Background and Objectives: Vibrio parahaemolyticus is the causative agent of gastroenteritis due to consumption of contaminated seafood. The aim of the present study was to determine the chemical composition of Essential Oils (EOs) of five plants (Artemisia absinthium, Zataria multiflora Boiss., Pulicaria gnaphalodes, Trachyspermum ammi and Cuminum cyminum) and to evaluate their antimicrobial activity against pathogenic and non-pathogenic V. parahaemolyticus.

Materials and Methods: The EOs were analyzed by gas chromatography mass spectrometry. The detection of inhibitory effect of the EOs on the tested bacteria was carried out by agar disc-diffusion method and then MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) of the EOs against both bacteria were determined.

Results: The analysis of the components of the EOs by gas chromatography mass spectrometry allowed the identification of 76 compounds. Of the five tested EOs, four oils exhibited an antimicrobial effect against both strains of V. parahaemolyticus. In all EOs tested, Pathogenic V. parahaemolyticus showed more sensitivity than non-pathogenic V. parahaemolyticus. The strongest EO against pathogenic V. parahaemolyticus were T. ammi with 63.42% thymol and C. cyminum with 29.02% cuminaldehyde and 20.70% α-terpinene-7-al, equally (31 mm inhibition zone). Non-pathogenic V. parahaemolyticus showed the most sensitivity against Z. multiflora Boiss. EO with 73.64% carvacrol (27 mm inhibition zone and the lowest MIC (0.025%) and MBC (0.05%)). Despite the large amount of thujone, A. absinthium EO in this study did not show antibacterial activity in disk diffusion assay, MIC or MBC values.

Conclusions: The results of this study suggest that Z. multiflora Boiss. and T. ammi have strong antimicrobial activity against both pathogenic and non-pathogenic V. parahaemolyticus.