Volatile constituents of Centaurea paniculata subsp. carueliana and C. rupestris s.l. (Asteraceae) from Mt. Ferrato (Tuscany, Italy)

The essential oil composition of two endemic species of Centaurea, collected on serpentine rocks on Mt. Ferrato (Tuscany, Italy), were investigated by GC and GC/MS. Several classes of compound were detected, of which sesquiterpenes, (representing the 25.6% of the total oil from C. paniculata and 74.5% from C. rupestris), alcohols (27.8% in C. paniculata and 4.3% in C. rupestris) and aldehydes (12.0% C. paniculata and 2.0% in C. rupestris) were the most abundant, followed by acids, monoterpenes, esters, ketones, hydrocarbons, diterpenes and miscellaneous. A series of unidentified compounds were also detected. Difference in qualitative and quantitative composition were evidenced and discusse