Synthetic nicotinic/isonicotinic thiosemicarbazides: In vitro urease inhibitory activities and molecular docking studies

Design and discovery of urease and Helicobacter pylori inhibitors based on benzofuran/benzothiophene-sulfonate and sulfamate scaffolds for the treatment of ureolytic bacterial infections

A series of sulfonate and sulfamate derivatives bearing benzofuran or benzothiophene scaffold exhibited potent inhibitory effect on urease enzyme. Most of the derivatives exhibited significantly higher potency than thiourea, the standard inhibitor. Compound 1s was identified as the most potent urease inhibitor with an IC50 value of 0.42 ± 0.08 μM, which is 53-fold more potent than thiourea, positive control (IC50 = 22.3 ± 0.031 μM). The docking results further revealed the binding interactions towards the urease active site. Phenotypic screening revealed that compounds 1c, 1d, 1e, 1f, 1j, 1n, and 1t exhibit high potency against H. pylori with MIC values ranging from 0.00625 to 0.05 mM and IC50 values ranging from 0.0031 to 0.0095 mM, much more potent than the positive control, acetohydroxamic acid (MIC and IC50 values were 12.5 and 7.38 mM, respectively). Additional studies were performed to investigate the toxicity of these compounds against the gastric epithelial cell line (AGS) and their selectivity profile against E. coli, and five Lactobacillus species representative of the gut microflora. Permeability characteristics of the most promising derivatives were investigated in Caco-2 cell line. The results indicate that the compounds could be targeted in the GIT only without systemic side effects.

Design and synthesis of novel anti-urease imidazothiazole derivatives with promising antibacterial activity against Helicobacter pylori

Urease enzyme is a known therapeutic drug target for treatment of Helicobacter pylori infection due to its role in settlement and growth in gastric mucosa. In this study, we designed a new series of sulfonates and sulfamates bearing imidazo[2,1-b]thiazole scaffold that exhibit a potent inhibitory activity of urease enzyme. The most potent compound 2c inhibited urease with an IC50 value of 2.94 ± 0.05 μM, which is 8-fold more potent than the thiourea positive control (IC50 = 22.3 ± 0.031 μM). Enzyme kinetics study showed that compound 2c is a competitive inhibitor of urease. Molecular modeling studies of the most potent inhibitors in the urease active site suggested multiple binding interactions with different amino acid residues. Phenotypic screening of the developed compounds against H. pylori delivered molecules of that possess high potency (1a, 1d, 1h, 2d, and 2f) in comparison to the positive control, acetohydroxamic acid. Additional studies to investigate the selectivity of these compounds against AGS gastric cell line and E. coli were performed. Permeability of the most promising derivatives (1a, 1d, 1h, 2d, and 2f) in Caco-2 cell line, was investigated. As a result, compound 1d presented itself as a lead drug candidate since it exhibited a promising inhibition against urease with an IC50 of 3.09 ± 0.07 μM, MIC value against H. pylori of 0.031 ± 0.011 mM, and SI against AGS of 6.05. Interestingly, compound 1d did not show activity against urease-negative E. coli and exhibited a low permeability in Caco-2 cells which supports the potential use of this compound for GIT infection without systemic effect.

N-Arylacetamide derivatives of methyl 1,2-benzothiazine-3-carboxylate as potential drug candidates for urease inhibition

Urease enzyme is an infectious factor that provokes the growth and colonization of virulence pathogenic bacteria in humans. To overcome the deleterious effects of bacterial infections, inhibition of urease enzyme is one of the promising approaches. The current study is designed to synthesize new 1,2-benzothiazine-N-arylacetamide derivatives 5(a-n) that can effectively provide a new drug candidate to avoid bacterial infections by urease inhibition. After structural elucidation by FT-IR, proton and carbon-13 NMR and mass spectroscopy, the synthesized compounds 5(a-n) were investigated to evaluate their inhibitory potential against urease enzyme. In vitro analysis against positive control of thiourea indicated that all the synthesized compounds have strong inhibitory strengths as compared to the reference drug. Compound 5k, being the most potent inhibitor, strongly inhibited the urease enzymes and revealed an IC₅₀ value of 9.8 ± 0.023 µM when compared with the IC₅₀ of thiourea (22.3 ± 0.031 µM)-a far more robust inhibitory potential. Docking studies of 5k within the urease active site revealed various significant interactions such as H-bond, π-alkyl with amino acid residues like Val744, Lys716, Ala16, Glu7452, Ala37 and Asp730.

