Specialized metabolites from the aerial parts of Centaurea polyclada DC.

PubMed ID: 28738242The genus Centaurea L. (Asteraceae) is represented by 200 taxa in the flora of Turkey and several Centaurea species are used as herbal remedies against different conditions. Previous phytochemical investigations on this genus generally revealed the isolation of sesquiterpene lactones and flavonoid derivatives. In our continuous search on Centaurea genus, a phytochemical study was performed on Centaurea polyclada DC., an endemic of West Anatolia. Previously undescribed two sesquiterpene-amino acid conjugates, an elemane and an eudesmane derivative were isolated from the aerial parts of Centaurea polyclada, together with eight known compounds; two elemane derivatives, three flavonoids, a lignan, a phenolic glucoside and a phenylpropanoid glucoside. Structural elucidation of the compounds was based on spectroscopic evidence, including 1D and 2D NMR and high-resolution mass spectrometry, chemical degradation results and reference data comparison. Sesquiterpene-amino acid conjugates are representatives of an unusual group of sesquiterpenes, and elemane-amino acid conjugates are herein reported for the first time in nature. © 2017 Elsevier LtdFirat University Scientific Research Projects Management Unit: 12-ECZ-009The authors would like to thank Assoc. Prof. Serdar Gokhan Senol for authenticating the plant material, and Dr. Salih Gunnaz for all NMR measurements. This research project was supported by the Scientific Research Projects Directorate of Ege University (Project No: 12-ECZ-009). -