Abstract:
In this experiment,optimization of extraction process of polysaccharide from Bublophyllum kwangtungense and its antioxidant activity were studied.On the basis of single factors experiments,orthogonal design and variance analysis were ultilized to investigate the effects of liquid-to-solid,extraction temperature and time,ethanol concentration for precipitation on the content of polysaccharide,and optimize the process.The optimal extraction conditions were determined as follows∶liquid-to-solid,50∶1(mL/g);extraction temperature,90  ℃,and extraction time,6 h;ethanol heavy concentration,95%.Under the optimal conditions,the yield of polysaccharide of 79.060 mg/g was gained,and the RSD value was 0.132%.Polysaccharide displays good antioxidant activity with that total reducing power is 0.035 times of L-ascorbic acid,and the EC₅₀ values for DPPH,hydroxyl radicals and superoxide anions are 2769.58,594.60,586.94 μg/mL,and the cleanrance ability are 0.68%,47.17% and 29.00% of L-ascorbic acid respectively.The chelating rate to Fe²⁺  with EC₅₀ values of 160.83 μg/mL,and the chelating ability is 2.12% of EDTA.These results provided a reference for the extraction,further development and ultilization of the polysaccharide in B.kwangtungense.

Key words: Bublophyllum kwangtungense, polysaccharide, single factor experiment, orthogonal design, antioxidant activity