C21 steroidal glycosides of seven sugar residues from Cynanchum otophyllum

Two new C21-steroidal glycosides having hepta-saccharide residue were isolated from the rhizome of Cynanchum otophyllum Schneid. Their structures were determined to be caudatin 3-O-α-l-cymaropyranosyl-(1 → 4)-α-d-oleandropyranosyl-(1 → 4)-α-l-cymaropyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 4)-α-d-oleandropyranosyl-(1 → 4)-β-d-oleandropyranosyl-(1 → 4)-β-d-diginopyranoside (1), and caudatin 3-O-β-d-cymaropyranosyl-(1 → 4)-α-d-oleandropyranosyl-(1 → 4)-α-l-cymaropyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 4)-β-d-oleandropyranosyl-(1 → 4)-β-d-cymaropyranosyl-(1 → 4)-β-d-diginopyranoside (2) by spectral methods, respectively.