Liu Li, Wang Haidi, Li Xuan, Zhang Liang, Zhang Xufeng, Xu Xiaojuan
Yunnan Key Laboratory of Modern Separation Analysis and Substance Transformation, College of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming 650092, China.
College of Chemistry and Molecular Sciences, Hubei Engineering Center of Natural Polymer-Based Medical Materials, Wuhan University, Wuhan 430072, China.
Int J Biol Macromol. 2025 Feb;291:139091. doi: 10.1016/j.ijbiomac.2024.139091. Epub 2024 Dec 21.
The purification of polysaccharides is an essential preliminary step in determining their chemical structure, although it presents significant challenges. In this research, a macro-porous monolith of quaternary chitosan cryogel was synthesized for the purification of a neutral polysaccharide from Boletus auripes. A homogeneous neutral polysaccharide (BAP-1a1) with a weight-average molecular weight of 4.13 × 10 Da and a polydispersity index of 1.28 was successfully isolated. The structure of BAP-1a1 was elucidated through a comprehensive characterization utilizing size exclusion chromatography (SEC) combined with laser light scattering (LLS), infrared spectroscopy, monosaccharide composition analysis, methylation analysis, and nuclear magnetic resonance (NMR) spectroscopy. The results revealed that the BAP-1a1 was characterized as a glucan with a backbone structure consisting of 1,4-α-D-Glcp and 1,3-β-D-Glcp glycosidic linkages in a molar ratio of 2:1. Additionally, a minority of branched chains of 1-α-D-Glcp are attached to 1,3-β-D-Glcp residues at the C6 position. In vitro antioxidant activity assays demonstrated that BAP-1a1 exhibits a dose-dependent scavenging effect on ABTS and DPPH radicals with EC values of 0.58 and 1.04 mg/mL, respectively. These findings indicated that Boletus auripes possesses the potential to be utilized as a natural agent in antioxidant functional foods.
多糖的纯化是确定其化学结构的重要前期步骤，尽管这存在重大挑战。在本研究中，合成了一种季铵化壳聚糖冷冻凝胶大孔整体柱，用于从黄牛肝菌中纯化一种中性多糖。成功分离出一种重均分子量为4.13×10 Da、多分散指数为1.28的均一中性多糖（BAP-1a1）。通过尺寸排阻色谱（SEC）结合激光光散射（LLS）、红外光谱、单糖组成分析、甲基化分析和核磁共振（NMR）光谱等综合表征手段阐明了BAP-1a1的结构。结果表明，BAP-1a1为一种葡聚糖，其主链结构由摩尔比为2:1的1,4-α-D-葡萄糖苷键和1,3-β-D-葡萄糖苷键组成。此外，少数1-α-D-葡萄糖的支链连接在1,3-β-D-葡萄糖残基的C6位。体外抗氧化活性测定表明，BAP-1a1对ABTS和DPPH自由基具有剂量依赖性清除作用，EC值分别为0.58和1.04 mg/mL。这些发现表明，黄牛肝菌有潜力作为抗氧化功能食品中的天然成分加以利用。
