Inhibition Of Jack Bean Urease Research Articles

Jack bean urease inhibition by different root fractions of Cleome gynandra L – Kinetic mechanism and computational molecular modelling

Natural products with urease inhibiting potentialities would be valuable for enhancing nitrogen fertilizer formulations and developing new therapeutics against infectious diseases. Main focus of this research was to assess the inhibitory impact of various parts of Cleome gynandra (Cleomaceae) on jack bean urease activity, identify the responsible compounds, and ascertain their mode of enzyme inhibition and interactions with urease enzyme. Urease inhibitory potentiality of different plant parts of C. gynandra was determined using the phenol-hypochlorite method and mode of enzyme inhibition by Lineweaver-Burk kinetic analysis. LC-HRMS was carried out to identify the compounds of the active fractions. Molecular docking and simulations were executed to find out the binding affinity and interaction pattern of the isolated compounds at the active site of urease enzyme and to verify stability of protein-inhibitor complexes. The root of C. gynandra exhibited highest urease inhibitory potentiality with IC50 value of 1.529 mg/ml compared with leaf and stem. Among the different root fractions, water fraction revealed maximum anti-urease activity with IC50 values of 1.477 mg/ml followed by methanol (1.655 mg/ml) and acetone fractions (1.955 mg/ml). Inhibition kinetics indicated that these fractions were strong inhibitors of urease and exhibited a non-competitive mode of inhibition with Ki values of 184.911 µg/ml, 147.34 µg/ml, and 233.75 µg/ml respectively at 1000 mg/L concentration. LC-HRMS analysis confirmed the occurrence of glucocapparin, fluticasone propionate and lauryl hydrogen sulfate etc. in water fraction. Molecular modelling and simulation study suggested strong and stable interactions between the specified compounds of water fraction and active site of urease. Hence, the water fraction of C. gynandra roots represent a valuable source of natural urease inhibitors, for possible therapeutic applications and sustainable agricultural practices.

Design, Synthesis, Characterization and Computational Studies of Mannich Bases Oxadiazole Derivatives as New Class of Jack Bean Urease Inhibitors.

Mannich bases consisting of 1,3,4-oxadiazole-2-thione (3 a-3 l) bearing various substituents were synthesized and found potent jack bean urease inhibitors. The prepared compounds showed significantly good inhibitory activities with IC50 values from 9.45±0.05 to 267.42±0.23 μM. The compound 3 k containing 4-chlorophenyl (-R) and 4-hydroxyphenyl (-R') was most active with IC50 9.45±0.05 μM followed by 3 e (IC50 22.52±0.15 μM) in which -R was phenyl and -R' was isopropyl group. However, when both -R and -R' were either 4-chlorophenyl groups (3 l) or only -R' was 4-nitrophenyl (3 i), both compounds were found inactive. The detailed binding affinities of the produced compounds with protein were explored through molecular docking and data-supported in-vitro enzyme inhibition profiles. Drug likeness was confirmed by in silico ADME investigations and molecular orbital analysis (HOMO-LUMO) and electrostatic potential maps were got from DFT calculations. ESP maps exposed that there are two potential binding sites with the most positive and most negative parts.

Using Machine Learning and Molecular Docking to Leverage Urease Inhibition Data for Virtual Screening.

Urease is a metalloenzyme that catalyzes the hydrolysis of urea, and its modulation has an important role in both the agricultural and medical industry. Even though numerous molecules have been tested against ureases of different species, their clinical translation has been limited due to chemical and metabolic stability as well as side effects. Therefore, screening new compounds against urease would be of interest in part due to rising concerns regarding antibiotic resistance. In this work, we collected and curated a diverse set of 2640 publicly available small-molecule inhibitors of jack bean urease and developed a classifier using a random forest machine learning method with high predictive performance. In addition, the physicochemical features of compounds were paired with molecular docking and protein-ligand fingerprint analysis to gather insight into the current activity landscape. We observed that the docking score could not differentiate active from inactive compounds within each chemical family, but scores were correlated with compound activity when all compounds were considered. Additionally, a decision tree model was built based on 2D and 3D Morgan fingerprints to mine patterns of the known active-class compounds. The final machine learning model showed good prediction performance against the test set (81% and 77% precision for active and inactive compounds, respectively). Finally, this model was employed, as a proof-of-concept, on an in-house library to predict new hits that were then tested against urease and found to be active. This is, to date, the largest, most diverse dataset of compounds used to develop predictive in silico models. Overall, the results highlight the usefulness of using machine learning classifiers and molecular docking to predict novel urease inhibitors.

