化学修饰对山药叶多糖结构、体外抗氧化及降糖活性的影响

王蓉; 冯薇; 徐高铖; 李紫薇

doi:10.13386/j.issn1002-0306.2026010021

化学修饰对山药叶多糖结构、体外抗氧化及降糖活性的影响

Effects of Chemical Modification on the Structure, in Vitro Antioxidant Activity, and Hypoglycemic Activity of Dioscorea opposita Thunb. Leaf Polysaccharides

摘要

摘要: 探究化学修饰对多糖结构、体外抗氧化与降糖能力的影响。本文以山药叶多糖（Dioscorea opposita Thunb. leaf polysaccharides，DOLP）为供试材料，采用乙酸酐法、碱-氯乙酸法、氯磺酸-吡啶法、硝酸-亚硒酸钠法分别制备乙酰化、羧甲基化、硫酸化、硒化多糖衍生物，并测定其取代度与硒含量。通过光谱与色谱技术对DOLP及其衍生物进行结构表征，并评估其体外抗氧化和降糖活性。乙酰化山药叶多糖（DOLP-Ac）、羧甲基化山药叶多糖（DOLP-C）、硫酸化山药叶多糖（DOLP-S）、硒化山药叶多糖（DOLP-Se）的取代度与硒含量分别为0.4±0.01、0.13±0.02、0.26±0.01、7.29%±0.44%。DOLP及其衍生物主要由鼠李糖、阿拉伯糖、甘露糖、葡萄糖、半乳糖组成，且具有三螺旋结构。红外光谱证实了DOLP化学修饰成功，并且衍生物表面形貌与热稳定性均发生改变，其中DOLP-Se的结晶度增加，DOLP-C和DOLP-S热稳定性提高。体外活性结果显示，DOLP-S对ABTS⁺自由基清除能力较强，IC₅₀为1.815 mg/mL；DOLP-Se对DPPH、OH自由基清除能力显著，IC₅₀分别为1.717、1.868 mg/mL，并具备一定还原力。DOLP-Se对α-淀粉酶、α-葡萄糖苷酶的抑制能力优异，IC₅₀分别为4.233、1.76 mg/mL。本研究为山药叶多糖的深入探索提供了理论依据，表明化学修饰能够有效调控多糖的理化性质与活性，有助于推动功能性多糖的开发与利用。

Abstract: Objective: Investigating the effects of chemical modification on the structure, in vitro antioxidant, and hypoglycemic activities of polysaccharides. Methods: This study employed the polysaccharide DOLP from the leaves of Dioscorea opposita Thunb. as the test material. Using the acetic anhydride method, alkali-chloroacetic acid method, chlorosulfonic acid-pyridine method, and nitric acid-sodium selenite method to prepare acetylated, carboxymethylated, sulfated, and selenated polysaccharide derivatives, respectively, and determined their degrees of substitution and selenium content. The structural characterization of DOLP and its derivatives was performed using spectroscopic and chromatographic techniques, and their in vitro antioxidant and hypoglycemic activities were evaluated. Results: The substitution degrees and selenium contents of DOLP-Ac, DOLP-C, DOLP-S, and DOLP-Se were 0.4±0.01, 0.13±0.02, 0.26±0.01, and 7.29%±0.44%, respectively. DOLP and its derivatives were primarily composed of rhamnose, arabinose, mannose, glucose, and galactose, and exhibit a triple-helix structure. Infrared spectroscopy confirmed the successful chemical modification of DOLP, with both the surface morphology and thermal stability of the derivatives altered. Specifically, the crystallinity of DOLP-Se increased, while DOLP-C and DOLP-S exhibited enhanced thermal stability. In vitro activity results indicate that DOLP-S exhibited strong ABTS⁺ radical scavenging capacity with an IC₅₀ of 1.815 mg/mL. DOLP-Se demonstrates significant scavenging activity against DPPH and OH radicals with IC₅₀ values of 1.717 and 1.868 mg/mL, respectively, and possesses certain reducing properties. DOLP-Se exhibited excellent inhibitory activity against α-amylase and α-glucosidase, with IC₅₀ values of 4.233 and 1.76 mg/mL, respectively. Conclusion: This study provides a theoretical basis for the in-depth exploration of the polysaccharides from the leaves of Dioscorea opposita Thunb., demonstrating that chemical modification can effectively regulate the physicochemical properties and activity of polysaccharides, thereby advancing the development and utilization of functional polysaccharides.