Synthesis of thiosemicarbazone derivatives of thiophene-2-carboxylic acid as potent urease inhibitors: in vitro evaluation, molecular docking, and density functional theory analysis.
AIMS To synthesize and evaluate a series of thiosemicarbazone derivatives (2a-2g) incorporating thiophene-2-carboxylic acid as urease inhibitors. MATERIALS AND METHODS The compounds were synthesized and characterized using modern spectroscopic techniques. In vitro urease inhibition was determined followed by computational analysis including docking, density functional theory (DFT), molecular dynamics simulations (MD), normal mode analysis (NMA), and SwissADME profiling. Compounds 2g, 2d, and 2b emerged as potent inhibitors with IC50 values of 5.48 ± 0.18 to 9.44 ± 0.32 µM, outperforming the reference thiourea (IC50 = 22.13 ± 2.82 µM). Structure-Activity Relationship (SAR) analysis revealed that electron-withdrawing nitro substituents at para positions dramatically enhanced inhibitory potency. Docking investigation demonstrated robust interactions with the urease active site that includes binuclear nickel center and residues His492, His519, and Asp633. DFT calculations established strong correlations between chemical reactivity indices and biological activity. Molecular docking and MD simulations validated stable binding interactions with key residues (His492, His519, and Asp633). NMA revealed enhanced flap flexibility (λ1 = 1.39 × 10-6) and motional coupling upon 2g binding. CONCLUSION These results expose the synthesized compounds, especially 2g as a potent urease inhibitor and provide a valuable insight for future anti-urease drug development.