目的 系统解析分级醇沉玉竹多糖（Polygonatum odoratum polysaccharides，POPs）各组分的精细结构，通过网络药理学预测其治疗糖尿病的作用机制，并对其抗氧化与α-葡萄糖苷酶抑制活性进行评价。方法 采用梯度调节乙醇终体积分数（35%、55%、70%、85%）分离获得4种POPs组分（POP-35、POP-55、POP-70、POP-85），通过傅里叶变换红外光谱（fourier transform infrared spectroscopy，FT-IR）、核磁共振波谱（nuclear magnetic resonance，NMR）、气相色谱-质谱联用（gas chromatography-mass spectrometry，GC-MS）、高效凝胶渗透色谱（high performance gel permeation chromatography，HPGPC）和高效阴离子交换色谱（high performance anion exchange chromatography，HPAEC）联合表征其理化性质，解析分子结构；基于网络药理学和分子对接技术，预测POPs治疗糖尿病的作用机制；采用1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picryl-hydrazyl，DPPH）自由基清除法、2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸 [2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)，ABTS]自由基清除法、Fe³⁺还原力测定法和α-葡萄糖苷酶抑制试验对POPs抗糖尿病活性进行评价；结果 4种POPs均为低相对分子质量（1.8×10³～2.4×10³）中性杂多糖，由果糖（84%～86%）与葡萄糖（14%～16%）构成。其中均一多糖POP-55的结构特征通过GC-MS与NMR波谱得以明确，其主链β-(2→1)-果糖残基和α-(1→6)-葡萄糖残基构成，侧链含β-(2→6)-果糖残基构成分支。网络药理学分析发现POP-55抗糖尿病的相关基因显著富集于碳水化合物消化吸收、胰岛素抵抗等信号通路，在相关基因中通过拓扑学分析筛选出信号转导与转录激活因子3（signal transducer and activator of transcription 3，STAT3）、半胱氨酸天冬氨酸蛋白酶3（Caspase 3，CASP3）、白细胞介素-2（interleukin-2，IL-2）等6个核心基因，分子对接证实其都与POP-55有较好的结合能力。体外实验表明，分级醇沉POPs具有显著的抗氧化和α-葡萄糖苷酶抑制活性，并且具有浓度相关性。结论 分级醇沉POPs为菊粉型果聚糖，其降糖效应可能通过竞争性抑制α-葡萄糖苷酶活性延缓碳水化合物分解和调控IL-2介导的炎症信号减轻胰岛β细胞氧化损伤双重途径实现。

Objective This study systematically elucidates the fine structural characteristics of graded ethanol-precipitated Polygonatum odoratum polysaccharides (POPs), predicts their therapeutic mechanisms against diabetes through network pharmacology, and evaluates their antioxidant and α-glucosidase inhibitory activities. Methods Four POPs fractions (POP-35, POP-55, POP-70, POP-85) were isolated by gradient ethanol precipitation (35%, 55%, 70%, 85%). Their physicochemical properties and molecular structures were characterized using Fourier-transform infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS), nuclear magnetic resonance (NMR), high-performance gel permeation chromatography (HPGPC), and high-performance anion-exchange chromatography (HPAEC). Network pharmacology and molecular docking were employed to predict antidiabetic mechanisms. Antidiabetic activities were assessed via DPPH/ABTS radical scavenging assays, ferric ion reducing power assay, and α-glucosidase inhibition assay. Results All four POPs fractions were low-molecular-weight (1.8×10³—2.4×10³) neutral heteropolysaccharides composed of fructose (84%—86%) and glucose (14%—16%). The homogeneous polysaccharide POP-55 exhibited a backbone of →2)-β-D-Fruf-(1→ glycosidic linkages with minor α-D-Glcp-(1→6) branched side chains, as confirmed by GC-MS and NMR. Network pharmacology analysis revealed that POP-55-related antidiabetic genes were significantly enriched in pathways such as carbohydrate digestion and absorption, insulin resistance and so on. Topological analysis identified six core targets (STAT3, CASP3, IL2, etc.) among these genes, which were further validated by molecular docking to exhibit strong binding affinities with POP-55. Conclusion Graded ethanol-precipitated POPs are inulin-type fructans exerting hypoglycemic effects through dual mechanisms: competitively inhibiting α-glucosidase to delay carbohydrate hydrolysis, and regulating IL2-mediated inflammatory signaling to alleviate oxidative damage in pancreatic β-cells.

R284.1

国家自然科学基金青年项目（82304133）；江苏省自然科学基金青年项目（BK20230590）