Browsing by Autor "Alberto Gimenez T."

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    Bioactive phenolic glycosides from Amburana cearensis
    (Elsevier BV, 1999) José A. Bravo B.; Michel Sauvain; Alberto Gimenez T.; Victoria Muñoz O; Jorgia Callapa; Louisette Le Men‐Olivier; Georges Massiot; Catherine Lavaud
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    Trypanocidal Withanolides and Withanolide Glycosides from <i>Dunalia brachyacantha</i>
    (American Chemical Society, 2001) José A. Bravo B.; Michel Sauvain; Alberto Gimenez T.; Elfride Balanza; Laurent Sérani; Olivier Laprévôte; Georges Massiot; Catherine Lavaud
    Two new withanolide glycosides, (20R,22R)-O-(3)-alpha-L-rhamnopyranosyl(1-->4)-beta-D-glucopyranosyl-1 alpha,12 beta-diacetoxy-20-hydroxywitha-5,24-dienolide (3) and (20R,22R)-O-(3)-beta-D-xylopyranosyl(1-->3)-[beta-D-xylopyranosyl(1-->4)]-beta-D-glucopyranosyl-1 alpha-acetoxy-12 beta,20-dihydroxywitha-5,24-dienolide (4), were isolated from the leaves and root of Dunalia brachyacantha. Their aglycones, (20R,22R)-1 alpha,12 beta-diacetoxy-3 beta,20-dihydroxywitha-5,24-dienolide (or 1 alpha,12 beta-diacetyldunawithagenine) and (20R,22R)-1 alpha-acetoxy-3 beta,12 beta,20-trihydroxywitha-5,24-dienolide (or 1 alpha-acetyl-12 beta-hydroxydunawithagenine), are novel. The known 18-acetoxywithanolide D (1) and 18-acetoxy-5,6-deoxy-5-withenolide D (2) were also isolated from the leaves. These last two compounds were shown to be responsible for the trypanocidal, leishmanicidal, and bactericidal activities manifested by the crude ethanolic extract. The structures were deduced from spectroscopic data and on the basis of chemical evidence.