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RESEARCH PRODUCT

Presenegenin Glycosides from Securidaca welwitschii

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) Centre de Recherche Phytochimique, Universite´ de Lie`ge, Institut de Chimie-B6, Sart Tilman,B-4000-Lie`ge IThe five new presenegenin glycosides 1–5 were isolated from Securidaca welwitschii, together withone known sucrose diester. Compounds 1–4 were obtained as pairs of inseparable (E)/(Z)-isomers of a3,4-dimethoxycinnamoyl derivative, i.e., 1/2 and 3/4. Their structures were elucidated mainly by 2D-NMR techniques and mass spectrometry as 3-O-(b-d-glucopyranosyl)presenegenin 28-{O-b-d-xylopyr-anosyl-(1!4)-O-a-l-rhamnopyranosyl-(1!2)-O-[b-d-glucopyranosyl-(1!3)]-4-O-[(E)-3,4-dimeth-oxycinnamoyl]-b-d-fucopyranosyl} ester (1) and its (Z)-isomer 2, 3-O-(b-d-glucopyranosyl)presenege-nin 28-{O-b-d-galactopyranosyl-(1!4)-O-b-d-xylopyranosyl-(1!4)-O-3-O-acetyl-a-l-rhamnopyrano-syl-(1!2)-O-[b-d-glucopyranosyl-(1!3)]-4-O-[(E)-3,4-dimethoxycinnamoyl]-b-d-fucopyranosyl} es-ter (3) and its (Z)-isomer 4, and 3-O-(b-d-glucopyranosyl)presenegenin 28-[O-b-d-galactopyranosyl-(1!3)-O-b-d-xylopyranosyl-(1!4)-O-a-l-rhamnopyranosyl-(1!2)-b-d-fucopyranosyl] ester (5)(presenegenin¼(2b,3b,4a)-2,3,27-trihydroxyolean-12-ene-23,28-dioic acid).