X-ray Structures and Computational Studies of Two Bioactive 2-(Adamantane-1-carbonyl)-N-substituted Hydrazine-1-carbothioamides

Two biologically active adamantane-linked hydrazine-1-carbothioamide derivatives, namely 2-(adamantane-1-carbonyl)-N-(tert-butyl)hydrazine-1-carbothioamide) 1 and 2-(adamantane-1-carbonyl)-N-cyclohexylhydrazine-1-carbothioamide 2, have been synthesized. X-ray analysis was conducted to study the effect of the t-butyl and cyclohexyl moieties on the intermolecular interactions and conformation of the molecules in the solid state. X-ray analysis reveals that compound 1 exhibits folded conformation, whereas compound 2 adopts extended conformation. The Hirshfeld surface analysis indicates that the contributions of the major intercontacts involved in the stabilization of the crystal structures do not change much as a result of the t-butyl and cyclohexyl moieties. However, the presence and absence of these contacts is revealed by the 2D-fingerprint plots. The CLP-Pixel method was used to identify the energetically significant molecular dimers. These dimers are stabilized by different types of intermolecular interactions such as N-H···S, N-H···O, C-H···S, C-H···O, H-H bonding and C-H···π interactions. The strength of these interactions was quantified by using the QTAIM approach. The results suggest that N-H···O interaction is found to be stronger among other interactions. The in vitro assay suggests that both compounds 1 and 2 exhibit urease inhibition potential, and these compounds also display moderate antiproliferative activities. Molecular docking analysis shows the key interaction between urease enzyme and title compounds.

Synthesis and Identification of New N,N-Disubstituted Thiourea, and Thiazolidinone Scaffolds Based on Quinolone Moiety as Urease Inhibitor

Synthesis of thiazolidinone based on quinolone moiety was established starting from 4-hydroxyquinol-2-ones. The strategy started with the reaction of ethyl bromoacetate with 4-hydroxyquinoline to give the corresponding ethyl oxoquinolinyl acetates, which reacted with hydrazine hydrate to afford the hydrazide derivatives. Subsequently, hydrazides reacted with isothiocyanate derivatives to give the corresponding N,N-disubstituted thioureas. Finally, on subjecting the N,N-disubstituted thioureas with dialkyl acetylenedicarboxylates, cyclization occurred, and thiazolidinone derivatives were obtained in good yields. The two series based on quinolone moiety, one containing N,N-disubstituted thioureas and the other containing thiazolidinone functionalities, were screened for their in vitro urease inhibition properties using thiourea and acetohydroxamic acid as standard inhibitors. The inhibition values of the synthesized thioureas and thiazolidinones exhibited moderate to good inhibitory effects. The structure-activity relationship revealed that N-methyl quinolonyl moiety exhibited a superior effect, since it was proved to be the most potent inhibitor in the present series achieving (IC₅₀ = 1.83 ± 0.79 µM). The previous compound exhibited relatively much greater activity, being approximately 12-fold more potent than thiourea and acetohydroxamic acid as references. Molecular docking analysis showed a good protein-ligand interaction profile against the urease target (PDBID: 4UBP), emphasizing the electronic and geometric effect of N,N-disubstituted thiourea.

