Essential oil composition and antioxidant activity of Stachys sylvatica L. (Lamiaceae) from different wild populations in Kosovo.

Leaves and inflorescences of Stachys sylvatica L. (Lamiaceae) were collected from three different wild populations in Kosovo to study the natural variation of the chemical composition of essential oils, total flavonoids, total phenolics and the antioxidant activity. Essential oils were obtained by steam distillation and analysed by GC-FID and GC-MS, whereas total flavonoids, total phenolics and antioxidant activities were determined by spectrophotometric methods. Yields of essential oils ranged from 0.001% to 0.007% (v per dry weight). Twenty-eight volatile constituents were identified. The main constituents were α-pinene, β-pinene and germacrene-D. Total phenolics ranged from 39.3 to 70.8 mg g⁻¹ dry mass, whereas total flavonoid content ranged from 30.44 to 70.63 mg g⁻¹ dm. The antioxidant activity, as measured by the DPPH method, exhibited a rather high degree of activity ranging from 25.5% to 57.2%, whereas the FRAP antioxidant activity showed a lower variability and ranged from 93 to 133.4 mg g⁻¹ dm.