Structure of steroidal saponins from underground parts of Allium nutans L.

Four steroidal glycosides including deltoside and nolinofuroside D and two novel saponins were isolated from underground parts of Allium nutans L. On the basis of the spectral (LSIMS and NMR) analysis, the structures of the new compounds were established as 25R Delta(5)-spirostan 3 beta-ol-3-O-{alpha-L-rhamnopyranosyl(1-->2)-[beta-D-glucopyranosyl(1-->4)]-O-beta-D-galactopyranoside} and 25R Delta(5)-spirostan 1 beta,3 beta-diol 1-O-beta-D-galactopyranoside. On the basis of the extraction efficiency, the concentration of saponins was established to be about 4% of dry matter, which makes this species a good source of steroidal saponins for commercial use.