金福菇多糖抗衰老作用及其构效关系研究

Edible fungi are rich in nutrition and effect in health protection. Polysaccharide, one of the active ingredients, has lots of important bioactivitiessuch as immunomodulatory, anti-tumor, antioxidant, anti-senescence and so on, which has become one of the research hotspot of many discipline. We have found that the polysaccharides fraction (TLH-3) extracted from Tricholoma lobayense owned strong scavenging ability on free radicals with IC50 values similar to Vc, which significantly improves SOD, GSH, Px in vivo in aging-model mice. Based on these previous work, the aim of project is to study the structure, anti-senescence effects and their structure-effect relationship on Tricholoma lobayense polysaccharides. In this study, high pressure homogenization and ultrafitration method will be applied to extract and separate of the Tricholoma lobayense polysaccharide; The purified polysaccharides will be characterized for their monosaccharide composition, molecular weight, structure and chain conformation; The Tricholoma lobayense polysaccharides will be degraded with combined methods of chemistry and enzyme in order to study their active oligosaccharide fragments and "structure-activity domain"; And the antioxidant activities will be determined in vitro and in vivo. Furthermore, it will be studied on Tricholoma lobayense polysaccharides for the relationship between their activities and their chemical structures. The significance of this research is to clarify the structure-activity relationship, and then to lay a foundation for the research and development of Tricholoma lobayense polysaccharides as functional health food and natural drug.

食用菌具有丰富的营养和保健作用，其活性成分中的多糖因具有免疫调节、抗肿瘤、抗氧化、抗衰老等多种功效已成为许多学科研究的热点。申请者研究发现金福菇多糖TLH-3组份清除自由基的能力较强，其IC50值与Vc相当,对衰老模型小鼠体内的SOD、GSH、Px有明显改善。在前期工作基础上，本项目旨在研究金福菇活性多糖的结构、抗衰老作用及构效关系等。采用高压均质和超滤方法提取分离金福菇活性多糖，纯化后用化学和仪器分析方法确定其单糖组成、分子量、分子结构及链构象；采用化学和酶法结合对金福菇活性多糖进行降解，研究其活性寡糖片段与"结构域"等；并在分子、细胞及动物水平上研究其抗衰老作用。在实验的基础上进一步从分子水平分析多糖化学结构、分子量和链构象等因素与活性之间的关系及多糖降解片段结构对抗衰老作用的影响。本研究意义在于阐明多糖结构和功能的关系，为金福菇多糖在功能性保健食品和天然新药研究开发等领域奠定基础。

食用菌多糖具有免疫调节、抗肿瘤、抗氧化、抗衰老等多种生物活性，已成为目前多糖研究的一大热点。本项目研究发现食用菌金福菇子实体多糖TLH-3活性组份具有显著的抗氧化、抗衰老作用，在金福菇活性多糖的制备方法、构效关系、生物活性及其作用机制等方面进行了深入的研究，已取得相关成果：（1）采用高压均质提取、季铵盐沉淀与膜分离等技术方法，研发了一条方法简单、高效快捷、可规模制备金福菇活性多糖TLH-3的新工艺；（2）确定了金福菇多糖TLH-1，TLH-2，TLH-3的分子结构，构效分析TLH-3的高活性是由于其水溶性大，分子量小，分支度高，富含半乳糖以及糖苷键连键方式多元化等因素；（3）三氧化硫-吡啶法对金福菇多糖TLH-3进行硫酸化修饰，发现其硫酸化活性多糖（STLH-3）的体外抗氧化活性明显增加，其抗肿瘤活性提高4-5倍；（4）TLH-3可提高小鼠的抗氧化防御系统功能，对t-BHP诱导的氧化损伤HELF细胞具有明显的保护作用；（5）通过TLR-4介导IκB-α-NF-κB信号通路，TLH-3可诱导巨噬细胞发生免疫调节作用。上述成果为揭示金福菇多糖活性组分与功能研究奠定了坚实理论基础与技术支撑。