Four New Steroidal Saponins from the Rhizomes of Helleborus orientalis

A phytochemical analysis has been carried out on the glycoside-enriched fraction of a MeOH extract of Helleborus orientalis rhizomes, resulting in the isolation of two new bisdesmosidic furostanol saponins (1 and 2) and two new furospirostanol saponins (3 and 4).The structures of 1-4 were determined on the basis of extensive spectroscopic analysis and acid hydrolysis followed by chromatographic and spectroscopic analysis.Compound (3) showed moderate cytotoxic activity against HSC-2 human squamous cell carcinoma cells with an IC 50 value of 16 µg/mL. INTROCUCTIONHelleborus orientalis, known by the name 'Lenten Rose' in Europe, is a perennial plant belonging to the family Ranunculaceae and is indigenous to Greece and Turkey. 1 Its rhizomes are known to contain several bufadienolide glycosides and were used as a cardiotonic agent. 2 Plants containing cardiac glycosides such as Digitalis purpurea 3 and Convallaria majalis 4 concomitantly produce steroidal glycosides.We have now made a phytochemical screening of the glycoside-enriched fraction prepared from a MeOH extract of the rhizomes of H. orientalis and isolated two new bisdesmosidic furostanol saponins (1 and 2) and two new furospirostanol saponins (3 and 4).This paper reports the structural elucidation of the new compounds on the basis of extensive spectroscopic analysis and acid hydrolysis followed by chromatographic and spectroscopic analysis.The cytotoxic activity of the isolated compounds against HSC-2 human squamous cell carcinoma cells is briefly described.