微波法制备甘露糖醛酸寡糖及其抗氧化活性研究Δ

目的 制备分离不同聚合度的甘露糖醛酸寡糖单体,测定其体外抗氧化活性。方法 采用微波辅助降解法,制备甘露糖醛酸寡糖混合物,采用Bio Gel P-6凝胶渗透色谱法对寡糖混合物进行分离纯化,得到7个寡糖组分；运用薄层色谱法(HPTLC)、荧光辅助糖电泳法(FACE)、红外光谱法(IR)、质谱法(MS)对不同组分进行分析；比较不同寡糖组分对羟基自由基、超氧自由基、DPPH自由基的清除作用及对亚铁离子络合作用的差异。结果和结论 采用微波辅助法能够实现对聚甘露糖醛酸的可控降解,通过对寡糖混合物进行分离纯化获得7个组分,分别为聚合度为1~7的饱和甘露糖醛酸寡糖。体外抗氧化研究表明,甘露糖醛酸寡糖具有清除DPPH、羟基自由基、超氧自由基及络合亚铁离子的能力,其活性与寡糖聚合度有关。清除DPPH、超氧自由基及络合亚铁离子的能力随着寡糖单体聚合度增大而降低；清除羟基自由基的能力随着聚合度增加而升高。

Preparation of mannuroic acid oligosaccharides by microwave- assistant method and study of their in vitro antioxidant activities

Objective: Prepare and isolate mannuronic acid oligosaccharides mixture to obtain the different oligomers and evaluate their antioxidant activities in vitro. Method: The mannuronic acid oligosaccharides (MOS) was prepared by microwave-irradiation method and seven fractions were separated from MOS by Bio-Gel P6 column. The components of each fraction were analyzed by TLC, FACE analysis, IR and MS. The antioxidant activities including superoxide, DPPH and hydroxyl radical scavenging activity and chelating ferrous ions were further investigated. Results and Conclusion: The 7 fractions were identified to be saturated mannuronic acid oligosaccharides with 1~7 degree of polymerization (DP). The activity of the six oligomers (DP 2-7) was dose-dependent and related to their DP. The MOS with low DP showed better effect of chelating ferrous ions, scavenging superoxide and DPPH radical scavenging activities. In contrast, the hydroxyl radical scavenging activity of the MOS increased with DP.