猴头菌不同发育阶段产生的多糖结构特征及免疫活性

Structural properties and immunological activities of polysaccharides from Hericium erinaceus fruiting bodies in different development stages

采收猴头菌Hericium erinaceus 7个不同发育阶段的子实体,经热水浸提后分别采用20%、50%、70%的乙醇终浓度进行分级沉淀,获得21个多糖组分,对它们的结构特征及体外免疫活性进行了研究。结果表明,在猴头菌发育过程中,多糖总得率呈现先增大后减小的趋势,在第5阶段达到最大值0.92%。20%醇沉的多糖含量也呈先增大后减小的趋势,在第5阶段达到最大值42.87%,其大分子量多糖(1 000–5 000k Da)所占比例最高。50%、70%醇沉多糖均为小分子量多糖,约为10–40k Da。获得的猴头菌多糖组分中,单糖组成多以岩藻糖、半乳糖、葡萄糖和甘露糖为主(相对比例存在一定差异);另外,第1阶段20%、70%醇沉多糖还含有少量的核糖,第7阶段20%醇沉多糖含有一定量的鼠李糖;7个时期50%醇沉多糖均含有一定量的葡萄糖醛酸。所得多糖样品均具有刺激巨噬细胞释放NO的活性,其中20%醇沉多糖的活性优于50%和70%醇沉多糖,在50μg/m L时就表现出显著的体外免疫活性。此外,在第5阶段即中菌刺期产生的多糖活性最优,说明在此阶段采摘可以获得最佳的猴头菌多糖原材料。本研究为猴头菌生长发育过程中活性多糖的动态形成研究提供了一定的理论基础。

Fruiting bodies of Hericium erinaceus harvested at seven different growth stages were extracted by hot water andgraded ethanol precipitation to final concentration of 20%, 50% and 70%, and 21 crude polysaccharide fractions were obtained. Then structural properties and immunity activities in vitro of polysaccharides were studied. Results showed that in the whole developmental stages of H. erinaceus fruiting bodies, the overall yield of polysaccharides appeared an increasing trend at first then decreasing after the fifth stage. At fifth stage the maximum yield was 0.92%. Polysaccharide content of 20% ethanol precipitation also showed an increasing trend at first then decreasing, and the maximum polysaccharide content was 42.87% at the fifth phase, in which high molecular weight polysaccharides（1 000–5 000 k Da） had the highest proportion. Polysaccharide molecular weights of 50% and 70% alcohol precipitation were all small, ranging from 10 to 40 k Da. Most of the H. erinaceus polysaccharides obtained consisted of fucose, galactose, glucose and mannose, while some differences in the relative proportions existed. The polysaccharides of 20%, 70% ethanol precipitations contained a small amount of ribose at the first stage and 20% ethanol precipitation contained some rhamnose at the seventh stage. All stages of 50% alcohol precipitation polysaccharides contained a certain amount of glucuronic acid. All the 21 fractions of polysaccharide could significantly stimulate macrophages to release NO in vitro, and activity of polysaccharides of 20% ethanol precipitation was better than that of 50% and 70% ethanol precipitation, which showed good immune activity in vitro at 50μg/m L. Results showed that the activities of polysaccharides at the fifth stage were best, indicating best medicinal and health protection effects, and the polysaccharides at this stage could be regarded as the best materials for production of health products. Our findings provided a theoretical basis for the study of polysaccharide dynamic formation during the development of H. erinaceus fruiting bodies.