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

Synthesis and evaluation of novel ebselen derivatives as urease inhibitors for combating Helicobacter pylori infections

The development of novel inhibitors targeting urease that affects the colonization of Helicobacter pylori (H. pylori) is a promising strategy to address the growing challenge of antibiotic resistance. In this study, a novel urease covalent inhibitor, XBP2 (IC50 = 0.14 ± 0.01 μM and MIC = 8 μg/mL), was identified through structure-based design using Ebselen as a template. XBP2 binds to a newly identified site, forming stable dipole interaction with residues ASP223 and HIS322, which enhances both stability and inhibitory activity against urease. It exhibits potent in vitro antibacterial activity, reducing cell apoptosis rates and significantly decreasing the fluorescence intensity of ROS and γH2AX in GES-1 cells infected with H. pylori. In the mouse gastritis model infected with H. pylori, XBP2 exhibits significant gastric mucosal protective effects. High-dose XBP2 (50 mg/kg) effectively prevented pathological changes such as bleeding and hyperplasia. Furthermore, acute toxicity test revealed that XBP2 does not display any detectable toxicity. These findings not only expand the structural diversity of Ebselen derivatives but also provide valuable insights for developing targeted therapies for eradicating H. pylori.

Construction of C-P Bonds from Free Cyclobutanone Oximes and Chlorophosphines via Radical-Radical Coupling

Herein, we report a catalyst-free reaction of cyclobutanone oximes with chlorophosphines (R2PCl), which forms a fragile C═N-O-PR2 species that undergoes N-O homolysis, fragmentation, and radical-radical coupling, leading to the formation of cyano-containing phosphine oxides in good yields. The reaction features an in situ activation of cyclobutanone oximes for radical generation, in which R2PCl plays a dual role as both an activator and a reactant.

Photoredox-Catalyzed Phosphonocarboxylation of Allenes with Phosphine Oxides and CO2

Phosphonocarboxylation of allenes with diarylphosphine oxides and CO2 via visible-light photoredox catalysis was developed for the first time. This work provided practical and sustainable access to highly valuable but otherwise difficult-to-access linear allylic β-phosphonyl carboxylic acids in moderate yields with exclusive regio- and stereoselectivity. This method was also characterized by step and atom economy and transition-metal free and mild conditions. Preliminary mechanistic studies suggested that allyl-methyl carbanion species are the key intermediates.

Exploration of Thiourea-Based Scaffolds for the Construction of Bacterial Ureases Inhibitors

A series of 32 thiourea-based urease inhibitors were synthesized and evaluated against native bacterial enzyme and whole cells of Sporosarcina pasteurii and Proteus mirabilis strains. The proposed inhibitors represented structurally diverse thiosemicarbazones and thiocarbohydrazones, benzyl-substituted thiazolyl thioureas, 1H-pyrazole-1-carbothioamides, and dihydropirimidine-2(1H)-thiones. Kinetic characteristics with purified S. pasteurii enzyme determined low micromolar inhibitors within each structural group. (E)-2-(1-Phenylethylidene)hydrazine-1-carbothioamide 19 (Ki = 0.39 ± 0.01 μM), (E)-2-(4-methylbenzylidene)hydrazine-1-carbothioamide 16 (Ki = 0.99 ± 0.04 μM), and N'-((1E,2E)-1,3-diphenylallylidene)hydrazinecarbothiohydrazide 29 (Ki = 2.23 ± 0.19 μM) were used in modeling studies that revealed sulfur ion coordination of the active site nickel ion and hydrogen bonds between the amide group and the side chain of Asp363 and Ala366 carbonyl moiety. Whole-cell studies proved the activity of compounds in Gram-positive and Gram-negative microorganisms. Ureolysis control observed in P. mirabilis PCM 543 (e.g., IC50 = 304 ± 14 μM for 1-benzyl-3-(4-(4-hydroxyphenyl)thiazol-2-yl)thiourea 52) is a valuable achievement, as urease is recognized as a major virulence factor of this urinary tract pathogen.

High performance self-assembled nano-chlorapatite in the presence of lactonic sophorolipid for the immobilization of cadmium in polluted sediment

A novel lactonic sophorolipid (LS) self-assembled nano-chlorapatite (LS-nClAP) was prepared for the immobilization of severe cadmium (Cd) in sediment. The experimental results indicated that the introduction of LS not only improved the dispersed performance of chlorapatite, but also brought massive hydroxyl and carboxyl groups, which significantly improved the immobilization efficiency of Cd and reduced its eco-toxicity in sediment. LS can significantly increase the effective utilization rate of phosphorus in chlorapatite, and reduce the content of available phosphorus (AP) by half after remediation compared with ClAP. Additionally, the participation of LS possessed a significant impact on the enzyme activities in the sediment, especially for urease, which was closely related to the effective stability of Cd and the introduction of LS. All experimental results of this study provided new insights into the possible effects of Cd immobilization by chlorapatite in contaminated sediments, demonstrating great application potential for sediment remediation in the future.

