Essential oil of Thymus vulgaris L. and Rosmarinus officinalis L.: Gas chromatography-mass spectrometry analysis, cytotoxicity and antioxidant properties and antibacterial activities against foodborne pathogens

Abstract

The\ressential oil composition of Thymus vulgaris L. and Rosmarinus officinalis L.\rendemic to France were determined by GC and GC-MS. Oils were assessed for their\rcytotoxic, antioxidant and antimicrobial activity. 31 and 37 different\rcompounds were identified representing 99.64% and 99.38% of the thyme and\rrosemary oils respectively, where oxygenated monoterpenes constituted the\rmain chemical class. Thymol (41.33%) and 1.8-cineole (24.10%) were identified\ras the main constituents of T. vulgaris L. and R. officinalis L., respectively.\rEssential oils (EOs) of selected plant species were evaluated for their in\rvitro cytotoxicity against the human lung adenocarcinoma epithelial cell line\r(A549). Cytotoxicity was measured using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphynyltetra-zolium bromide] colorimetric assay. Dose-dependent studies revealed IC50 of\r8.50 ± 0.01 μg/mL and 10.50 ± 0.01 μg/mL after 72 h on the A549 cells for R.\rofficinalis L. and T. vulgaris L., respectively. Antioxidant activity was\rdetermined using a quantitative DPPH (1,1-diphenyl- 2-picryl hydrazyl) assay.\rThymus and rosemary EOs exhibited effective radical scavenging capacity with\r50% inhibitory concentration (IC50) of 437 ± 5.46 μg/mL and 189 ± 2.38 μg/mL\rrespectively and therefore acts as a natural antioxidant agent. The\rantimicrobial activity of these species has also been studied against several\rfoodborne pathogens and food isolated Salmonella spp. including S.\renteritidis of significant importance. According to the results, T. vulgaris\rL. showed higher bactericidal effect than those from R. officinalis L. These\rresults suggest that the essential oil from T. vulgaris L. and R. officinalis\rL. have potential to be used as a natural cytotoxic, antioxidant and antimicrobial\ragent in food processing.