Chemical composition of essential oil of Centaurea urvillei subsp. deinacantha and Centaurea pterocaula Trautv

Both Centaurea pterocaula Trautv. and Centaurea urvillei DC. are a type of cornflower. The aim of this study is to determine the chemical composition of essential oils of C. urvillei and C. pterocaula for food, cosmetics-health industry and medicinal uses. The plant parts of C. urvillei and C. pterocaula were collected at flowering stage from Urmia (Ghasemloo Valley) and Zanjan in 2010 and 2011. The plant parts including stem, leaf and inflorescence were dried in laboratory and crushed to particles. The essential oils were obtained by hydrodistillation and were analyzed by GC-FID and GC/MS. The essential oil yield of stem plus leaf and inflorescence of Centaurea pterocaula (w/w dried weight) were 0.06% and 0.09%, respectively. The major constituents of stem plus leaf and inflorescence essential oils were germacrene D (20.4% and 5.4%), thymol (10.6% and 3.8%), cyperene (3.5% and 11.5%), spathulenol (7.7% and 4.9%), caryophyllene oxide (6.8% and 13.4%) and E-caryophyllene (4.9% and 8.1%), respectively. The essential oil yield of stem plus leaf and inflorescence of Centaurea urvillei (w/w dried weight) were 0.023% and 0.065%, respectively. The major constituents of stem plus leaf oils were benzyl benzoate (38.7%), caryophyllene oxide (17.9%) and b-eudesmol (19.8%) and the major constituents of inflorescence oil were caryophyllene oxide (25.7%), spathulenol (14.8%) and eudesma-4(15)-7-dien-1-β-ol (21.0%).