Abstract
The essential oils of Centaurea sicana (S) and C. giardinae (G) were studied by GC and GC-MS. Thirty constituents for S, representing 81.5% of the total oil, and 24 compounds for G (94.2% of the total) were identified. The oils were rich in sesquiterpenoids (47.9% for S and 54.7% for G) and hydrocarbons (25.9% for S and 31.7% for G). Germacrene D (13.3%), (E)-β-farnesene (8.3%), nonacosane (7.3%), heptacosane (6.5%) and phytol (6%) were recognized as the main constituents for S, while caryophyllene oxide (17.7%), nonacosane (14.5%), germacrene D (11.5%), caryophyllene (11.2%) and heptacosane (10.3%) were the main compounds for G.
