Exploring the phytochemical composition of Crepis heldreichiana (Kuntze) Greuter: A unique endemic species of Greece

Within the genus Crepis of the Asteraceae family (Cichorieae), Crepis heldreichiana (Kuntze) Greuter is recognized as a native plant in the Greek flora, with a distribution limited to the Taigetos and Parnonas mountains of the Peloponnese. Taking into consideration the restricted geographic range and the unexplored chemical profile of C. heldreichiana. This study was designed to unveil its phytochemical profile revealing 13 compounds, among which four are identified as sesquiterpene lactones, including a previously unreported one, as well as an apocaroteonoid, while the remaining are primarily phenolic derivatives. Various spectrometric and spectroscopic techniques were employed to elucidate the structures of the isolated compounds. The relative configurations of the compounds were established through analysis of NMR spectroscopic and HRESIMS spectrometric data, complemented by CD spectroscopic measurements.