Inhibition Of Carbonic anhydrase-II Research Articles

Synthesis, Biochemical Characterization, and in-Silico Investigations of Acyl-3-(Ciprofloxacinyl) Thioureas as Inhibitors of Carbonic Anhydrase-II

A new series of 1-(acyl/aroyl)-3-(ciprofloxacinyl) thioureas (5a–o) was synthesized by the reaction of ciprofloxacin (4) in dry acetone with acyl isothiocyanate intermediate (3). The synthesized compounds were characterized by FT-IR, 1H-NMR, and 13C-NMR. Furthermore, the synthesized compounds were tested for inhibitory potential against carbonic anhydrase (CA-II) and 15 lipoxygenase (LOX) enzymes. The tested compounds exhibited maximum inhibition of CA-11 with moderate anti-inflammatory potential, at the same concentration, i.e. 100 µM, therefore, can be considered as the selective inhibitors of CA-II. Among the tested derivatives 5g showed remarkable inhibitory activity against CA enzyme with IC50 value of 0.97 ± 0.11 µM and this derivative exhibited approximately 40% inhibition of 15-LOX, indicating that compound has moderate anti-inflammatory properties. The molecular docking studies, density functional theory (DFT) calculations, and molecular dynamic (MD) simulation studies were performed to evaluate their binding affinities, stability, and chemical reactivity within the active pocket of the targeted enzymes. The docking analysis and MD simulation studies revealed that the most active inhibitor 5g showed important interactions within the binding pockets of CA-II and may be responsible for the inhibitory activity of the compound toward the targeted enzymes. Therefore, the screened derivatives provided an outstanding platform for further development of CA inhibitors.

Biochemical and in silico inhibition of bovine and human carbonic anhydrase-II by 1H-1,2,3-triazole analogs.

A series of 1H-1,2,3-triazole analogs (7a-7d and 9a-9s) were synthesized via "click" chemistry and evaluated for in vitro carbonic anhydrase-II (bovine and human) inhibitory activity. The synthesis of intermediates, 7a and 7c, was achieved by using (S)-(-)ethyl lactate as a starting material. These compounds (7a and 7c) underwent Suzuki-Miyaura cross-coupling reaction with different arylboronic acids in 1,4-dioxane, reflux at 90-120°C for 8h using Pd(PPh3)4 as a catalyst (5mol%), and K2CO3 (3.0 equiv)/K2PO4 (3.0 equiv) as a base to produce target 1H-1,2,3-triazole molecules (9a-9s) for a good yield of 67-86%. All the synthesized compounds were characterized through NMR spectroscopic techniques. Furthermore, all those compounds have shown significant inhibitory potential for both sources of carbonic anhydrase-II (CA-II). In the case of bCA-II, compounds 9i, 7d, 9h, 9o, 9g, and 9e showed potent activity with IC50 values in the range of 11.1-17.8µM. Whereas for hCA-II, compounds 9i, 9c, 9o, and 9j showed great potential with IC50 values in the range of 10.9-18.5µM. The preliminary structure-activity relationship indicates that the presence of the 1H-1,2,3-triazole moiety in those synthesized 1H-1,2,3-triazole analogs (7a-7d and 9a-9s) significantly contributes to the overall activity. However, several substitutions on this scaffold affect the activity to several folds. The selectivity index showed that compounds 9c, 9k, and 9p are selective inhibitors of hCA-II. Kinetics studies showed that these compounds inhibited both enzymes (bCA-II and hCA-II) in a competitive manner. Molecular docking indicates that all the active compounds fit well in the active site of CA-II. This study has explored the role of 1H-1,2,3-triazole-containing compounds in the inhibition of CA-II to combat CA-II-related disorders.

Inhibitory Efficacy of Thiosemicarbazones for Carbonic Anhydrase II (Bovine and Human) as a Target of Calcification and Tumorigenicity.

