| Abstract: | Guided by in vitro immunological tests, three immunomodulating steroidal glycosides, stemucronatosides A ( 1 ), B ( 2 ), and C ( 3 ), were isolated from the roots of Stephanotis mucronata. On the basis of chemical evidence and extensive spectroscopic methods including 1D and 2D NMR, their structures were determined as 12‐O‐deacetylmetaplexigenin 3‐O‐6‐deoxy‐3‐O‐methyl‐β‐D ‐allopyranosyl‐(1→4)‐O‐β‐D ‐cymaropyranosyl‐(1→4)‐β‐D ‐cymaropyranoside], 12‐O‐deacetylmetaplexigenin 3‐O‐β‐D ‐thevetopyranosyl‐(1→4)‐O‐β‐D ‐cymaropyranosyl‐(1→4)‐β‐D ‐cymaropyranoside], and metaplexigenin 3‐O‐β‐D ‐glucopyranosyl‐(1→4)‐O‐6‐deoxy‐3‐O‐methyl‐β‐D ‐allopyranosyl‐(1→4)‐O‐β‐D ‐cymaropyranosyl‐(1→4)‐β‐D ‐cymaropyranoside], respectively. These compounds showed immunomodulating activities in vitro. |
