Synthesis, molecular properties and DFT studies of new phosphoramidates as potential urease inhibitors

Paper-based analytical device with colorimetric detection for urease activity determination in soils and evaluation of potential inhibitors

Urease is an enzyme associated with the degradation of urea, an important nitrogen fertilizer in agriculture. Thus, this current report describes the use of a paper-based analytical device (UrePAD) designed to contain a microzone array for colorimetric determination of urease activity in soils in the absence/presence of potential enzyme inhibitors. The UrePAD can be used at the point-of-need (point-of-care), and it offers advantages such as low cost, simplicity in handling, low sample/reagent volumes, and no use of toxic reagents. The acid-base indicator phenol red was used to monitor the urea hydrolysis reaction catalyzed by urease in the evaluated systems. The images were digitalized in a bench scanner, and the analysis was performed using Corel Draw X8 software. The device offered a LOD of 0.10 U mL^-1 with linearity between 0.25 and 4.0 U mL^-1 and a relative standard deviation ≤ 1.38%. UrePAD was tested in four soil samples of different characteristics and with eight urease inhibitors of varied classes. The results obtained through the proposed device did not differ statistically (95% confidence interval) from those employing the classic method based on the Berthelot reaction, thus indicating that UrePAD was effective for determining urease activity and screening inhibitors, besides showing the capacity to simplify fieldwork involving the application of urea in the soil.

Insights into the Design of Inhibitors of the Urease Enzyme - A Major Target for the Treatment of Helicobacter pylori Infections

Expressed by a variety of plants, fungi and bacteria, the urease enzyme is directly associated with the virulence factor of many bacteria, including Helicobacter pylori, a gram-negative bacterium related to several gastrointestinal diseases and responsible for one of the most frequent bacterial infections throughout the world. The Helicobacter pylori Urease (HPU) is a nickel-dependent metalloenzyme expressed in response to the environmental stress caused by the acidic pH of the stomach. The enzyme promotes the increase of gastric pH through acid neutralization by the products of urea hydrolysis, then critically contributing to the colonization and pathogenesis of the microorganism. At the same time, standard treatments for Helicobacter pylori infections have limitations such as the increasing bacterial resistance to the antibiotics used in the clinical practice. As a strategy for the development of novel treatments, urease inhibitors have proved to be promising, with a wide range of chemical compounds, including natural, synthetic and semisynthetic products to be researched and potentially developed as new drugs. In this context, this review highlights the advances in the field of HPU inhibition, presenting and discussing the basis for the research of new molecules aiming at the identification of more efficient therapeutic entities.

Antiureolytic Activity of Substituted 2,5-Diaminobenzoquinones

A series of 2,5-bis(alkyl/arylamino)-1,4-benzoquinones (1-12) were investigated in vitro for their potential to inhibit the activity of jack bean urease. Compounds 1-6, 8, 9, 11 and 12 effectively inhibited the jack bean urease activity by 90.8 % when tested at 5 μm, whereas 7 and 10 had relatively little effect. The IC₅₀ for most compounds was in the nanomolar range (31.4 nm and 36.0 nm for 2 and 8, respectively). The mechanism of enzyme inhibition shown by 2 and 8 is typical of mixed-type inhibitors, whose affinity for the active site is over 6- and 2-fold higher (K_i =30.0 and 22.8 nm, for 2 and 8, respectively) than that of an allosteric site. Molecular docking studies revealed that both 2 and 8 establish hydrogen bonds with the amino acids residues Asp494, Met588, His593 and Ala636 in the active site of jack bean urease. These results indicate that such aminoquinones are useful leads for the development of more efficient urease inhibitors of wider utility.

Ionic liquid-assisted synthesis of dihydropyrimidin(thi)one Biginelli adducts and investigation of their mechanism of urease inhibition

Three out of twenty-six synthesized Biginelli adducts were identified as potent competitive urease inhibitors.

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.

In vitroinhibition ofHelicobacter pyloriand interaction studies of lichen natural products with jack bean urease

The interaction between lichen metabolites and jack bean urease was investigated by molecular spectroscopy at pH 7.4 and kinetics assay.

Design, syntheses and evaluation of benzoylthioureas as urease inhibitors of agricultural interest

Urea is one of the most used nitrogen fertilizers worldwide.