Chemical composition, antioxidative‎, antibacterial‎‎, and time-kill activities of some selected plant essential oils against foodborne pathogenic and spoilage organisms

Abstract

Essential oils (EOs) have been utilized as a growth inhibitor of microorganisms. This study was aimed to recognize the composition, antioxidative‎, antibacterial‎‎‎‎‎‎‎‎, and time-kill activities of Origanum vulgare, Zataria multiflora, Syzygium aromaticum; and Cinnamomum verum EOs against Listeria monocytogenes, Escherichia coli O157:H7, Shewanella putrefaciens and Pseudomonas fluorescens. Gas chromatography-mass spectrometry was used to determine the chemical composition of EOs. Disc diffusion, minimum inhibitory concentration, minimum bactericidal concentration, and time-kill methods were used to determine the antibacterial ‎‎activity of EOs. The antioxidative ‎ activity of EOs were determined by 2, 20-diphenyl-1-picrylhydrazyl radical scavenging and ferric reducing antioxidative ‎ power methods. All EOs exhibited antibacterial ‎‎activity, however, Z. multiflora EO was the most effective followed by O. vulgare EO. The lowest antibacterial‎‎‎‎‎ activity was observed in C. verum EO. The most sensitive among tested bacteria to Z. multiflora and O. vulgare EOs was E. coli O157:H7 and to S. aromaticum; and C. verum EOs were S. putrefaciens and P. fluorescens, respectively. Z. multiflora and O. vulgare EOs were able to kill 85.00% and 80.00% of the E. coli O157: H7 and S. putrefaciens cells in 4 hr, respectively. The highest antioxidative ‎activity was observed in Z. multiflora EO. The tested EOs showed the highest antioxidative ‎activity at a concentration of 2.00 g L^-1. Ferric reducing antioxidant power value of Z. multiflora, O. vulgare, S. aromaticum and C. verum was 2.01 ± 0.03, 1.47 ± 0.04, 1.01 ± 0.03, and 0.66 ± 0.34, respectively. High concentrations of tested EOs showed a decrease in antioxidative ‎ activity.

Keywords: Antibacterial‎‎ activity; Antioxidative ‎ assay; Essential oil; Minimum bactericidal concentration; Minimum inhibitory concentration.

Fig. 1

A) Killing curves of Zataria multiflora essential oil (ZEO) against foodborne pathogenic and spoilage organisms indicated by the variation of optical density (590 nm) at 16 hr incubation time, B) Killing curves of Origanum vulgare essential oil (OEO) against foodborne pathogenic and spoilage organisms indicated by the variation of optical density (590 nm) at 16 hr incubation time

Fig. 2

The antioxidative ‎ capacity in the different concentrations of essential oils determined using the ferric reducing antioxidative ‎ power assay. BHT: Butylated hydroxytoluene; OEO: Origanum vulgare essential oil; ZEO: Zataria multiflora essential oil; SEO: Syzygium aromaticum essential oil; CEO: Cinnamomum verum essential oil