Seco-pregnane steroidal glycosides from the roots of Cynanchum stauntonii

By analyzing the steroidal content of the roots of Cynanchum stauntonii, we isolated three new C₂₁ steroidal glycosides named cynastauosides A-C (1–3), all of which shared the 14,15-secopregnane-type skeleton. Their structures were determined on the basis of detailed spectroscopic analysis, including 2D NMR and qualitative chemical tests. Anti-inflammatory activities of compounds 1–3 were evaluated in vitro, with 2 and 3 inhibiting nitric oxide production in C57bl/6j mouse peritoneal macrophages by 17.0% and 6.9% of inhibition rate at a concentration of 10 μM, respectively.