蛹虫草MF27菌糠多糖对肝细胞氧化损伤的保护作用

蛹虫草是一种可利用大米、小麦等谷物培育的名贵药用真菌,其采收后的菌糠里仍富含许多生物活性物质。本研究立足于蛹虫草菌糠多糖,先分析其化学抗氧化活性,再以H₂O₂诱导氧化应激损伤的LO2细胞为模型,评价其对肝细胞氧化损伤的保护作用,进而解析活性多糖的单糖组分。结果显示,菌糠多糖能够有效清除DPPH自由基、羟基（?OH）自由基和ABTS自由基,EC₅₀分别为0.26mg/mL、1.03mg/mL、0.57mg/mL,提示其具有良好的抗氧化能力;在H₂O₂诱导氧化应激损伤的LO2细胞中,菌糠多糖能有效地保护细胞形态的完整性,并且随浓度梯度递增式地提高细胞存活率,当多糖浓度为5mg/mL时,细胞存活率可达91.83%;在分析其作用机制上,与模型组对比,菌糠多糖能通过调节细胞抗氧化酶SOD（提高4.91倍）和CAT（提高3.40倍）的表达来清除ROS含量（P<0.01）,降低氧化损害;经检测,虫草菌糠活性多糖主要含有葡萄糖、甘露糖、半乳糖、阿拉伯糖、葡萄糖醛酸、木糖、半乳糖醛酸、鼠李糖和岩藻糖等单糖。研究结果表明蛹虫草MF27菌糠多糖具有保护肝细胞氧化损伤的作用,为进一步开发和利用虫草菌糠提供了重要理论依据。

Protective effects of polysaccharides from post-harvest waste substrate of Cordyceps militaris MF27 on oxidative damage to liver cells

Cordyceps militaris is one of valuable medicinal fungi, easily cultured in corn substrate such as rice and wheat. Post-harvest waste substrate was still rich in active substances. In this study the polysaccharides from waste substrate of C. militaris were extracted and their chemical antioxidant activity and protective effect on liver cell oxidative damage in LO2 cell model induced by hydrogen peroxide were evaluated. The monosaccharide components were also analyzed. The result shows that polysaccharides of waste substrate could scavenge DPPH free radical, ?OH free radical and ABTS free radical, and the EC₅₀ was 0.26mg/mL, 1.03mg/mL and 0.57mg/mL, respectively, indicating the polysaccharides still possessed effective antioxidant activity. The polysaccharides could significantly protect LO2 cell morphology and improve cell survival rate through concentration-dependent manner, and the cell viability reached 91.83% at the concentration of 5mg/mL. The polysaccharides of the waste substrate could decrease the levels of ROS (P<0.01) through increasing SOD and CAT activity by 4.91 times and 3.40 times respectively. The polysaccharide mainly contains glucose, mannose, galactose, L-arabinose, glucose aldehyde, xylose, galactose aldehyde, L-rhamnose monohydrate, fucose and other monosaccharides. These results indicated post-harvest waste substrate of C. militaris could be reused for further extracting valuable active substants.