6533b858fe1ef96bd12b580e

RESEARCH PRODUCT

New Acylated Triterpene Saponins fromPolygala arenaria

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description

Eight new acylated triterpene saponins 1–8 were isolated from the roots of Polygala arenaria as four inseparable (E)/(Z) mixtures of the 4-methoxycinnamoyl and 3,4-dimethoxycinnamoyl derivatives by repeated MPLC over silica gel. Their structures were established mainly by 600-MHz 2D-NMR techniques (1H,1H-COSY, TOCSY, NOESY, HSQC, HMBC) as 3-O-(β-D-glucopyranosyl)presenegenin 28-(O-β-D-galactopyranosyl-(14)-O-[β-D-glucopyranosyl-(13)]-O-β-D-xylopyranosyl-(14)-O-α-L-rhamnopyranosyl-(12)-{4-O-[(E)-4-methoxycinnamoyl]}-β-D-fucopyranosyl) ester and its (Z)-isomer (1/2), 3-O-(β-D-glucopyranosyl)presenegenin 28-(O-β-D-galactopyranosyl-(14)-O-[β-D-glucopyranosyl-(13)]-O-β-D-xylopyranosyl-(14)-O-α-L-rhamnopyranosyl-(12)-{4-O-[(E)-3,4-dimethoxycinnamoyl]}-β-D-fucopyranosyl) ester and its (Z)-isomer (3/4), 3-O-(β-D-glucopyranosyl)presenegenin 28-(O-β-D-glucopyranosyl-(13)-O-α-L-arabinopyranosyl-(14)-O-α-L-rhamnopyranosyl-(12)-{4-O-[(E)-4-methoxycinnamoyl]}-β-D-fucopyranosyl) ester and its (Z)-isomer (5/6), and 3-O-(β-D-glucopyranosyl)presenegenin 28-(O-β-D-glucopyranosyl-(13)-O-α-L-arabinopyranosyl-(14)-O-α-L-rhamnopyranosyl-(12)-{4-O-[(E)-3,4-dimethoxycinnamoyl]}-β-D-fucopyranosyl) ester and its (Z)-isomer (7/8) (presenegenin=(2β,3β)-2,3,27-trihydroxyolean-12-ene-23,28-dioic acid). In our in vitro lymphocyte proliferation assay (Jurkat T-leukemia cells), a fraction containing 1–4 showed a concentration-dependent immunomodulatory effect. This effect was not found for the prosapogenin (tenuifolin=3-O-(β-D-glucopyranosyl)presenegenin), underlining the importance of the acyloligosaccharidic moiety.