Enzyme-mediated biofilm inhibition of Hedychium venustum against Pseudomonas aeruginosa

Bacteria produces biofilm to protect itself from adverse conditions. These biofilms are made of exopolysaccharides which safeguards it from host immune system and make it resistant to antibiotics. This causes most of the infections in human body. The autoinducers help to maintain the bacterial community at a threshold, this density dependent process is called quorum sensing. In this study, biofilm quantification was performed by crystal violet assay. At 40 mg/mL concentration, the Hedychium venustum hydro-methanolic crude extract (6:4) inhibited 40% of Pseudomonas aeruginosa biofilm. In fluorescence microscopic analysis, the dead cells in red colour revealed that the cells in the biofilm were affected by the plant extract. The scanning electron micrographs displayed that the coupon surface of untreated sample was rough since there were irregularities due to bacterial metabolism, while the coupon surface of treated sample was smooth due to the prevention of attachment of bacteria to the surface. Significant amylolytic activity with 62.183 U total enzymatic activity have correlation with the biofilm inhibition property. This is the first report on amylolytic and anti-biofilm activity of rhizome extract of H. venustum against P. aeruginosa. Since biofilms contribute significantly to the development of antimicrobial resistance, there is a necessity of alternative antimicrobial compounds that can inhibit biofilm formation. After further studies, the extract can also be considered a natural anti-biofilm agent.