竹茹多糖的化学结构及体外免疫活性研究

Structure and in vitro Immunomodulatory Activity of Polysaccharides from Bamboo(Phyllostachys pubescens Mazel) Shavings

目的:研究竹茹多糖(BSP)的结构特性及体外免疫调节活性。方法:利用甲基化分析及核磁共振波谱法解析BSP的化学结构;采用小鼠脾脏淋巴细胞转化增殖试验,RAW264.7巨噬细胞吞噬中性红以及分泌NO试验评价BSP的体外免疫调节活性。结果:BSP为乙酰化的阿拉伯糖基4-O-甲基葡萄糖醛酸木聚糖,其结构为:以β-1,4-D-木糖为骨架,在木糖基的C-2位上连接有乙酰基或4-O-甲基-α-D-葡萄糖醛酸,C-3位上连接有乙酰基或α-L-阿拉伯糖;BSP在10~100μg/m L范围内能促进刀豆蛋白或脂多糖诱导的小鼠脾脏淋巴细胞增殖;BSP在10~1 000μg/m L范围可显著提高RAW 264.7巨噬细胞吞噬中性红及生成NO的能力,并呈明显的剂量依赖性。结论:原料来源丰富的竹茹多糖具有作为天然免疫调节剂的潜力。

Objective： to investigate the structure and in vitro immunomodulatory activity of polysaccharides from bamboo shavings（BSP）. Methods： the structure was analyzed by the methods of methylation and nuclear magnetic resonance spectroscopy; the in vitro immunomodulatory activity was evaluated by the assays of mouse splenic lymphocyte proliferation, the phagocytosis of neutral red and NO secretion of RAW264.7 cell. Results： BSP was O-acetyl-（4-O-methylglucurono）-arabinoxylans consisting of a linear（1→4）-β-D-xylopyranosyl backbone decorated with branches at O-2 of 4-O-methylglucuronic acid units and acetyl groups or O-3 of α-L-arabinofuranosyl and acetyl groups. The structural element could be expressed as below： 1,4-β-D-[2-O-Ac][3-O-Ac][4-O-Me-D-Glcp A-（1→2）][α-L-Araf-（1→3）]-xylp;BSP could evidently strengthen concanavalin A or lipopolysaccharide-induced splenic lymphocyte proliferation at 10-100μg/m L; BSP could significantly enhance the phagocytosis activity and NO production of RAW264.7 cell at 10-1 000 μg/m L in a dose-dependent manner. Conclusion： BSP exhibits excellent immunostimulatory activity in vitro, and can be considered as an ideal source of bio-active polysaccharides due to the abundance of its raw material.