New C21 steroidal glycosides from the roots of Cynanchum stauntonii and their protective effects on hypoxia/reoxygenation induced cardiomyocyte injury

Four new C21 steroidal glycosides (1-4) were obtained from the roots of Cynanchum stauntonii and their chemical structures were characterized by sophisticated analyses of IR, HRESI-TOF-MS, 1D, and 2D-NMR data, together with chemical methods They were interesting 13,14:14,15-disecopregnane-type skeleton or 14, 15-secopregnane-type skeleton C21 steroidal glycosides.