Complex interplay of hydrogen bonding, halogen bonding and π-interactions in methyl 2-(7-chloro-1H-pyrazolo[3,4-b]quinolin-1-yl)acetate: Synthesis, X-ray crystallography, energetic features and anti-urease efficacy

The present study investigates the influence of noncovalent interactions in the design and structural control of crystal packing of pyrazoloquinoline derivative. Compound 3 was prepared in a two-step process in excellent yield. The reaction of 2,7-dichloroquinoline-3-carbaldehyde (1) and hydrazine monohydrate gave access to intermediate 2 which was alkylated regioselectively at the N1 pyrazole nitrogen. The synergistic effects of noncovalent interactions such as H-bonding (C-H…O, C-H…N), halogen bonding (Cl…O) and π-contacts (π…π, Cl…π and CH…π) remained crucial in leading the structural topology of pyrazoloquinoline skeleton. The types of noncovalent interactions was energetically evaluated using Hirshfeld analysis and DFT calculations. The π-stacking and halogen bonding contacts have been studied using QTAIM and NCIPlot techniques. The pharmacological evaluation of compound 3 as anti-urease agent revealed considerably strong potency (IC50 = 8.51 ± 0.10 µM) when compared with positive control, thiourea. In vitro inhibitory data were confirmed through molecular modeling investigation where several key binding interactions were revealed between pyrazoloquinoline and vital residues inside the binding pocket of urease enzyme. ADME investigation successfully predicted various pharmacokinetic properties satisfying the druggable criteria and presenting the title compound to act as a lead inhibitor of Jack bean urease for further investigations.

Exploring Amantadine Derivatives as Urease Inhibitors: Molecular Docking and Structure-Activity Relationship (SAR) Studies.

This article describes the design and synthesis of a series of novel amantadine-thiourea conjugates (3a–j) as Jack bean urease inhibitors. The synthesized hybrids were assayed for their in vitro urease inhibition. Accordingly, N-(adamantan-1-ylcarbamothioyl)octanamide (3j) possessing a 7-carbon alkyl chain showed excellent activity with IC50 value 0.0085 ± 0.0011 µM indicating that the long alkyl chain plays a vital role in enzyme inhibition. Whilst N-(adamantan-1-ylcarbamothioyl)-2-chlorobenzamide (3g) possessing a 2-chlorophenyl substitution was the next most efficient compound belonging to the aryl series with IC50 value of 0.0087 ± 0.001 µM. The kinetic mechanism analyzed by Lineweaver–Burk plots revealed the non-competitive mode of inhibition for compound 3j. Moreover, in silico molecular docking against target protein (PDBID 4H9M) indicated that most of the synthesized compounds exhibit good binding affinity with protein. The compound 3j forms two hydrogen bonds with amino acid residue VAL391 having a binding distance of 1.858 Å and 2.240 Å. The interaction of 3j with amino acid residue located outside the catalytic site showed its non-competitive mode of inhibition. Based upon these results, it is anticipated that compound 3j may serve as a lead structure for the design of more potent urease inhibitors.

