Hederagenin glycosides from the flowers of Cephalaria transsylvanica.
Mots clés
Abstrait
Three new triterpenoidal saponins, 3-O-[beta-D-glucopyranosyl(1-->4)-beta-D-Glucopyranosyl(1-->3)-alpha-L- rhamnopyranosyl (1-->4)-beta-D-xylopyranosyl]-hederagenin 28-O-[beta-D-glucopyranosyl (1-->4)-beta-D-glucopyranosyl] ester (1), 3-O-[beta-D-glucopyranosyl (1-->3)-alpha-L-rhamnopyranosyl(1-->2)-beta-D-xylopyranosyl]-hederage nin 28-O-[beta-D-glucopyranosyl(1-->4)-beta-D-glucopyranosyl] ester (2), and 3-O-[alpha-L-rhamnopyranosyl(1-->4)-beta-D-xylopyranosyl]-hederagenin (3) were isolated from the flowers of Cephalaria transsylvanica. Two new prosapogenins, 3-O-[beta-D-glucopyranosyl (1-->4)-beta-D-glucopyranosyl(1-->3)-alpha-L-rhamnopyranosyl(1-->4)- beta-D-xylopyranosyl]-hederagenin (4) and 3-O-[beta-D-glucopyranosyl (1-->3)-alpha-L-rhamnopyranosyl(1-->2)-beta-D-xylopyranosyl]-hederage nin (5) were also isolated after cleavage of the ester-glycosidic linkage of the bisdesmosidic compounds. Structure elucidation was carried out chemically and spectroscopically.
