Caballero-George Catherina, Vanderheyden Patrick M L, De Bruyne Tess, Shahat Abdel-Atty, Van den Heuvel Hilde, Solis Pablo N, Gupta Mahabir P, Claeys Magda, Pieters Luc, Vauquelin Georges, Vlietinck Arnold J
Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium.
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.
对危地马拉榆叶（Guazuma ulmifolia Lam.）树皮70%丙酮提取物进行生物测定引导的分级分离，以研究其对血管紧张素II与AT1受体结合的抑制作用，从而分离并鉴定出主要由（-）-表儿茶素单元组成的具有生物活性的寡聚和聚合原花青素。[3H]-血管紧张素II结合的置换呈剂量依赖性，且与含有原花青素的不同级分的聚合程度相关。残留级分显示出强烈的置换作用，表明最具活性的物质对应于高度聚合的原花青素。血管紧张素II AT1受体结合可能被视为原花青素潜在有趣的生物活性，这有助于缩合单宁具有非常广泛的生物活性。
