l, 6j, 6o and 6u were selected for docking analysis on isoform I, II, IX, XII to illustrate the potential interaction with the enzyme to better understand the activity against the different isoforms.

New Pyridinium Salt Derivatives of 2-(Hydrazinocarbonyl)-3-phenyl-1H-indole-5- sulfonamide as Selective Inhibitors of Tumour-Related Human Carbonic Anhydrase Isoforms IX and XII.

The positively charged membrane impermeant sulfonamides were evaluated as a remarkable class of carbonic anhydrase inhibitors (CAIs) previously. Without affecting the human carbonic anhydrase (hCA), cytosolic isoforms hCA I and II, inhibition of two membrane-associated isoforms hCA IX and XII especially overexpressed in hypoxic tumour cells, makes the pyridinium salt derivatives potent promising therapeutic agents. A novel series of tri, tetra, and cyclo-substituted pyridinium salt derivatives of the lead compound 2- (hydrazinocarbonyl)-3-phenyl-1H-indole-5-sulfonamide has been prepared by using sixteen different pyrylium salts, for the search of selective inhibitors of transmembrane tumour-associated human carbonic anhydrase hCA IX and XII. Molecular modeling studies were carried out to understand and rationalize the in vitro enzyme inhibition data. Six of the new compounds showed good inhibitory profiles with low nanomolar range (< 100 nM) against hCA IX/XII, and compound 5 showed excellent potency with Ki values lower than 10 nM. In addition, molecular modelling studies have presented the possible binding modes of the ligands. Most of the compounds displayed potent inhibitory activity against the tumor-associated hCA IX and XII in the low nanomolar range and selectivity over the off-targeted isoforms hCA I and II. Due to their cationic structure and membrane-impermeant behavior, it is also expected to maximize the selectivity over cytosolic isoforms hCA I/II while inhibiting tumor overexpressed isoforms hCA XI/XII of new compounds in in vivo conditions.

Efficient One-pot Synthesis of 3,3-di(indolyl)indolin-2-ones from Isatin and Indole Catalyzed by VOSO4 as Non-Sulfonamide Carbonic Anhydrase Inhibitors.

A high yielding green protocol has been developed and delineated for the synthesis of 3,3- di(indolyl)indolin-2-ones, potentially bioactive compounds, involving one pot aqueous medium condensation of isatin with indole in the presence of VOSO4. The synthesized compounds were screened for their carbonic anhydrase inhibitory activity against human (h) isoforms hCA I, hCA II, hCA IX, and hCA XII. These non-sulfonamide derivatives selectively inhibited hCA II in the micromolar range. To develop a high yielding green protocol to synthesize 3,3-diindolyl oxindole derivatives using water as solvent media and screening the synthesized molecules for their carbonic anhydrase inhibitory activity. The target compound is obtained by taking isatin, indole, VOSO4, and H2O in one-pot at 70oC. The designed molecules were synthesized by using the new method. The molecules were screened for their CA inhibitory activity, which shows selective inhibition toward hCA II.The result showed an excellent yield without any loss or decrease in catalytic activity, proving the catalyst's performance and recyclability. An efficient, simple, and green protocol was established that provides a facile and straightforward approach for the preparation of 3,3-diindolyl oxindole derivatives (3a-r) from Isatin and Indole by using 10 mol% VOSO4 in high yields in a short period of time by a one-pot coupling reaction. Furthermore, the catalyst can also be recovered and reused for three consecutive catalytic cycles without any loss of its efficiency, which was confirmed by performing the experiment with 3a. The newly synthesized molecules (3a-r) were screened for their carbonic anhydrase inhibition potency against four isoforms, hCA I, II, IX, and XII and most of the compounds were found potent against hCA II with potency low to submicromolar range.

Synthesis and Biological Evaluation of Coumarin Carboxamides as Selective and Potent Inhibitors of Carbonic Anhydrases IX and XII

Carbonic anhydrases (CAs, EC 4.2.1.1) catalyze the reversible hydration of carbon dioxide to bicarbonate and proton. Inhibition of isoforms IX and XII could aid in the amelioration of cancer. A series of coumarin carboxamides (6a-j) were synthesized and were assayed against hCA isoforms I, II, IX, and XII. Thin Layer Chromatography (TLC) analysis was done by utilizing Merck silica gel 60 F254 aluminum plates. Stuart Digital Melting Point Apparatus (SMP 30) was used in determining the melting points of the compounds, which are uncorrected. High Resolution Mass Spectra (HRMS) were determined by Agilent QTOF mass spectrometer 6540 series instrument and were performed using ESI techniques at 70eV. All the compounds selectively inhibited isoforms IX and XII as against hCAs I and II. Compounds 6a-e exhibited the best inhibitory profiles against hCA IX (Ki &lt; 25 nM). The isoform hCA XII was effectively inhibited by all compounds showing the Ki values less than 65 nM. The Compounds 6a, 6b, 6g, 6h, and 6j exhibited Ki values less than 10 nM. The binding interactions of the most potent compounds, 6a and 6b, were investigated through docking studies with hCAs IX and XII. These compounds may be utilized as useful starting points for the design and development of selective and potent hCA IX and XII inhibitors.