Purification, chemical characterization and evaluation of the antioxidant potential of carvacrol from <i>Thymus vulgaris</i>

This work focuses on the purification, chemical characterization and evaluation of the antioxidant activity of carvacrol in order to determine its contribution in the high antioxidant potential of Thymus vulgaris essential oil (TEO). Firstly, 68% of carvacrol was purified from TEO using chromatography on silica gel column and then chemically characterized using spectroscopic techniques (IR, MS and 1H and 13C NMR). In vitro, the antioxidant activity has been determined using DPPH, ABTS•+ and iron chelating assays. All assays proved the strong radical scavenging and reducing power of carvacrol. In vivo, antioxidant capacity towards stressed Saccharomyces cerevisiae cells was investigated by evaluating cell viability, antioxidant enzymes’ activity, the level of lipid peroxidation (LPO) as well as the activity of succinate dehydrogenase (SDH). Using carvacrol in a dose dependent manner (6.25-25 μg/mL), cell viability was outstandingly improved by 34.5-55% compared to stressed cells. Antioxidant enzymes (CAT, SOD, GR) activities were also brought back to values comparable to control cells along with lower LPO (0.81±0.07 nmol/mg) and SDH (1.15± 0.07 μmol/min/mg of protein) at 25 μg/mL. These findings suggest that the powerful antioxidant properties of TEO found in our previous study were mainly associated to its main component (carvacrol) that showed higher antioxidant activity compared to the other components. Therefore, carvacrol can be of a great use as a pharmacological agent against damages related to oxidative stress.</p

The chemical composition, in vitro, and in silico studies of Lavandula mairei essential oil

Lavandula mairei is an aromatic, and medicinal plant endemic to Morocco, mainly found in the southeastern region of the Kingdom, and used in traditional medicine for its many benefits. The purpose of the study was to identify the chemical composition of Lavandula mairei essential oil using Gas Chromatography - Tandem Mass Spectrometry, to evaluate the antimicrobial activity of the plant against bacterial strains (Staphylococcus aureus, Staphylococcus aureus MRSA, Enterococcus faecalis, Escherichia coli ATCC 25922, Escherichia coli ESBL, Klebsiella pneumoniae ATCC 700603), and two fungal strains (Aspergillus niger ATCC 10231, Candida albicans ATCC 16404) in order to measure the microbial growth inhibition zone diameter, and to determine the minimum inhibitory, bactericidal, and fungicidal concentration of the essential oil (MIC, MBC, and MFC). Concerning antioxidant activity, six assays (6DPPH, and 1ABTS Free Radical Scavenging Assay, Total Antioxidant Capacity, Hydroxyl Radical, Reducing Power, and β-Carotene Bleaching Inhibition) were performed to determine the antioxidant potential of the essential oil. For the in silico aspect, molecular docking studies were performed to explore the potential interactions of some compounds with five microbial targets (i) Dihydropteroate synthase (1AJ0), ii) The elongation factor EF-Tu (1OB2), iii) d-alanine ligase (2I80), iv) DNA gyrase (2XCT), v) The cytochrome P450 monooxygenase (5V5Z), and 2ADMET prediction analysis was completed on a compound designated as dehydroabietinol. Carvacrol was identified as the major compound (36.38%) by analysis of the chemical composition, E. coli ATCC 25922 (MIC = 1.87 mg/mL ± 0.00, MBC = 15.00 mg/mL ± 0.00), and Enterococcus faecalis (MIC = 0.23 mg/mL ± 0.00, MBC = 5.53 mg/mL ± 2.77) were the most sensitive to the antibacterial treatment, and Candida albicans was resistant to the essential oil. The highest antioxidant potential of the plant was observed in the β-carotene bleaching inhibition test (IC50 = 1.55 mg/mL ± 0.009 and 90 % of inhibition). In the in silico study, the compound dehydroabietinol provided relevant evidence for molecular docking, and this was confirmed by the ADMET prediction analysis. The results of the study were significant, and further experiments will be necessary to find out more about the biological properties of Lavandula mairei