假芝菌丝体多糖ARP的纯化、结构及抗氧化活性

Purification,structural characteristics,and in vitro antioxidant activities of polysaccharides ARP from a wild Amauroderma rugosum mycelium

以贵州册亨县的野生假芝(Amauroderma rugosum)为材料,分离菌丝体后液体发酵,采用水煮醇沉方法提取粗多糖,进一步脱蛋白、脱色、柱层析纯化后,得到精制多糖(ARP),采用多种色谱手段对多糖结构进行表征,测定、比较了粗多糖和精制多糖的体外抗氧化活性。结果表明:菌丝体精制多糖分子量为1. 86×10~4Da,红外和核磁显示有明显多糖特征峰,该多糖由鼠李糖、甘露糖和半乳糖组成,单糖摩尔比组成为1∶1. 24∶3. 51;从菌丝体提取的多糖抗氧化活性良好,粗多糖的抗氧化活性优于精制多糖,在质量浓度为1 mg/mL时,粗多糖的总还原力是精制多糖的1. 72倍;对DPPH·和ABTS·清除率良好,粗多糖对应EC50值是0. 05和0. 15 mg/mL;精制多糖是1. 15和1. 49 mg/mL。研究结果为假芝多糖的开发利用提供了科学依据。

A wild Amauroderma rugosum was collected from Ceheng, Guizhou. Its crude polysaccharides were extracted from liquid fermentation of isolated mycelium by hot water and ethanol precipitation. The crude polysaccharides were further purified by deproteinization, decoloration, and column chromatography, resulted refined polysaccharides (ARP). The structural characteristics of ARP were elucidated by chromatographic methods. Meanwhile, the antioxidant activities of crude and refined polysaccharides were compared. The results showed that the molecular weight of ARP was 1.86×10 4 Da. Moreover, IR and NMR chromatograms showed that they had characteristic peaks of polysaccharides. Its monosaccharide composition included rhamnose (Rha), mannose (Man), and galactose (Gal), with a molar ratio of 1∶ 1.24∶ 3.51. Furthermore, the mycelium polysaccharides demonstrated excellent antioxidant activities in vitro , and crude polysaccharides exhibited better antioxidative effects. When the concentration of polysaccharides was 1mg/mL, the total reducing activity of crude polysaccharides was 1.72 times higher than that of the refined one. Both of these two polysaccharides were good at scavenging DPPH·(EC50: 0.05 and 1.15mg/mL for crude and refined polysaccharides , respectively) and ABTS·(EC50∶ 0.15 and 1.49mg/mL for crude and refined polysaccharides , respectively). This research provides scientific basis for exploiting and utilizing polysaccharides from A.rugosum.