REQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
REQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
Biochim Biophys Acta Biomembr. 2020 Feb 1;1862(2):183133. doi: 10.1016/j.bbamem.2019.183133. Epub 2019 Nov 28.
Food polyphenols in fruits juices, tea, coffee, wine and beer confer sensory properties such as colour, astringency and bitterness. The development of functional healthy drinks without the unpleasant sensory feeling is boosting research for a clearer understanding on the interactions of polyphenols within the oral mucosa. In this study we investigated the interaction of astringent polyphenols, namely ECG, EGCG, procyanidin B4 and PGG, with lipids in model membranes by spectroscopic techniques. The membrane model was built varying the cholesterol content to mimic mouth regions and experiments were conducted at pH 5 to mimic the pH drop at the moment of beverage (e.g. green tea, red wine) intake. Fluorescence quenching results conducted on LUVs with cholesterol molar fractions ranging between 0.34 < χ < 0.74 and similar size distributions (122.9 ± 3.7 nm) showed that interaction of polyphenols is structure- and concentration-dependent. Also, the decrease of partition constants (K) with increasing cholesterol content (χchol) suggest that the affinity of polyphenols is weaker in cholesterol-rich liposomes. STD results revealed that the interaction of EGCG and PGG with membrane lipids involved mainly galloyl residues. Overall, spectroscopic data show that polyphenols interact to higher extent with more polar regions found in buccal, flour of the mouth and gingiva regions than with more hydrophobic regions located in the palate and tongue supporting that lipid microenvironments play a role in oral sensory perception.
水果汁、茶、咖啡、酒和啤酒中的食物多酚赋予了感官特性，如颜色、涩味和苦味。开发没有令人不快的感官感觉的功能性健康饮料，促进了对多酚在口腔黏膜内相互作用的更清晰理解的研究。在这项研究中，我们通过光谱技术研究了收敛性多酚，即 ECG、EGCG、原花青素 B4 和 PGG 与模型膜中脂质的相互作用。通过改变胆固醇含量来模拟口腔区域构建膜模型，并在 pH 5 下进行实验以模拟饮料（例如绿茶、红酒）摄入时的 pH 值下降。在胆固醇摩尔分数为 0.34 < χ < 0.74 且相似尺寸分布（122.9 ± 3.7nm）的 LUV 上进行的荧光猝灭结果表明，多酚的相互作用是结构和浓度依赖性的。此外，随着胆固醇含量（χchol）的增加，分配常数（K）的降低表明多酚在富含胆固醇的脂质体中的亲和力较弱。STD 结果表明，EGCG 和 PGG 与膜脂质的相互作用主要涉及没食子酰残基。总的来说，光谱数据表明，多酚与颊、口粉和牙龈区域中发现的更极性区域相互作用程度更高，而与位于腭和舌中的更疏水区相互作用程度较低，这支持了脂质微环境在口腔感官感知中发挥作用。
