Evaluation of Antioxidant, Antibacterial, and Antifungal Properties of Satureja hortensis Essential Oil

Satureja is a genus belonging to the aromatic plants of Lamiaceae family. The genus Satureja L. (Lamiaceae) comprises more than 30 species of aromatic herbs and shrubs, widely distributed over the Mediterranean region. The genus is represented by 14 species in Iran of which, eight are endemic. Many species of the genus Satureja are reported to have aromatic and medicinal properties. The leaves, flowers, and stems of this plant are used as herbal tea and in treatment of various ailments in traditional medicine. The aim of this study was to investigate antimicrobial and antioxidant activity of essential oil (EO) of Satureja hortensis (Lamiaceae) that grows in Sabalan Mountain (Ardebil province, Iran). This EO was tested in vitro against two bacterial species by disk and agar well diffusion methods and against four bacterial species and three Candida strains by broth microdilution method. Total phenol, flavonoid, and free radical scavenging activity of EO were evaluated. Total phenolic content was determined by using Folin-Ciocalteu reagent (32.65 mg/g), which was presented as gallic acid equivalent in 1 g of sample. IC50 of EO and ascorbic acid in DPPH method were respectively 277.9 and 19.34 µg. Minimum inhibitory concentration of the EO of S. hortensis against Salmonella typhimurium, Listeria monocytogenes, Escherichia coli, and Bacillus cereus was respectively 2.5%, 2.5%, 5%, and 2.5%. The inhibition zone of EO in disk and agar well diffusion method showed that inhibitory zone on B. cereus was higher than that on S. typhimurium in both methods and B. cereus was more sensitive to EO. MIC to minimal fungicidal concentration (MFC) ratio of S. hortensis EO against Candida albicans, Candida parapsilosis, and Candida krusei in broth microdilution method were respectively 0.048%:0.048%, 0.024%:0.024%, and 0.012%:0.012%. The data of the study clearly indicated that the EO of S. hortensis has a strong antioxidant, antibacterial, and antifungal activity.