Antimicrobial and antibiofilm effects of total flavonoids from Potentilla kleiniana Wight et Arn on Pseudomonas aeruginosa and its potential application to stainless steel surfaces

Pseudomonas aeruginosa (P. aeruginosa) contamination poses challenges to the food industry. Total flavonoids of Potentilla Kleiniana Wight et Arn (TFP) are poorly understood for their antibiofilm effects against P. aeruginosa. Therefore, the inhibitory effects of TFP against planktonic cells were determined by agar diffusion, microtiter plate and time-kill curve assays. The mechanism of inhibition is evaluated by changes in membrane (potential, permeability and damage), cell motility and virulence factors production. Morphological changes were verified by transmission electron microscopy (TEM). A modified microtiter-plate assay determined its inhibitory effects against biofilm cells. The inhibitory mechanism was studied by changes in extracellular polymeric substances (EPS) and cell surface hydrophobicity. These inhibition effects were verified by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Finally, TFP was applied to stainless steel surfaces to evaluate its potential application in food production. TFP damaged P. aeruginosa cell membrane integrity, inhibited bacterial motility, virulence factors, surface hydrophobicity and colony counting on stainless steel. These results provide evidence for the utilization of TFP as a novel natural bioactive preservative in food processing.