Antitumor Activity and Physicochemical Properties of New Thiosemicarbazide Derivative and Its Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) Complexes

A novel biologically active thiosemicarbazide derivative ligand L (N-[(phenylcarbamothioyl)amino]pyridine-3-carboxamide) and a series of its five metal(II) complexes, namely: [Co(L)Cl₂], [Ni(L)Cl₂(H₂O)], [Cu(L)Cl₂(H₂O)], [Zn(L)Cl₂] and [Cd(L)Cl₂(H₂O)] have been synthesized and thoroughly investigated. The physicochemical characterization of the newly obtained compounds has been performed using appropriate analytical techniques, such as ¹H and ^l3C nuclear magnetic resonance (NMR), inductively coupled plasma (ICP), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR) and magnetic measurements. In order to study the pharmacokinetic profile of the compounds, ADMET analysis was performed. The in vitro studies revealed that the synthesized compounds exhibit potent biological activity against A549 human cancer cell line.

Synthesis, Antimicrobial Evaluation, and Molecular Modeling Studies of New Thiosemicarbazide-Triazole Hybrid Derivatives of (S)-Naproxen

The discovery of new antimicrobial molecules is crucial for combating drug-resistant bacterial and fungal infections that pose a dangerous threat to human health. In the current research, we applied a molecular hybridization approach to synthesize original thiosemicarbazide-triazole derivatives starting from ( S )-Naproxen ( 7a-7k ). After structural characterization using FT-IR, 1 H NMR, 13 C NMR, and HR-MS, the obtained compounds were screened for their antimicrobial activities against Staphylococcus aureus ATCC 29213 , Escherichia coli ATCC 25922 , Candida albicans ATCC 10231 and their isolates, as well. Although all compounds were found to be moderate antimicrobial agents, in general, their antibacterial activities were better than antifungal effects. Among the tested compounds, 7j carrying nitrophenyl group on the thiosemicarbazide functionality represented the best MIC value against S. aureus isolate. Finally, molecular docking studies were performed in the active pocket of S. aureus flavohemoglobin to rationalize the obtained biological data.

Antiurease screening of alkyl chain-linked thiourea derivatives: in vitro biological activities, molecular docking, and dynamic simulations studies

Urease has become an important therapeutic target because it stimulates the pathogenesis of many human health conditions, such as pyelonephritis, the development of urolithiasis, hepatic encephalopathy, peptic ulcers, gastritis and gastric cancer. A series of alkyl chain-linked thiourea derivatives were synthesized to screen for urease inhibition activity. Structure elucidation of these compounds was done by spectral studies, such as IR, ¹H NMR and ¹³C NMR, and MS analysis. In vitro urease enzyme inhibition assay revealed that compound 3c was the most potent thiourea derivative among the series with IC₅₀ values of 10.65 ± 0.45 μM, while compound 3g also exhibited good activity with an IC₅₀ value of 15.19 ± 0.58 μM compared to standard thiourea with an IC₅₀ value of 15.51 ± 0.11 μM. The other compounds in the series possessed moderate to weak urease inhibition activity with IC₅₀ values ranging from 20.16 ± 0.48 to 60.11 ± 0.78 μM. The most potent compounds 3c and 3g were docked to jack bean urease (PDB ID: 4H9M) to evaluate their binding affinities and to find the plausible binding poses. The docked complexes were refined through 100 ns-long MD simulations. The simulation results revealed that the average RMSD of 3c was less than that of the 3g compound. Furthermore, the radius of gyration plots for both complexes showed that 3c and 3g docking predicted binding modes did not induce any conformational change in the urease structure.

Urease has become an important therapeutic target because it stimulates the pathogenesis of many human health conditions, such as pyelonephritis, the development of urolithiasis, hepatic encephalopathy, peptic ulcers, gastritis and gastric cancer.

