The roots of Cynanchum caudatum M. (Asclepiadaceae) affored 21 new pre
gnane glycosides which had sibirigenin, cynanchogenin, gagaminin, 12-O
-nicotinoyllineolon and rostratamine as the aglycone moiety and 2,6-di
deoxy-3-O-methylhexopyranoses as component sugars. The structures of t
hese compounds were elucidated by spectroscopic methods and chemical e
vidence.