Design, synthesis, and biological studies of the new cysteine-N-arylacetamide derivatives as a potent urease inhibitor

Inhibition of Helicobacter pylori urease is an effective method in the treatment of several gastrointestinal diseases in humans. This bacterium plays an important role in the pathogenesis of gastritis and peptic ulceration. Considering the presence of cysteine and N-arylacetamide derivatives in potent urease inhibitors, here, we designed hybrid derivatives of these pharmacophores. Therefore, cysteine-N-arylacetamide derivatives 5a-l were synthesized through simple nucleophilic reactions with good yield. In vitro urease inhibitory activity assay of these compounds demonstrated that all newly synthesized compounds exhibited high inhibitory activity (IC₅₀ values = 0.35-5.83 μM) when compared with standard drugs (thiourea: IC₅₀ = 21.1 ± 0.11 μM and hydroxyurea: IC₅₀ = 100.0 ± 0.01 μM). Representatively, compound 5e with IC₅₀ = 0.35 μM was 60 times more potent than strong urease inhibitor thiourea. Enzyme kinetic study of this compound revealed that compound 5e is a competitive urease inhibitor. Moreover, a docking study of compound 5e was performed to explore crucial interactions at the urease active site. This study revealed that compound 5e is capable to inhibit urease by interactions with two crucial residues at the active site: Ni and CME592. Furthermore, a molecular dynamics study confirmed the stability of the 5e-urease complex and Ni chelating properties of this compound. It should be considered that, in the following study, the focus was placed on jack bean urease instead of H. pylori urease, and this was acknowledged as a limitation.

Cysteine; Kinetic study; Molecular docking; Molecular dynamics; Urease inhibitor.