Carbonic anhydrase II (CA-II) is associated with calcification, tumorigenicity, epilepsy, osteoporosis, and several other physiological or pathological processes. CA-II inhibitors can be used to reduce the intraocular pressure usually associated with glaucoma. In search for potent CA-II inhibitors, a series of thiosemicarbazone derivatives (3a-u) was synthesized. This series was evaluated against bovine and human carbonic anhydrase II (bCA-II and hCA-II) and their docking studies were carried out. In the preliminary screening, most of the compounds exhibited significant inhibition of bCA-II and hCA-II. The predictive structure-activity relationship suggested that the thiosemicarbazide moiety plays a key role in the inhibition of enzyme activity and substitution at R position and has a remarkable contribution to the overall activity. The kinetic studies of the most active inhibitors of bCA-II (3d, 3e, 3l, 3f, and 3p) and hCA-II (3g) were performed against bCA-II and hCA-II, respectively to investigate their mode of inhibition and dissociation constants (Ki). Subsequently, (3e, 3f, 3l and 3p) were identified as competitive inhibitors of bCA-II with Ki values of 5.02-14.70 μM, while (3d) as a noncompetitive inhibitor of bCA-II (Ki = 2.5 ± 0.015 μM), however, (3g) demonstrated competitive inhibition of hCA-II with a Ki value of 5.95 ± 0.002 μM. The selectivity index reflects that compound (3g) is more selective for hCA-II. The binding modes of these compounds with bCA-II and hCA-II were investigated by structure-based molecular docking, and the docking results are in complete agreement with the experimental findings.

Enzymes Inhibition and Antioxidant Potential of Medicinal Plants Growing in Oman.

The recent study was designed to explore Dodonaea viscosa, Juniperus excelsa, Helianthemum lippii, and Euryops pinifolius using methanolic (MeOH) extract. Their subfractions were examined against urease, carbonic anhydrase II (CA-II), α-glucosidase enzymes, and free radicals scavenging significance based on local practices via standard methods. Significance potential against the urease enzyme was presented by ethyl acetate fraction (EtOAc) of D. viscosa with (IC50 = 125 ± 1.75 μg/mL), whereas the H. lippii (IC50 = 146 ± 1.39 μg/mL) in the EtOAc was found efficient to scavenge the free radicals. Besides, that appreciable capacity was observed by the J. excelsa, D. viscosa, J. excelsa, and E. pinifolius as compared to the standard acarbose (IC50 = 377.24 ± 1.14 μg/mL). Maximum significance was noticed in methanolic (MeOH) extract of J. excelsa and presented carbonic anhydrase CA-II (IC50 = 5.1 ± 0.20 μg/mL) inhibition as compared to the standard (acetazolamide). We are reporting, for the first time, the CA-II inhibition of all the selected medicinal plants and α-glucosidase, urease, and antioxidant activities of the E. pinifolius. Thus, further screening is needed to isolate the promising bioactive ingredients which act as an alternative remedy to scavenge the free radicals, antiulcer, and act as a potential source to develop new antidiabetic drugs for controlling postprandial blood sugar as well as carbonic anhydrase inhibitors.

Evaluation of indole-picolinamide hybrid molecules as carbonic anhydrase-II inhibitors: Biological and computational studies

The present study reports the successful synthesis and evaluation of a series of indole-picolinamide hybrids as potent inhibitors of bovine carbonic anhydrase II, a promising therapeutic target for the treatment of neurological disorders, osteoporosis, glaucoma, cancer, and obesity. Various multistep synthetic approaches were utilized to access the desired structures having exclusive sites for chemical modifications and diverse spots for biological interactions between the ligand and enzyme. Compound 1a was observed as a potent inhibitor of the bovine CA-II with an IC50 value of 0.0440 ± 0.009 µM. The inhibition potency was about 22-fold higher than the standard drug acetazolamide (IC50 = 0.9618 ± 0.180 µM). Several impactful structure-activity relationships were deduced that enlighten the crucial role of substituents as well as the key pharmacophores involved in the inhibition process. Molecular docking tools reinforced the in vitro assay results. The most active compound 1a was also investigated for anticancer potential using sulforhodamine B assay and results showed two-fold efficacy against HeLa cells when compared to standard drug cisplatin (IC50 = 8.045 ± 3.791 µg/mL and 4.128 ± 1.473 µg/mL, respectively). These findings were also confirmed by flow cytometry and comet tests. Moreover, fluorescence microscopy with DAPI staining revealed apoptosis as a mechanism of cancer cell death.

