Abstract: The chitosan was isolated from Armillariella mellea(AMC),and its relevant physical and chemical properties were analysed.The effects of chitosan from Arillariella mellea(AMC)on the lifespan of Drosophila melanogaster and D-galactose. induced mice aging were observed,and also the ability of learning and memory,the activities of SOD,the levels of MDA in serum,the thymus index and the spleen index were assayed.Results showed that the purity of such chitosan is 95%,the degree of deacetylation is 92%,and the viscosity average molecular weight is 85000.The AMC has remarkable anti-aging effects.

Key words: Armillariella mellea, chitosan, isolation, physical and chemical property, aging