Inhibition of quorum sensing and biofilm in Pseudomonas aeruginosa by erythrinin B: Bioinformatic evidence for the LasR binding

Quorum sensing (QS)-regulated virulence factors and biofilm formation are major contributors to antimicrobial resistance in Pseudomonas aeruginosa . This highlights the urgent need for novel anti-virulence strategies that can disrupt these pathways and reduce such infections. The objective of this study was to evaluate the inhibitory potential of erythrinin B against QS-regulated virulence factors and biofilm formation in P. aeruginosa PAO1. Erythrinin B significantly suppressed pyocyanin (72.27%), pyoverdin (68.22%), protease (83.08%), and elastase (62.16%) production in a dose-dependent manner, while rhamnolipid inhibition was lesser (29.17%). Biofilm biomass was reduced by 73.02% at 300 μg/mL, corroborated by microscopy, which revealed diminished adherence and scattered planktonic cells. EPS (exopolysaccharides) and alginate levels were also markedly decreased, indicating disruption of biofilm matrix integrity. Molecular docking demonstrated that erythrinin B binds to LasR receptor (−11.7 kcal/mol), forming hydrogen bonds with Thr75, Tyr56, Tyr64, and Ser129, alongside hydrophobic and van der Waals contacts. MD simulations confirmed the stability of complex, with minor conformational changes compared to apo LasR. MM/GBSA analysis revealed favourable binding energy (−26.89 ± 2.04 kcal/mol), dominated by van der Waals interactions, with key contributions from Val76, Trp88, and Leu36. These findings indicate erythrinin B as potent QS inhibitor that attenuates virulence and biofilm formation in P. aeruginosa .