Antioxidative Properties of Thymus vulgaris Leaves: Comparison of Different Extracts and Essential Oil Chemotypes
- 26 July 2008
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of Agricultural and Food Chemistry
- Vol. 56 (16), 6897-6904
- https://doi.org/10.1021/jf800617g
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 ʼDeutscher Winterʼ 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 Fe3+ reduction (FRAP). Both extraction techniques used, in the water bath at 40 °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.Keywords
This publication has 24 references indexed in Scilit:
- Extraction of phenolics and essential oil from dried sage (Salvia officinalis) using ethanol–water mixturesFood Chemistry, 2007
- Murciano-Granadina goat feeding with aromatic plant by-products. Effect on the milk production and presence of polyphenols in „Al Vino“ Murciano goat cheesePlanta Medica, 2007
- Southern French thyme oils: chromatographic study of chemotypesJournal of the Science of Food and Agriculture, 2005
- RP-HPLC Analysis of the Phenolic Compounds of Plant Extracts. Investigation of Their Antioxidant Capacity and Antimicrobial ActivityJournal of Agricultural and Food Chemistry, 2005
- Characterisation of the antioxidant properties of de-odourised aqueous extracts from selected Lamiaceae herbsFood Chemistry, 2003
- Qualitative and Quantitative Variation in Monoterpene Co-Occurrence and Composition in the Essential Oil of Thymus vulgaris ChemotypesJournal of Chemical Ecology, 2003
- Isolation and Structure Elucidation of Radical Scavengers from Thymus vulgaris LeavesJournal of Natural Products, 2002
- Antioxidant Activity of Chemical Components from Sage (Salvia officinalis L.) and Thyme (Thymus vulgaris L.) Measured by the Oil Stability Index MethodJournal of Agricultural and Food Chemistry, 2002
- Antioxidant activity of selected essential oil components in two lipid model systemsFood Chemistry, 2000
- Antiperoxidative Components inThymus vulgarisPlanta Medica, 1996