Essential oil of <i>Satureja montana</i> as a multifunctional agent: Insights into antioxidant activity, antibacterial properties, cancer cell cytotoxicity, and cell cycle effects

In this study, the antibacterial, antioxidant, and anticancer effects of essential oil extracted from the aromatic plant species Satureja montana from Montenegro were examined. Chemical characterization of S. montana essential oil (SMEO) was performed using GC-MS. The antibacterial activity was assessed using the microdilution method and antioxidant activity was measured using DPPH and FRAP assays. Cytotoxicity was examined in cancer cell lines and normal fibroblasts using the MTT assay. Flow cytometry was used to examine cell cycle, cell death, and cytoprotective effects. The effects on gene and miRNA expression were investigated using RT-qPCR. Oxygenated monoterpenes and monoterpane hydrocarbons were the most abundant in SMEO, with p-cymene (28.65%), thymol (22.1%), linalool (4.86%), trans-caryophyllene (4.52%), and carvacrol (3.28%) as the major compounds. SMEO had inhibitory effect on growth of 6 bacterial strains, with MIC values ranging from 0.78 μL/mL to 12.5 μL/mL. SMEO showed antioxidative activity with an EC50 value of 3.44 μL/mL. Strong cytotoxic activity of SMEO was observed against cervical adenocarcinoma HeLa, malignant melanoma A375, colorectal adenocarcinoma LS 174T, and lung carcinoma A549 cells (IC50 from 0.12 to 0.18 μL/mL). Treatment with SMEO triggered apoptosis in HeLa cells, decreased MMP2 gene expression levels, and increased the expression of tumor-suppressive miR-16 and miR-34a. SMEO decreased the levels of reactive oxygen species in normal fibroblasts MRC-5. Numerous beneficial biological properties, including antibacterial, antioxidant, and cytoprotective effects, in addition to the strong cytotoxicity, proapoptotic, and anti-invasive effects of SMEO, suggest its prospective role in the treatment of different human diseases, including cancer.