The antibiofilm activity of Murraya koenigii essential oil (EO) against Pseudomonas aeruginosa PAO1 was investigated in this study. A decrease in the production of rhamnolipid, extracellular polymeric substance and swarming motility was observed by the EO treatment (0.3% v/v). The static microtitre plate assay revealed 80% reduction in biofilm formation by P. aeruginosa PAO1 on M. koenigii EO treatment. Fluorescence microscopy and scanning electron microscopy analyses confirmed the reduction of biofilm formation in P. aeruginosa PAO1 when treated with M. koenigii EO. Gas chromatography-mass spectrometry analysis of the EO revealed the presence of well-known antibiofilm agents such as spathulenol (5.85%), cinnamaldehyde (0.37%) and linalool (0.04%). Cinnamaldehyde has not been previously reported in M. koenigii EO. The potent antibiofilm properties of M. koenigii EO may be effectively exploited in food and pharmaceutical industries as well as in controlling Pseudomonas biofilms on indwelling medical devices.
Keywords: Murraya koenigii essential oil; Pseudomonas aeruginosa PAO1; antibiofilm; rhamnolipid; swarming motility.