Abstract：
Medicago sativa polysaccharides (MSPs) are beneficial compounds extracted from Medicago sativa L. that exhibit multiple medicinal activities. However, little is known about their hypoglycemic effects. In this study, MSP-II-a, a neutral polysaccharide with an Mw of 4.3 × 104 Da, was isolated and purified from M. sativa L. Monosaccharide composition analysis determined that MSP-II-a was composed of arabinose, glucose, galactose, mannose, rhamnose, and xylose in a molar ratio of 2.1:4.0:1.1:0.4:1.4:1.1. Structural characterization of MSP-II was performed using a combination of methylation analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. The results showed that MSP-II-a was mainly comprised of 1,4-p-Glc, 1,3,4-Rha, and 1,3-p-Gal glycosidic linkages, revealing a mesh-like texture with irregular blade shapes. In vitro assays demonstrated that MSP-II-a, at concentrations of 200 and 400 μg/mL, promoted glucose uptake in insulin-resistant 3T3-L1 adipocytes. In vivo studies have shown that MSP-II-a significantly alleviates insulin resistance by reducing fasting blood glucose levels and increasing hepatic glycogen synthesis in HFD/STZ-induced diabetic mice. These findings revealed that MSP-II-a is a promising source of bioactive polysaccharides with potential hypoglycemic activity.
摘要：
紫花苜蓿多糖（MSP）是从紫花苜蓿中提取的有益化合物，具有多种药用活性。然而,对它们的降血糖作用知之甚少。在这项研究中,MSP-II-a,Mw为4.3×104Da的中性多糖，从紫花苜蓿中分离和纯化。单糖组成分析确定MSP-II-a由阿拉伯糖组成，葡萄糖，半乳糖,甘露糖,鼠李糖,和木糖的摩尔比为2.1:4.0:1.1:0.4:1.4:1.1。MSP-II的结构表征使用甲基化分析的组合进行，傅里叶变换红外光谱,和扫描电子显微镜。结果表明，MSP-II-a主要由1,4-p-Glc组成，1,3,4-Rha,和1,3-p-Gal糖苷键，显示具有不规则叶片形状的网状纹理。体外实验表明，MSP-II-a，在200和400μg/mL的浓度下，促进胰岛素抵抗3T3-L1脂肪细胞的葡萄糖摄取。体内研究表明，MSP-II-a通过降低HFD/STZ诱导的糖尿病小鼠的空腹血糖水平和增加肝糖原合成，可显着减轻胰岛素抵抗。这些发现揭示了MSP-II-a是具有潜在降血糖活性的生物活性多糖的有希望的来源。
