Antibacterial Mechanisms of 4-Chlorobenzyl p-Coumarate: Inhibition of MepA and NorA Efflux Pumps

Introduction: Bacterial infections, especially those caused by multidrug-resistant strains, remain a major health concern. This study investigates 4-chlorobenzyl p-coumarate, assessing its antibacterial mechanism, pharmacokinetic profile, and potential to modulate antimicrobial resistance. Methods: In silico studies were conducted, including molecular docking, molecular dynamics simulations, and pharmacokinetic predictions, alongside in vitro assays assessing efflux pump inhibition, antibiotic modulation, and bacterial DNA analysis. Results: The compound showed higher binding affinity and complex stability with the enzyme phosphatidylglycerol phosphate synthase, while also exhibiting reduced residue fluctuations and better flexibility with the NAD+-dependent DNA ligase. Molecular interactions with the efflux proteins MepA and NorA were also observed. Pharmacokinetic predictions indicated a favorable profile, including suitability for oral administration. Experimentally, the compound inhibited the MepA and NorA efflux pumps, modulated the activity of the antibiotics ciprofloxacin and norfloxacin, and reduced DNA concentration in treated cells. Conclusions: The findings suggest that the compound acts through dual mechanisms, with a prediction of activity by disrupting phosphatidylglycerol synthesis and DNA replication while inhibiting and modulating MepA and NorA efflux pumps.