Objective: Quorum sensing (QS) is a chemical communication mechanism that allows bacteria to produce intercellular signal molecules in a certain density. In this study, it was aimed to detect the inhibition effects of aromaterapeutic Rosa damascena Mill. (Rose) essential oil (AREO) against QS mechanism and biofilm production of human pathogenic microorganisms.

Method: In the study, minimum inhibition concentration (MIC) values of AREO were determined by the microdilution method. The QS inhibition effects of the AREO were determined in Chromobacterium violaceum ATCC 12472 by agar well diffusion and violacein pigment production. The biofilm formation, swarm and swim motilities of Pseudomonas aeruginosa PAO1 strain were also tested.

Results: The MIC values of AREO were found to be in the range of 0.0125-0.1% v/v. AREO (sub-MIC: 0.01% v/v) significantly decreased (98.04%±1.40, p<0.05) the violacein production. AREO (sub-MIC: 0.2% v/v) strongly inhibited biofilm formation in PAO1 (93.07%±1.90, p<0.05), and significantly (p<0.05) hindered the swarm (44.88%±0.54- 88.05%±0.67) and swim (47.60%±0.06-85.48%±0.10) motilies of PAO1 according to the concentration ranges (0.0125-0.2% v/v). Additionally, AREO significantly (p<0.05) inhibited the biofilm formation of gram- positive (32.15%±0.20-52.40%±1.30) and gram-negative (32.01%±1.65- 61.00%±0.84) acteria.

Conclusion: This study reveals the promising potential of AREO used as anti-microbial, anti-biofilm and anti-QS agents in the future. To the best of our knowledge, the biofilm inhibition effects of AREO in human pathogenic microorganisms have been studied in detail for the first time, and this work clearly reveals that the production and use of AREO is extremely necessary and important for Turkey. Therefore, the anti-QS and anti-biofilm activity research about natural compounds should be worked in detail.