Seasonal Variation in Essential Oil Content, Chemical Composition and Antioxidant Activity of Teucrium polium L. Growing in Mascara (North West of Algeria)

Introduction: Phytochemicals are one wide class of nutraceuticals found in plants which act as antioxidants. In this research, the essential oil (EO) of Teucrium polium L., Lamiaceae, collected from Mascara province, situated in the Algerian northwestern, where their chemical composition varies according to geographical origin, season variation, and climatic conditions were studied. Materials and Methods: The extraction of EO was performed by hydrodistillation. Then, the chemical compounds were identified by gaz chromatography coupled to a mass spectrometer (GC–MS). In parallel, the antioxidant activity was evaluated using the DPPH test. Results: The yield of the EO of T. polium L. varied during different seasons with the highest in winter season, at vegetative stage (S1), while the same EO (S1) was significantly more efficient as an antioxidant than the EO harvasted at the flowering stage (S2) with IC50 values 3.90±0.05, 16.14±0.15 mg/mL, respectively (P < 0.001). These extracts are predominantly constituted by limonene (29.87%-26.39%), spathulenol (17.24%-13.29%), camphor (0.0%-8.20%), pinocarvone (7.76%-5.60%), tau-cadinol (5.41%-3.67%), pinene oxide (0.0%-4.78%), α-terpineol (0.0%-4.6%), 1-adamantanemethylamine (0.0%-9.80%) and β- myrcene (0.0%-4.02%). Conclusions: The results show that both EOs can be considered as potential sources of natural antioxidants. However, the vegetative stage was the best stage for harvesting the EO of T. polium L. which can be used as an alternative source of synthetic compounds.