Abstract
Pseudomonas aeruginosa often causes various acute and chronic infections in humans exploiting biofilm. Molecules interfering with microbial biofilm formation could be explored for the sustainable management of infections linked to biofilm. Towards this direction, the antimicrobial and antibiofilm activity of cuminaldehyde, an active ingredient of the essential oil of Cuminum cyminum was tested against Pseudomonas aeruginosa. In this regard, the minimum inhibitory concentration (MIC) of cuminaldehyde was found to be 150 μg/mL against the test organism. Experiments such as crystal violet assay, estimation of total biofilm protein, fluorescence microscopy and measurement of extracellular polymeric substances (EPS) indicated that the sub-MIC doses (up to 60 µg/mL) of cuminaldehyde demonstrated considerable antibiofilm activity without showing any antimicrobial activity to the test organism. Moreover, cuminaldehyde treatment resulted in substantial accumulation of cellular reactive oxygen species (ROS) that led to the inhibition of microbial biofilm formation. To this end, the exposure of ascorbic acid was found to restore the biofilm-forming ability of the cuminaldehyde-treated cells. Besides, a noticeable reduction in proteolytic activity was also observed when the organism was treated with cuminaldehyde. Taken together, the results demonstrated that cuminaldehyde could be used as a promising molecule to inhibit the biofilm formation of Pseudomonas aeruginosa.