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Guaianolides from Crepis dioscoridis L.
The genus Crepis L. is well known for its abundance in sesquiterpene lactones, the majority of which belong to the costunolide type guaianolides . Due to the pharmacological and chemosystematic interest of these compounds, we investigated the chemical profile of C. dioscoridis L. collected in W. Greece. Air-dried and macerated aerial parts were extracted with a mixture of cyclohexane, diethyl ether and methanol (1:1:1). The extract was concentrated in vacuo and fractioned by V.L.C. followed by repeated CC on silicagel using mixtures of DM:MeOH of increasing polarity. The fractions were monitored by TLC and 1H-NMR. 8-Epigrosheimin and 11βH-11,13-dihydrointegrifolin  were yielded by RP18-HPLC (MeOH:H2O 3:2), while three costus type and two hieracin type glucosides were isolated by RP18-HPLC (MeOH:H2O 9:11). The structures of the isolated compounds were elucidated by high-field NMR spectroscopy (1H-NMR, 1H-1H COSY, NOESY, HSQC and HMBC).
Acknowledgements: The authors wish to thank Assistant Prof. Th. Constantinidis (Lab. of Systematic Botany, Faculty of Biology) for the identification of the plant material
References: 1. Zidorn C. (2008) Phytochemistry 69:2270–96.
2. Kisiel W. et al. (2000) Phytochemistry. 54:763–6.