STEROIDAL SAPONINS FROM THE UNDERGROUND PARTS OF CHLOROPHYTUM-COMOSUMAND THEIR INHIBITORY ACTIVITY ON TUMOR PROMOTER-INDUCED PHOSPHOLIPIDSMETABOLISM OF HELA-CELLS

Three new spirostanol pentaglycosides embracing beta-D-apiofuranose we re isolated from the fresh underground parts of Chlorophytum comosum t ogether with four known saponins. The structures of new compounds were determined by spectroscopic data, including two-dimensional NMR, and partial acid-catalysed hydrolysis to be (25R)-5 alpha-spirostane-2 alp ha, 3 beta-diol 3-O-{O-beta-D-glucopyranosyl-(1 --> 2)-O-[O-beta-D-api ofuranosyl-(1 --> 4)-beta-D-glucopyranosyl-(1 --> 3)]-O-beta-D-glucopy ranosyl-(1 --> 4)-beta-D-galactopyranoside}, (25R)-3 beta-hydroxy-5 al pha-spirostan-12-one (hecogenin) 3-O-{O-beta-D-glucopyranosyl-(1 --> 2 )-O-[O-beta-D-apiofuranosyl-(1 --> 4)-beta-D-xylopyranosyl-(1 --> 3)]- O-beta-D-glucopyranosyl-(1 --> 4)-beta-D-galactopyranoside} and hecoge nin 3-O-{O-beta-D-glucopyranosyl-(1 --> 2)-O-[O-beta-D-apiofuranosyl-( 1 --> 4)-beta-D-glucopyranosyl-(1 --> 3)]-O-beta-D-glucopyranosyl-(1 - -> 4)-beta-D-galactopyranoside}, respectively. The isolated saponins w ere examined for inhibitory activity using 12-O-tetradecanoylphorbor-1 3-acetate-stimulated P-32-incorporation into phospholipids of HeLa cel ls as the primary screening test to identify new antitumour-promoter c ompounds.