目的 系統(tǒng)解析分級醇沉玉竹多糖（Polygonatum odoratum polysaccharides，POPs）各組分的精細結構，通過網絡藥理學預測其治療糖尿病的作用機制，并對其抗氧化與α-葡萄糖苷酶抑制活性進行評價。方法 采用梯度調節(jié)乙醇終體積分數（35%、55%、70%、85%）分離獲得4種POPs組分（POP-35、POP-55、POP-70、POP-85），通過傅里葉變換紅外光譜（fourier transform infrared spectroscopy，FT-IR）、核磁共振波譜（nuclear magnetic resonance，NMR）、氣相色譜-質譜聯(lián)用（gas chromatography-mass spectrometry，GC-MS）、高效凝膠滲透色譜（high performance gel permeation chromatography，HPGPC）和高效陰離子交換色譜（high performance anion exchange chromatography，HPAEC）聯(lián)合表征其理化性質，解析分子結構；基于網絡藥理學和分子對接技術，預測POPs治療糖尿病的作用機制；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'-聯(lián)氮-雙-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⁺還原力測定法和α-葡萄糖苷酶抑制試驗對POPs抗糖尿病活性進行評價；結果 4種POPs均為低相對分子質量（1.8×10³～2.4×10³）中性雜多糖，由果糖（84%～86%）與葡萄糖（14%～16%）構成。其中均一多糖POP-55的結構特征通過GC-MS與NMR波譜得以明確，其主鏈β-(2→1)-果糖殘基和α-(1→6)-葡萄糖殘基構成，側鏈含β-(2→6)-果糖殘基構成分支。網絡藥理學分析發(fā)現POP-55抗糖尿病的相關基因顯著富集于碳水化合物消化吸收、胰島素抵抗等信號通路，在相關基因中通過拓撲學分析篩選出信號轉導與轉錄激活因子3（signal transducer and activator of transcription 3，STAT3）、半胱氨酸天冬氨酸蛋白酶3（Caspase 3，CASP3）、白細胞介素-2（interleukin-2，IL-2）等6個核心基因，分子對接證實其都與POP-55有較好的結合能力。體外實驗表明，分級醇沉POPs具有顯著的抗氧化和α-葡萄糖苷酶抑制活性，并且具有濃度相關性。結論 分級醇沉POPs為菊粉型果聚糖，其降糖效應可能通過競爭性抑制α-葡萄糖苷酶活性延緩碳水化合物分解和調控IL-2介導的炎癥信號減輕胰島β細胞氧化損傷雙重途徑實現。

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

國家自然科學基金青年項目（82304133）；江蘇省自然科學基金青年項目（BK20230590）