New acetylphenol-based acyl thioureas broaden the scope of drug candidates for urease inhibition: synthesis, in vitro screening and in silico analysis

Helicobacter pylori urease remains a validated drug target for the eradication of pervasive chronic stomach infection that leads to severe human health diseases such as gastritis and stomach cancer. The increased failure of current treatment protocols because of resistance to broadband antibiotics, severe side effects and low compliance underscore the need for a targeted eradication therapy. Therefore, in the present research, we have developed a new series of acetylphenol-based acyl thioureas that can potentially provide a new template for drug candidates to inhibit urease enzyme. Newly synthesized compounds 7a-j were evaluated for urease inhibitory strength using thiourea as a positive control. In vitro inhibitory results revealed that all the tested compounds were significantly potent than the standard drug. The most active lead 7f competitively inhibited the enzyme and displayed an IC₅₀ value of 0.054 ± 0.002 μM, a ~413-fold strong inhibitory potential than thiourea (IC₅₀ = 22.3 ± 0.031 μM). Various insightful structure-activity relationships were developed showing the key structural requirements for potent inhibitory effects. Molecular docking analysis of 7f inside the active pocket of urease suggested several important interactions with amino acid residues such as ILE411, MET637, ARG439, GLN635, ALA636 and ALA440. Finally, pharmacokinetic properties suggested that the tested derivatives are safe to develop as low-molecular-weight drugs to treat ureolytic bacterial infections.

Anti-Helicobacter pylori Compounds from Oliveria decumbens Vent. through Urease Inhibitory In-vitro and In-silico Studies

Oliveria decumbens Vent. has been used by indigenous people of southwest Iran for treating peptic ulcers and gastrointestinal infections. This study aimed to investigate the antibacterial activity of Oliveria decumbens extract and fractions and to analyze the bioactive components of the fractions. Total plant extract and different fractions of Oliveria decumbens Vent. were prepared. Antibacterial activities were evaluated against the clinical strain of Helicobacter pylori and standard strains of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa using agar dilution and disc diffusion methods. Phytochemical analysis of the fractions was performed using silica gel chromatography and 1D and 2D NMR spectroscopy. Moreover, the urease inhibitory effects of the isolated compounds were assessed in-vitro and in-silico. Three novel kaempferol derivatives and two thymol derivatives were isolated from Oliveria decumbens aerial parts, and the structures were determined by comparison with published data. The n-hexane fraction was found to exert the most significant anti-H. pylori activity with the minimum inhibitory concentration of 50 µg/mL. All fractions demonstrated antibacterial activity toward S. aureus. In-vitro urease inhibition assay showed that stigmasterol, tiliroside, and carvacrol were found to be the most potent enzyme inhibitors in the isolated compounds. Molecular interactions of the compounds with the active site of urease were supported by the molecular docking analysis. Novel bioactive compounds in Oliveria decumbens were described in this study. The antibacterial effects suggested the potential use of the compounds in pharmaceutical formulations inconsistent with the traditional use of the plant in the treatment of gastrointestinal infections.

Discovery of urease inhibitory effect of sulfamate derivatives: Biological and computational studies

The discovery of life-changing medicines continues to be the driving force for the rapid exploration and expansion of chemical space, enabling access to innovative small molecules of medicinal importance. These small molecules remain the backbone for modern drug discovery. In this context, the treatment of ureolytic bacterial infections inspires the identification of potent and effective inhibitors of urease, a promising and highly needed target for H. pylori eradication. The present study explores the evaluation of sulfamate derivatives for the inhibition of urease enzyme. The tested compounds showed remarkable inhibitory effect and high level of potency. Compound 1q emerged as the lead inhibitor with an IC₅₀ value of 0.062 ± 0.001 µM, ∼360-fold more potent than thiourea (IC₅₀ = 22.31 ± 0.031 µM). The assessment of various contributing factors towards the inhibition profile allowed for the establishment of diverse structure-activity relationships. Kinetics studies revealed the competitive mode of inhibition of compound 1q while molecular modeling analysis identified various crucial binding interactions with ARG609, ARG439, HIS519, HIS492, HIS593, ALA440, and ALA636 in the active pocket of the enzyme. Finally, the calculated pharmacokinetic properties suggest a promising profile of our potent sulfamate-based urease inhibitors.