Synthesis, characterization and urease inhibitory activities of Zn(II) complexes bearing C1-symmetric ligands derived from (R)-phenylethanamine

ABSTRACT. A series of Zn(II) complexes, supported with N-substituted phenylethanamine derivatives, [LnZnCl2] (where Ln = LA ((R)-1-phenyl-N-(thiophene-2-ylmethyl)ethanamine; LB (R)-N-(5-meyhylthiophene-2-yl)methyl-1-phenylethanamine; LC ((R)-N-(furan-2-ylmeththyl)-1-phenylethanamine and LD (R)-N-((5-methylfuran-2-yl)methyl)-1-phenylethanamine) were synthesized and characterized. The urease inhibitory activities of these complexes were determined against selected urease inhibitors where [LBZnCl2] was found to be the most prominent inhibitor of Jack bean urease (J. B. urease) (IC50 = 10.39±0.78 μM), whereas the activity of Bacillus pasteurii urease (B. P. urease) was predominantly inhibited by [LAZnCl2] (IC50 = 8.68±0.7 μM). Additionally, MOE-Dock program was used to affirm the probable binding modes of these complexes into the crystal structure of J. B. urease which certainly verified the inhibitory mechanism of these novel complexes.
 
 KEY WORDS: Zn(II) complexes, (R)-Phenylethanamine, Urease inhibition, Molecular docking
 
 Bull. Chem. Soc. Ethiop. 2021, 35(2), 301-314.
 DOI: https://dx.doi.org/10.4314/bcse.v35i2.7

Soil urease inhibition by various plant extracts.

Urea is the most popular and widely used nitrogenous fertilizer. High soil urease activity rapidly hydrolyses applied urea to ammonia which contributes to soil nitrogen (N) losses and reduces N use efficiency of crop plants. The ammonia losses can be minimized by the inhibition of soil urease activity which has been explored using various potential chemical inhibitors. However, the soil urease activity inhibition potential of plant extracts is rarely explored to date. In the present study, extracts of 35 plant materials were taken and evaluated against jack bean urease. Eleven extracts, showing >50% jack bean urease inhibition, were selected and further investigated in 13 soils collected from various districts of Punjab, Pakistan. Interestingly, except Capsicum annum, Melia azedarach, Citrus reticulata and Quercus infectoria, the plant extracts showed urease inhibition activities in soils, the extent of which was lower as compared to that observed in jack bean urease though. Maximum urea hydrolysis inhibition (70%) was noted with Vachellia nilotica which was 40% more than that of hydroquinone (50%) followed by that of Eucalyptus camaldulensis (24%). The extracts of V. nilotica and E. camaldulensis were coated on urea and applied to soil in the next step. At 21st day, 239% and 116% more urea-N was recovered from soil treated with V. nilotica and E. camaldulensis extracts coated urea, respectively, as compared to uncoated urea. Conclusively, these results indicated that the coating of V. nilotica and E. camaldulensis extracts on urea prills prolonged urea persistence in soil owing to minimum urea hydrolysis, probably, the extracts of V. nilotica and E. camaldulensis showed their urease inhibition potential. The results of this study provide a base line for the identification of new soil urease inhibitor compounds from plant materials in future.

Inhibition of jack bean urease by amphiphilic peptides

In the current study, amphiphilic peptides were designed and screened against Jack bean urease by using computer aided drug discovery approach. The result showed that out of thirty-eight amphiphilic peptides 1, 3, 12, 18, 30, and 33 exhibit stronger binding affinity with the active site of the enzyme through chelation of charged amino acids with the nickel ions i.e., Ni+2 841 and Ni+2 842 as well as hydrophobic contacts of the nonpolar tail with the nonpolar residues in the active site. The selected amphiphilic peptides were synthesized by solid-phase peptide synthesis strategy, characterized by fast atomic bombardment mass spectroscopy (FAB-MS) and nuclear magnetic resonance spectroscopy (1H and 13C-NMR) and in vitro urease inhibitory activity of amphiphilic peptides was studied. Amphiphilic peptides 12 and 33 showed excellent urease inhibitory activity, (p < 0.001) with IC50 values 20.5 ± 0.01, and 28.1 ± 0.03 µM respectively, which was considerably better than thiourea used as positive control.

New isolate from Salvinia molesta with antioxidant and urease inhibitory activity.

