Acetylated glucuronide triterpene bidesmosidic saponins from Symplocos glomerata.

Abstract Nine new bidesmosidic 3- O -glucuronide oleanane triterpenoid saponins were isolated from the stem bark of Symplocos glomerata King along with two known saponins, salsoloside C and copteroside E, and two major lignans, (−)-pinoresinol and (−)-pinoresinol-4′- O -β- d -glucopyranoside. The structures of the new saponins were established using one- and two-dimensional NMR spectroscopy and mass spectrometry as, 3- O -[β- d -xylopyranosyl(1→4)-[2- O -acetyl]-β- d -glucuronopyranosyl]-28- O -[β- d -glucopyranosyl]-oleanolic acid, 3- O -[β- d -xylopyranosyl(1→4)-[3- O -acetyl]-β- d -glucuronopyranosyl]-28- O -[β- d -glucopyranosyl]-oleanolic acid, 3- O -[β- d -xylopyranosyl (1→4)-[2,3- O -diacetyl]-β- d -glucuronopyranosyl]-28- O -[β- d -glucopyranosyl]-oleanolic acid, 3- O -[α- l -arabinopyranosyl(1→4)-β- d -glucuronopyranosyl]-28- O -[β- d -glucopyranosyl]-oleanolic acid, 3- O -[α- l -arabinopyranosyl (1→4)-[2- O -acetyl]-β- d -glucuronopyranosyl]-28- O -[β- d -glucopyranosyl]-oleanolic acid, 3- O -{[β- d -xylopyranosyl (1→2)]-[β- d -xylopyranosyl (1→4)]-[3- O -acetyl]-β- d -glucuronopyranosyl}-28- O -[β- d -glucopyranosyl]-oleanolic acid, 3- O -{[β- d -glucopyranosyl (1→2)]-[β- d -xylopyranosyl (1→4)]-[3- O -acetyl]-β- d -glucuronopyranosyl}-28- O -[β- d -glucopyranosyl]-oleanolic acid, 3- O -{[β- d -glucopyranosyl (1→2)]-[α- l -arabinofuranosyl (1→4)]-[3- O -acetyl]-β- d -glucuronopyranosyl}-28- O -[β- d -glucopyranosyl]-oleanolic acid, and 3β- O -[β- d -xylopyranosyl(1→4)-[2- O -acetyl]-β- d -glucuronopyranosyl]-28- O -[β- d -glucopyranosyl]-morolic acid. The EtOH and EtOAc extracts of the stem bark showed no cytotoxic activity. At a concentration of 370 μg/ml, the saponin mixture showed haemolytic activity and caused 50% haemolysis of a 10% suspension of sheep erythrocytes.