Five new C21 steroidal glycosides from Cynanchum komarovii Al.!Iljinski

Five new C-21 steroidal glycosides, namely, komarosides D (1), E (2), F (3), G (4), and H (5), along with two known C-21 steroidal glycosides cynatratoside E (6) and hancoside A (7), were isolated from the ethanol extract of the roots of Cynanchum komarovii Al.Iljinski (Asclepiadaceae). Their structures were determined by physiochemical and spectroscopic analysis. Among these glycosides, five had an aberrant 13,14:14,15-disecopregnane-type skeleton, and the other two had normal four-ring C-21 steroid skeletons. The existence of more than one type Of C-21 steroid skeleton in one species is rare in the plants of the family Asclepiadaceae, and this has chemotaxonomic significance for this species. (C) 2004 Elsevier Inc. All rights reserved.