Abstract: This article mainly studied the extraction,purification,structure and antioxidant effects of a polysaccharide (MSP) purified from the fruiting bodies of Morchella sextelata M.Kuo.The polysaccharides of M.sextelata were extracted with boiling water and purified by DE-52 column and Sephadex G-100 column.The molecular weight,monosaccharide composition were analyzed by HPGPC and HPLC.In order to investigate the neuroprotective role of MSP,the antioxidant activity of MSP against the H₂O₂-induced cytotoxicity and the underlying preventative mechanisms in rat pheochromocytoma (PC12) cells were illustrated.It was shown that the molecular weight of MSP was 287 588 Da(287 588 Da),the monosaccharide composition of MSPwasmainly composed of mannose,glucose and galactose,with a ratio near 9:1:6.MSP can considerably enhance the viability of PC12 cells exposure to H₂O₂ and increase the activities of antioxidant enzyme like SOD,CAT and GSH-Px.It inhibited cell apoptosis via reducing caspase-3 activation and down-regulation Bax/Bcl-2 ratio.Accordingly,MSP can be used as a promising neuroprotective compound for nervous diseases treatment.

Key words: Morchella sextelata, extraction of polysaccharide, PC-12 cell, antioxidant, neuroprotective