Abstract
Four new type oligosaccharides C1, D2, F1 and F2 of Bei-Wujiapi (cortex of Periploca sepium BGE.) were elucidated to be 2-O-acetyl-β-D-digitalopyranosyl (1→4)-β-D-cymaropyranosyl (1→4)-β-D-cymaropyranosyl (1→4)-L-oleandronic acid-δ-lactone (Ia), 2-O-acetyl-β-D-digitalopyranosyl (1→4)-β-D-cymaropyranosyl (1→4)-β-D-canaropyranosyl (1→4)-β-D-digitoxopyranosyl (1→4)-L-oleandronic acid-δ-lactone (IIa), β-D-digitalopyranosyl (1→4)-β-D-cymaropyranosyl (1→4)-β-D-cymaropyranosyl (1→4)-L-oleandronic acid-δ-lactone (IIIa) and β-D-digitalopyranosyl (1→4)-β-D-cymaropyranosyl (1→4)-β-D-canaropyranosyl (1→4)-β-D-digitoxopyranosyl (1→4)-L-oleandronic acid-δ-lactone (IVa). It should be noted that Ia, IIa, IIIa and IVa are the first oligosaccharides composed of 2, 6-dideoxysugars and 2, 6-dideoxyaldonic lactone. Furthermore, it is interesting that the sugar sequences of these oligosaccharides are ruled by the regularity in cardiac and pregnane type glycosides of Asclepiadaceous plants.
