ABSTRACT
Objective: To investigate the chemical structures of glycosides in the roots of Cynanchum otophyllum (Asclepiadaceae) and to find new glycosides. Methods: The total glycosides in the roots of C. olophyllum were separated by silica gel column chromatography. The structures of the resulting compounds were determined by NMR and FAB-MS spectra. Results: Three C21 steroidal glycosides were separated. Their structures were determined as caudatin 3-O-(4-O-methyl-β-D-cymaropyranosyl)-(1→4)-α-D-oleandropyranosyl-(1→4)-β-D-glucopyranosyl-(1→4)-α-L-rhamnopyranoside (1), caudatin 3-O-β-D-digitoxopyranosyl-(1→4)-α-D-oleandropyranosyl-(1→4)-β-Ddiginopyranosyl-(1→4)-β-D-glucopyranoside (2), and caudatin 3-O-β-D-diginopyranosyl-(1→4)-α-D-oleandropyranosyl-(1→4)-α-D-oleandropyranosyl-(1→4)-β-D-glucopyranoside (3), respectively. Conclusion: Glycosides 1-3 are new compounds.
ABSTRACT
Objective: To study the chemical structures of saponins in the rhizome of Cynanchum otophyllum (Asclepiadaceae), and to find new compounds. Methods: The total saponins of the rhizome were separated by silica gel column chromatography. The chemical structures of obtained compounds were determined by NMR and FAB-MS spectra. Results: Three C21 steroidal saponins were separated. Their structures were determined as caudatin 3-O-β-D-glucopyranosyl-(1→4)-β-D-digitoxopyranosyl-(1→40)-β-D-digino-pyranosyl-(1→4)-α-D-oleandropyranoside (1), caudatin 3-O-β-D-oleandropyranosyl-(1→4)-α-D-oleandropyranosyl-(1→4)-α-D-oleandropyranoside (2), and caudatin 3-O-β-D-glucopyranosyl-(1→4)-α-D-oleandropyranosyl-(1→4)-β-D-diginopyranosyl-(1→4)-α-D-oleandropyranoside (3), respectively. Conclusion: Saponins 1-3 are new compounds.
ABSTRACT
Objective: To investigate the structures of compounds in the rhizome of Cynanchum otophyllum (Asclepiadaceae), and to find new C21 steroidal glycosides. Methods: The ethyl acetate extract from the rhizome was subjected to acidic hydrolysis and isolated by column chromatography; The structures of the purified compounds were determined by spectral methods. Literature search confirmed whether those compounds were of new structures. Results: Three compounds were isolated and their structures were deacetylmetaplexigenin 3-. O-β-. D-oleandropyranosyl-(1→4)-α-. D-oleandropyranosyl-(1→4)-α-. D-oleandropyranoside (1), deacetylmetaplexigenin 3-. O-α-. D-oleandropyranosyl-(1→4)-β-. D-thevetopyranosyl-(1→4)-α-. D-oleandropyranoside (2), and deacetylmetaplexigenin 3-. O-β-. D-cymaropyranosyl-(1→4)-α-. D-oleandropyranoside (3), respectively. Conclusion: Compounds 1-3 are new compounds.