Kinetics and Computational Evaluation of Eugenol and Vanillic Acid on Inhibition of a Potential Enzyme of a Nosocomial Pathogen that Promotes Struvite Formation

Background: Struvite/infection stone is one of the major clinical burdens in urinary tract infections that is caused by the ureolytic behavior of pathogenic bacteria. Objective: The current strategy for treating infective stones is mostly antibiotic therapy, which ends in promoting resistance to the organisms. Hence in the present study, we investigated two phytocompounds, eugenol (an allyl-substituted guaiacol) and vanillic acid (a phenolic acid) that are found to be effective in inhibiting the urease enzyme of a nosocomial pathogen Proteus mirabilis. Methods: The enzyme was purified to apparent homogeneity and the kinetic parameters were studied in the presence and in the absence of eugenol and vanillic acid. Molecular docking and simulation were done to understand the level of protein-ligand interactions and the interacting residues. Results: Kinetic parameters obtained from the Michaelis-Menten plot show that both eugenol and vanillic acid exhibit non-competitive inhibition of urease enzyme in a dose-dependent manner. In silico studies showed that eugenol and vanillic acid have almost similar binding affinities to the regulatory pocket of the modeled protein. Dynamics and simulation results indicate that the interaction of ligands with the ARG373 residue of the protein provides a stable bound conformation. Conclusion: Overall, our results suggest that both the phytocompounds eugenol and vanillic acid have a potential application as a new therapy for the inhibition of urease enzyme that could possibly replace the complexions related to struvite stone formation.