Structural and conformational analysis of proanthocyanidins from Parapiptadenia rigida and their wound-healing properties

J Nat Prod. 2011 Jun 24;74(6):1427-36. doi: 10.1021/np200158g. Epub 2011 May 10.

Abstract

Structure elucidation and conformation analysis of four proanthocyanidins isolated from the bark of Parapiptadenia rigida were performed by two-dimensional NMR spectroscopy, HRESIMS, CD, and molecular mechanics (MM+) force field calculations. The known prodelphinidin, epigallocatechin-(4β→8)-epigallocatechin-3-O-gallate (1) was accompanied by the new epigallocatechin-(4β→8)-4'-O-methylgallocatechin (2), epicatechin-(4β→8)-4'-O-methylgallocatechin (3), and (4α→8)-bis-4'-O-methylgallocatechin (4). Compound 4 was previously published but the earlier structure must presumably be revised to 4'-O-methylgallocatechin-(4α→8)-4'-O-methylepigallocatechin. Conformational studies showed the compact rotamer with B and E rings in quasi-equatorial orientations as the preferred conformation for compounds 1-3, whereas 4 consists of two stable rotamers, each with a quasi-equatorial orientation of ring B and E, respectively. The isolated compounds were studied for their wound-healing effects in a scratch assay and showed promising results.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brazil
  • Crystallography, X-Ray
  • Fabaceae / chemistry*
  • Humans
  • Molecular Conformation
  • Molecular Structure
  • Nuclear Magnetic Resonance, Biomolecular
  • Plant Bark / chemistry
  • Proanthocyanidins* / chemistry
  • Proanthocyanidins* / isolation & purification
  • Proanthocyanidins* / pharmacology
  • Wound Healing / drug effects*

Substances

  • Proanthocyanidins