Abstract:
The aim of this study is the isolation and identification of the physiologically active terpenic constituents of the plants Centaurea cuneifolia Sm. (Compositae) and Centaurea cheirolopha Wagenitz (Compositae). Former studies with Centaurea species have resulted in the identification of terpenoids as well as flavonoids and other natural compounds. Centaurea cuneifolia Sm. yielded two sesquiterpene lactones which have been identified on the basis of Infra Red and Nuclear Magnetic Resonance Spectra. The two sesquiterpene lactones identified are Dihydromelitensin and 8a-(3,4-dihydroxy-2-methylene butanoic acid) ester of Dihydromelitensin.Centaurea cheirolopha Wagenitz yielded four sesquiterpene lactones. Infra Red, Nuclear Magnetic Resonance, and Mass Spectra have been used in the identification of the four sesquiterpene lactones, namely Aguarin B, Cynaropicrin, 8a-(2,3-dihydroxy-2-methyl propanoic acid) ester of Zaluzanin-C and 15-deschloro-15-hydroxychlorojanerin. Eventhough 15-deschloro-15-hydroxychlorojanerin has been formerly isolated from other plant species, this is the first study where it has been isolated from Centaurea species. The structure of this sesquiterpene lactone has been identified on the basis of 13C NMR (Attached Proton Test-APT) in addition to the previous spectroscopic methods.
