Thermal stability of the essential oils isolated from Tunisian<i>Thymus capitatus</i>Hoff. et Link.: Effect on the chemical composition and the antioxidant and antibacterial activities

Abstract

The chemical composition, the antioxidant and the antibacterial activities of essential oils, isolated from the aerial parts of Tunisian Thymus capitatus during the flowering phase, and stored in the dark during 37 days in the oven, at 60 °C were evaluated. Samples taken periodically were used to evaluate the chemical composition, the antioxidant and the antibacterial activities. With some fluctuations, carvacrol (68–74%) was the major component of the oil independent of the storage period. α-Terpinene and γ-terpinene decreased over time, whereas p -cymene increased in the same period. Despite the thirty-seven days of storage at 60 °C, T. capitatus essential oil still showed high antioxidant and stable antimicrobial activity.