Intrapilosins I-VII, Pentasaccharides from the Seeds of Ipomoea intrapilosa

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• 作者：Moustapha Bah ; Lilia Ché ; rigo ; Alexandre T. Cardoso Taketa ; Mabel Fragoso-Serrano ; Gerald B. Hammond ; Rogelio Pereda-Miranda
• 刊名：Journal of Natural Products
• 出版年：2007
• 出版时间：July 2007
• 年：2007
• 卷：70
• 期：7
• 页码：1153 - 1157
• 全文大小：60K
• 年卷期：v.70,no.7(July 2007)
• ISSN：1520-6025

文摘

Purification of a CHCl₃-soluble extract from seeds of the Mexican medicinal arborescent morning glory, Ipomoeaintrapilosa, by means of preparative-scale recycling HPLC, yielded seven new resin glycosides, intrapilosins I-VII(1-7). Their structures were established through the interpretation of their NMR spectroscopic and FABMS data. Allpentasaccharides were found to be macrolactones of the known operculinic acid A with different fatty acids esterifyingthe same positions: C-2 on the second rhamnose unit and C-3 and C-4 on the third rhamnose moiety. The lactonizationsite of the aglycon could be placed at C-2 of the second saccharide. The fatty acid components of 1-7 were identifiedas (+)-(2S)-methylbutanoic, octanoic (caprylic), dodecanoic (lauric), and trans-cinnamic. The less common (-)-(2R)-methylbutanoic acid was also isolated as one of the saponification-liberated residues from intrapilosin IV (4). Thepresence of the (2R)- and (2S)-methylbutanoyl enantiomers bonded to the same oligosaccharide core in intrapilosins IV(4) and V (5) represents an example of diastereoisomerism due to a chiral esterifying moiety in the resin glycosidemixtures of a morning glory species.