Potent Urease Inhibitors Research Articles

Bisindolylmethane thiosemicarbazides as potential inhibitors of urease: Synthesis and molecular modeling studies

Bisindolylmethane thiosemicarbazides 1-18 were synthesized, characterized by 1H NMR and ESI MS and evaluated for urease inhibitory potential. All analogs showed outstanding urease inhibitory potentials with IC50 values ranging between 0.14 ± 0.01 to 18.50 ± 0.90 μM when compared with the standard inhibitor thiourea having IC50 value 21.25 ± 0.90 μM. Among the series, analog 9 (0.14 ± 0.01 μM) with di-chloro substitution on phenyl ring was identified as the most potent inhibitor of urease. The structure activity relationship has been also established on the basis of binding interactions of the active analogs. These binding interactions were identified by molecular docking studies.

5-Acetyl-6-methyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones: As potent urease inhibitors; synthesis, in vitro screening, and molecular modeling study

5-Acetyl-6-methyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones 1–43 were synthesized in a “one-pot” three component reaction and structurally characterized by various spectroscopic techniques such as 1H, 13C NMR, EI-MS, HREI-MS, and IR. All compounds were evaluated for their in vitro urease inhibitory activity. It is worth mentioning that except derivatives 1, 11, 12, and 14, all were found to be more potent than the standard thiourea (IC50 = 21.25 ± 0.15 µM) and showed their urease inhibitory potential in the range of IC50 = 3.70 ± 0.5–20.14 ± 0.1 µM. Structure-activity relationship (SAR) was rationalized by looking at the varying structural features of the molecules. However, molecular modeling study was performed to confirm the binding interactions of the molecules (ligand) with the active site of enzyme.

Biological Evaluation and Molecular Docking of Protocatechuic Acid from Hibiscus sabdariffa L. as a Potent Urease Inhibitor by an ESI-MS Based Method.

Studies on enzyme inhibition remain a crucial area in drug discovery since these studies have led to the discoveries of new lead compounds useful in the treatment of several diseases. In this study, protocatechuic acid (PCA), an active compound from Hibiscus sabdariffa L. has been evaluated for its inhibitory properties against jack bean urease (JBU) as well as its possible toxic effect on human gastric epithelial cells (GES-1). Anti-urease activity was evaluated by an Electrospray Ionization-Mass Spectrometry (ESI-MS) based method, while cytotoxicity was assayed by the MTT method. PCA exerted notable anti-JBU activity compared with that of acetohydroxamic acid (AHA), with IC50 values of 1.7 and 3.2 µM, respectively. PCA did not show any significant cytotoxic effect on (GES-1) cells at concentrations ranging from 1.12 to 3.12 µM. Molecular docking study revealed high spontaneous binding ability of PCA to the active site of urease. Additionally, the anti-urease activity was found to be related to the presence of hydroxyl moieties of PCA. This study presents PCA as a natural urease inhibitor, which could be used safely in the treatment of diseases caused by urease-producing bacteria.

3,4-Dimethoxybenzohydrazide derivatives as antiulcer: Molecular modeling and density functional studies

3,4-Dimethoxybenzohydrazide derivatives (1–25) have been synthesized and evaluated for their urease inhibitory potential. Among the series, compounds 2, 3, 4 and 5 with IC50 values 12.61 ± 0.07, 18.24 ± 0.14, 19.22 ± 0.21, and 8.40 ± 0.05 µM, respectively, showed excellent urease inhibitory potentials when compared with standard thiourea (IC50 value 21.40 ± 0.21 µM). Compounds 1, 6, 8, 18, 19 and 20 also showed good to moderate inhibition, while the remaining compounds were found to be completely inactive. The structures of compounds 6 and 25 were confirmed through X-ray crystallography while the structures of remaining compounds were confirmed through ESI-MS and 1H NMR. Molecular docking studies were performed understand the binding interactions with enzyme active site. The synthesized compounds were evaluated for cytotoxicity and found to be nontoxic.

Microwave Assisted Extraction and in vitro Evaluation of urease Inhibition Potential of Stem Bark of Terminalia arjuna

Microwave Assisted Extraction and in vitro Evaluation of urease Inhibition Potential of Stem Bark of Terminalia arjuna

Sulfonamide-Linked Ciprofloxacin, Sulfadiazine and Amantadine Derivatives as a Novel Class of Inhibitors of Jack Bean Urease; Synthesis, Kinetic Mechanism and Molecular Docking.

