Planta Med 2002; 68(12): 1066-1071
DOI: 10.1055/s-2002-36344
Original Paper
© Georg Thieme Verlag Stuttgart · New York

In Vitro Inhibition of [3 H]-Angiotensin II Binding on the Human AT1 Receptor by Proanthocyanidins from Guazuma ulmifolia Bark

Catherina Caballero-George1 , Patrick M. L. Vanderheyden2 , Tess De Bruyne1 , Abdel-Atty Shahat1 , Hilde Van den Heuvel1 , Pablo N. Solis3 , Mahabir P. Gupta3 , Magda Claeys1 , Luc Pieters1 , Georges Vauquelin2 , Arnold J. Vlietinck1
  • 1Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium
  • 2Department of Molecular and Biochemical Pharmacology, Free University of Brussels (VUB), St.Genesius-Rode, Belgium
  • 3Center for Pharmacognostic Research on Panamanian Flora (CIFLORPAN), School of Pharmacy, University of Panama, Panama
Further Information

Publication History

Received: April 25, 2002

Accepted: July 13, 2002

Publication Date:
20 December 2002 (online)


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 AT1 receptor led to the isolation and identification of bioactive oligomeric and polymeric proanthocyanidins consisting mainly of (-)-epicatechin units. The displacement of [3 H]-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 AT1 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.

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Prof. Dr. A. J. Vlietinck

Department of Pharmaceutical Sciences

University of Antwerp (UIA)


2610, Antwerpen



Fax: +32 3820-2709