Two New Steroidal Saponins from the Processed Polygonatum kingianum

Two new spirostanol saponins, kingianoside I (1) and kingianoside K (2), corresponding to (3β,23S,25R)-23-hydroxy-12-oxospirost-5-en-3-yl 4-O-β-D-glucopyranosyl-β-D-galactopyranoside (1) and (3β,25R)-7-oxospirost-5-en-3-yl α-L-arabinofuranosyl-(14)-[6-deoxy-α-L-mannopyranosyl-(12)]-β-D-glucopyranoside (2), along with 13 known compounds, daucosterol, (25R)-kingianoside G, (25RS)-kingianoside A, pratioside D1, (25RS)-pratioside D1, (25S)-kingianoside C, kingianoside C, ginsenoside Rb1, saponins Tb and Pb, dioscin, gracillin, and saponin Pa, were isolated from the processed rhizomes of Polygonatum kingianum. The structures of the new compounds were elucidated by detailed spectroscopic analyses, including 1D- and 2D-NMR techniques, and chemical methods. Compound 2 contains a novel unusual spirostanol saponin aglycone. Ginsenoside Rb1 and saponin Tb were isolated for the first time from the genus Polygonatum. The 13 known compounds were detected for the first time in the processed Polygonatum kingianum.