Sulfonamide derivatives serve as an important building blocks in the drug design discovery and development (4D) process. Ciprofloxacin-, sulfadiazine- and amantadine-based sulfonamides were synthesized as potent inhibitors of jack bean urease and free radical scavengers. Molecular diversity was explored and electronic factors were also examined. All 24 synthesized compounds exhibited excellent potential against urease enzyme. Compound 3e (IC50 = 0.081 ± 0.003 µM), 6a (IC50 = 0.0022 ± 0.0002 µM), 9e (IC50 = 0.0250 ± 0.0007 µM) and 12d (IC50 = 0.0266 ± 0.0021 µM) were found to be the lead compounds compared to standard (thiourea, IC50 = 17.814 ± 0.096 µM). Molecular docking studies were performed to delineate the binding affinity of the molecules and a kinetic mechanism of enzyme inhibition was propounded. Compounds 3e, 6a and 12d exhibited a mixed type of inhibition, while derivative 9e revealed a non-competitive mode of inhibition. Compounds 12a, 12b, 12d, 12e and 12f showed excellent radical scavenging potency in comparison to the reference drug vitamin C.

Studies on new urease inhibitors by using biochemical, STD-NMR spectroscopy, and molecular docking methods

Discovery of new urease inhibitors is an important approach towards the treatment of diseases caused by ureolytic bacteria. Urease has an important role in several pathologies, such as urolithiasis, peptic and duodenal ulcers, etc. In this regard, urease inhibitory activity of heterocyclic synthetic compounds 1–14, belonging to different chemical classes was evaluated by employing in vitro biochemical assay, and saturation transfer difference-NMR technique. Compounds 1, 3–5, 7, 10, and 12 have shown urease inhibitory potential in vitro. Among them, compound 1 was found to be more potent (IC50 of 12.90 ± 0.63 µM) than a clinical drug, acetohydroxamic acid (IC50 = 41.5 ± 1.50 µM) (Standard). Compounds 3 (IC50 = 15.0 ± 1.10 µM), 4 (IC50 = 24.67 ± 2.87 µM), and 5 (IC50 = 25.50 ± 0.63 µM) were also identified as potent inhibitors of urease enzyme. These compounds showed strong interactions with the urease enzyme (receptor) in saturation transfer difference-NMR spectra. Specifically, aromatic protons of active compounds received maximum Rf saturation from the receptor protein, thus were inferred to be as in close proximity to the protein. New inhibitors identified through biochemical assay and saturation transfer difference-nuclear magnetic resonance techniques were then subjected to kinetic and molecular docking studies to investigate their mode of inhibition, and production of their interactions with the protein at atomic level, respectively. Active compounds were found to be non-cytotoxic against mouse fibroblast (3T3) cell line MTT assay. Present study thereby identifies new inhibitors of urease enzyme in vitro as leads for further investigation towards the development of novel mechanism-based urease inhibitors.

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.

Synthesis and molecular docking study of some 5,6-dichloro-2-cyclopropyl-1H-benzimidazole derivatives bearing triazole, oxadiazole, and imine functionalities as potent inhibitors of urease

A new series of benzimidazole compounds including hydrazinecarbothioamide, 1,2,4-triazole, 1,3,4-oxadiazole and imine function were synthesized starting from 5,6-dichloro-2-cyclopropyl-1H-benzimidazole. All of the benzimidazole derivatives exhibited good urease inhibitor activity. Compound 6a proved to be the most potent showing an enzyme inhibitory activity with an IC50=0.06µM. Molecular docking studies were also conducted on enzyme extracted from Jack bean urease to identify the binding mode of the newly synthesized compounds.

Novel organophosphorus scaffolds of urease inhibitors obtained by substitution of Morita-Baylis-Hillman adducts with phosphorus nucleophiles

The reactivity of Morita-Baylis-Hillman allyl acetates was employed to introduce phosphorus-containing functionalities to the side chain of the cinnamic acid conjugated system by nucleophilic displacement. The proximity of two acidic groups, the carboxylate and phosphonate/phosphinate groups, was necessary to form interactions in the active site of urease by recently described inhibitor frameworks. Several organophosphorus scaffolds were obtained and screened for inhibition of the bacterial urease, an enzyme that is essential for survival of urinary and gastrointestinal tract pathogens. α-Substituted phosphonomethyl- and 2-phosphonoethyl-cinnamate appeared to be the most potent and were further optimized. As a result, one of the most potent organophosphorus inhibitors of urease, α-phosphonomethyl-p-methylcinnamic acid, was identified, with Ki = 0.6 μM for Sporosarcina pasteurii urease. High complementarity to the enzyme active site was achieved with this structure, as any further modifications significantly decreased its affinity. Finally, this work describes the challenges faced in developing ligands for urease.

