Synthesis, inhibitory activity and inhibitory mechanism studies of Schiff base Cu(II) complex as the fourth type urease inhibitors

Fabrication of multinuclear copper cluster-based coordination polymers as urease inhibitors

This study focused on the design and synthesis of two Cu-based coordination polymers, [Cu2(4-dpye)(5-HSIP)(μ3-O)(H2O)2]·3H2O (Cu-CP-1) and [Cu(4-dpye)0.5(BCA)2] (Cu-CP-2), where 4-dpye = N,N'-bis(4-pyridinecarboxamide)-1,2-ethane, 5-H3SIP = 5-sulfoisophthalic acid, and HBCA = benzoic acid, by using a hydrothermal method. Single-crystal X-ray diffraction (SCXRD) study revealed that by adding various auxiliary ligands, the architectures of the Cu-CPs could be altered, yielding two distinct multinuclear Cu clusters. Moreover, the Cu-CPs can be used as urease inhibitors (UIs). In vitro experiments showed that the Cu-CPs had good urease inhibition effects with IC50 values of 0.53 ± 0.01 μM for Cu-CP-1 and 1.44 ± 0.01 μM for Cu-CP-2 and 98.48% (Cu-CP-1) and 96.27% (Cu-CP-2) inhibition of urease was achieved at a concentration of 100 μM, respectively. Furthermore, the inhibition effect of the tetranuclear Cu-CP was better than that of the binuclear Cu-CP. To better understand the potential mechanism of inhibition of the two copper complexes, we performed kinetic analysis using Lineweaver-Burk (L-B) plots in the presence of different concentrations of urea and different concentrations of inhibitors, and both Cu-CP-1 and Cu-CP-2 showed a non-competitive mode of inhibition. In addition, molecular docking analysis showed that the Cu-CPs were able to enter well into the urease binding pocket, thus interacting with key amino acid residues of urease to different degrees. Both kinetic and molecular docking studies theoretically explain and demonstrate the inhibition effect of both Cu-CPs on urease activity in vitro, which is expected to provide reasonable guidance and effective strategies for the development of novel, efficient, stable and safe CP-based UIs.

An overview: metal-based inhibitors of urease

Urease is a kind of nickel-dependent metalloenzyme, which exists in the biological world widely, and can catalyse the hydrolysis of urea into ammonia and carbon dioxide to provide a nitrogen source for organisms. Urease has important uses in agriculture and medicine because it can catalyse the production of ammonia. Therefore, in this review, metal-based inhibitors of urease will be summarised according to different transition metal ions. Including the urease inhibition, structure-activity relationship, and molecular docking. Importantly, among these reviewed effective urease inhibitors, most of copper metal complexes exhibited stronger urease inhibition with IC50 values ranging from 0.46 μM to 41.1 μM. Significantly, the collected comprehensive information looks forward to providing rational guidance and effective strategies for the development of novel, potent, and safe metal-based urease inhibitors, which are better for practical applications in the future.

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.