Two new steroidal glycosides from the root of Cynanchum auriculatum

Two new steroidal glycosides named cyanoauriculoside A (1) and B (2), have been isolated from the roots of Cynanchum auriculatum Royle ex Wight. The structure of cyanoauriculoside A (1) was determined to be 20-O-acetyl-penupogenin-3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyranosyl-(1→4)-α-L-cymaropyranosyl-(1→4)-β-D-cymaropyranosyl-(1→4)-α-L-diginopy-ranosyl-(1→4)-β-D-cymaropyranoside. Cyanoauriculoside B (2) was characterized as 20-O-acetylpenupogenin-3-O-β-D-glucopyranosyl-(1→4)-α-L-cymaropyranosyl-(1→4)-β-D-cymaropyranosyl-(1→4)-α-L-diginopyranosyl-(1→4)-β-D-cymaropyranoside. The structures of these compounds were elucidated based on the chemical and spectroscopic evidence.