梯棱羊肚菌多糖的理化性质及神经保护活性研究

Physical and Chemical Properties of Polysaccharide Isolated from the Fruiting Bodies of Morchella importuna and Its Neuroprotective Effect

摘要:

分离纯化人工栽培的梯棱羊肚菌子实体多糖，对其结构和神经保护作用进行研究。采用水提醇沉法提取梯棱羊肚菌子实体多糖（MIP），采用DE-52纤维素柱和Sephadex G-100进行多糖的分离纯化，借助高效凝胶渗透色谱（HPGPC）和高效液相色谱（HPLC）测定多糖分子量及单糖组成。通过1,1-二苯基-2-三硝基苯肼（DPPH）自由基、羟自由基和超氧阴离子自由基的清除作用，评价MIP自由基清除能力。构建H2O2介导的氧化压力损伤的PC12细胞模型，评估其基于抗氧化的神经保护作用并探索作用通路。结果表明：MIP得率1.15%，平均分子量为1.35×106 u，平均粒径为432.20 nm，异头碳为β-构型，由木糖、葡萄糖、半乳糖和少量岩藻糖组成。MIP具有优良的自由基清除活性，对DPPH自由基的IC50值为（1.18±0.04）mg/mL。MIP能够重塑PC12细胞内源性抗氧化酶系，将受损的SOD活性提高62.15%，通过调节凋亡分子开关Bax/Bcl的比例和Caspase蛋白家族的活化，抑制细胞凋亡。MIP可作为一种预防及辅助治疗神经退行性疾病的功效成分加以开发利用。

Abstract:

The extraction, purification, structure and neuroprotective effects of a polysaccharide (MIP) purified from the fruiting bodies of Morchella importuna M. Kuo were investigated in this work. The polysaccharides of M. importuna were extracted with boiling water and then purified by DE-52 column and Sephadex G-100 column. The molecular weight and monosaccharide composition were analyzed by HPGPC and HPLC, respectviely. In order to investigate the neuroprotective role of MIP, the antioxidant activity of MIP against the H2O2-induced cytotoxicity and the underlying preventative mechanisms in rat pheochromocytoma (PC12) cells were illustrated. The results showed that the yield of MIP was 1.15%, the molecular weight of MIP was 1.35×106 U, the average particle size was 432.20 nm and the monosaccharide composition of MIP was mainly composed of xylose, glucose, galactose and a small amount of fucose. The heterocarbon of MIP was β configuration. MIP had excellent free radical scavenging activity and the IC50 value for the DPPH free radical was 1.18±0.04 mg/ mL. MIP could considerably enhance the viability of PC12 cells exposure to H2O2 and increase the activities of antioxidant enzyme like SOD, CAT and GSH-Px. It was worth noting that MIP could increase the activity of damaged SOD by 62.15%. It inhibited cell apoptosis via reducing caspase-3 activation and down-regulation Bax /Bcl-2 ratio. Accordingly, MIP could be used as a promising neuroprotective compound for nervous diseases treatment.