Synthesis, molecular docking, and evaluation of antibacterial activity of 1,2,4-triazole-norfloxacin hybrids

A series of 1,2,4-triazole-norfloxacin hybrids was designed, synthesized, and evaluated for in vitro antibacterial activity against common pathogens. All the newly synthesized compounds were characterized by Fourier-transform infrared spectrophotometry, proton and carbon nuclear magnetic resonance, and electrospray ionization-mass spectrometry. Representative compounds from each step of the synthesis were further characterized by X-ray crystallography. Many of the compounds synthesized exhibited antibacterial activity superior to that of norfloxacin toward both, gram-positive and gram-negative bacteria. The toxicity of the 1,2,4-triazole-norfloxacin hybrids toward bacterial cells was 32-512 times higher than that toward mouse fibroblast cells. Moreover, hemolysis was not observed at concentrations of 64 μg/mL, suggesting good biocompatibility. Molecular docking showed a least binding energy of -9.4 to -9.7 kcal/mol, and all compounds were predicted to show remarkable affinity for the bacterial topoisomerase IV.

Exploring biologically active hybrid pharmacophore N-substituted hydrazine-carbothioamides for urease inhibition: In vitro and in silico approach

Urease is potential target for various human's health complications, such as peptic ulcer, gastric cancer and kidney stone formation. The present study was based on synthesis of new hybrid pharmacophore N-substituted hydrazine-carbothioamides as potential urease inhibitors. Presented method gave excellent yield in range of 85-95% for hydrazine-carbothioamides derivatives (3a-s) after reaction of mono- and disubstituted hydrazides (1a-k) and substituted isothiocyanates (2a-d). All newly derivatives were characterized by advanced spectroscopic techniques (FTIR, ¹HNMR, ¹³CNMR, EMS) and were assessed for their urease inhibition potential. All analogs except for 3k, 3l and 3m demonstrated strong inhibitory potential for urease with IC₅₀ values of 8.45 ± 0.14 to 25.72 ± 0.23 μM as compared to standard thiourea (IC₅₀ 21.26 ± 0.35 μM). The structure-activity relationship and mode of interaction was established by molecular docking studies. It was revealed that the N-substituted hydrazine-carbothioamides interacted with nickel atoms present in the active site of urease and supported the correlations with the experimental findings. Therefore, the afforded hydrazine-carbothioamides derivatives are interesting hits for urease inhibition studies with future prospects of modification and optimization.

Flavonoid analogues as urease inhibitors: Synthesis, biological evaluation, molecular docking studies and in-silico ADME evaluation

A series of novel flavonoid analogues were designed and synthesized. The aimed compounds for urease inhibitory activities were clearly superior to the control drug thiourea (more than 10 times). Among these compounds, L2 (IC₅₀ = 1.343 µM) and L12 (IC₅₀ = 1.207 µM) exhibited the most excellent urease inhibitory activity in vitro. The molecular dockings of L2, L12 and L22 into urease were performed to explore the binding modes and their structure-activity relationship. Furthermore, these aimed compounds showed good druggable properties.

Novel thiobarbiturates as potent urease inhibitors with potential antibacterial activity: Design, synthesis, radiolabeling and biodistribution study

