Acylated preatroxigenin glycosides from Atroxima congolana

Six new acylated bisdesmosidic preatroxigenin saponins named atroximasaponins E-1, E-2 (1, 2), F-1, F-2 (3, 4), and G(1), G(2) (5, 6) were isolated as three inseparable mixtures of the trans- and cis-p-methoxycinnamoyl derivatives, from the roots of Atroxima congolana. Their structures were established through extensive NMR spectroscopic analysis as 3-O-beta-D-glucopyranosylpreatroxigenin-28-O-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->3)]-[4-O-trans-p-methoxycinnamoyl]-beta-D-fucopyranoside (atroximasaponin E-1, 1), and its cis-isomer, atroximasaponin E-2 (2), 3-O-beta-D-glucopyranosylpreatroxigenin-28-O-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-[6-O-acetyl-beta-D-glucopyranosyl-(1-->3)]-[4-O-trans-p-methoxycinnamoyl]-beta-D-fucopyranoside (atroximasaponin F-1, 3), and its cis-isomer, atroximasaponin F-2 (4), 3-O-beta-D-glucopyranosylpreatroxigenin-28-O-beta-D-apiofuranosyl-(1-->3)-[alpha-L-rhamnopyranosyl-(1-->2)]-[4-O-trans-p-methoxycinnamoyl]-beta-D-fucopyranoside (atroximasaponin G(1), 5), and its cis-isomer, atroximasaponin G(2) (6), respectively.