Abstract
The sapogenol constituents of five Japanese Primulaceous plants : i) Primula sieboldi E. MORREN, roots (Japanese name : sakuraso), ii) P. japonica A, GRAY, roots and fruits (kurinso), iii) Lysimachia mauritiana LAM., Fruits (hamabossu), iv) L. clethroides DUBY, roots (okatoranoo), v) L. japonica THUNB., roots (konasubi), have been investigated. It has been elucidated that the major sapogenols obtained by acid hydrolysis of saponin of each plant material are primulagenin A (VIII) and/or dihydropriverogenin A (XIII), while periodate oxidation followed by alkaline treatment of saponin furnished the inconsistent sapogenol compositions and the genuine sapogenols have been shown to possess a 13β, 28-oxide moiety as seen in protoprimulagenin A (XV), a newly isolated sapogenol from i), ii), iv), and v), and priverogenin B (XII). The structure of protoprimulagenin A (XV) has been established on the basis of chemical and physicochemical evidences.
