Syntheses, structures, and inhibition studies of Jack bean urease by copper(II) complexes derived from a tridentate hydrazone ligand

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.

Dinuclear cobalt and nickel complexes of a mercaptoacetic acid substituted 1,2,4-triazole ligand: syntheses, structures and urease inhibitory studies

Because of its versatile coordination modes and strong coordination ability, the mercaptoacetic acid substituted 1,2,4-triazole 2-{[5-(pyridin-2-yl)-4H-1,2,4-triazol-3-yl]sulfanyl}acetic acid (H₂L) was synthesized and characterized. Treatment of H₂L with cobalt and nickel acetate afforded the dinuclear complexes {μ-3-[(carboxylatomethyl)sulfanyl]-5-(pyridin-2-yl)-4H-1,2,4-triazol-4-ido-κ²N¹,N⁵:N²,O}bis[aqua(methanol-κO)cobalt(II)] methanol disolvate, [Co₂(C₉H₆N₄O₂S)₂(CH₃OH)₂(H₂O)₂]·2CH₃OH (1), and {μ-3-[(carboxylatomethyl)sulfanyl]-5-(pyridin-2-yl)-4H-1,2,4-triazol-4-ido-κ²N¹,N⁵:N²,O}bis[diaquanickel(II)] methanol disolvate dihydrate, [Ni₂(C₉H₆N₄O₂S)₂(H₂O)₄]·2CH₃OH·2H₂O (2), respectively. Complex 1 crystallized in the monoclinic space group P2₁/c, while 2 crystallized in the tetragonal space group I4₁/a. Single-crystal X-ray diffraction studies revealed that H₂L is doubly deprotonated and acts as a tetradentate bridging ligand in complexes 1 and 2. For both of the obtained complexes, extensive hydrogen-bond interactions contribute to the formation of their three-dimensional supermolecular structures. Hirshfeld surface analysis was used to illustrate the intermolecular interactions. Additionally, the urease inhibitory activities of 1, 2 and H₂L were investigated against jack bean urease, where the two complexes revealed strong urease inhibition activities.

Synthesis, structure and bioactivity of Ni2+ and Cu2+ acylhydrazone complexes

Two acylhydrazone complexes, bis{6-methyl-N'-[1-(pyrazin-2-yl-κN¹)ethylidene]nicotinohydrazidato-κ²N',O}nickel(II), [Ni(C₁₃H₁₂N₅O)₂], (I), and di-μ-azido-κ⁴N¹:N¹-bis({6-methyl-N'-[1-(pyrazin-2-yl-κN¹)ethylidene]nicotinohydrazidato-κ²N',O}nickel(II)), [Cu₂(C₁₃H₁₂N₅O)₂(N₃)₂], (II), derived from 6-methyl-N'-[1-(pyrazin-2-yl)ethylidene]nicotinohydrazide (HL) and azide salts, have been synthesized. HL acts as an N,N',O-tridentate ligand in both complexes. Complex (I) crystallizes in the orthorhombic space group Pbcn and has a mononuclear structure, the azide co-ligand is not involved in crystallization and the Ni²⁺ centre lies in a distorted {N₄O₂} octahedral coordination environment. Complex (II) crystallizes in the triclinic space group P-1 and is a centrosymmetric binuclear complex with a crystallographically independent Cu²⁺ centre coordinating to three donor atoms from the deprotonated L^- ligand and to two N atoms belonging to two bridging azide anions. The two- and one-dimensional supramolecular structures are constructed by hydrogen-bonding interactions in (I) and (II), respectively. The in vitro urease inhibitory evaluation revealed that complex (II) showed a better inhibitory activity, with the IC₅₀ value being 1.32±0.4 µM. Both complexes can effectively bind to bovine serum albumin (BSA) by 1:1 binding, which was assessed via tryptophan emission-quenching measurements. The bioactivities of the two complexes towards jack bean urease were also studied by molecular docking. The effects of the metal ions and the coordination environments in the two complexes on in vitro urease inhibitory activity are preliminarily discussed.

Symmetrical Heterocyclic Cage Skeleton: Synthesis, Urease Inhibition Activity, Kinetic Mechanistic Insight, and Molecular Docking Analyses

The present study focuses on the design and synthesis of a cage-like organic skeleton containing two triazole rings jointed via imine linkage. These molecules can act as urease inhibitors. The in-vitro urease inhibition screening results showed that the combination of the two triazole skeleton in the cage-like morphology exhibited comparable urease inhibition activity to that of the reference thiourea while the metallic complexation, especially with copper, nickel, and palladium, showed excellent activity results with IC50 values of 0.94 ± 0.13, 3.71 ± 0.61, and 7.64 ± 1.21 (3a⁻c), and 1.20 ± 0.52, 3.93 ± 0.45, and 12.87 ± 2.11 µM (4a⁻c). However, the rest of compounds among the targeted series exhibited a low to moderate enzyme inhibition potential. To better understand the compounds' underlying mechanisms of the inhibitory effect (3a and 4a) and their most active metal complexes (3b and 4b), we performed an enzymatic kinetic analysis using the Lineweaver⁻Burk plot in the presence of different concentrations of inhibitors to represent the non-competitive inhibition nature of the compounds, 3a, 4a, and 4b, while mixed type inhibition was represented by the compound, 3b. Moreover, molecular docking confirmed the binding interactive behavior of 3a within the active site of the target protein.

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.