Urease plays a significant role in the pathogenesis of urolithiasis pyelonephritis, urinary catheter encrustation, hepatic coma, hepatic encephalopathy, and peptic acid duodenal ulcers. Salvinia molesta was explored to identify new bioactive compounds with particular emphasis on urease inhibitors. The aqueous methanol extract was fractionated using solvents of increasing polarity. A series of column chromatography and later HPLC were performed on butanol extract. The structures of the resulting pure compounds were resolved using NMR (1D and 2D), infrared, and mass spectroscopy. The novel isolate was evaluated for antioxidant activity (using DPPH, superoxide anion radical scavenging, oxidative burst, and Fe+2 chelation assays), anti-glycation behavior, anticancer activity, carbonic anhydrase inhibition, phosphodiesterase inhibition, and urease inhibition. One new glucopyranose derivative 6'-O-(3,4-dihydroxybenzoyl)-4'-O-(4-hydroxybenzoyl)-α/β-D-glucopyranoside (1) and four known glycosides were identified. Glycoside 1 demonstrated promising antioxidant potential with IC50 values of 48.2 ± 0.3, 60.3 ± 0.6, and 42.1 ± 1.8μM against DPPH, superoxide radical, and oxidative burst, respectively. Its IC50 in the Jack bean urease inhibition assay was 99.1 ± 0.8μM. The mechanism-based kinetic studies presented that compound 1 is a mixed-type inhibitor of urease with a Ki value of 91.8 ± 0.1μM. Finally, molecular dynamic simulations exploring the binding mode of compound 1 with urease provided quantitative agreement between estimated binding free energies and the experimental results. The studies corroborate the use of compound 1 as a lead for QSAR studies as an antioxidant and urease inhibitor. Moreover, it needs to be further evaluated through the animal model, that is, in vivo or tissue culture-based ex-vivo studies, to establish their therapeutic potential against oxidative stress phosphodiesterase-II and urease-induced pathologies.

Synthesis, molecular docking, and biological evaluation of nitroimidazole derivatives as potent urease inhibitors

The objective of this study was to design new nitroimidazole-based derivatives as strong urease inhibitors for the treatment of H. pylori infections. New series of nitroimidazole derivatives, 4a–k, were synthesized by using TBTU as the catalyst and assayed as Jack bean urease inhibitors. The facile synthetic approach was employed for the preparation of targeted molecular designs in good to excellent yields, ranged from 65 to 92%. Accordingly, all the synthesized compounds, 4a–k (IC50 = 1.43–7.72 μM), were more potent than the standard urease inhibitors, thiourea, and hydroxyurea. Among the derivatives, 4d had the most urease inhibitor activity (IC50 = 1.43 μM), over 15-fold more potent than thiourea and 70-fold than hydroxyurea. True to form, the result of molecular docking studies was in good congruence with those obtained from in vitro tests.

Synthesis, Characterization, Crystal Structures, and Biological Activity of Nickel(II), Manganese(II) and Cadmium(II) Complexes Derived from 4-Bromo-N'-(1-(Pyridin-2-YL)ethylidene)benzohydrazide

Three nickel(II), manganese(II) and cadmium(II) complexes, [NiL2] (I), [MnL2] (II) and [Cd(HL)2(NO3)]·NO3 (III), derived from 4-bromo-N'-(1-(pyridin-2-yl)ethylidene)benzohydrazide (HL) were prepared and characterized by IR and UV spectra. Structures of the complexes were further confirmed by single crystal X-ray diffraction techniques (CIF files CCDC nos. 1874307 (I), 1874308 (II), and 1874309 (III)). The Ni atom in complex I and the Mn atom in complex II are in octahedral coordination. The Cd atom in complex III is in square antiprism coordination. The nickel complex is effective on the inhibition of Jack bean urease.

Enzyme Inhibitory Kinetics and Molecular Docking Studies of Halo-Substituted Mixed Ester/Amide-Based Derivatives as Jack Bean Urease Inhibitors.

