Thyme essential oils from Spain: Aromatic profile ascertained by GC–MS, and their antioxidant, anti-lipoxygenase and antimicrobial activities

Abstract

Six samples of red thyme (Thymus zygis) and two samples of winter thyme (Thymus hyemalis) essential oils (EOs) were obtained from plants cultivated in south-eastern Spain and extracted by steam distillation. Analysis by gas chromatography coupled with mass spectrometry detection provided the relative (%) and absolute (mM) concentrations. Thymol (30–54%), p-cymene (14–27%) and γ-terpinene (8–28%) were the most abundant components of T. zygis EO, while 1,8-Cineole (3–37%), p-cymene (1–29%), linalool (8–13%) and thymol (0–19%) were the most abundant components in the case of T. hyemalis EO. Enantioselective gas chromatography identified (−)-linalool, (−)-borneol and (+)-limonene as the main enantiomers. Several methods to evaluate antioxidant capacities were applied to the EOs, concluding that their activities were mainly due to thymol and linalool. The inhibition of lipoxygenase activity, mainly due to thymol, p-cymene and linalool, suggested their possible use as anti-inflammatories. The high antibacterial and antifungal activities determined for the EOs means that they can be used as natural preservatives. The results support the potential use of Thymus sp. EOs as natural food, cosmetic and pharmaceutical ingredients.