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目的研究黄芪多糖MAPS-5的化学结构及其体外淋巴细胞增殖活性。方法联用微波辅助提取和膜过滤富集黄芪粗多糖,经DEAE-Cellulose弱阴离子交换树脂及Sephacryl S-400H-R凝胶柱色谱纯化得到一个黄芪均一多糖MAPS-5。采用酸水解、GC、IR、高碘酸氧化、Smith降解、甲基化、NMR、刚果红反应、原子力显微镜、电镜扫描等方法对其化学结构进行研究。并利用对刀豆蛋白(Con A)和脂多糖(LPS)诱导小鼠脾脏淋巴细胞增殖的影响,研究MAPS-5的免疫调节活性。结果MAPS-5是由α-D-(1-4)Glcp连接构成主链,且平均约每15个糖残基中有2个糖残基的C-6位被末端葡萄糖取代,其相对分子质量为1.32×10~4;构象研究表明MAPS-5的糖链在水溶液中不具备三股螺旋结构。MAPS-5体外可促进由Con A诱导的T淋巴细胞增殖(P<0.01、0.001),但对LPS诱导的B淋巴细胞增殖没有显著影响(P>0.05)。结论MAPS-5是黄芪中首次分离到的均一葡聚糖,具有促进由Con A诱导的T淋巴细胞增殖的活性。
Aim To study the chemical structure of MAPS-5 and its lymphocyte proliferative activity in vitro. Methods Microwave-assisted extraction and membrane filtration were used to enrich Astragalus polysaccharides. Purified Astragalus polysaccharide MAPS-5 was purified by DEAE-Cellulose weak anion exchange resin and Sephacryl S-400H-R gel column chromatography. The chemical structure was studied by acid hydrolysis, GC, IR, periodic acid oxidation, Smith degradation, methylation, NMR, Congo red reaction, atomic force microscopy and electron microscopy. The immunomodulatory activity of MAPS-5 was studied by using the effects of Con A and LPS on the splenic lymphocyte proliferation in mice. Results MAPS-5 was made up of α-D- (1-4) Glcp linkages and on average about 2 out of every 15 sugar residues were replaced by terminal glucose at position C-6, and their relative molecules The mass was 1.32 × 10 ~ 4. The conformational studies indicated that the sugar chains of MAPS-5 do not possess triple helical structure in aqueous solution. MAPS-5 promoted the proliferation of T lymphocytes induced by Con A (P <0.01, 0.001) in vitro, but had no significant effect on the proliferation of B lymphocytes induced by LPS (P> 0.05). Conclusions MAPS-5 is the first isolated dextran in Astragalus membranaceus. It has the activity of promoting the proliferation of T lymphocytes induced by Con A.