A series of halo-substituted mixed ester/amide-based analogues 4a-l have been prepared as jack bean urease inhibitor, which showed good to excellent inhibition of enzyme activity. The role of halo-substituted benzoyl moieties and alkyl substituted anilines in urease inhibitory kinetics was also investigated. The alkyl-substituted anilines 1a–b reacted with chloroacetyl chloride to afford intermediates 2a-b, which were then reacted with different halo-substituted benzoic acids 3a–f to prepare the title compounds 4a-l. The chemical structures of final products 4a-l were ascertained by FTIR, 1H NMR, 13C NMR, and mass spectra. The compound 4b showed remarkable activity with IC501.6 ± 0.2 nM, better than the standard thiourea having IC50472.1 ± 135.1 nM. The 2-chloro-substituted phenyl ring on one side of compound 4b and 4-isopropyl-substituted benzene on the other side play an essential role in inhibition of urease activity. Lineweaver–Burk plots (kinetics study) indicated about 4b derivative as a mixed type of inhibitor. The virtual screening performed against urease enzyme (PDBID 4H9M) showed that compounds 4b and 4e have binding energies of −7.8 and −7.9 Kcal/mol, respectively. Based upon our results, it was found that derivative 4b is a highly potent urease inhibitor, better than the standard thiourea.

Synthesis, density functional theory (DFT) studies and urease inhibition activity of chiral benzimidazoles

A variety of benzimidazole by the heterocyclization of orthophenylenediamine were synthesized in 69–86% yields. The synthesized compounds 3a-f and 6a-f were characterized and further investigated as jack bean urease inhibitors. Density functional theory (DFT) studies were performed utilizing the basis set B3LYP/6-31G (d, p) to acquire perception into their structural properties. Frontier molecular orbital (FMO) analysis of all compounds 3a–f and 6a-f was computed at the same level of theory to get a notion about their chemical reactivity and stability. The mapping of the molecular electrostatic potential (MEP) over the entire stabilized molecular geometry indicated the reactive centers. They exhibited urease inhibition activity with IC50 between 22 and 99 μM. Compounds containing withdrawing groups on the benzene ring (3d, 6d) were not showing significant urease inhibition. The value obtained for 3a, 3b, 3f had shown their significant urease inhibition for both theoretical and experimental. Notably, the compound having S-configuration (3a) (22.26 ± 6.2 μM) was good as compared to its R enantiomer 3f (31.42 ± 23.3 μM). Despite this, we elaborated the computational studies of the corresponding compounds, to highlight electronic effect which include HOMO, LUMO, Molecular electrostatic potential (MEP) and molecular docking.

Synthesis of novel xanthene based analogues: Their optical properties, jack bean urease inhibition and molecular modelling studies.

In this work, a series of the rhodamine 6G based derivatives 5a-5g, were synthesized. The structural framework of the synthesized compounds was established by using 1H NMR, 13C NMR, FT-IR, and LC-MS analytical methods. The spectroscopic properties of the target compounds were determined by using absorption and fluorescence study in four different solvents. Furthermore, the synthesized derivatives were assessed for in-vitro screening against jack bean urease inhibition and in-silico molecular docking study. The result reveals that all the compounds exhibit good urease inhibitory activity against this enzyme but among the series, the compound 5a &5c with an IC50 values of 0.1108 ± 0.0038 μM and 0.1136 ± 0.0295 μM shows to be most auspicious inhibitory activity compared to a standard drug (Thiourea) having IC50 value 4.7201 ± 0.0546 μM. Subsequently, the molecular docking experiment was analysed to distinguish the enzyme-inhibitor binding interaction.

4-Aminocoumarin based Aroylthioureas as Potential Jack Bean Urease Inhibitors; Synthesis, Enzyme Inhibitory Kinetics and Docking Studies.

