Corona Giulia, Ji Yang, Anegboonlap Prapaporn, Hotchkiss Sarah, Gill Chris, Yaqoob Parveen, Spencer Jeremy P E, Rowland Ian
1Health Sciences Research Centre,University of Roehampton,London SW15 4JD,UK.
2Department of Food and Nutritional Sciences,University of Reading,Reading RG6 6AP,UK.
Br J Nutr. 2016 Apr 14;115(7):1240-53. doi: 10.1017/S0007114516000210. Epub 2016 Feb 16.
Brown seaweeds such as Ascophyllum nodosum are a rich source of phlorotannins (oligomers and polymers of phloroglucinol units), a class of polyphenols that are unique to Phaeophyceae. At present, there is no information on the bioavailability of seaweed polyphenols and limited evidence on their bioactivity in vivo. Consequently, we investigated the gastrointestinal modifications in vitro of seaweed phlorotannins from A. nodosum and their bioavailability and effect on inflammatory markers in healthy participants. In vitro, some phlorotannin oligomers were identified after digestion and colonic fermentation. In addition, seven metabolites corresponding to in vitro-absorbed metabolites were identified. Urine and plasma samples contained a variety of metabolites attributed to both unconjugated and conjugated metabolites (glucuronides and/or sulphates). In both urine and plasma, the majority of the metabolites were found in samples collected at late time points (6-24 h), suggesting colonic metabolism of high-molecular-weight phlorotannins, with three phlorotannin oligomers (hydroxytrifuhalol A, 7-hydroxyeckol, C-O-C dimer of phloroglucinol) identified in urine samples. A significant increase of the cytokine IL-8 was also observed. Our study shows for the first time that seaweed phlorotannins are metabolised and absorbed, predominantly in the large intestine, and there is a large inter-individual variation in their metabolic profile. Three phlorotannin oligomers present in the capsule are excreted in urine. Our study is the first investigation of the metabolism and bioavailability of seaweed phlorotannins and the role of colonic biotransformation. In addition, IL-8 is a possible target for phlorotannin bioactivity.
诸如泡叶藻之类的褐藻是间苯三酚单宁（间苯三酚单元的低聚物和聚合物）的丰富来源，间苯三酚单宁是一类褐藻纲特有的多酚。目前，关于海藻多酚的生物利用度尚无信息，且其体内生物活性的证据有限。因此，我们研究了泡叶藻海藻间苯三酚单宁在体外的胃肠道变化及其生物利用度，以及对健康参与者炎症标志物的影响。在体外，消化和结肠发酵后鉴定出了一些间苯三酚单宁低聚物。此外，还鉴定出了七种与体外吸收代谢物相对应的代谢物。尿液和血浆样本中含有多种归因于未结合和结合代谢物（葡萄糖醛酸苷和/或硫酸盐）的代谢物。在尿液和血浆中，大多数代谢物在较晚时间点（6 - 24小时）采集的样本中被发现，这表明高分子量间苯三酚单宁的结肠代谢，尿液样本中鉴定出了三种间苯三酚单宁低聚物（羟基三卤酚A、7 - 羟基eckol、间苯三酚的C - O - C二聚体）。还观察到细胞因子IL - 8显著增加。我们的研究首次表明，海藻间苯三酚单宁主要在大肠中被代谢和吸收，并且其代谢谱存在很大的个体间差异。胶囊中存在的三种间苯三酚单宁低聚物经尿液排泄。我们的研究是对海藻间苯三酚单宁的代谢、生物利用度以及结肠生物转化作用的首次调查。此外，IL - 8可能是间苯三酚单宁生物活性的一个靶点。
