紫甘薯多糖分离、组分鉴定及抗氧化代谢机理

本实验以紫甘薯为研究对象，通过提取紫甘薯多糖并利用高速逆流色谱对其进行分离纯化，获得一种具有一定抗氧化活性的多糖PSPP03，并对其结构进行理化性质和生物活性分析。结果表明，PSPP03分子质量为29.1 kDa，主要由阿拉伯糖（arabinose,Ara）、甘露糖（mannose,Man）、鼠李糖（rhamnose,Rha）、葡萄糖醛酸（glucuronic acid,GlcA）和葡萄糖（glucose,Glc）组成，物质的量比为16.2∶25.3∶7.1∶8.6∶10.8。甲基化分析结果表明PSPP03的糖苷键构成主要为→1)-Araf-(→3、→3)-Manp-(1→、→3,4)-Manp-(1→、→3,6)-Manp-(1→、→3)-Glcp-(1→、Glcp-(1→和→4)-Rhap-(1→。液相色谱-串联质谱分析结果表明多糖结构中含有芍药素-3-槐糖苷-5-葡萄糖和矢车菊素-3-槐糖苷-5-葡萄糖。细胞氧化实验分析结果表明25、100?μg/mL PSPP03可以极显著降低氧化损伤细胞模型内活性氧、丙二醛和氧化型谷胱甘肽水平（P<0.01），极显著提高过氧化氢酶、谷胱...

Isolation and Structural Characterization of an Antioxidant Polysaccharide from Purple Sweet Potato and Metabonomic Evaluation of Its Antioxidant Mechanism

In the present study, a polysaccharide with antioxidant activity, named PSPP03, was obtained from purple sweet potato by purification using high-speed countercurrent chromatography. Its structural, physicochemical and biological properties were evaluated. The results showed that the molecular mass of PSPP03 was estimated to be 29.1 kDa and it was mainly composed of arabinose (Ara), mannose (Man), rhabose (Rha), glucuronic acid (GlcA) and glucose (Glc) with a molar ratio of 16.2:25.3:7.1:8.6:10.8. The glycosidic bond composition of PSPP03 was analyzed after methylation, revealing that it mainly contained →1)-Araf-(→3,→3)-Manp-(1→, →3,4)-Manp-(1→, →3,6)-Manp-(1→, →3)-Glcp-(1→, Glcp-(1→ and →4)-Rhap-(1→. Cyanidin-3-sophoroside-5-glucoside and peonidin-3-sophoroside-5-glucoside were detected in the structure of PSPP03 by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Cellular antioxidant tests showed that PSPP03 at 25 and 100 μg/mL significantly reduced the levels of reactive oxygen species (ROS), malondialdehyde (MDA) and glutathione disulfide (GSSG) (P < 0.01), and increased activities of catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) as well as the content of glutathione (GSH) (P < 0.01). Metabolomic analysis suggested that PSPP03 may reduce cellular oxidative damage by promoting the metabolism of related amino acids and the tricarboxylic acid cycle. The results of this study will provide a theoretical basis for the application of purple sweet potato polysaccharides, which is of great significance for the comprehensive development of purple sweet potato.