Anti-virulence activity of dihydrocuminyl aldehyde and nisin against spoilage bacterium Pseudomonas aeruginosa XZ01

The aim of this study was to investigate the anti-virulence potential and mechanism of Perilla frutescens-derived dihydrocuminyl aldehyde (DCA) against the spoilage bacterium Pseudomonas aeruginosa XZ01 derived from rotten chicken meat using transcriptome sequencing and 1H NMR-based metabolomics. At concentrations ranging from 1 to 3 μL/mL, DCA notably reduced the production of protease, elastase, pyocyanin, and rhamnolipid. The synergistic effects of DCA and nisin on biofilm formation and their ability to disrupt the preformed biofilms of P. aeruginosa XZ01 were also investigated through scanning electron microscopy and confocal laser scanning microscopy. Mechanistically, the potential of DCA to down-regulate quorum sensing (QS)-related genes, boost membrane permeability, and suppress the efflux system and outer membrane porin facilitated the anti-virulence effects and increased susceptibility of biofilm cells to nisin. DCA treatment also induced energy metabolism disorder, inhibited antioxidant enzymes, and intensified oxidative stress, leading to protein metabolism and DNA synthesis disorder, and ultimately attenuated virulence and spoilage efficiency of P. aeruginosa XZ01. Our results indicate that DCA has the potential to function as an anti-virulence agent to defend against foodborne pathogens.