The quorum-sensing inhibiting effects of stilbenoids and their potential structure-activity relationship.

Stilbenoids, known an important phytoalexins in plants, were renowned for their beneficial effects on cardiovascular, neurological and hepatic systems. In the present study, quorum sensing inhibition activity of ten stilbenoids were tested using Chromobacterium violaceum CV026 as the bio-indicator strain and the structure-activity relationship was also investigated. Among them, resveratrol (1), piceatannol (2) and oxyresveratrol (3) showed potential anti-QS activities. At the sub-MIC concentrations, 1-3 demonstrated a statistically significant reduction of violacein in C. violaceum CV026 in a concentration dependent manner. Furthermore, the effects of 1-3 on QS regulated virulence factors in Pseudomonas aeruginosa PAO1 were also evaluated. Our results showed that the stilbenoids 1-3 can markedly decreased the production of pyocyanin and swarming motility of P. aeruginosa PAO1. Further transcriptome analyses showed that 1-3 suppressed the expression of QS-induced genes: lasR, lasI, rhlR and rhlI.