Design, Synthesis and Molecular Docking Study of Novel 3-Phenyl-β-Alanine-Based Oxadiazole Analogues as Potent Carbonic Anhydrase II Inhibitors.

Carbonic anhydrase-II (CA-II) is strongly related with gastric, glaucoma, tumors, malignant brain, renal and pancreatic carcinomas and is mainly involved in the regulation of the bicarbonate concentration in the eyes. With an aim to develop novel heterocyclic hybrids as potent enzyme inhibitors, we synthesized a series of twelve novel 3-phenyl-β-alanine 1,3,4-oxadiazole hybrids (4a–l), characterized by 1H- and 13C-NMR with the support of HRESIMS, and evaluated for their inhibitory activity against CA-II. The CA-II inhibition results clearly indicated that the 3-phenyl-β-alanine 1,3,4-oxadiazole derivatives 4a–l exhibited selective inhibition against CA-II. All the compounds (except 4d) exhibited good to moderate CA-II inhibitory activities with IC50 value in range of 12.1 to 53.6 µM. Among all the compounds, 4a (12.1 ± 0.86 µM), 4c (13.8 ± 0.64 µM), 4b (19.1 ± 0.88 µM) and 4h (20.7 ± 1.13 µM) are the most active hybrids against carbonic CA-II. Moreover, molecular docking was performed to understand the putative binding mode of the active compounds. The docking results indicates that these compounds block the biological activity of CA-II by nicely fitting at the entrance of the active site of CA-II. These compounds specifically mediating hydrogen bonding with Thr199, Thr200, Gln92 of CA-II.

New Carbonic Anhydrase-II Inhibitors from Marine Macro Brown Alga Dictyopteris hoytii Supported by In Silico Studies.

In continuation of phytochemical investigations of the methanolic extract of Dictyopteris hoytii, we have obtained twelve compounds (1–12) through column chromatography. Herein, three compounds, namely, dimethyl 2-bromoterepthalate (3), dimethyl 2,6-dibromoterepthalate (4), and (E)-3-(4-(dimethoxymethyl)phenyl) acrylic acid (5) are isolated for the first time as a natural product, while the rest of the compounds (1, 2, 6–12) are known and isolated for the first time from this source. The structures of the isolated compounds were elucidated by advanced spectroscopic 1D and 2D NMR techniques including 1H, 13C, DEPT, HSQC, HMBC, COSY, NEOSY, and HR-MS and comparison with the reported literature. Furthermore, eight compounds (13–20) previously isolated by our group from the same source along with the currently isolated compounds (1–12) were screened against the CA-II enzyme. All compounds, except 6, 8, 14, and 17, were evaluated for in vitro bovine carbonic anhydrase-II (CA-II) inhibitory activity. Eventually, eleven compounds (1, 4, 5, 7, 9, 10, 12, 13, 15, 18, and 19) exhibited significant inhibitory activity against CA-II with IC50 values ranging from 13.4 to 71.6 μM. Additionally, the active molecules were subjected to molecular docking studies to predict the binding behavior of those compounds. It was observed that the compounds exhibit the inhibitory potential by specifically interacting with the ZN ion present in the active site of CA-II. In addition to ZN ion, two residues (His94 and Thr199) play an important role in binding with the compounds that possess a carboxylate group in their structure.

