In vitro inhibition of [3H]-angiotensin II binding on the human AT1 receptor by proanthocyanidins from Guazuma ulmifolia bark

Planta Med. 2002 Dec;68(12):1066-71. doi: 10.1055/s-2002-36344.


A bioassay-guided fractionation of the 70% acetone extract of the bark of Guazuma ulmifolia Lam. on the inhibition of angiotensin II binding to the AT 1 receptor led to the isolation and identification of bioactive oligomeric and polymeric proanthocyanidins consisting mainly of (-)-epicatechin units. The displacement of [3H]-angiotensin II binding was dose-dependent and correlated with the degree of polymerization of the different fractions containing proanthocyanidins. A strong displacement was seen for the residual fraction suggesting that the most active substances corresponding to the highly polymerized proanthocyanidins. Angiotensin II AT 1 receptor binding might be considered as a potentially interesting biological activity of proanthocyanidins contributing to the very broad spectrum of biological activities of the condensed tannins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin II / metabolism*
  • Anthocyanins / pharmacology*
  • Binding Sites / drug effects
  • Binding, Competitive / drug effects
  • Dose-Response Relationship, Drug
  • Humans
  • Malvaceae*
  • Plant Bark / chemistry*
  • Plant Extracts / pharmacology
  • Proanthocyanidins*
  • Receptor, Angiotensin, Type 1
  • Receptors, Angiotensin / drug effects
  • Receptors, Angiotensin / metabolism*
  • Tritium


  • Anthocyanins
  • Plant Extracts
  • Proanthocyanidins
  • Receptor, Angiotensin, Type 1
  • Receptors, Angiotensin
  • Tritium
  • Angiotensin II
  • proanthocyanidin