Acylated preatroxigenin glycosides from Atroxima congolana

Abstract

Six new acylated bisdesmosidic preatroxigenin saponins named atroximasaponins E1, E2 (1, 2), F1, F 2 (3, 4), and G1, G2 (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-β -D-glucopyranosylpreatroxigenin-28-O-β-D-xylopyranosyl-(1→4) -α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→3)] -[4-O-trans-p-methoxycinnamoyl]-β-D-fucopyranoside (atroximasaponin E 1, 1), and its cis-isomer, atroximasaponin E2 (2), 3-O-β-D-glucopyranosylpreatroxigenin-28-O-β-D-xylopyranosyl-(1→4) -α-L-rhamnopyranosyl-(1→2)-[6-O-acetyl-β -D-glucopyranosyl-(1→3)1-[4-O-trans-p-methoxycinnamoyl]-β -D-fucopyranoside (atroximasaponin F1, 3), and its cis-isomer, atroximasaponin F2 (4), 3-O-β -D-glucopyranosylpreatroxigenin-28-O-β-D-apiofuranosyl-(1→3) -[α-L-rhamnopyranosyl-(1→2)]-[4-O-trans-p-methoxycinnamoyl] -β-D-fucopyranoside (atroximasaponin G1, 5), and its cis-isomer, atroximasaponin G2 (6), respectively.