Intrapilosins I-VII, pentasaccharides from the seeds of Ipomoea intrapilosa

J Nat Prod. 2007 Jul;70(7):1153-7. doi: 10.1021/np0701529. Epub 2007 Jun 13.

Abstract

Purification 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Glycosides / analysis
  • Ipomoea / chemistry*
  • Mexico
  • Molecular Structure
  • Nuclear Magnetic Resonance, Biomolecular
  • Oligosaccharides / chemistry*
  • Oligosaccharides / isolation & purification*
  • Plants, Medicinal / chemistry*
  • Resins, Plant / chemistry*
  • Seeds / chemistry
  • Stereoisomerism
  • Structure-Activity Relationship

Substances

  • Glycosides
  • Oligosaccharides
  • Resins, Plant