Targeting Quorum Sensing-Mediated Virulence and Biofilm Formation in Pseudomonas aeruginosa Using Ferulic Acid

Background: Pseudomonas aeruginosa is a clinically significant opportunistic bacterium that exhibits intrinsic antimicrobial resistance, biofilm formation, and quorum-sensing-regulated virulence. Nowadays, plant-derived compounds are gaining attention as alternative agents for targeting bacterial virulence pathways. Objectives: This study aimed to determine the efficacy of Ferulic Acid (FA) against P. aeruginosa by antibacterial, anti-biofilm formation and anti-quorum sensing activity. Materials and Methods: Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) experiments were used to assess Anti-bacterial activity. Biofilm inhibition and metabolic activity were evaluated by using Crystal violet staining and an XTT reduction assay. Fluorescence microscopy was employed to assess bacterial viability, membrane integrity and intracellular Reactive Oxygen Species (ROS) generation. Quorum-sensing regulator lasR gene expression was analyzed by qPCR. Results: FA exhibited a concentration-dependent inhibition of bacterial growth and bactericidal activity at higher concentrations. A significant reduction was observed in biofilm biomass and metabolic activities, including fluorescence analysis, which revealed compromised membrane integrity and reduced cellular viability in treated cells. Elevated intracellular ROS generation suggested oxidative stress-mediated antibacterial activity. The lasR gene, a quorum-sensing regulator, showed downregulation, confirming interference with quorum-sensing-controlled virulence mechanisms. Conclusion: The findings demonstrate that FA exerts a multi-targeted antibacterial and anti-virulence effect against P. aeruginosa, demonstrating its potential as a naturally occurring phytochemical for the development of an alternative therapeutic approach for targeting resistant and biofilm-associated infections.