Urease enzyme catalyzes the hydrolysis of urea into ammonia and CO2, excess ammonia causes global warming and crop reduction. Ureases are also responsible for certain human diseases such as stomach cancer, peptic ulceration, pyelonephritis, and kidney stones. New urease inhibitors are developed to get rid of such problems. This article describes the synthesis of a series of novel 1-aroyl-3-(2-oxo-2H-chromen-4- yl)thiourea derivatives (5a-j) as Jack bean urease inhibitors. Freshly prepared aryl isothiocyanates were reacted with 4-aminocoumarin in the same pot in an anhydrous medium of acetone. The structures of the title thioureas (5a-j) were ascertained by their spectroscopic data. The inhibitory effects against jack bean urease were determined. It was found that compounds 5i and 5j showed excellent activity with IC50 values 0.0065 and 0.0293, µM respectively. Compound 5i bearing 4-methyl substituted phenyl ring plays a vital role in enzyme inhibitory activity. The kinetic mechanism analyzed by Lineweavere-Burk plots revealed that compound 5i inhibits the enzyme non-competitively. The Michaelis-Menten constant Km and inhibition constants Ki calculated from Lineweavere-Burk plots for compound 5i are 4.155mM and 0.00032µM, respectively. The antioxidant activity results displayed that compound 5j showed excellent radical scavenging activity. The cytotoxic effects determined against brine shrimp assay showed that all of the synthesized compounds are non-toxic to shrimp larvae. Molecular docking studies were performed against target protein (PDBID 4H9M) and it was determined that most of the synthesized compounds exhibited good binding affinity with the target protein. Molecular dynamics simulation (MDS) results revealed that compound 5i forms a stable complex with target protein showing little fluctuation. Based upon our investigations, it is proposed that 5i derivative may serve as a lead structure for devising more potent urease inhibitors.

Investigation on the effect of alkyl chain linked mono-thioureas as Jack bean urease inhibitors, SAR, pharmacokinetics ADMET parameters and molecular docking studies

The increasing resistance of pathogens to common antibiotics, as well as the need to control urease activity to improve the yield of soil nitrogen fertilization in agricultural applications, has stimulated the development of novel classes of molecules that target urease as an enzyme. In this context, the newly developed compounds on the basis of 1-heptanoyl-3-arylthiourea family were evaluated for Jack bean urease enzyme inhibition activity to validate their role as potent inhibitors of this enzyme. 1-Heptanoyl-3-arylthioureas were obtained in excellent yield and characterized through spectral and elemental analysis. All the compounds displayed remarkable potency against urease inhibition as compared to thiourea standard. It was found that novel compounds fulfill the criteria of drug-likeness by obeying Lipinski’s rule of five. Particularly compound 4a and 4c can serve as lead molecules in 4D (drug designing discovery and development). Kinetic mechanism and molecular docking studies also carried out to delineate the mode of inhibition and binding affinity of the molecules.

WITHDRAWN: Coptisine, an alkaloid from Rhizoma Coptidis, inhibits Helicobacter pylori urease activity by targeting its active site and maturation process

// Cailan Li 1, * , Ping Huang 2, * , Kambo Wong 3 , Yifei Xu 2 , Lihua Tan 1 , Hanbin Chen 4 , Qiang Lu 5 , Chaodan Luo 1 , Chunlai Tam 3 , Lixiang Zhu 2 , Ziren Su 1, 6 and Jianhui Xie 7 1 Guangdong Provincial Key Laboratory of New Drug Development and Research of Chinese Medicine, Mathematical Engineering Academy of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, P. R. China 2 School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, P. R. China 3 School of Life Sciences, Center for Protein Science and Crystallography, The Chinese University of Hong Kong, Hong Kong, P. R. China 4 The First Affiliated Hospital of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, P. R. China 5 Key Laboratory of Ministry of Education, Research Center of Chinese Herbal Resources and Engineering, Guangzhou University of Chinese Medicine, Guangzhou, P. R. China 6 Dongguan Mathematical Engineering Academy of Chinese Medicine, Guangzhou University of Chinese Medicine, Dongguan, P. R. China 7 Guangdong Provincial Key Laboratory of Clinical Research on Traditional Chinese Medicine Syndrome, The Second Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, P. R. China * These authors have contributed equally to this work Correspondence to: Ziren Su, email: suziren@gzucm.edu.cn Jianhui Xie, email: xiejianhui888@hotmail.com Keywords: coptisine; Helicobacter pylori urease; sulfhydryl group; nickel ion; UreG Received: May 18, 2017 Accepted: January 01, 2018 Published: January 02, 2018 ABSTRACT In this study, we examined the anti- Helicobactor pylori effects of the main protoberberine-type alkaloids in Rhizoma Coptidis. Coptisine exerted varying antibacterial and bactericidal effects against three standard H. pylori strains and eleven clinical isolates, including four drug-resistant strains, with MICs ranging from 25 to 50 μg/mL and MBCs ranging from 37.5 to 125 μg/mL. Coptisine’s anti- H. pylori effects derived from specific inhibition of urease in vivo . In vitro , coptisine inactivated urease in a concentration-dependent manner through slow-binding inhibition and involved binding to the urease active site sulfhydryl group. Coptisine inhibition of H. pylori urease (HPU) was mixed type, while inhibition of jack bean urease (JBU) was non-competitive. Importantly, coptisine also inhibited HPU by binding to its nickel metallocenter. Besides, Coptisine interfered with urease maturation by inhibiting activity of prototypical urease accessory protein UreG and formation of UreG dimers and by promoting dissociation of nickel from UreG dimers. These findings demonstrate that coptisine inhibits urease activity by targeting its active site and inhibiting its maturation, thereby effectively inhibiting H. pylori . Coptisine may thus be an effective anti- H. pylori agent.

