Secondary metabolites of three endemic Centaurea L. species

Abstract

The aerial parts of three endemic Centaurea L. species, namely C. tomorosii Micevski, C. soskae Hayek and C. galicicae Micevski, afforded sesquiterpene lactone cnicin (1) and seven flavonoids: apigenin (2), isokaempferide (3), hispidulin (4), eupatorin (5), cirsimaritin (6), santaflavone (7) and salvigenin (8). The structures of the isolated compounds were determined by UV, 1H NMR and 13C NMR spectroscopy and HR-ESI-MS spectrometry. 1H NMR spectroscopy was used as a method for quantitative analysis of sesquiterpene lactone cnicin.