Abstract: The extraction of polysaccharide from the bulb of Lycoris aurea was investigated by response surface methodology.After optimized by single factor test,the extraction temperature,extraction duration and liquid/solid ratio were selected as the impact factor and the yield of polysaccharide was set as response value.The regression equation for extraction yield of polysaccharide was established through Box-Benhnken central-united experiment design.The optimal extraction condition for polysaccharide was determined as follows:extraction temperature of 70 ℃,extraction duration of 7.7 h,liquid/solid ratio of 23:1 (mL:g).Under the optimized extraction conditions,the yield of polysaccharides was 42%.In addition,the content of polysaccharide in bulb,stem and leaf of different species in genus Lycoris was further investigated.The results showed that the content of polysaccharide in bulbs was significantly higher than that in stem and leaf.The highest content of polysaccharides was detected in the bulb of L.radiata, which was up to 49.21%.

Key words: Lycoris aurea, polysaccharides extraction, response surface methodology, different active part