Anti-quorum sensing activity of Boerhavia diffusa against Pseudomonas aeruginosa PAO1.

Quorum sensing (QS) is one of the key virulence factors in Pseudomonas aeruginosa and causes recalcitrant infections. Multi-drug resistance and biofilm formation seem to be regulated by cell-to-cell communication system through QS. Thus this study is aimed to assess the efficacy of ethanolic leaf extract of Boerhavia diffusa in acting against the QS-regulated virulence traits. Fresh leaves of B. diffusa were dried and the ethanolic crude extract was checked for antimicrobial and anti biofilm effect against P. aeruginosa. The active components and the biological structures were elucidated by GC-MS, HPLC and NMR analysis respectively. Further, computational analyses were also performed to assess the drug ligand interactions based on the docking scores and binding energy. The results suggested that the MIC concentration showed a significant effect in inhibiting the QS network circuit of P. aeruginosa. The docking results showed that leaf had bioactive compounds that exhibit strong binding affinity towards transcriptional activators of the QS circuit in P. aeruginosa, i.e., LasR, as compared to the natural ligands, 3-oxo-C12-HSL and C4-HSL. These results clearly depictthe efficacy of Boerhavia diffusa and its phytoconstituents as promising QS antagonist which can be further applied in the treatment strategies for the diseases caused by P. aeruginosa.