Saponins from Pisonia umbellifera.

Six saponins were isolated from the leaves of Pisonia umbellifera. Three are new oleanolic acid saponins, and two of them contain an unusual seco-glycopyranosyl moiety. Their structures were determined using a combination of H-1 and C-13 NMR, and mass spectrometry as 3-O-{beta-D-glucopyranosyl(1-->2)[beta-D-glucopyranosyl(1-->2)-beta-D-xylopyranosyl(1-->3)]-beta-D-glucuronopyranosyl} 28-O-beta-D-glucopyranosyl olean-12-en-3 beta-ol-28-oic acid, 3-O-{2'-(2 "-O-glycolyl)-glyoxylyl-beta-D-glucuronopyranosyl} 28-O-beta-D-glucopyranosyl olean-12-en-3 beta-ol-28-oic acid and 3-O-{2'-O-glycolyl)-glyoxylyl-beta-D-glucuronopyranosyl} olean-12-en-3 beta-ol-28-oic acid. Copyright (C) 1996 Elsevier Science Ltd