Studies on the constituents of asclepiadaceae plants. LVIII. The structures of five glycosides, cynatratoside-A, -B, -C, -D, and -E, from the Chinese drug 'pai-wei,' Cynanchum atratum Bunge

The chemical components of the Chinese crude drug "Pai-Wei, " dried root of Cynanchum atratum BUNGE (Asclepiadaceae), have been studied. Five new oligoglycosides named cynatratoside-A (3), -B (4), -C (6), -D (8), and -E (9) were isolated by column chromatography and their structures were determined on the basis of chemical and spectral evidence.