Discovery of Natural Compounds as Potential Inhibitors of Human Carbonic Anhydrase II: An Integrated Virtual Screening, Docking, and Molecular Dynamics Simulation Study

Carbonic anhydrase II (CAII) is one of the zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide, leading to the formation of bicarbonate and proton. CAII plays a significant role in health and disease. For example, CAII helps to maintain eye pressure while regulating the pH of the tumor microenvironment, and by extension, contributing to cancer progression. Owing to its remarkable role in cancer, visual health, and other human diseases, CAII can serve as an attractive therapeutic target. We report an original study based on high-throughput virtual screening of natural compounds from the ZINC database in search of potential inhibitors of CAII. We selected the hits based on the physicochemical, absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties, pan-assay interference compound (PAINS) patterns, and interaction analysis. Importantly, two natural compounds were identified, ZINC08918123 and ZINC00952700, bearing considerable affinity and specific interactions to the residues of the CAII-binding pocket with well-organized conformational fitting compatibility. We investigated the conformational dynamics of CAII in complex with the identified compounds through molecular dynamics simulation, which revealed the formation of a stable complex preserved throughout the 100 ns trajectories. The stability of the protein/ligand complexes is maintained by significant numbers of noncovalent interactions throughout the simulations. In conclusion, natural compounds identified in the present study specifically and computer-assisted drug design broadly offer a reliable resource and strategy to discover potential promising therapeutic inhibitors of CAII to cure various cancers and glaucoma after further experimental validation and clinical studies.

Inhibition Profiling of Urease and Carbonic Anhydrase II by High- Throughput Screening and Molecular Docking Studies of Structurally Diverse Organic Compounds

Background:: Structurally diverse organic compounds and available drugs were screened against urease and carbonic anhydrase II in a formulation acceptable for high-throughput screening. Objective: The study was conducted to find out potential inhibitors of urease and carbonic anhydrase II. Methods:: Quantification of the possible HITs was carried out by determining their IC50 values. Results: The results of several screened compounds, including derivatives of oxadiazole, coumarins, chromane-2, 4-diones and metal complexes of cysteine-omeprazole showed promising inhibitory activities with IC50 ranging from 47 μM to 412 μM against the urease. The interactions of active compounds with active sites of enzymes were investigated through molecular docking studies which revealed that (R)-1-(4-amino-4-(5-(thiophen-2-yl)-1,3,4-oxadiazol-2-yl) butyl) guanidine possessing IC50 of 47 μM interacts with one of the nickel metal atoms of urease besides further interactions as predictable hydrogen bonds with KCX490, Asp633, His492, His407 and His409 along with Ala440 and 636. Bi-ligand metal complexes of 4-aminoantipyrine based Schiff bases showed activation of urease with AC50 ranging from 68 μM to 112 μM. Almost 21 compounds with varying functional groups including pyrimidines, oxadiazoles, imidazoles, hydrazides and tin based compounds were active carbonic anhydrase II inhibitors presenting 98 μM to 390 μM IC50 values. Several N-substituted sulfonamide derivatives were inactive against carbonic anhydrase II. Conclusion:: Among all the screened compounds, the highly active inhibitor of carbonic anhydrase II was (4-(3-hydroxyphenyl)-6-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl)phenyl) methanone with IC50 of 98.0 μM. This particular compound showed metallic interaction with Zn ion of carbonic anhydrase II through the hydroxyl group of the phenyl ring.

Quinazolinones as Competitive Inhibitors of Carbonic Anhydrase-II (Human and Bovine): Synthesis, in-vitro, in-silico, Selectivity, and Kinetics Studies.

