冬枣多糖的分离纯化及抗氧化活性研究

目的:分离纯化冬枣多糖,并研究其组分、结构特征和抗氧化活性。方法:采用水提醇沉、脱蛋白脱色、DEAE-52纤维素柱和Sephadex G-100凝胶色谱柱分离纯化冬枣多糖;利用Sephadex G-100凝胶色谱柱进行纯度鉴定和分子质量的测定;通过紫外光谱、红外光谱、气相色谱法进行了初步结构分析;采用邻二氮菲法和1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)体系对纯化多糖进行抗氧化活性的研究。结果:冬枣多糖经DEAE-52分离和Sephadex G-100纯化得到2个组分DPA和DPB,经Sephadex G-100鉴定均为均一组分,DPA和DPB分子质量分别为1.04×10~4、3.02×10~5 D,不含蛋白质和核酸,为吡喃型糖苷环骨架,DPA的单糖组成为阿拉伯糖、甘露糖、葡萄糖、半乳糖,其物质的量比为6.66∶1.00∶6.75∶2.09;DPB的单糖组成为鼠李糖、阿拉伯糖、甘露糖、葡萄糖、半乳糖,其物质的量比为4.33∶10.90∶1.00∶3.25∶4.78;DPA和DPB均具有一定的抗氧化活性,随着多糖质量浓度的增加,其抗氧化活性增强,在质量浓度为8 mg/m L时对羟自由基清除率分别为28.52%、78.79%,在质量浓度为0.4 mg/m L时对DPPH自由基清除率分别为9.97%、24.54%。结论:DPA和DPB均具有一定的抗氧化活性。

Isolation,Purification and Antioxidant Activity of Polysaccharides from Zizyphus jujube cv. Dongzao

Objective: To study the monosaccharide composition, structure and antioxidant activity of polysaccharide
fractions isolated and purified from Zizyphus jujube cv. Dongzao. Methods: The extraction of polysaccharides was performed
by water extraction and subsequent ethanol precipitation, and after removal of proteins and pigments, the polysaccharides
were purified by successive DEAE-52 cellulose column and Sephadex G-100 gel column chromatography. The purity
and molecular weights of the purified polysaccharides were determined by Sephadex G-100 column chromatography.
Preliminary structural characterization was carried out by ultraviolet-visible (UV-VIS) spectroscopy, infrared (IR)
spectroscopy and gas chromatography (GC). The antioxidant activity of the crude and purified polysaccharides was evaluated
using the phenanthroline method and 1, 1-diphenyl-2-picrylhydroxyl (DPPH) radical scavenging activity assay. Results:
Two polysaccharide fractions (DPA and DPB) were purified to homogeneity from the crude polysaccharides as identified by
Sephadex G-100. The molecular weight of DPA and DPB was 1.04 × 104 and 3.02 × 105 D, respectively. DPA and DPB did
not contain protein or nucleic acid, but contained the pyranose ring skeleton glucoside. The monosaccharide composition
of DPA consisted of arabinose, mannose, glucose and galactose with a molar ratio of 6.66:1.00:6.75:2.09, whereas that of
DPB consisted of rhamnose, arabinose, mannose, glucose and galactose with a molar ratio of 4.33:10.90:1.00:3.25:4.78.
The crude polysaccharides, DPA and DPB all had antioxidant activity in a concentration dependent manner. The scavenging
percentages of DPA and DPB at 8 mg/mL for hydroxyl radical were 28.52% and 78.79% respectively, which were 9.97%
and 24.54% at 0.4 mg/mL, respectively. Conclusion: Both DPA and DPB had antioxidant activity.