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目的从扁玉螺(Neverita didyma)中提取和分离纯化多糖,并对其基本理化性质和结构组成进行分析。方法依次采用水提和碱提方法从扁玉螺中提取粗多糖,采用DEAE Sepharose FF阴离子交换和Sephacryl S-300凝胶柱层析对粗多糖进行分离纯化,并对其总糖、蛋白、氨基糖、糖醛酸和硫酸根含量,相对分子质量和单糖组成进行分析。对多糖纯化组分采用甲基化、气质联用(GC-MS)、红外光谱(IR)、电喷雾质谱(ESI-MS)和核磁共振波谱(NMR)对其化学结构进行分析。结果扁玉螺水提粗多糖(BYL-S)中不含有糖醛酸和硫酸基,其单糖组成只含Glc,进一步分离得到了4种水溶性多糖组分。碱提粗多糖(BYL-J)单糖组成相对复杂,除含有Glc外,还含有Man、GlcN、GalN、Gal和Fuc,其摩尔比为Glc∶Man∶GlcN∶GalN∶Gal∶Fuc=78.9∶1.7∶3.4∶2.2∶5.2∶5.6,进一步分离得到了3种多糖组分。对水提多糖纯化组分BYL-S2的结构分析表明其是以α-(1→4)为主链,含有少量β-(1→3,4)和β-(1→3)分支的D-吡喃型葡聚糖。结论从扁玉螺中提取分离得到了7种多糖组分,并确定了一种水溶性葡聚糖的结构,为扁玉螺多糖结构和活性的深入研究提供了基础。
Objective To extract and purify polysaccharides from Neverita didyma and to analyze its basic physical and chemical properties and structure. Methods Crude polysaccharides were extracted from Biloba by sequential extraction with water and alkali. The crude polysaccharides were separated and purified by DEAE Sepharose FF anion exchange chromatography and Sephacryl S-300 gel column chromatography. The total sugar, protein, amino Sugar, uronic acid and sulfate content, relative molecular mass and monosaccharide composition were analyzed. The chemical constituents of polysaccharides were analyzed by methylation, GC-MS, IR, ESI-MS and NMR. Results The results showed that BYL-S contained no uronic acid and sulfate groups, and its monosaccharide composition only contained Glc. Four water-soluble polysaccharide components were further isolated. The composition of BYL-J monosaccharide is relatively complex, and contains not only Glc, but also Man, GlcN, GalN, Gal and Fuc in a molar ratio of Glc: Man: GlcN: GalN: Gal: Fuc = 78.9: 1.7: 3.4: 2.2: 5.2: 5.6, further separation of the three polysaccharide components. The structural analysis of the purified polysaccharide BYL-S2 showed that it was mainly composed of α- (1 → 4) with a small amount of D- (1 → 3,4) and β- (1 → 3) - glucopyranose. Conclusion Seven kinds of polysaccharides were isolated and isolated from Biloba, and the structure of one kind of water-soluble dextran was determined. It provided the basis for further study on the structure and activity of polysaccharides from Biloba.