蜈蚣藻多糖的降解及其体外抗氧化活性研究

Degradation of sulfated polysaccharides from Grateloupia filicina and their antioxidant activities in vitro

本文通过研究和优化降解条件,建立了一套降解快速、反应条件温和的蜈蚣藻多糖降解方法,并进一步制备得到不同分子量多糖,对其理化性质及体外抗氧化活性进行了研究。首先通过比较微波辅助降解法和传统加热降解法,验证了微波辅助降解法的高效性,并进一步对微波功率,不同配比的H2O2和HCl,及降解温度进行研究,研究结果表明微波功率600 W,1%H2O2(V/V),pH 2,降解温度70℃的降解条件为最优降解条件。并通过控制不同反应时间降解得到了4种低分子量蜈蚣藻多糖,分别为LGFP-1:40.8 kDa、LGFP-2:22.6 kDa、LGFP-3:5.1 kDa、LGFP-4:3.0 kDa。其理化性质分析表明,降解反应在一定程度上降低了蜈蚣藻多糖的总糖、硫酸根含量,而对蛋白含量和单糖组成无显著影响,红外光谱显示降解反应未破坏多糖的主要糖结构,并通过扫描电镜观察降解前后多糖具有明显差异,多糖结构越发松散,由原本的平面片状结构逐渐变成线状结构,并出现球状结节。不同分子量蜈蚣藻多糖显示出不同的抗氧化活性,其中低分子量蜈蚣藻多糖LGFP-2、LGFP-3、LGFP-4显示出更强的DPPH自由基、羟自由基清除能力和更强的还原能力。

The research was conducted to optimize the method for degradation of Grateloupia filicina polysaccharide(GFP)and established an effective technique for the preparation of low molecular weight(MW)polysaccharides.Five different MW polysaccharides were prepared and the chemical characterization and antioxidant capability were tested.Briefly,a comparison was made between the microwave irradiation method and the traditional heat method,and the former was used for the next study due to efficiency.More research has been conducted on microwave power,the dosage of H2O2 and HCl,as well as temperature.As a result,the optimum method with 600 W,1%H2O2(V/V),pH 2,70℃was established and low MW GFP(LGFP-1:40.8 kDa,LGFP-2:22.6 kDa,LGFP-3:5.1 kDa,LGFP-4:3.0 kDa)was prepared in this way.Moreover,the degradation process decreased the total sugar and sulfate content of LGFP1-4 from chemical analysis and FT-IR spectrum,but did not destroy the main structure and had little effect on protein and monosaccharide composition,and SEM photographs showed different surfaces from flat to line with nodules.As for antioxidant ability,LGFP-2,LGFP-3,LGFP-4 showed relatively high DPPH radical and hydroxyl radical scavenging,as well as reduced power.