薇菜多糖的分离纯化及体外抗氧化活性

通过水提醇沉法制备薇菜粗多糖（water-soluble polysaccharide of Osmunda japonica，WOJP），并用二乙氨乙基（diethylaminoethyl，DEAE）-纤维素层析法对其进行分离纯化，获得2?个多糖组分薇菜中性糖（neutral WOJP，WOJP-N）和薇菜酸性糖（acidic WOJP，WOJP-A）。WOJP-N的分子质量为31.8?kDa，由鼠李糖、半乳糖醛酸、葡萄糖、半乳糖、木糖和阿拉伯糖组成，对应各成分物质的量比为9.1∶5.7∶13.3∶37.6∶5.6∶11.8；WOJP-A的分子质量为15.7?kDa，由鼠李糖、半乳糖醛酸、半乳糖和阿拉伯糖组成，对应各成分物质的量比为7.0∶56.4∶26.1∶5.2。傅里叶变换红外光谱分析结果表明，WOJP-N主要由β-构型的半乳糖组成；WOJP-A主要由吡喃半乳糖醛酸组成，且存在部分酯化修饰。体外抗氧化活性实验结果表明，WOJP的Fe3＋还原能力、1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl，DPPH）清除能力和超氧阴离子清除能力与VC相当，具有较好的抗氧化活性，其中WOJP-N和WOJP-A在WOJP发挥抗氧化活性时具有协同作用，两者均是WOJP发挥抗氧化活性的多糖组分。本研究结果可为进一步研究薇菜多糖的构效关系和开发功能性食品提供依据，并为薇菜的应用提供理论参考。

Isolation,Purification and Antioxidant Activity of Polysaccharides from Osmunda japonica

In this study, water-soluble polysaccharide from Osmunda japonica (WOJP), obtained by sequential water extraction and ethanol precipitation, was purified and fractionated by chromatography on diethylaminoethyl (DEAE)-cellulose columns into two major fractions: neutral WOJP (WOJP-N) and acidic WOJP (WOJP-A). As determined by high performance liquid chromatography (HPLC), the molecular mass of WOJP-N was 31.8 kDa, composed of rhamnose, galacturonic acid, glucose, galactose, xylose and arabinose, with a molar ratio of 9.1:5.7:13.3:37.6:5.6:11.8; WOJP-A had a molecular mass of 15.7 kDa, composed of rhamnose, galacturonic acid, galactose, and arabinose, with a molar ratio of 7.0:56.4:26.1:5.2. Fourier transform infrared spectroscopic (FTIR) analysis showed that WOJP-N was mainly composed of β-galactose; WOJP-A was mainly composed of galactopyranouronic acid with partial esterification modification. The antioxidant experiments showed that the Fe3+ reducing power, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, and superoxide anion radical scavenging capacity of WOJP were similar to those of vitamin C (VC), indicating that WOJP had good antioxidant activity. WOJP-N and WOJP-A played synergistic roles in antioxidant activity, and both of them were active components of WOJP. These results will provide a basis for further studies on the structure-activity relationship of polysaccharides from Osmunda oleracea and the development of potential functional foods, and also provide a reference for the application of Osmunda oleracea.