Potent covalent inhibitors of bacterial urease identified by activity-reactivity profiling

Covalent enzyme inhibitors constitute a highly important group of biologically active compounds, with numerous drugs available on the market. Although the discovery of inhibitors of urease, a urea hydrolyzing enzyme crucial for the survival of some human pathogens, is a field of medicinal chemistry that has grown in recent years, covalent urease inhibitors have been rarely investigated until now. Forty Michael acceptor-type compounds were screened for their inhibitory activities against bacterial urease, and several structures exhibited high potency in the nanomolar range. The correlation between chemical reactivity towards thiols and inhibitory potency indicated the most valuable compound — acetylenedicarboxylic acid, with Ki∗=42.5nM and logkGSH=-2.14. Molecular modelling studies revealed that acetylenedicarboxylic acid is the first example of highly effective mode of binding based on simultaneous bonding to a cysteine residue and interaction with nickel ions present in the active site. Activity-reactivity profiling of reversible covalent enzyme inhibitors is a general method for the identification of valuable drug candidates.

Synthesis, Characterization and Biological Activities of Creatinine Amides and Creatinine Schiff Bases.

In spite of substantial progress in scientific cognizance and medical technology, still infectious diseases are among the leading cause of morbidity and mortality. Creatinine and Schiff bases are well known for their diverse range of biological activities and thought to be emerging and useful therapeutic target for the treatment of several diseases. The present work was aimed to illustrate the influence of substitution of amides and Schiff bases on creatinine and their antimicrobial, antioxidant and anti-urease effectiveness was determined. Creatinine substituted amides (1-2) and creatinine Schiff bases (3-7) were synthesized and characterized by NMR and IR spectral data in combination with elemental analysis. All the compounds (1-7) were investigated on Jack bean urease for their urease inhibitory potential. Investigation of antimicrobial activity of the compounds was made by the agar dilution method. Moreover, 1,1-diphenyl-2- picrylhydrazyl (DPPH) method was used to determine their antioxidant potential. Molecular docking studies were also carried out to elucidate their relationship with the binding pockets of the enzyme. The compounds were found to be potent inhibitors of urease. The synthesized derivatives exhibited significant inhibition against Gram-positive and Gram-negative bacterial strains, as compared to standard, ciprofloxacin. Creatinine based derivatives exhibited potential antifungal activity when tested on infectious and pathogenic fungal strains. Similarly, most of the compounds exhibited good antioxidant activity. These derivatives may serve as a source of potential antioxidants and also help to retard microbial growth in food industry. Similarly, the studies provide a basis for further research to develop more potent urease inhibitory compounds of medicinal /agricultural interest.

A cheap, simple high throughput method for screening native Helicobacter pylori urease inhibitors using a recombinant Escherichia coli, its validation and demonstration of Pistacia atlantica methanolic extract effectivity and specificity

Helicobacter pylori is the most frequent and persistent bacterial infection worldwide, and a risk factor for active gastritis, peptic ulcers, mucosa-associated lymphoid tissue lymphoma, and gastric cancer. Although combined antibiotics treatment is effective cases of antibiotic resistance are reported at an alarming rate. The H. pylori urease enzyme is essential for the bacteria establishment in the gastric mucosa, resulting urease inhibitors being sought after as effective and specific anti- H. pylori treatment. To-date, screening assays are based mostly on the analog plant urease enzyme but difference in properties of the plant and bacterial enzymes hamper these efforts. We have developed a screening assay based on recombinant Escherichia coli expressing native H. pylori urease, and validated this assay using thiourea and a methanolic extract of Pistacia atlantica. The assay demonstrated the thiourea and the extract to be potent urease inhibitors, with the extract having strong bacteriostatic activity against clinical isolates of H. pylori, including such with antibiotic resistance. The extract was also found to be neutral toward common probiotic bacteria, supporting its specificity and compatibility with digestive system desired microflora and suggesting it could be a good source for anti-H. pylori compounds.The assay has proven to be cheap, simple and native alternative to the plant enzyme based assay and could allow for high throughput screening for new urease inhibitors and could expedite screening and development of novel, better H. pylori remedies helping us to combat this infection.

Urease inhibition potential of Di-naphthodiospyrol from Diospyros lotus roots

The dimeric napthoquione 5,8,4′-trihydroxy-1′-methoxy-6, 6′-dimethyl-7,3′-binaphtyl-1,4,5′,8′-tetraone (1) was isolated from the chloroform fraction of Diospyros lotus extract. Compound 1 was screened for its inhibitory effects against four enzymes: urease, phosphodiesterase-I, carbonic anhydrase-II and α-chymotrypsin, and showed selective activity against urease enzyme with an IC50 value of 254.1 ± 3.82 μM as compared to the standard thiourea (IC50 = 21 ± 0.11 μM). Furthermore, in silico docking study was carried out to explain the molecular mechanism of compound 1 against the target receptor.

