Steroidal saponins from the bulbs of Allium karataviense

Chemical examination of the bulbs of Allium karataviense led to the isolation of five new spirostanol saponins (7-11) and a new furostanol saponin (12), together with a known steroidal sapogenin (1) and five known saponins (2-6). The structures of the new saponins were determined by detailed analysis of their spectral data, including two-dimensional NMR spectroscopy. The steroidal saponins produced by A. karataviense, except for 5 and 6, were found to be based upon (25R)-5 alpha-spirostane-2 alpha,3 beta,5,6 beta-tetrol (alliogenin) and contain a beta-D-glucopyranosyl moiety with the formation of an O-glycoside linkage to C-2 of the polyhydroxylated steroidal skeleton as the common structural feature. The isolated compounds were evaluated for cytostatic activity against human promyelocytic leukemia HL-60 cells.