Coptisine-induced inhibition of Helicobacter pylori: elucidation of specific mechanisms by probing urease active site and its maturation process

In this study, we examined the anti-Helicobactor pylori effects of the main protoberberine-type alkaloids in Rhizoma Coptidis. Coptisine exerted varying antibacterial and bactericidal effects against three standard H. pylori strains and eleven clinical isolates, including four drug-resistant strains, with minimum inhibitory concentrations ranging from 25 to 50 μg/mL and minimal bactericidal concentrations ranging from 37.5 to 125 μg/mL. Coptisine’s anti-H. pylori effects derived from specific inhibition of urease in vivo. In vitro, coptisine inactivated urease in a concentration-dependent manner through slow-binding inhibition and involved binding to the urease active site sulfhydryl group. Coptisine inhibition of H. pylori urease (HPU) was mixed type, while inhibition of jack bean urease was non-competitive. Importantly, coptisine also inhibited HPU by binding to its nickel metallocentre. Besides, coptisine interfered with urease maturation by inhibiting activity of prototypical urease accessory protein UreG and formation of UreG dimers and by promoting dissociation of nickel from UreG dimers. These findings demonstrate that coptisine inhibits urease activity by targeting its active site and inhibiting its maturation, thereby effectively inhibiting H. pylori. Coptisine may thus be an effective anti-H. pylori agent.

Synthesis, enzyme inhibitory kinetics, and computational studies of novel 1-(2-(4-isobutylphenyl) propanoyl)-3-arylthioureas as Jack bean urease inhibitors.

In this article, synthesis of a novel 1-(2-(4-isobutylphenyl)propanoyl)-3-arylthioureas (4a-j) as jack bean urease inhibitors has been described. Freshly prepared 2-(4-isobutylphenyl) propanoyl isothiocyanate was treated with substituted aromatic anilines in one pot using anhydrous acetone. The compounds 4e, 4h, and 4j showed IC50 values 0.0086nm, 0.0081nm, and 0.0094nm, respectively. The enzyme inhibitory kinetics results showed that compound 4h inhibit the enzyme competitively while derivatives 4e and 4j are the mixed type inhibitors. The compound 4h reversibly binds the urease enzyme showing Ki value 0.0012nm. The Ki values for 4e and 4j are 0.0025nm and 0.003nm, respectively. The antioxidant activity results reflected that compounds 4b, 4i, and 4j showed excellent radical scavenging activity. Moreover, the cytotoxic activity of the target compounds was evaluated using brine shrimp assay and it was found that all of the synthesized compounds exhibited no cytotoxic effects to brine shrimps. The computational molecular docking and molecular dynamic simulation of title compounds were also performed, and results showed that the wet laboratory findings are in good agreement to the dry laboratory results. Based upon our results, it is proposed that compound 4h may act as a lead candidate to design the clinically useful urease inhibitors.

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.