Abstract: The extraction of crude polysaccharides from cultivated Cardamine hupingshanensis was optimized by the combined use of one-factor-at-a-time method and response surface methodology. The results of one-factor-at-a-time experiments demonstrated hydrolysis with a mixture (2:1, m/m) of cellulase and pectinase at a dosage of 2% (m/m) at 60 ℃ and an initial pH of 4.0 for 90 min to be optimum for the extraction of polysaccharides. Furthermore, the extraction conditions optimized by response surface methodology were as follows: hydrolysis time, 91.8 min; hydrolysis temperature, 57.1 ℃; and intial pH, 4.17. Under these conditions, the predicted maximum yield of polysaccharides of 4.14% was obtained, and experiments gave an average value of 4.07%, indicating a relative error of about 1.62% the predicted and experimental values. The results of antioxidant assays showed that Cardamine hupingshanensis. polysaccharides possessed antioxidant activity better than that of VC. Our experimental results provide an experimental basis for studying the extraction and properties of Cardamine hupingshanensis polysaccharides.

Key words: Cardamine hupingshanensis, polysaccharide, extraction parameters, optimization