Chemotaxonomic value of magastigmane glucosides of Cichorium calvum.

Morphological characters and molecular analyses of Cichorium calvum and C. pumilum do not allow clear discrimination between these closely related wild species. Therefore, the aim of this study was to characterize the secondary metabolites of C. calvum and to select chemical markers which are unique to this species. From roots of C. calvum, ten sesquiterpene lactones were isolated, including seven lactucin-type guaianolides reported earlier from C. pumilum. Aerial parts also afforded secondary metabolites common to both species, along with the megastigmane glucosides staphylionoside D, saussureoside B and komaroveside A. This is the first report of the occurrence of these norisoprenoids in Cichorium species and the second record of their isolation from plants. Therefore, chemical discrimination of C. calvum is possible on the basis of its norisoprenoid composition.