Antibiofilm formation and anti-adhesive (to HEp-2 cells) effects of rosemary water extract against some food-related pathogens

The present work aimed to determine the bioactive compounds in two rosemary water extracts (RWE1 and RWE2) and to assess their antimicrobial, anti-adhesive and antibiofilm potentials against the food-related Bacillus and Pseudomonas species at concentrations; 4, 8, 12, 16 and 20mgmL(-1). Phenolic compounds and isoflavones in the RWEs were determined using HPLC. The concentrations of most bioactive compounds of RWE1 (benzoic, ellagic, gallic and rosmarinic acids, daidzein and genistein) were higher than that of RWE2. The MIC90 of RWE1 and RWE2 against all tested bacteria was 12 and 16mgmL(-1), respectively. The anti-adhesive and antibiofilm doses were higher than MIC90. RWE1 and RWE2 showed potential reduction in the bacterial cell adhesion to HEp-2 cells - 17.5-64.7 and 12.2-52.9%, respectively. In conclusion, this study emphasises the effective use of RWE as a natural anti-adhesive and antibiofilm agent against Bacillus and Pseudomonas, without difficult extraction procedure.