Essential oil composition of Senecio graciliflorus DC: comparative analysis of different parts and evaluation of antioxidant and cytotoxic activities.

The essential oil of different parts of Senecio graciliflorus DC was obtained by hydrodistillation and analysed by GC-FID and GC-MS for the first time. A total of 17, 20, 19 and 17 constituents were identified comprising 99.90, 95.50, 98.93 and 95.96% of the essential oil of flower, leaf, stem and root parts of Senecio graciliflorus respectively. Monoterpene hydrocarbons predominated in the essential oil with 85.28% in flower, 57.53% in leaf, 67.74% in stem and 64.98% in root oil. α-pinene, cis-ocimene, 1,2,3-trimethylcyclohexane and β-pinene were the major constituents of the essential oil. The flower essential oil exhibited a strong antioxidant potential displaying IC50 values of 21.6±0.6 and 26.0±1.0μg/ml in DPPH and hydroxyl radical assays respectively. On the other hand the essential oil of flower and root displayed highest cytotoxicity against lung (A-549) cancer cell lines (IC50=19.1±0.9 and 21.3±1.1μg/ml respectively. This study which represents the first report of the essential oil composition and bioevaluation of Senecio graciliflorus, can serve as a new source of cytotoxic and antioxidant activity.