Optimization of Extraction Technology and Investigation of Anti-oxidant Effects of Polysaccharides from Stems of Megacarpaea delavayi

Objective: To optimize extracting conditions of polysaccharides from stems of Megacarpaea delavayi,and investigate its anti-oxidation effects.Method: Polysaccharide in stems of M.delavayi was isolated by water extracting-alcohol precipitating method,taking extraction rate of polysaccharides as index,optimal extracting conditions were studied by orthogonal test.The content of polysaccharides was determined.by phenolsulfuric acid method,moreover,in vitro activities on scavenging free radicals of.OH and O2-.of the polysaccharide were also observed.Result: Optimal extraction conditions of polysaccharides were as followings: extracted 12 h with 15 times the amount of water at 80 ℃;under these conditions,the average yield of polysaccharides was 1.973%(RSD 1.87%),the conversion factor between glucose and the polysaccharides was 1.127(n = 5),the content of polysaccharides was 80.17%(RSD 2.13%) in the crude polysaccharides.In addition,the polysaccharides had a certain effect on scavenging free radicals of.OH and O2-.in vitro and exhibited the dose-effect relation.Conclusion: This optimized technology was stable and feasible with high extraction rate;Polysaccharides in stems of M.delavayi possessed a certain anti-oxidant effect.