GC-MS composition and antiproliferative activity of Inula graveolens (L.) Desf. essential oil
The composition of the essential oil isolated from the aerial parts of Inula graveolens (L.), (Asteraceae) was determined by GC and GC-MS using two extraction methods, namely hydrodistillation and Solid Phase Micro-Extraction (SPME). Oxygenated monoterpenes had the highest contribution to the hydro-distilled essential oil content (87.32 %) with bornyl acetate being the main component detected in this fraction (70.58 %). Both oxygenated monoterpenes, borneol (11.36%) and bornyl acetate (58.30%) remained as the major constituents while camphene was detected as the major hydrocarbon monoterpene (16.58%) in the SPME extracted oil. The antiproliferative activity of the crude oil and of some pure volatile compounds was evaluated using two breast cancer cell lines (MCF7 and T47D) and compared to reference drugs. The IC50 values of reference drugs; cisplatin and doxorubicin were 7.3 ± 1. 9 μM and 0.16 ± 0.0 μM for MCF7 cells, 21.3 ± 9.7 μM and 0.2 ± 0.0 μM for T47D cells, respectively. Caryophylline oxide was the main active compound of the volatile fraction with the IC values (μg/mL) for MCF7 cells and T47D cells, respectively (8.098 ± 0.71; 6.121 ± 0.818).This is the first time to investigate the essential oil composition of the aerial parts of I. graveolens using SPME. The findings of the present study demonstrated qualitative and quantitative variation in the composition of the essential oil between the two different extraction methods. The strong antiproliferative activity of caryophyllene oxide justifies the plants' use as an anticancer agent in the traditional medicine.