Nanoemulsion of satureja sahendica bornm essential oil: antibacterial and antioxidant activities

This study was conducted to prepare a food-grade nanoemulsion of Satureja sahendica Bornm essential oil (SEO) and to investigate its physical (droplet size and polydispersity index and thermodynamic stability), antibacterial (paper disc diffusion, MIC and MBC) and antioxidant (DPPH and FRAP) properties. GC-MS analysis indicated that the main components of SEO were thymol (43.4%), p-cymene (31.2%) and γ-terpinene (14.1%). The average droplet size and polydispersity index of the SEO nanoemulsion were 473.2 nm and 0.182, respectively, and the nanoemulsion showed good stability for at least 14 days. The antibacterial properties against common foodborne pathogens (Staphylococcus aureus, Bacillus cereus, Shigella sonnei, Salmonella Typhi and Escherichia coli) showed that S. aureus was the most sensitive microorganisms to SEO nanoemulsion with an inhibition zone of 18.1 mm, MIC of 2.25 µg/mL and MBC of 3.50 µg/mL, while E. coli was the most resistant bacteria against SEO with an inhibition zone of 9.7 mm, MIC of 5.25 µg/mL and MBC of 7.75 µg/mL. Moreover, the inhibitory effects of SEO nanoemulsions against pathogens were significantly (P ≤ 0.05) higher than those of free SEO. It was also found that the SEO nanoemulsion showed higher antioxidant activity compared with free SEO. As a result, nanoemulsification enhanced SEO’s antibacterial and antioxidant activities, promoting its potential application in food and beverage fields.