Paeonol eradicates biofilm in porcine-source Escherichia coli by targeting the quorum sensing system

Natural active compounds hold significant potential to overcome biofilm-mediated resistance, offering a promising therapeutic strategy for combating bacterial biofilms resistance. The present study was designed to investigate the efficacy of paeonol in eradicating biofilms formed by porcine-derived Escherichia coli (strain Ec032), and to elucidate the underlying mechanisms of paeonol eradicating Ec032 biofilm. The results indicated that treatment with paeonol at a concentration of 2,048 µg/mL for 3 h significantly reduced the number of viable bacteria in the mature biofilms of Ec032, resulting the highest biofilms eradication rate. RT-qPCR analysis suggested that paeonol might attenuate biofilms maturation by modulating the expression of quorum sensing (QS)-related and flagellum assembly-related genes. The Data Independent Acquisition (DIA) proteomic further revealed that paeonol treatment markedly inhibited flagellar motility and reduced the extracellular polysaccharide (EPS) content, leading to structural loosening of structure of the mature biofilms. Additionally, paeonol acted as a QS inhibitor (QSI), suppressing violacein in Chromobacterium violaceum 026 (CV026). Molecular docking analysis indicated that the outer membrane proteins regulator (OmpR) serve as a potential key target of paeonol. The research demonstrated that paeonol functions as an effective QSI, reducing biofilm biomass through downregulation of key QS and EPS matrix-associated genes and proteins, leading to effective eradication Ec032 biofilms. These findings provided a scientific foundation for the development of paeonol as a novel biofilm-disrupting agent and offer valuable insights for the treatment of E.coli biofilm-associated infections (BAI).