Antioxidative Properties of Thymus vulgaris Leaves: Comparison of Different Extracts and Essential Oil Chemotypes

Abstract

Thyme (Thymus vulgaris L., Lamiaceae) is a subshrub from the Lamiaceae family with plants that are rich in essential oils and antioxidative phenolic substances. Twelve accessions originating from southern France and the variety 'Deutscher Winter' were grown in an experimental field in eastern Austria. Leaf samples from these plants as well as from a commercial thyme rich in thymol were analyzed for their essential oil and the antioxidative potential in various extracts. The assays for antioxidative activity were the total phenolics according to the Folin-Ciocalteu method, DPPH decoloration, and Fe(3+) reduction (FRAP). Both extraction techniques used, in the water bath at 40 degrees C and in the ultrasonic bath at room temperature, proved to be efficient. The best results were obtained with 60% ethanol as extractant. In the comparison of the different accessions the less active and the most active of these extracts differed by factors of 2.1 and 2.6 in the total phenolics and FRAP assay, respectively, and by factors 1.5-2.0 in the DPPH assay. Rosmarinic acid accounted for 22-55% of the antioxidant activity in the ethanolic extracts. Essential oils with high proportions of the phenolic components thymol and/or carvacrol showed the highest antioxidant activity. Ethanolic extracts from the residues after distillation were considerably lower in antioxidant activity than the respective extracts from the dried leaves. Extracts with CH2Cl2 in the ultrasonic bath contained volatiles in proportions close to the essential oil but displayed very low antioxidant activity.

Antimicrobial, Antioxidant, and Anti-Inflammatory Activities of Essential Oils from Five Selected Herbs

“…Although the IC 50 value of the T. vulgaris essential oil was greater than that of -tocopherol (the positive control), the T. vulgaris essential oil might prove an effective antioxidant in many applications. The antioxidant activities of the T. vulgaris essential oil were similar to those determined in previous studies, 28,29) but the antioxidant activities of the L. anagallis and P. fragrans essential oils are described for the first time here.…”

“…This correlates with the antioxidant activities of the T. vulgaris essential oil, because essential oils with elevated proportions of thymol and carvacrol exhibit upregulated antioxidant activities. 28) Also, previous research has indicated that carvacrol in thyme oils suppresses the LPS-induced expression of cyclooxygenase-2 (COX-2) mRNA and protein, which can cause repression of inflammation. 34) Thus, the T. vulgaris essential oil (which consists of 2.03% carvacrol) exhibited a significant anti-inflammatory activity in this study.…”

Antioxidant and Antiproliferative Properties of the Essential Oils of Satureja thymbra and Satureja parnassica and their Major Constituents

“…Finally, in a study where different extracts and essential oil chemotypes of Thymus vulgaris were screened, the highest activity was shown by the oils that were abundant in thymol (22).…”

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

“…Regarding Rosmarinus officinalis EOs (Lamiaceae family), it has been previously reported variations in the chemical composition and biological activity of plants growing in different countries [8,20]. This oil was rich in phenolic acids such as rosmarinic acid and carnosic acid with strong antioxidant properties, it has been proposed to be used as preservation for certain foods and nutraceutical products to avoid synthetic antioxidants [21]. However, data regarding this activity of essential oils of thyme and rosemary are not abundant and the methods for determination are different [22,23].…”