Five new C21 steroidal glycosides from the stems of Marsdenia tenacissima

Five new C21 steroidal glycosides (1–5) were isolated from the stems of Marsdenia tenacissima. The chemical structures and relative configurations of the new compounds were elucidated by mass spectrometry and NMR spectroscopy. Cellular assay of these compounds showed that they are weak cytotoxic to various cell lines.