Department of Agri-Food Industry, Food & Nutrition, "Luiz de Queiroz" College of Agriculture, University of São Paulo, P.O. Box 9, CEP 13418-900 Piracicaba, SP, Brazil.
Department of Agri-Food Industry, Food & Nutrition, "Luiz de Queiroz" College of Agriculture, University of São Paulo, P.O. Box 9, CEP 13418-900 Piracicaba, SP, Brazil; Department of Food Science, Faculty of Food Engineering, University of Campinas, CEP 13083-862 Campinas, SP, Brazil.
Food Res Int. 2020 May;131:108532. doi: 10.1016/j.foodres.2019.108532. Epub 2019 Jul 3.
Winemaking generates large amounts of by-products, a well recognized source of phenolic compounds. However, less attention has been paid to the polysaccharide-rich fraction (PRF) and effects of fractionation techniques on its potential bioactivity. Therefore, PRFs from Syrah and Tempranillo winemaking by-products were extracted under aqueous (neutral pH conditions), acidic and alkaline conditions. PRFs were screened for their monosaccharide composition, uronic acid content, homogeneity and molecular weight. Anti-inflammatory activity of PRFs were evaluated on stimulated RAW 264.7 macrophages. PRF obtained in water and/or under acidic conditions showed heterogeneous profiles. As like as in the others, a heterogeneous and complex profile was detected in extracts procured under alkaline conditions. A high content of uronic acid was found in aqueous extracts, thus indicating the presence of pectin. Pectin and hemicellulose were present in PRFs procured under acidic conditions. Alkaline conditions rendered extracts containing a complex mixture of monosaccharides, mainly xylose. This latter PRF was the only one exhibiting anti-inflammatory potential (at 100 μg/mL) by reducing the release of TNF-α and activation of NF-κB in LPS-activated RAW 264.7 macrophages, with no effect on cell viability. Regardless of the grape variety, PRFs obtained under alkaline conditions were the best option to obtain bioactive polysaccharides with potential application as a source of anti-inflammatory compounds. A complex mixture of polymers may be responsible for the anti-inflammatory effects. Finally, according to results procured by NMR, it is possible to suggest that bioactive fractions are composed of a chain of α-L-Araf-(1 → 3) linked, β-D-Xylp- (1 → 4), α-D-Glcp-(1 → 4) linked, α-D-GalpA-(1 → 4), α-D-Gal-(1 → 2) forming possible RG I and RG II and xylan chains.
酿酒产生大量副产物，这是酚类化合物的公认来源。然而，人们对富含多糖的馏分（PRF）及其分馏技术对其潜在生物活性的影响关注较少。因此，从西拉和添普兰尼洛酿酒副产物中提取了 PRF，提取条件分别为水相（中性 pH 条件）、酸性和碱性条件。对 PRF 的单糖组成、糖醛酸含量、均一性和分子量进行了筛选。用刺激 RAW 264.7 巨噬细胞评估 PRF 的抗炎活性。在水和/或酸性条件下获得的 PRF 显示出不均匀的图谱。与其他条件一样，在碱性条件下提取的提取物中也检测到不均匀和复杂的图谱。水提取物中发现了高含量的糖醛酸，表明存在果胶。在酸性条件下提取的 PRF 中存在果胶和半纤维素。碱性条件使提取物中含有复杂的单糖混合物，主要是木糖。这种 PRF 是唯一具有抗炎潜力的提取物（在 100μg/ml 时），可减少 LPS 激活的 RAW 264.7 巨噬细胞中 TNF-α 的释放和 NF-κB 的激活，对细胞活力没有影响。无论葡萄品种如何，在碱性条件下获得的 PRF 都是获得具有潜在抗炎化合物应用的生物活性多糖的最佳选择。复杂的聚合物混合物可能是抗炎作用的原因。最后，根据 NMR 结果，可以推测生物活性馏分由α-L-Araf-（1→3）连接的链、β-D-Xylp-（1→4）、α-D-Glcp-（1→4）连接的链、α-D-GalpA-（1→4）、α-D-Gal-（1→2）组成，可能形成 RG I 和 RG II 和木聚糖链。