Carbonic anhydrase-II (CA-II) is associated with glaucoma, malignant brain tumors, and renal, gastric, and pancreatic carcinomas and is mainly involved in the regulation of the bicarbonate concentration in the eyes. CA-II inhibitors can be used to reduce the intraocular pressure usually associated with glaucoma. In search of potent CA-II inhibitors, a series of quinazolinones derivatives (4a-p) were synthesized and characterized by IR and NMR spectroscopy. The inhibitory potential of all the compounds was evaluated against bovine carbonic anhydrase-II (bCA-II) and human carbonic anhydrase-II (hCA-II), and compounds displayed moderate to significant inhibition with IC50 values of 8.9–67.3 and 14.0–59.6 μM, respectively. A preliminary structure-activity relationship suggested that the presence of a nitro group on the phenyl ring at R position contributes significantly to the overall activity. Kinetics studies of the most active inhibitor, 4d, against both bCA-II and hCA-II were performed to investigate the mode of inhibition and to determine the inhibition constants (Ki). According to the kinetics results, 4d is a competitive inhibitor of bCA-II and hCA-II with Ki values of 13.0 ± 0.013 and 14.25 ± 0.017 μM, respectively. However, the selectivity index reflects that the compounds 4g and 4o are more selective for hCA-II. The binding mode of these compounds within the active sites of bCA-II and hCA-II was investigated by structure-based molecular docking. The docking results are in complete agreement with the experimental findings.

Identification and Validation of Carbonic Anhydrase II as the First Target of the Anti-Inflammatory Drug Actarit.

Background and purpose: Identifying the macromolecular targets of drug molecules is a fundamental aspect of drug discovery and pharmacology. Several drugs remain without known targets (orphan) despite large-scale in silico and in vitro target prediction efforts. Ligand-centric chemical-similarity-based methods for in silico target prediction have been found to be particularly powerful, but the question remains of whether they are able to discover targets for target-orphan drugs. Experimental Approach: We used one of these in silico methods to carry out a target prediction analysis for two orphan drugs: actarit and malotilate. The top target predicted for each drug was carbonic anhydrase II (CAII). Each drug was therefore quantitatively evaluated for CAII inhibition to validate these two prospective predictions. Key Results: Actarit showed in vitro concentration-dependent inhibition of CAII activity with submicromolar potency (IC50 = 422 nM) whilst no consistent inhibition was observed for malotilate. Among the other 25 targets predicted for actarit, RORγ (RAR-related orphan receptor-gamma) is promising in that it is strongly related to actarit’s indication, rheumatoid arthritis (RA). Conclusion and Implications: This study is a proof-of-concept of the utility of MolTarPred for the fast and cost-effective identification of targets of orphan drugs. Furthermore, the mechanism of action of actarit as an anti-RA agent can now be re-examined from a CAII-inhibitor perspective, given existing relationships between this target and RA. Moreover, the confirmed CAII-actarit association supports investigating the repositioning of actarit on other CAII-linked indications (e.g., hypertension, epilepsy, migraine, anemia and bone, eye and cardiac disorders).

Benzilydene and thiourea derivatives as new classes of carbonic anhydrase inhibitors: an in vitro and molecular docking study

Carbonic anhydrase-II (CA-II) catalyzes reversible hydration of carbon dioxide leading to the formation of bicarbonate and a proton. CA-II inhibitors act as biomarkers and therapeutic targets for various diseases such as epilepsy, glaucoma, leukemia, and cystic fibrosis. In the present work, a number of thiourea and benzylidene derivatives were evaluated as CA-II inhibitors. For this, detection of CA-II inhibition was tested through high throughput biochemical mechanism-based assay. Results indicated that thiourea derivatives exhibit remarkable inhibition activity with IC50 values ranging from 1.90 ± 1.30 to 25.90 ± 2.05 µM, when compared with the standard inhibitor acetazolamide IC50 = 0.13 ± 0.05. On the other hand, bezylidene derivatives showed weak inhibition potential with IC50 values in the range of 52.68 ± 0.47 to 348.57 ± 3.32 µM when compared with the thiourea derivatives; the Ez-Fit enzyme kinetics software was used for IC50 calculations from the percentage inhibition. In addition, 3T3 normal cell line was employed to determine the toxicity profile of identified inhibitors of CA-II. In silico modeling was performed to decipher the molecular nature of thiourea and benzylidene derivatives with key residues of carbonic anhydrase; results were in agreement with experiments related to inhibition of carbonic anhydrase.

