Studies on the constituents of Zizyphi Fructus. III. Structures of dammarane-type saponins.

Zizyphus saponins I, II, III and jujuboside B were isolated from Zizyphi Fructus. On Smith-de Mayo degradation, zizyphus saponins I, II and III yielded jujubogenin as a genuine aglycone. The configuration of the sugar linkages in each saponin was determined on the basis of PMR and CMR examinations and application of Klyne's rule on molecular rotation, and the structures of zizyphus saponins I, II and III were established as (I), (II) and (III), respectively. 6-Deoxy-L-talose was isolated as a sugar component of zizyphus saponins I and III.