Investigation of Anti-quorum sensing & Anti-biofilm activity of Derris trifoliata.

Conventional treatments for bacterial infections target bacterial viability, an approach that exerts a strong selective survival pressure on bacteria, leading to the development of multidrug resistant mutants. The number of multidrug resistant strains is increasing exponentially, far outpacing the development of new antibiotics. The conventional antibiotics are no longer the magic bullets they were once thought to be and there is an urgent need to develop new antibiotics and/or novel strategies that do not induce bacterial resistance. Bacteria employ a population-dependent cell-to-cell communication system known as quorum sensing (QS) to express various pathogenic traits such as virulence factor (pyocyanin) production and biofilm formation. Therefore, QS inhibition is a promising novel strategy to selectively control multidrug-resistant pathogenic bacteria, without exerting evolutionary pressures and development of resistance. This project focused on the extraction and evaluation of natural compounds from Derris trifoliata stem, a mangrove medicinal plant for possible anti-quorum sensing and antibiofilm activity. Inhibition of pyocyanin production and arresting of swarming motility of Pseudomonas aeruginosa bacterial strain were measured for evaluating the anti-QS activity. And the intensity of live bacterial cell (absorbance after resuspending) adhered to a solid surface (well of incubating plate for overnight) was measured in absence and presence of testing extracts for evaluating the anti-biofilm activity. For all the experiments, the ethyl acetate fraction of Derris trifoliate stem showed significant biofilm and anti-QS activity. This study indicates that this plant may be a good candidate for further studies to introduce promising new leads for the development of novel anti-QS and anti-biofilm based antimicrobial compounds.

• Research Project