Triterpenoid saponins from the ground part of Aster ageratoides var. ovatus

Abstract

Abstract Eight new oleanane-type triterpene glycosides, ageratosides A 1 –A 5 , B 1 , B 2 and C 1 , were isolated from the ground part of Aster ageratoides Turcz. var. ovatus Nakai (Compositae) along with scaberoside A 2 . Their structures were determined based on spectral and chemical evidence as follows. Ageratoside A 1 , 3- O -[ O -β- d -xylopyranosyl-(1→4)-β- d -glucopyranosyl] 2β,3β,16α-trihydroxyolean-12-ene-23,28-dioic acid (zanhic acid) 28- O -β- d -apiofuranosyl-(1→3)- O -(4- O -acetyl)-α- l -rhamnopyranosyl-(1→2)- O -α- l -arabinopyranosyl ester; ageratoside A 2 , 3- O -[ O -β- d -glucopyranosyl-(1→4)-β- d -glucopyranosyl] zanhic acid 28- O -β- d -apiofuranosyl-(1→3)- O -(4- O -acetyl)-α- l -rhamnopyranosyl-(1→2)- O -α- l -arabinopyranosyl ester; ageratoside A 3 , 3- O -[ O -β- d -xylopyranosyl-(1→4)-β- d -glucopyranosyl] zanhic acid 28- O -α- l -arabinopyranosyl-(1→3)- O -(4- O -acetyl)-α- l -rhamnopyranosyl-(1→2)- O -α- l -arabinopyranosyl ester; ageratoside A 4 , 3- O -β- d -glucopyranosyl zanhic acid 28- O -α- l -arabinopyranosyl-(1→3)- O -(4- O -acetyl)-α- l -rhamnopyranosyl-(1→2)- O -α- l -arabinopyranosyl ester; ageratoside A 5 , 3- O -β- d -glucopyranosyl zanhic acid 28- O -β- d -apiofuranosyl-(1→3)- O -(4- O -acetyl)-α- l -rhamnopyranosyl-(1→2)- O -α- l -arabinopyranosyl ester; ageratoside B 1 , 3- O -β- d -glucopyranosyl 2β,3β-dihydroxyolean-12-ene-23,28-dioic acid (medicagenic acid) 28- O -β- d -glucopyranosyl-(1→6)- O -β- d -glucopyranosyl ester; ageratoside B 2 , 3- O -[ O -β- d -xylopyranosyl-(1→4)-β- d -glucopyranosyl] medicagenic acid 28- O -β- d -xylopyranosyl-(1→3)- O -α- l -rhamnopyranosyl-(1→2)- O -α- l -arabinopyranosyl ester; and ageratoside C 1 , 3- O -[ O -β- d -xylopyranosyl-(1→4)-β- d -glucopyranosyl] 2β,3β,16α,21β-tetrahydroxyolean-12-ene-23,28-dioic acid 21,28-lactone.