Isolation and structural elucidation of some sapogenols from Abrus cantoniensis

After hydrolysis of the saponin fraction of the roots of Abrus cantoniensis, a new triterpenoid sapogenol, cantoniensistriol, was isolated together with sophoradiol, soyasapogenol B and soyasapogenol A. The structures of cantoniensistriol and sophoradiol were elucidated by spectroscopic methods. On the basis of the relation between cantoniensistriol and soyasapogenol A, the steric assignment of the C-21 and C-22 hydroxyl groups of the latter was discussed.