Urease enzyme is a virulence factor that helps in colonization and maintenance of highly pathogenic bacteria in human. Hence, the inhibition of urease enzymes is well-established to be a promising approach for preventing deleterious effects of ureolytic bacterial infections. In this work, novel thiobarbiturate derivatives were synthesized and evaluated for their urease inhibitory activity. All tested compounds effectively inhibited the activity of urease enzyme. Compounds 1, 2a, 2b, 4 and 9 displayed remarkable anti-urease activity (IC₅₀ = 8.21-16.95 μM) superior to that of thiourea reference standard (IC₅₀ = 20.04 μM). Moreover, compounds 3a, 3g, 5 and 8 were equipotent to thiourea. Among the tested compounds, morpholine derivative 4 (IC₅₀ = 8.21 µM) was the most potent one, showing 2.5 folds the activity of thiourea. In addition, the antibacterial activity of the synthesized compounds was estimated against both standard strains and clinical isolates of urease producing bacteria. Compound 4 explored the highest potency exceeding that of cephalexin reference drug. Moreover, biodistribution study using radiolabeling approach revealed a remarked uptake of ^99mTc-compound 4 into infection induced in mice. Furthermore, a molecular docking analysis revealed proper orientation of title compounds into the urease active site rationalizing their potent anti-urease activity.

N-monosubstituted thiosemicarbazide as novel Ure inhibitors: synthesis, biological evaluation and molecular docking

Background: Identification of novel Ure inhibitors with high potency has received considerable attention. Methodology & results: Ure inhibition was determined using the indophenol method, the affinities to Ure were estimated via surface plasmon resonance. Seventeen new plus ten known N-monosubstituted thiosemicarbazides were synthesized and identified as novel Ure inhibitors. Out of these compounds, compound b5 shows excellent activity against both crude Ure from Helicobacter pylori (IC₅₀ = 0.04 μM) and Ure in living cell (IC₅₀ = 0.27 μM), with the potency being over 600-fold higher than clinical used drug acetohyroxamic acid, respectively. Surface plasmon resonance demonstrated the high affinity (K_d.#x00A0;= 6.32 nM) of b5 to Ure. Conclusion: This work provides a class of novel and promising Ure inhibitors.

Synthesis, Biological Evaluation and Molecular Docking of Deferasirox and Substituted 1,2,4-Triazole Derivatives as Novel Potent Urease Inhibitors: Proposing Repositioning Candidate

A series of new deferasirox derivatives were synthesized through the reaction of monosubstituted hydrazides with 2-(2-hydroxyphenyl)-4H-benzo[e][1,3]oxazin-4-one. For the first time, deferasirox and some of its derivatives were evaluated for their in vitro inhibitory activity against Jack bean urease. The potencies of the members of this class of compounds are higher than that of acetohydroxamic acid. Two compounds, bearing tetrazole and hydrazine derivatives (bioisoester of carboxylate group), represented the most potent urease inhibitory activity with IC₅₀ values of 1.268 and 3.254 μm, respectively. In silico docking studies were performed to delineate possible binding modes of the compounds with the enzyme, urease. Docking analysis suggests that the synthesized compounds were anchored well in the catalytic site and extending to the entrance of binding pocket and thus restrict the mobility of the flap by interacting with its crucial amino acid residues, CME592 and His593. The overall results of urease inhibition have shown that these target compounds can be further optimized and developed as a lead skeleton for the discovery of novel urease inhibitors.

Identification and molecular modeling of new quinolin-2-one thiosemicarbazide scaffold with antimicrobial urease inhibitory activity

A new series of 6-substituted quinolin-2-one thiosemicarbazides 6a-j has been synthesized. The structure of the target compounds was proved by different spectroscopic and elemental analyses. All the designed final compounds were evaluated for their in vitro activity against the urease-producing R. mucilaginosa and Proteus mirabilis bacteria as fungal and bacterial pathogens, respectively. Moreover, all compounds were in vitro tested as potential urease inhibitors using the cup-plate diffusion method. Compounds 6a and 6b were the most active with (IC₅₀ = 0.58 ± 0.15 and 0.43 ± 0.09 µM), respectively, in comparison with lead compound I (IC₅₀ = 1.13 ± 0.00 µM). Also, the designed compounds were docked into urease proteins (ID: 3LA4 and ID: 4UBP) using Open Eye^® software to understand correctly about ligand-receptor interactions. The docking results revealed that the designed compounds can interact with the active site of the enzyme through multiple strong hydrogen bonds. Moreover, rapid overlay of chemical structures' analysis was described to understand the 3D QSAR of synthesized compounds as urease inhibitors. The results emphasize the importance of polar thiosemicarbazide directly linked to 6-substituted quinolone moieties as promising antimicrobial urease inhibitors.

