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

Abstract

The essential oil composition of Thymus vulgaris L. and Rosmarinus officinalis L. endemic to France were determined by GC and GC-MS. Oils were assessed for their cytotoxic, antioxidant and antimicrobial activity. 31 and 37 different compounds were identified representing 99.64% and 99.38% of the thyme and rosemary oils respectively, where oxygenated monoterpenes constituted the main chemical class. Thymol (41.33%) and 1.8-cineole (24.10%) were identified as the main constituents of T. vulgaris L. and R. officinalis L., respectively. Essential oils (EOs) of selected plant species were evaluated for their in vitro cytotoxicity against the human lung adenocarcinoma epithelial cell line (A549). Cytotoxicity was measured using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphynyltetrazolium bromide] colorimetric assay. Dose-dependent studies revealed IC 50 of 8.50 ± 0.01 µg/mL and 10.50 ± 0.01 µg/mL after 72 h on the A549 cells for R. officinalis L. and T. vulgaris L., respectively. Antioxidant activity was determined using a quantitative DPPH (1,1-diphenyl-2-picryl hydrazyl) assay. Thymus and rosemary EOs exhibited effective radical scavenging capacity with 50% inhibitory concentration (IC 50 ) of 437 ± 5.46 µg/mL and 189 ± 2.38 µg/mL respectively and therefore acts as a natural antioxidant agent. The antimicrobial activity of these species has also been studied against several foodborne pathogens and food isolated Salmonella spp. including S. enteritidis of significant importance. According to the results, T. vulgaris L. showed higher bactericidal effect than those from R. officinalis L. These results suggest that the essential oil from T. vulgaris L. and R. officinalis L. have potential to be used as a natural cytotoxic, antioxidant and antimicrobial agent in food processing.

ANTIMICROBIAL AND ANTIOXIDANT PROPERTIES OF THYME (Thymus vulgaris L.), ROSEMARY (Rosmarinus officinalis L.) AND LAUREL (Lauris nobilis L.) ESSENTIAL OILS AND THEIR MIXTURES

“…The higher antimicrobial activity of TEO could be attributed to its thymol content, a monoterpene with a phenolic ring (Miladi et al, 2013). However, the main component of REO and LEO is 1,8-cineole belonging to the ethers group (Celikel and Kavas, 2008;Miladi et al, 2013). Similar to our findings, Abdollahzadeh et al (2014) showed that TEO oil had a higher antimicrobial activity than REO against L. monocytogenes (PTCC 1163).…”

“…1, in general E. coli O157:H7 was less sensitive to the inhibitory activity of TEO, REO and LEO and their mixtures than S. aureus and L. monocytogenes. Generally, Gram-positive bacteria are known to be more susceptible to the essential oils or antibacterial compounds than Gram-negative bacteria, which are in a good agreement with previous findings (Miladi et al, 2013;Mith et al, 2014). This resistance could be attributed to the structure of cellular walls of Gram-negative bacteria, mainly with regard to the presence of lipoproteins and lipopolysaccharides that form a barrier to restrict entry of hydrophobic compounds (Mith et al, 2014).…”

“…Diameters of the inhibition zones of essential oils S. Tural, S. Turhan and their mixtures vary according to their components (Abdullah et al, 2015) and bacteria strains (Lambert et al, 2001). The higher antimicrobial activity of TEO could be attributed to its thymol content, a monoterpene with a phenolic ring (Miladi et al, 2013). However, the main component of REO and LEO is 1,8-cineole belonging to the ethers group (Celikel and Kavas, 2008;Miladi et al, 2013).…”

Chemotypic Characterization and Biological Activity of Rosmarinus officinalis

“…In contrast, rosemary oil from cultivated plants from Mauritius did show tyrosinase inhibitory activity (median inhibitory concentration, IC 50 = 97 μg/mL) [101]. Rosemary oil was found to be relatively non-toxic to SK-OV-3, HO-8910, Bel-7402 (IC 50 ≥250 μg/mL) [102], MCF-7, LNCaP, and NIH-3T3 cells (IC 50 >180 μg/mL) [32], but active against A549 cells (IC 50 = 80 μg/mL) [103]. In summary, the enzyme inhibitory potential of rosemary oil is fairly low.…”

Phytochemical, antioxidant and antimicrobial parameters of essential oils and hydrosols of colombian Thyme and Rosemary obtained using two different steam distillation methods

“…Imelouane et al, 13 Hajlaoui et al, 14 Zaouali et al, 15 Miladi et al 16 The research of these authors was used to compare the results obtained in this study. HDs have not been researched as extensively as EOs and their use in industry is much less important in spite of their important indirect production.…”