Holt Roberta R, Lazarus Sheryl A, Sullards M Cameron, Zhu Qin Yan, Schramm Derek D, Hammerstone John F, Fraga Cesar G, Schmitz Harold H, Keen Carl L
Department of Nutrition, University of California, Davis 95616-8669, USA.
Am J Clin Nutr. 2002 Oct;76(4):798-804. doi: 10.1093/ajcn/76.4.798.
Epidemiologic studies have linked flavonoid-rich foods with a reduced risk of cardiovascular mortality. Some cocoas are flavonoid-rich and contain the monomeric flavanols (-)-epicatechin and (+)-catechin and oligomeric procyanidins formed from these monomeric units. Both the monomers and the oligomers have shown potential in favorably influencing cardiovascular health in in vitro and preliminary clinical studies. Although previous investigations have shown increasing concentrations of (-)-epicatechin in human plasma after cocoa consumption, no information is available in the published literature regarding the presence of procyanidins in human plasma.
This study sought to determine whether procyanidins can be detected and quantified in human plasma after acute consumption of a flavanol-rich cocoa.
Peripheral blood was obtained from 5 healthy adult subjects before (baseline, 0 h) and 0.5, 2, and 6 h after consumption of 0.375 g cocoa/kg body wt as a beverage. Plasma samples were analyzed for monomers and procyanidins with the use of reversed-phase HPLC with coulometric electrochemical array detection and liquid chromatography-tandem mass spectrometry.
Procyanidin dimer, (-)-epicatechin, and (+)-catechin were detected in the plasma of human subjects as early as 0.5 h (16 +/- 5 nmol/L, 2.61 +/- 0.46 micro mol/L, and 0.13 +/- 0.03 micro mol/L, respectively) after acute cocoa consumption and reached maximal concentrations by 2 h (41 +/- 4 nmol/L, 5.92 +/- 0.60 micro mol/L, and 0.16 +/- 0.03 micro mol/L, respectively).
Dimeric procyanidins can be detected in human plasma as early as 30 min after the consumption of a flavanol-rich food such as cocoa.
流行病学研究表明，富含类黄酮的食物可降低心血管疾病死亡率。一些可可富含类黄酮，含有单体黄烷醇（-）-表儿茶素和（+）-儿茶素以及由这些单体单元形成的低聚原花青素。在体外和初步临床研究中，单体和低聚物均显示出对心血管健康有潜在的有利影响。尽管先前的研究表明，食用可可后人体血浆中（-）-表儿茶素的浓度会升高，但已发表的文献中没有关于人体血浆中原花青素存在情况的信息。
本研究旨在确定急性食用富含黄烷醇的可可后，人体血浆中是否能检测到原花青素并进行定量。
从5名健康成年受试者身上采集外周血，分别在饮用含0.375 g可可/千克体重的饮料前（基线，0小时）以及饮用后0.5、2和6小时采集。使用反相高效液相色谱法结合库仑电化学阵列检测和液相色谱-串联质谱法分析血浆样品中的单体和原花青素。
急性食用可可后，最早在0.5小时即可在人体受试者血浆中检测到原花青素二聚体、（-）-表儿茶素和（+）-儿茶素（分别为16±5 nmol/L、2.61±0.46 μmol/L和0.13±0.03 μmol/L），并在2小时时达到最高浓度（分别为41±4 nmol/L、5.92±0.60 μmol/L和0.16±0.03 μmol/L）。
食用富含黄烷醇的食物（如可可）后30分钟，人体血浆中即可检测到二聚体原花青素。
