Research Data 1

Polysaccharides from Glycyrrhiza are known to have several bioactive effects. However, the relationship of immune activity and structure of low-molecular-weight purified polysaccharide (GP) originated from Glycyrrhiza remains not entirely cleared. In this work, low molecular weight G. polysaccharides (GP1) were obtained through DEAE cellulose-52 column and sephadex G-100 chromatogram. Physicochemical property analysis indicates that GP1 is the low-weight-molecular polysaccharides (6.5 kDa), mainly composed of glucose (98.59%). The backbone structure of GP1 was determined as→4)-α-D-Glcp-(1→ (58.8%) and →6)-α-D-Glcp-(1→ (9.3%) residues, with branching at O-4 position of →4,6)-α-D-Glcp-(1→ mainly by α-D-Glcp-(1→. Moreover, GP1 had good antioxidant ability, and enhanced the phagocytic ability of macrophages RAW264.7 and increased the secretion of NO and cytokines IL-1β, IL-6 and TNF-α. In vitro simulation experiment showed that GP1 was degraded under the action of intestinal flora, and produced a large number of SCFAs and promoted the proliferation of Lactobacillus, HT002 and Ligilactobacillus. In addition, in vivo experiments showed that GP1 significantly enhanced the immune organ index of mice, repaired the intestinal structure, increased the number of goblet cells, CD4+ and CD8+ T cells, the amount of mucus and cytokines secretion (IL-1β, IL-6 and TNF-α). GP1 also significantly alleviates CTX-induced immunosuppression and intestinal damage by up-regulating TLR2, TLR4 and TLR6 signaling pathways. These findings supplied a foundation for further research on the possible mechanism of low-weight-molecular G. polysaccharide regulation of immune response.已知甘草（Glycyrrhiza）来源的多糖具有多种生物活性功效。然而，源自甘草的低分子纯化多糖（GP）的免疫活性与其结构之间的关联仍未完全阐明。本研究通过二乙氨基乙基纤维素-52（DEAE cellulose-52）柱色谱与葡聚糖凝胶G-100（Sephadex G-100）色谱法，分离得到低分子甘草多糖（GP1）。理化性质分析结果显示，GP1为分子量6.5 kDa的低分子多糖，主要组成单糖为葡萄糖，占比达98.59%。经解析，GP1的主链结构由→4)-α-D-葡萄糖吡喃糖基-(1→（占比58.8%）与→6)-α-D-葡萄糖吡喃糖基-(1→（占比9.3%）残基构成，其分支主要通过α-D-葡萄糖吡喃糖基-(1→连接于→4,6)-α-D-葡萄糖吡喃糖基-(1→的O-4位。此外，GP1具备良好的抗氧化能力，可增强RAW264.7巨噬细胞的吞噬功能，并促进一氧化氮（NO）及细胞因子IL-1β、IL-6与TNF-α的分泌。体外模拟实验表明，GP1可在肠道菌群作用下降解，产生大量短链脂肪酸（SCFAs），并促进乳杆菌属（Lactobacillus）、HT002以及Ligilactobacillus的增殖。体内实验结果显示，GP1可显著提升小鼠的免疫器官指数，修复肠道组织结构，增加杯状细胞、CD4+与CD8+ T细胞的数量，提升黏液分泌量及细胞因子（IL-1β、IL-6与TNF-α）的分泌水平。GP1还可通过上调TLR2、TLR4及TLR6信号通路，显著缓解环磷酰胺（CTX）诱导的免疫抑制与肠道损伤。上述研究结果为低分子甘草多糖调控免疫应答的潜在作用机制的后续研究提供了理论依据。