Propolis Biomolecules Attenuates Virulence Factors of Multi-Drug Resistant Pseudomonas aeruginosa: In Vitro and In Silico Investigation

The perilous increase of Pseudomonas aeruginosa resistance and its great ability to produce several virulence factors is an emergent global health problem. Further investigation and docking study were further performed to predict the ideal identified compounds of propolis ethanolic extract with high affinity to interact with some selected virulence factors receptors. The results showed that propolis had a rich repertoire of polyphenols, cynarin, ellagic acid, and chrysin were detected as the major compounds. Furthermore, propolis ethanolic extract showed potent antioxidant activity. Minimal inhibitory concentrations values ranged from 2.5 to 10 mg/ml, representing a significant antibacterial activity against P. aeruginosa strains. Similarly, propolis ethanolic extract effectively inhibited the biofilm development of multi-drug resistant P. aeruginosa strains and completely decreased the expression of the quorum-sensing of the prototype bacterium Chromobacterium violaceum 12472. Furthermore, propolis ethanolic extract restricted P. aeruginosa swarming and pyoverdine secretion in a dose-dependent way. The virtual docking study showed that propolis ethanolic extract exerted a remarkable down-regulation of different virulence factors of multi-drug resistant P. aeruginosa. Overall, these findings indicate that propolis can be regarded as a promising virulence factors inhibitor that could be used as an alternate remedy for the treatment of severe P. aeruginosa infections.