Corchorus olitorius aqueous extract attenuates quorum sensing-regulated virulence factor production and biofilm formation

Objective: To investigate the effect of Corchorus olitorius aqueous fraction (COAF) on quorum sensing (QS)-regulated virulence factors and biofilm formation in Pseudomonas aeruginosa (PAO1). Methods: The preliminary screening of the anti-QS effect of COAF was performed by evaluating the anti-pathogenic activity against Chromobacterium violaceum CV026 biosensor strain. Next, the inhibitory effects of COAF on QS-regulated pyocyanin production, proteolytic and elastolytic activities, swarming motility, and biofilm formation were evaluated in PAO1. Results: The results showed that the treatment of COAF significantly decreased the biofilm biomass, attenuated virulence factors, and inhibited swarming motility of PAO1 without affecting the growth of the bacteria in a dose-dependent manner. COAF at 2 000 μg/mL significantly decreased Las B elastase activity in PAO1 culture, exopolysaccharide production, swarming motility, pyocyanin level, and biomass of PAO1 by 55% (P<0.05), 60% (P<0.01), 61% (P<0.01), 65%(P<0.01) and 73% (P<0.01), respectively. In addition, the production of violacein was decreased by 62% (P<0.01) with the treatment of a high dose of COAF. Conclusions: These findings indicate that COAF can be a potential source of anti-QS agents.