Intrapilosins I−VII, Pentasaccharides from the Seeds of Ipomoea intrapilosa
2007; American Chemical Society; Volume: 70; Issue: 7 Linguagem: Inglês
10.1021/np0701529
ISSN1520-6025
AutoresMoustapha Bah, Lilia Chérigo, Alexandre Toshirrico Cardoso Taketa, Mabel Fragoso‐Serrano, Gerald B. Hammond, Rogelio Pereda‐Miranda,
Tópico(s)Phytochemistry and Biological Activities
ResumoPurification of a CHCl3-soluble extract from seeds of the Mexican medicinal arborescent morning glory, Ipomoea intrapilosa, 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. All pentasaccharides were found to be macrolactones of the known operculinic acid A with different fatty acids esterifying the same positions: C-2 on the second rhamnose unit and C-3 and C-4 on the third rhamnose moiety. The lactonization site of the aglycon could be placed at C-2 of the second saccharide. The fatty acid components of 1−7 were identified as (+)-(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). The presence 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 glycoside mixtures of a morning glory species.
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