Phytochemical reinvestigation of Xysmalobium undulatum roots (Uzara).

Four major cardenolide glycosides of Xysmalobium undulatum (L.) R. Br. roots (Uzara) have been isolated for the first time in pure form. The structures were elucidated by spectral analyses and determined as sophorosides and their 17-epimers, respectively. Thus, the structural elucidation of uzarin and xysmalorin, the two main glycosides, has been completed. The corresponding H-17beta isomers, allouzarin and alloxysmalorin, were characterized as genuine compounds.