Steroidal saponins from the underground parts of Chlorophytum comosum and their inhibitory activity on tumour promoter-induced phospholipids metabolism of HeLa cells.

Three new spirostanol pentaglycosides embracing beta-D-apiofuranose were isolated from the fresh underground parts of Chlorophytum comosum together 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 alpha,3 beta-diol 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], (25R)-3 beta-hydroxy-5 alpha-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 hecogenin 3-O-[O-beta-D-glucopyranosyl-(1-->2)-O-[O-beta-D- apiofuranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)]-O-beta-D-gluc opyranosyl- (1-->4)-beta-D-galactopyranoside], respectively. The isolated saponins were examined for inhibitory activity using 12-O-tetradecanoylphorbor-13-acetate-stimulated 32P-incorporation into phospholipids of HeLa cells as the primary screening test to identify new antitumour-promoter compounds.