Essential oils of 11 commercial Lamiaceae species cultivated in Serbia: chemical composition, antioxidant and antidiabetic activities

Lamiaceae is one of the largest families of flowering plants encompassing more than 7,200 species. Subfamily Nepetoideae is especially rich in aromatic plants that are highly valuated in traditional medicine and cookery, possessing a broad range of biological activities. The aim of this research was to examine the chemical composition, antioxidant and antidiabetic activities of the essential oils of 11 selected Lamiaceae species commercially grown on the fields of the Institute for Medicinal Plant Research „Dr Josif Pančić“: Hyssopus officinalis, Lavandula angustifolia, Mentha x piperita, Ocimum basilicum, Origanum heracleoticum, Origanum vulgare, Salvia officinalis, Satureja montana, Thymus serpyllum and Thymus vulgaris. Essential oils were isolated by hydrodistillation and their chemical composition was analysed using GC-FID and GC-MS. Antioxidant activity was evaluated using total reducing power (TRP) assay, while antidiabetic activity was assessed in terms of inhibition of α-glucosidase. With the exception of O. vulgare, the oils of all analysed species predominantly contained oxygenated monoterpenes comprising up to 89.47% of the total oil. The most abundant components in the oils were linalool, cis-pinocamphone, isomenthol, germacrene D, camphor, 1,8-cineole, geraniol, bornyl-acetate and thymol. The strongest antioxidant activity showed the oil of Th. vulgaris, followed by Th. serpyllum (174.76 and 165.81 µmol AAE/g, respectively). The same species showed the most prominent inhibition of α-glucosidase (81.80% and 79.78%, respectively). These results indicate that bornyl-acetate and thymol as the major components of the most active oils should be considered as promising antioxidant and antidiabetic agents.