Synthesis, in vitro biological evaluation and in silico studies of certain arylnicotinic acids conjugated with aryl (thio)semicarbazides as a novel class of anti-leishmanial agents

Herein we introduce new compounds as conjugates of arylnicotinic acids with aryl (thio)semicarbazide derivatives. Based on a structure-guided approach, they were designed to possess anti-leishmanial activity through anti-folate mechanism, via targeting Leishmania major pteridine reductase 1 (Lm-PTR1). The in vitro anti-promastigote and anti-amastigote activity were promising for many thiosemicarbazide derivatives and superior to the reference miltefosine. The most active compounds 8i and 8j exhibited their anti-amastigote activity with IC₅₀ values of 4.2 and 3.3 μM, respectively, compared to reference miltefosine (IC₅₀ value of 7.3). Their anti-folate mechanism was confirmed via the ability of folic and folinic acids to reverse the anti-leishmanial activity of these compounds, comparably to Lm-PTR1 inhibitor trimethoprim. Interestingly, the in vitro cytotoxicity test of the most active compounds displayed higher selectivity indices than that of miltefosine emphasizing their safety on mammalian cells. Furthermore, the docking experiments on Lm-PTR1 as a putative target rationalized the in vitro anti-leishmanial activity. The in silico predictions exhibited promising pharmacokinetics and drug-likeness profiles of the most active compounds. Generally, this work introduces a fruitful matrix for new anti-leishmanial chemotype which would extend the chemical space for the anti-leishmanial activity.

Studies on Isoniazid Derivatives through a Medicinal Chemistry Approach for the Identification of New Inhibitors of Urease and Inflammatory Markers

A library of thiosemicarbazide derivatives of isoniazid 3-27, was synthesized and evaluated for their anti-inflammatory and urease inhibition activities, by using in vitro bioassays. Among these compounds 9, 10, 12, 21, and 26 were identified as new derivatives. Prolonged use of non-steroidal anti-inflammatory drugs (NSAIDs) and infections caused by Helicobacter pylori (ureolytic bacteria), are the two most significant causes of gastric and peptic ulcers. We focused on the identification of the dual inhibitors of inflammation and urease enzyme. Compound 23 was identified as the best dual inhibitor of inflammation (ROS; IC50 = 12.3 µg/mL), and urease enzyme inhibition activity (IC50 = 22.4 µM). Many of these compounds showed comparable activities to the standard anti-inflammatory drug (ibuprofen, IC50 = 11.2 µg/mL) and urease inhibitor (thiourea/acetohydraoxamic acid, IC50 = 21.1/20.3 µM). Compound 12 was found to be the most potent urease inhibitor (IC50 = 12.3 µM) and good inhibitor of inflammation (IC50 = 27.7 µg/mL). Compounds 19, 11, 13, 9, 17, 10, and 16, were also found to be potent inhibitors of urease. Cytotoxicity was also evaluated and all the compounds were found to be non-cytotoxic, except compound 18 and the parent drug isoniazid (IC50 = 29.5 and 28.5 µM, respectively).

Developing potential Helicobacter pylori urease inhibitors from novel oxoindoline derivatives: Synthesis, biological evaluation and in silico study

By recruiting the important moiety from Shikonin, a series of novel oxoindoline derivatives S1-S20 have been synthesized for inhibiting H. pylori urease. The most potent compound S18 displayed better activity (IC₅₀ = 0.71 μM; MIC = 0.48 μM) than the positive controls AHA (IC₅₀ = 17.2 μM) and Metronidazole (MIC = 31.3 μM). With low cytotoxicity, it showed considerable potential for further development. Docking simulation revealed the possible binding pattern of this series. 3D QSAR model was built to discuss SAR and give useful hints for future modification.