Antivirulence potential of morin hydrate against Pseudomonas aeruginosa: Inhibition of biofilm formation, quorum sensing, and virulence gene expression

Document Type : Original Article

Author

Department of Medical Laboratory Sciences, Mutah University, Mutah, Karak, Jordan.

10.21608/mb.2025.383488.1314

Abstract

Conventional antibiotics are ineffective in treating infections caused by biofilm-forming pathogens because of the protection offered by biofilm and virulence controlled by the quorum sensing (QS) system. This research was conducted to investigate the antibiofilm, anti-QS, and antivirulence potential of morin using a combination of phenotypic and genotypic assays. The pathogenic strain of Pseudomonas aeruginosa was isolated, and subsequently treated with morin. The effect of morin on additional characteristics of the pathogen, such as exopolysaccharide (EPS), hydrophobicity, aggregation, and swarming, was also investigated, as these characteristics play a role in biofilm formation. The virulence factors such as proteases, rhamnolipids and pyocyanin were also examined. Anti-QS activity was examined by evaluating Acyl Homoserein Lactone (AHL) and violacein generation utilizing Chromobacterium violaceum. RT-PCR was conducted to analyze QS genes. As per the results, inhibition of biofilm by morin (0.11-0.004 mg/mL) was dose-dependent, with minimal effect on the viability of cells. EPS, hydrophobicity, aggregation and swarm motility were also negatively affected by morin. In addition to these effects, morin caused inhibition of virulence factors produced by the bacteria, leading to a 40% inhibition of Las A protease and up to 50% inhibition in pyocyanin. More than 60% inhibition of AHL and violacein production by 0.11mg/mL showed that morin also impairs the QS system. The experiments complemented this finding by revealing the downregulation of rhlR and rhlI genes. Morin can be utilized as an antivirulence resistance-sparing therapeutic agent against biofilm-forming pathogens.

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