Synthesis and urease inhibitory activities of benzophenone semicarbazones/thiosemicarbazones

Twenty-five benzophenone semicarbazones and thiosemicarbazones 3–27 were synthesized starting from benzophenones via hydrazones treated with different aryl isocyanates and isothiocyantes under reflux. All synthetic derivatives were evaluated for their urease inhibitory potential. Good to moderate inhibition trend against urease was observed with the IC50 values in the range of 8.7–119.5 µM, when compared with the standard thiourea (IC50 = 21.2 ± 1.3 µM). Compound 15 showed better inhibition than the standard having the IC50 value of 8.7 ± 0.6 µM. Compounds 3, 4, 8, 11–14, 16, and 17 with the IC50 values within the range of 26.1 to 43.6 µM, demonstrated good to moderate activities while compound 9 (IC50 = 119.5 ± 1.6 µM) displayed very weak activity. The enzyme kinetic studies on the most active compounds 15 and 17 were performed to deduce their modes of inhibition and dissociation constants K i.

Synthesis of 2-acylated and sulfonated 4-hydroxycoumarins: In vitro urease inhibition and molecular docking studies

Sixteen 4-hydroxycoumarin derivatives were synthesized, characterized through EI-MS and 1H NMR and screened for urease inhibitory potential. Three compounds exhibited better urease inhibition than the standard inhibitor thiourea (IC50=21±0.11μM) while other four compounds exhibited good to moderate inhibition with IC50 values between 29.45±1.1μM and 69.53±0.9μM. Structure activity relationship was established on the basis of molecular docking studies, which helped to predict the binding interactions of the most active compounds.

Robust Synthesis of Ciprofloxacin-Capped Metallic Nanoparticles and Their Urease Inhibitory Assay.

The fluoroquinolone antibacterial drug ciprofloxacin (cip) has been used to cap metallic (silver and gold) nanoparticles by a robust one pot synthetic method under optimized conditions, using NaBH4 as a mild reducing agent. Metallic nanoparticles (MNPs) showed constancy against variations in pH, table salt (NaCl) solution, and heat. Capping with metal ions (Ag/Au-cip) has significant implications for the solubility, pharmacokinetics and bioavailability of fluoroquinolone molecules. The metallic nanoparticles were characterized by several techniques such as ultraviolet visible spectroscopy (UV), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) methods. The nanoparticles synthesized using silver and gold were subjected to energy dispersive X-ray tests in order to show their metallic composition. The NH moiety of the piperazine group capped the Ag/Au surfaces, as revealed by spectroscopic studies. The synthesized nanoparticles were also assessed for urease inhibition potential. Fascinatingly, both Ag-cip and Au-cip NPs exhibited significant urease enzyme inhibitory potential, with IC50 = 1.181 ± 0.02 µg/mL and 52.55 ± 2.3 µg/mL, compared to ciprofloxacin (IC50 = 82.95 ± 1.62 µg/mL). MNPs also exhibited significant antibacterial activity against selected bacterial strains.

Hybrid benzothiazole analogs as antiurease agent: Synthesis and molecular docking studies

Benzothiazole analogs (1–20) have been synthesized, characterized by EI-MS and 1H NMR, and evaluated for urease inhibition activity. All compounds showed excellent urease inhibitory potential varying from 1.4±0.10 to 34.43±2.10μM when compared with standard thiourea (IC50 19.46±1.20μM). Among the series seventeen (17) analogs 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, and 18 showed outstanding urease inhibitory potential. Analogs 15 and 19 also showed good urease inhibition activity. When we compare the activity of N-phenylthiourea 20 with all substituted phenyl derivatives (1–18) we found that compound 15 showed less activity than compound 20 having 3-methoxy substituent. The binding interactions of these active analogs were confirmed through molecular docking.

Synthesis of Some Spiro Indeno[1,2-b]pyrido[2,3-d]Pyrimidine-5,3'-Indolines as New Urease Inhibitors.

New series of spiro indeno[1,2-b]pyrido[2,3-d]pyrimidine-5,3'-indolines as new urease inhibitors were synthesized by the catalytic procedure in high yield and short reaction time. In this method, biacidic carbon was prepared as a novel heterogeneous acid and was subsequently used as an efficient catalyst. The inhibitory activities of synthesized compounds were tested against Jack bean urease using Berthelot colorimetric assay and docking simulation using AutoDock 4.2. The compound 4a with IC50 =1.94 µM has the most inhibitor activity in this study. Other derivatives such as 4b, 4d, 4e and 7a were found to be more potent urease inhibitors than the standard inhibitor hydroxyurea, yielding IC50 values of 4.35, 5.557, 7.44, 2.81 and 14.46 μM, respectively (IC50 of hydroxyurea = 100 μM).

Coumarin-based thiosemicarbazones as potent urease inhibitors: synthesis, solid state self-assembly and molecular docking

A series of coumarin-based thiosemicarbazones and their metal complexes have been synthesized and theirin vitropotency against urease was evaluated.