Antimicrobial effects of thymus vulgaris, cinnamomum zeylanicum and zingiber officinale essential oils on salmonella enterica serovar enteritidis infections

Abstract

Salmonella enterica serovar Enteritidis infections are among the leading causes of human foodborne illness mainly due to the consumption of contaminated poultry meat and eggs. Therefore, the aim of this study was to investigate the antimicrobial effects of essential oils (EOs) derived from Thymus vulgaris (thyme), Cinnamomum zeylanicum (cinnamon) and Zingiber officinale (ginger) on these infections. These EOs were added to Salmonella enterica ser. Enteritidis cultures in 96-well microplates in a sealed pouch and incubated at 37°C for 24 h minimum inhibitory concentration was measured to determine their antimicrobial effects. Ciprofloxacin (1 mg/mL) added to the culture medium served as the positive control to test the antibacterial effect. In this in vitro cell culture study, the cytotoxic effects of all EOs on healthy fibroblasts were investigated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide cell viability test. Cinnamon EO showed antibacterial effects at all concentrations, whereas ginger EO was effective only in combination with thyme EO at 50% concentration. Further, thyme EO was found to be bactericidal at 50% concentration and bacteriostatic at 25% concentration. None of the EOs were cytotoxic to fibroblasts. In conclusion, cinnamon EO is highly effective and safe for the treatment of Salmonella enterica ser. Enteritidis infections, followed by thyme EO.