Department of Nutrition, University of California at Davis, Davis, CA 95616, USA.
Free Radic Biol Med. 2011 Jan 15;50(2):237-44. doi: 10.1016/j.freeradbiomed.2010.11.005. Epub 2010 Nov 11.
Extensive epidemiological and clinical evidence associates diets high in flavanol-containing foods with cardiovascular health benefits in humans. Catechin and epicatechin, the most common flavanols in foods, are present in the diet in different enantiomeric forms. This study investigated the influence of the stereochemical configuration of flavanols on their absorption, metabolism, and biological activity. Healthy adult males were asked to consume equal amounts of the stereochemically pure flavanols (-)-epicatechin, (-)-catechin, (+)-catechin, and (+)-epicatechin (1.5mg/kg bw) in a well-defined cocoa-based, dairy-containing drink matrix, and flavanol levels were subsequently determined in plasma and 24-h urine. The results obtained show that the stereochemical configuration of flavanols has a profound influence on their uptake and metabolism in humans. In addition, we assessed the vasodilatory activity of each flavanol stereoisomer in vivo and found (-)-epicatechin to be the single stereoisomer capable of mediating a significant arterial dilation response. Importantly, this effect was independent of the classic antioxidant properties of flavanols. Overall, these results indicate that the proposed beneficial health effects associated with the consumption of flavanol-containing foods will significantly depend on the stereochemical configuration of the flavanols ingested.
大量的流行病学和临床证据表明，富含黄烷醇的饮食对人类的心血管健康有益。儿茶素和表儿茶素是食物中最常见的黄烷醇，以不同的对映体形式存在于饮食中。本研究探讨了黄烷醇立体化学构型对其吸收、代谢和生物活性的影响。健康成年男性被要求在一种明确的可可基、含乳制品的饮料基质中摄入等量的立体化学纯黄烷醇（-）-表儿茶素、（-）-儿茶素、（+）-儿茶素和（+）-表儿茶素（1.5mg/kg bw），随后在血浆和 24 小时尿液中测定黄烷醇水平。结果表明，黄烷醇的立体化学构型对其在人体中的吸收和代谢有深远的影响。此外，我们评估了每种黄烷醇立体异构体的血管扩张活性，发现（-）-表儿茶素是唯一能够介导显著动脉扩张反应的立体异构体。重要的是，这种作用独立于黄烷醇的经典抗氧化特性。总的来说，这些结果表明，与摄入含黄烷醇的食物相关的有益健康的效果将显著取决于摄入的黄烷醇的立体化学构型。