Anti-breast Adenocarcinoma and Anti-urease Anti-tyrosinase Properties of 5-Pentylresorcinol as Natural Compound with Molecular Docking Studies

5-Pentylresorcinol is a type of the group of resorcinol compounds that is resorcinol in that has hydrogen atom at position 5 is replaced by a pentyl group. It has a role as a lichen metabolite. This compound showed excellent to good inhibitory activities against studied these enzymes with IC₅₀ values of 65.96 µM for urease and 34.81 µM for tyrosinase. Standard compounds for enzymes had IC₅₀ values of 1.94±0.24 µM against urease and 84.36±5.17 µM against tyrosinase. The IC₅₀ of 5-pentylresorcinol against MCF7 cell line was 165.72 µg/mL; against Hs 578Bst cell line was 102.14 µg/mL; against Hs 319.T cell line was 12.34 µg/mL; and against UACC-3133 cell line was 73.07 µg/mL, respectively. The chemical activities of 5-pentylresorcinol against urease and tyrosinase were evaluated using the molecular modeling study. The anti-cancer activity of 5-pentylresorcinol was also investigated by treating the compound on the BRCT repeat region from the breast cancer-associated protein (BRCA1), and their interactions were assessed utilizing the molecular docking calculations. The results revealed the probable interactions and their characteristics at an atomic level. The docking scores of 5-pentylresorcinol against urease, tyrosinase, and BRCA1 are -3.073, -5.262, and -3.238 (kcal/mol), respectively.

Rational Development of Bacterial Ureases Inhibitors

Urease, an enzyme that catalyzes the hydrolysis of urea, is a virulence factor of various pathogenic bacteria. In particular, Helicobacter pylori, that colonizes the digestive tract and Proteus spp., that can infect the urinary tract, are related to urease activity. Therefore, urease inhibitors are considered as potential therapeutics against these infections. This review describes current knowledge of the structures, activity, and biological importance of bacterial ureases. Moreover, the structure-based design of several classes of bacterial urease inhibitors is presented and discussed. Phosphinic and phosphonic acids were applied as transition-state analogues, while Michael acceptors and ebselen derivatives were applied as covalent binders of cysteine residue. This review incorporates bacterial urease inhibitors from literature published between 2008 and 2021.

Covalent Inhibition of Bacterial Urease by Bifunctional Catechol-Based Phosphonates and Phosphinates

In this study, a new class of bifunctional inhibitors of bacterial ureases, important molecular targets for antimicrobial therapies, was developed. The structures of the inhibitors consist of a combination of a phosphonate or (2-carboxyethyl)phosphinate functionality with a catechol-based fragment, which are designed for complexation of the catalytic nickel ions and covalent bonding with the thiol group of Cys322, respectively. Compounds with three types of frameworks, including β-3,4-dihydroxyphenyl-, α-3,4-dihydroxybenzyl-, and α-3,4-dihydroxybenzylidene-substituted derivatives, exhibited complex and varying structure-dependent kinetics of inhibition. Among irreversible binders, methyl β-(3,4-dihydroxyphenyl)-β-(2-carboxyethyl)phosphorylpropionate was observed to be a remarkably reactive inhibitor of Sporosarcina pasteurii urease (k_inact/K_I = 10 420 s^-1 M^-1). The high potential of this group of compounds was also confirmed in Proteus mirabilis whole-cell-based inhibition assays. Some compounds followed slow-binding and reversible kinetics, e.g., methyl β-(3,4-dihydroxyphenyl)-β-phosphonopropionate, with K_i* = 0.13 μM, and an atypical low dissociation rate (residence time τ = 205 min).

How does the microenvironment change during the stabilization of cadmium in exogenous remediation sediment?

The pollution degree of heavy metals is closely related to the sediment microenvironment. This study aims to give a comprehensive account of the changes of microenvironment in sediment during the stabilization of cadmium (Cd) by the sodium lignosulphonate (SLS) modified chlorapatites (SLS@nClAP). Chemical speciation change demonstrated that SLS@nClAP possessed better stabilizing capacity (65.84 %-76.66 %) for Cd than unmodified chlorapatites (ClAP) (45.88 %). It might be since that the surface of SLS@nClAP presented a more dispersive thin sheet structure with sulfonate groups compared with the aggregate block structure of ClAP. High-throughput sequencing results displayed that succession of microbial community occurred after remediation in sediment. Most importantly, the dominant genus changed from massilia to phosphate-solubilizing bacterium-pseudomonas which might be due to the remediation of chlorapatites and the stabilization of Cd. Moreover, enzyme activity changes showed that the activity of catalase and urease were highly influenced by the stability and bioavailability of Cd during the incubation. This study not only provided a novel remediation technology for Cd-polluted sediment but also confirmed that the change of microenvironment was closely related to the stability and bioavailability of Cd in sediment.

