Effect of Drought Stress on Essential Oil Composition of Thymus vulgaris L. (Chemotype 1, 8-cineole) from wild populations of Eastern Iberian Peninsula

[EN] 1,8-cineole defines a typical chemotype of Thymus vulgaris L. in Iberian Peninsula. This compound has a wide range of potentially useful bioactive properties. In order to study the influence of drought stress in the essential oil (EO) composition of this chemotype, sixty plants from six wild populations of Eastern Iberian Peninsula were distilled and analyzed by GC and GC/MS. The harvest dates (May and August) were selected in such a way that the typical summer drought in Mediterranean climates was the critical factor affecting EO composition. Despite the high intrapopulational variability, significant increases of 1,8-cineole were found after the drought period (21.8%-43.2%, in May, up to 42.6%-68.5% in August). On the other hand, individuals from one of the populations showed different profiles rich in linalool and camphor or sesquiterpenoid compounds, such as a-cadinol.Llorens Molina, JA.; Vacas González, S. (2016). Effect of Drought Stress on Essential Oil Composition of Thymus vulgaris L. (Chemotype 1, 8-cineole) from wild populations of Eastern Iberian Peninsula. Journal of Essential Oil Research. 29(2):145-155. doi:10.1080/10412905.2016.1211561S14515529

Comparative study of GC-MS characterization, antioxidant activity and hyaluronidase inhibition of different species of Lavandula and Thymus essential oils

The chemical compositions of essential oils of Lavandula angustifolia, Lavandula latifolia, Lavandula hybrida cultivar Grosso and cultivar Super, Thymus zygis with high proportions of thymol and linalool and Thymus hyemalis, from Murcia country (Spain), were studied in relative (%), absolute (mM) and chiral concentrations by GC/MS. Hyaluronidase inhibition and antioxidant activities of the essential oils were evaluated using ABTS(center dot+), DPPH center dot, ORAC, chelating power, hydroxyl radical, nitric oxide, TBARS and reducing power assays. Linalool and linalyl acetate were the most abundant components in the Lavandula genus whereas thymol, linalool and 1,8-cineole were the most abundant molecules in the respective Thymus species. Chiral determination of the main components showed (+)-enantiomers like terpinen-4-ol, beta-pinene, borneol and a-terpineol and (-)-enantiomers like linalool, linalyl acetate and camphene in Lavandula sp. In the case of Thymus sp. (+)-enantiomers like a-pinene, limonene, terpinen-4-ol and a-terpineol and (-)-enantiomers like borneol were found. Essential oils containing thymol were found especially powerful in all assays but chelating power, ORAC and hydroxyl radical scavenging assays. The capacity for inhibiting hyaluronidase showed that T. zygis with a high proportion of thymol was the most effective inhibitor. Essential oils containing thymol and linalool/linalyl acetate have a potential use as antioxidant agents. Thymol shows strong inhibition of hyaluronidase. Copyright (C) 2015 John Wiley & Sons, Ltd