Structure-Based Discovery of Epigallocatechin Gallate and Withaferin A as Inhibitors of Clostridium difficile Toxin Pathogenesis

Clostridium difficile is a Gram-positive bacterium and a major global health concern due to its role in severe infectious diseases affecting humans and animals. Its prevalence in healthcare settings places a significant burden on healthcare systems worldwide. The primary virulence factors of C. difficile are the toxins TCDA and TCDB, which disrupt host cellular machinery and impair normal organ function. Despite ongoing efforts to develop effective therapeutic strategies, no universally successful treatment or preventive measure is currently available. This study focuses on identifying potential compounds to inhibit the production of TCDA and TCDB toxins, aiming to mitigate C. difficile infections. Using a combination of ADMET analysis, molecular docking, post-docking analysis, and molecular dynamics simulations, five candidate compounds were evaluated. Among them, Epigallocatechin Gallate (CID: 65064) and Withaferin A (CID: 265237) demonstrated the highest binding affinities, with docking scores of -8.9 kcal/mol and -9.2 kcal/mol, respectively. Post-docking MMGBSA analysis further validated their binding free energies as -64 kcal/mol and -54 kcal/mol. The interaction analysis revealed that Epigallocatechin Gallate binds with multiple key residues, including TYR283, ASP285, and ARG272, while Withaferin A interacts with residues such as VAL455, ARG462, and SER517. Both compounds exhibited favorable ADMET properties, confirming their safety profiles. Molecular dynamics simulations further assessed their stability under real-time conditions through analyses such as RMSD, RMSF, SASA, H-bonds, MMGBSA, and PCA. The findings suggest that Epigallocatechin Gallate and Withaferin A hold promise as potential inhibitors of C. difficile toxin production, paving the way for future therapeutic development