Lead Molecules for Targeted Urease Inhibition: An Updated Review from 2010 -2018

The field of enzyme inhibition is a tremendous and quickly growing territory of research. Urease a nickel containing metalloenzyme found in bacteria, algae, fungi, and plants brings hydrolysis of urea and plays important role in environmental nitrogen cycle. Apart from this it was found to be responsible for many pathological conditions due to its presence in many microorganisms such as H. Pylori, a ureolytic bacteria having urease which elevates pH of gastric medium by hydrolyzing urea present in alimentary canal and help the bacteria to colonize and spread infection. Due to the infections caused by the various bacterial ureases such as Bacillus pasteurii, Brucella abortus, H. pylori, H. mustelae, Klebsiella aerogenes, Klebsiella tuberculosis, Mycobacterium tuberculosis, Pseudomonas putida, Sporosarcina pasteurii and Yersinia enterocolitica, it has been the current topic of today's research. About a wide range of compounds from the exhaustive literature survey has been discussed in this review which is enveloped into two expansive classes, as Inhibitors from synthetic origin and Inhibitors from natural origin. Moreover active site details of enzyme, mechanism of catalysis of substrate by enzyme, uses of plant urease and its pathogenic behavior has been included in the current review. So, overall, this review article diagrams the current landscape of the developments in the improvements in the thriving field of urease inhibitory movement in medicinal chemistry from year 2010 to 2018, with an emphasis on mechanism of action of inhibitors that may be used for more development of recent and strong urease inhibitors and open up new doors for assist examinations in a standout amongst the most lively and promising regions of research.

Transition metal-free phosphonocarboxylation of alkenes with carbon dioxide via visible-light photoredox catalysis

Catalytic difunctionalization of alkenes has been an ideal strategy to generate structurally complex molecules with diverse substitution patterns. Although both phosphonyl and carboxyl groups are valuable functional groups, the simultaneous incorporation of them via catalytic difunctionalization of alkenes, ideally from abundant, inexpensive and easy-to-handle raw materials, has not been realized. Herein, we report the phosphonocarboxylation of alkenes with CO2 via visible-light photoredox catalysis. This strategy is sustainable, general and practical, providing facile access to important β-phosphono carboxylic acids, including structurally complex unnatural α-amino acids. Diverse alkenes, including enamides, styrenes, enolsilanes and acrylates, undergo such reactions efficiently under mild reaction conditions. Moreover, this method represents a rare example of redox-neutral difunctionalization of alkenes with H-P(O) compounds, including diaryl- and dialkyl- phosphine oxides and phosphites. Importantly, these transition-metal-free reactions also feature low catalyst loading, high regio- and chemo-selectivities, good functional group tolerance, easy scalability and potential for product derivatization.

Bisphosphonic acids and related compounds as inhibitors of nucleotide- and polyphosphate-processing enzymes: A PPK1 and PPK2 case study

Bisphosphonic acids, which are structural analogs of pyrophosphate, constitute a class of compounds with very high potential for the construction of effective inhibitors of enzymes operating on oligo- and polyphosphates. The bisphosphonate-based methodology was applied for the discovery of inhibitors of two families of polyphosphate kinases (PPK1 and PPK2). Screening of thirty-two structurally diverse bisphosphonic acids and related compounds revealed several micromolar inhibitors of both enzymes. Importantly, selectivity of bisphosphonates could be achieved by application of the appropriate side chain.

F. A review on the development of urease inhibitors as antimicrobial agents against pathogenic bacteria

Ureases are enzymes that hydrolyze urea into ammonium and carbon dioxide. They have received considerable attention due to their impacts on living organism health, since the urease activity in microorganisms, particularly in bacteria, are potential causes and/or factors contributing to the persistence of some pathogen infections. This review compiles examples of the most potent antiurease organic substances. Emphasis was given to systematic screening studies on the inhibitory activity of rationally designed series of compounds with the corresponding SAR considerations. Ureases of Canavalia ensiformis, the usual model in antiureolytic studies, are emphasized. Although the active site of this class of hydrolases is conserved among bacteria and vegetal ureases, the same is not observerd for allosteric site. Therefore, inhibitors acting by participating in interactions with the allosteric site are more susceptible to a potential lack of association among their inhibitory profile for different ureases. The information about the inhibitory activity of different classes of compounds can be usefull to guide the development of new urease inhibitors that may be used in future in small molecular therapy against pathogenic bacteria.

Recent advances in design of new urease inhibitors: A review

Urease is a nickel-dependent metalloenzyme found in plants, some bacteria, and fungi. Bacterial enzyme is of special importance since it has been demonstrated as a potent virulence factor for some species. Especially it is central to Helicobacter pylori metabolism and virulence being necessary for its colonization of the gastric mucosa, and is a potent immunogen that elicits a vigorous immune response. Therefore, it is not surprising that efforts to design, synthesize and evaluate of new inhibitors of urease are and active field of medicinal chemistry. In this paper recent advances on this field are reviewed.