Quantum chemical and experimental exploration of biological activity and inhibitory potential of new acylated oligosaccharides from Pistacia integerrima J. L. Stewart ex Brandis

The new biologically active integrisides A (1) and B (2) have been isolated from the methanolic extract of Pistacia integerrima J. L. Stewart ex Brandis. The antibacterial activity of both the integrisides were tested against four pathogenic bacterial strains, two Gram-positive (Staphylococcus aureus, Streptococcus pyogenes) and two Gram-negative (Escherichia coli, Pseudomonas aeruginosa) as well as four fungal strains (Microsporum canis, Aspergillus clavatus, Candida albicans and Candida glabrata). Both the isolated compounds showed significant results analogous with Imipenam and Miconazole standard drugs. Carbonic anhydrase-II inhibition of integriside A (1) and B (2) with IC50 value 1.56 µM and 2.85 µM respectively, as compared to standard drug acetazolamide (1.57 µM). Cholinesterase activity was carried out with acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) IC50 values of integriside A (1) (8.6, 4.8) and B (2) (0.91, 2.5) were found as compared with standard galanthamine (0.05, 0.92) and Eserine (0.6, 8.7). Here, various molecular descriptors, frontier molecular orbitals (FMO), electron affinity (E.A), ionization potential (IP), molecular electrostatic potential (MEP), and Hirshfeld analysis were carried out to understand the active sites and biological active nature of the integrisides A (1) and B (2). The energy gap, MEP, Hirshfeld analysis, and reactivity descriptors values demonstrate that the integriside A (1) and B (2) retain decent reactivity, which is in good agreement with current experimental and quantum chemical studies.

A New Strategy for Reporting Specific Protein Binding Events at Aqueous-Liquid Crystal Interfaces in the Presence of Non-Specific Proteins.

Aqueous-liquid crystal (LC) interfaces offer promise as responsive interfaces at which biomolecular recognition events can be amplified into macroscopic signals. However, the design of LC interfaces that distinguish between specific and non-specific protein interactions remains an unresolved challenge. Herein, we report the synthesis of amphiphilic monomers, dimers, and trimers conjugated to sulfonamide ligands via triazole rings, their assembly at aqueous-LC interfaces, and the orientational response of LCs to the interactions of carbonic anhydrase II (CAII) and serum albumin with the oligomer-decorated LC interfaces. Of six oligomers synthesized, only dimers without amide methylation were found to assemble at aqueous interfaces of nematic 4-cyano-4'-pentylbiphenyl (5CB) to induce perpendicular LC orientations. At dimer-decorated LC interfaces, we found that concentrations of CAII less than 4 μM did not measurably perturb the LC but prevented non-specific adsorption and penetration of serum albumin into the dimer-decorated interface that otherwise triggered bright, globular LC optical domains. These experiments and others (including competitive adsorption of CAII, BSA, and lysozyme) support our hypothesis that specific binding of CAII to the dimer prevents LC anchoring transitions triggered by non-specific adsorption of serum albumin. We illustrate the utility of the approach by reporting (i) the relative activity of two small-molecule inhibitors (6-ethoxy-2-benzothiazolesulfonamide and benzenesulfonamide) of CAII to sulfonamide and (ii) proteolytic digestion of a protein (CAII) by thermolysin. Overall, the results in this paper provide new insight into the interactions of proteins at aqueous-LC interfaces and fresh ideas for either blocking non-specific interactions of proteins at surfaces or reporting specific binding events at LC interfaces in the presence of non-specific proteins.

Development of a Fingerprint-Based Scoring Function for the Prediction of the Binding Mode of Carbonic Anhydrase II Inhibitors.

