STEROIDAL SAPONINS FROM THE UNDERGROUND PARTS OF HOSTA LONGIPES AND THEIR INHIBITORY ACTIVITY ON TUMOR PROMOTER-INDUCED PHOSPHOLIPID-METABOLISM

Phytochemical study on the underground parts of Hosta longipes gave si x new steroidal saponins together with a known one. The structures of the new compounds were determined by detailed analysis of their H-1- a nd C-13-NMR spectra including two-dimensional NMR spectroscopy, acid-c atalyzed hydrolysis followed by chemical correlation, and by compariso n with spectral data of known compounds. The isolated saponins and the ir aglycones were examined for inhibitory activity on 12-O-tetradecano ylphorbol-13-acetate (TPA)-stimulated P-32-incorporation into phosphol ipids of HeLa cells to identify new antitumor-promoter compounds.