6533b827fe1ef96bd1286e7d

RESEARCH PRODUCT

New Acylated Preatroxigenin Saponins from Atroxima congolana

subject

description

Eight new acylated preatroxigenin saponins 1–8 were isolated as four inseparable mixtures of the trans- and cis-4-methoxycinnamoyl derivatives, atroximasaponins A1/A2 (1/2), B1/B2 (3/4), C1/C2 (5/6) and D1/D2 (7/8) from the roots of Atroxima congolana. These compounds are the first examples of triterpene saponins containing preatroxigenin (=(2β,3β,4α,22β)-2,3,22,27-tetrahydroxyolean-12-ene-23,28-dioic acid as aglycone. Their structures were elucidated on the basis of extensive 1D- and 2D-NMR studies and FAB-MS as 3-O(β-D-glucopyranosyl)preatroxigenin 28-{O-β-D-xylopyranosyl-(14)-O-α-L-rhamnopyranosyl-(12)-O-[O-β-D-glucopyranosyl-(13)-β-D-glucopyranosyl-(13)]-4-O-(trans-4-methoxycinnamoyl)-β-D-fucopyranoyl} ester (1) and its cis-isomer 2, 3-O-(β-D-glucopyranosyl)preatroxigenin 28-{O-β-D-xylopyranosyl-(14)-O-α-L-rhamnopyranosyl-(1 2)-O-[O-6-O-acetyl-β-D-glucopyranosyl-(13)-β-D-glucopyranosyl-(13)]-4-O-(trans- 4-methoxycinnamoyl)-β-D-fucopyranosyl} ester (3) and its cis-isomer 4, 3-O-(β-D-glucopyranosyl)preatroxigenin 28-{O-β-D-xylopyranosyl-(14)-O-[β-D-apiofuranosyl-(13)]-O-α-L-rhamnopyranosyl-(12)-O-[O-6- O-acetyl-β-D-glucopyranosyl-(13)-β-D-glucopyranosyl-(13)]-4-O-(trans-4-methoxycinnamoyl)-β-D-fucopyranoyl} ester (5) and its cis-isomer 6, 3-O-(β-D-glucopyranosyl)preatroxigenin 28-{O-β-D-xylopyranosyl-(14)-O-[β-D-apiofuranosyl-(13)]-O-α-L-rhamnopyranosyl-(12)-O-[O-β-D-xylopyranosyl-(13)-β-D-glucopyranosyl-(13)]-4-O-(trans-4-methoxycinnamoyl)-β-D-fucopyranosyl ester (7) and its cis-isomer 8.