Chemical composition and biological activity of essential oil from flowerheads of Centaurea polymorpha Lag. (Asteraceae) growing wild in Spain.

The volatile constituents of the flowerheads of Centaurea polymorpha Lag. were extracted by hydrodistillation and analysed by GC and GC-MS. 63 components, amounting to 91.6% of the oil, were identified. Waxes and sesquiterpenes were the most abundant components in the oil. a-Cedrene (3.9%), ß-cedrene (3.6%) and ß-curcumene (3.0%) were the most representative sesquiterpene hydrocarbons while caryophyllene oxide (2.6%) was the most abundant oxygen containing sesquiterpene. The study on the biological activity of the oils showed no significant activity.