Cajaninstilbene acid analogues as novel quorum sensing and biofilm inhibitors of Pseudomonas aeruginosa.

Biofilm formation and virulence factor secretion in opportunistic pathogen Pseudomonas aeruginosa are essential for establishment of chronic and recurrent infection, which are regulated by quorum sensing (QS) system. In this study, a set of cajaninstilbene acid analogues were designed and synthesized, and their abilities to inhibit QS and biofilm formation were investigated. Among all the compounds, compounds 3g, 3m and 3o showed potent anti-biofilm activity, especially 3o exhibited promising biofilm inhibitory activity with biofilm inhibition ratio of 49.50 ± 1.35% at 50 μM. Three lacZ reporter strains were constructed to identify the effects of compound 3o on different QS systems. Compound 3o showed the suppression on the expression of lasB-lacZ and pqsA-lacZ as well as on the production of their corresponding virulence factors. Therefore, compound 3o is expected to be generated as a lead compound with inhibition of biofilm formation and QS of Pseudomonas aeruginosa.