Carbonic anhydrase II (CAII) is a zinc-containing metalloenzyme whose aberrant activity is associated with various diseases such as glaucoma, osteoporosis, and different types of tumors; therefore, the development of CAII inhibitors, which can represent promising therapeutic agents for the treatment of these pathologies, is a current topic in medicinal chemistry. Molecular docking is a commonly used tool in structure-based drug design of enzyme inhibitors. However, there is still a need for improving docking reliability, especially in terms of scoring functions, since the complex pattern of energetic contributions driving ligand–protein binding cannot be properly described by mathematical functions only including approximated energetic terms. Here we report a novel CAII-specific fingerprint-based (IFP) scoring function developed according to the ligand–protein interactions detected in the CAII-inhibitor co-crystal structures of the most potent CAII ligands. Our IFP scoring function outperformed the ability of Autodock4 scoring function to identify native-like docking poses of CAII inhibitors and thus allowed a considerable improvement of docking reliability. Moreover, the ligand–protein interaction fingerprints showed a useful application in the binding mode analysis of structurally diverse CAII ligands.

Implication of sulfonylurea derivatives as prospective inhibitors of human carbonic anhydrase II

Selective carbonic anhydrase (CA) inhibitors have gained a lot of importance owing to the implication of specific isoforms of CA in certain diseases like glaucoma, leukemia, cystic fibrosis, and epilepsy. A novel class of sulfonylurea derivatives was synthesized from corresponding sulfonyl chlorides and amines. Compounds with different pendant moieties in the sulfonylurea derivatives show significant interactions with human carbonic anhydrase II (CAII). In vitro evaluation of the sulfonylurea derivatives revealed that three compounds possess admirable inhibitory activity against CAII. Compounds containing methyl (G2), isopropyl (G4) and o-tosyl (G5) groups displayed IC50 (109-137 μm) for CAII. Fluorescence binding and cytotoxicity studies revealed that these compounds are showing good binding affinity (18-34 μM) to CAII and non- toxic to human cells. Further, molecular docking studies of G2, G4 and G5 with CAII showed that these compounds fit nicely in the active site of CAII. Molecular dynamics simulation studies of these compounds complexed with CAII showed that essential interactions were maintained up to 50 ns of simulation. These results indicate the promising nature of the sulfonylurea scaffold towards CAII inhibition and opens scope of hit to-lead optimization for discovery of effective drugs against CAII-associated disorders.

Synthesis and Molecular Docking Studies of (E)-4-(Substituted-benzylideneamino)-2H-Chromen-2-one Derivatives: Entry to New Carbonic Anhydrase Class Of Inhibitors.

The present article illustrated the synthesis and characterization of a novel series of (E)-4-(substituted-benzylideneamino)-2H-chromen-2-one derivatives 4A-4J: in good to excellent yields. The target compounds were synthesized by refluxing 4-aminocoumarin with aromatic aldehydes in ethanol. The structural confirmation was achieved by spectroscopic techniques such as (1H, 13C-NMR and FT-IR) and elemental analysis. The synthesized compounds were evaluated for carbonic anhydrase II (CA-II) inhibition and free radical scavenging activity. All the compounds showed CA-II inhibition in the micro molar range. The compound 4C: exhibited higher potential in the series with IC50=0.0928±0.00545 µM (standard Acetazolamide IC50=0.997±0.0586 µM). Pharmacological investigations showed that the synthesized compounds 4A-4J: obey Lipinsk's rule. Compound 4C: elicited drug likeness and showed drug score value of 0.05. Molecular docking analysis showed that compound 4C: interacts with Asn66 and Gln91 amino acid residues. Graphical Abstract.

Carbonic Anhydrase and Urease Inhibitory Potential of Various Plant Phenolics Using invitro and in silico Methods.

Plant phenolics are known to display many pharmacological activities. In the current study, eight phenolic compounds, e.g., luteolin 5-O-β-glucoside (1), methyl rosmarinate (2), apigenin (3), vicenin 2 (4), lithospermic acid (5), soyasaponin II (6), rubiadin 3-O-β-primeveroside (7), and 4-(β-d-glucopyranosyloxy)benzyl 3,4-dihydroxybenzoate (8), isolated from various plant species were tested at 0.2mm against carbonic anhydrase-II (CA-II) and urease using microtiter assays. Urease inhibition rate for compounds 1-8 ranged between 5.0-41.7%, while only compounds 1, 2, and 4 showed a considerable inhibition over 50% against CA-II with the IC50 values of 73.5±1.05, 39.5±1.14, and 104.5±2.50μm, respectively, where IC50 of the reference (acetazolamide) was 21.0±0.12μm. In silico experiments were also performed through two docking softwares (Autodock Vina and i-GEMDOCK) in order to find out interactions between the compounds and CA-II. Actually, compounds 6 (30.0%) and 7 (42.0%) possessed a better binding capability toward the active site of CA-II. According to our results obtained in this study, among the phenolic compounds screened, particularly 1, 2, and 4 appear to be the promising inhibitors of CA-II and may be further investigated as possible leads for diuretic, anti-glaucoma, and antiepileptic agents.

Determination of activities of human carbonic anhydrase II inhibitors from curcumin analogs

Purpose: To evaluate the activities of new curcumin analogs as carbonic anhydrase II (CA-II) inhibitor. Methods: Carbonic anhydrase II (CA-II) inhibition was determined by each ligand capability to inhibit the esterase activity of CA-II using 4-NPA as a substrate in 96-well plates. Dimethyl sulfoxide was used to dissolve each curcumin analog compound, and then diluted with biological buffer. They were then mixed with CA-II solution and to start the reaction, 4-NPA was added. Hydrolysis of the substrate was evaluated at 405 nm after incubation for 2 h at 25 °C. The IC 50 value of compounds with inhibitory activity higher than 40 % was then evaluated. Molecular docking was also used to predict enzymeinhibitor interaction. Results: Eight new curcumin analogs were potent to inhibit CA-II activity with IC 50 values ranging from 7.92 ± 0.54 to 72.31 ± 2.21 μmol; the lowest value was exhibited by (3E,5E)-3,5-bis[(2- hydroxyphenyl)methylidene]piperidin-4-one (a1). Molecular docking analysis revealed that this molecule formed hydrogen bonds with Thr199, Thr200 and Gln92 at the active site of CA-II. Conclusion: These curcumin analogs have inhibitory potential against CA-II; (3E, 5E)-3,5-bis[(2- hydroxyphenyl)methylidene]piperidin-4-one (a1) has the highest inhibitory activity and may be useful in the development of CA-II inhibitors for glaucoma treatment. Keywords: Carbonic anhydrase II inhibitor, Curcumin analogs, Molecular docking

Synthesis and Evaluation of the Biological Profile of Novel Analogues of Nucleosides and of Potential Mimetics of Sugar Phosphates and Nucleotides

The synthesis of purine/triazole 6'-isonucleosides and of glucuronic acid/glucuronamide-derived N-glycosylsulfonohydrazides through efficient and stereo- or regioselective methodologies is described. Their structures were envisaged to mimic nucleosides, sugar phosphates, or nucleotides, and were expected to provide potential inhibitors of therapeutically relevant enzymes, the active sites of which could potentially bind their structural fragments or functional groups. Such enzymes include cholinesterases, carbonic anhydrase II (CA-II) and cyclin-dependent kinase 2 (CDK-2). A (triazolyl)methyl amide-linked disaccharide nucleoside, based on a new prospective structural framework for analogues of nucleoside diphosphate sugars, was synthesized. The synthetic strategies employed unprotected or partially protected carbohydrate derivatives as precursors, including ribose, glucuronic acid, glucuronolactone, and glycopyranosides and relied on stereoselective N-glycosylation, regioselective Mitsunobu coupling and ‘click chemistry’ approaches. Some 6'-isonucleosides and triazole-containing glycoderivatives displayed moderate selective acetylcholinesterase inhibitory activities. The best inhibitor was an aminomethyltriazole 6'-isonucleoside with a K i value of 11.9 μM. N-Glucuronylsulfonohydrazide showed good inhibition of CA-II (K i = 9.5 μM). Molecular docking of the most active compounds into the effected enzymes showed interactions with key amino acid residues for substrate recognition. In addition, the tested compounds did not show toxicity to normal cells.