Response Surface Methodology as An Approach for Optimization of Simultaneous Extraction of Polysaccharides and Total Flavonoids from Radix Puerariae

Radix Puerariae was used as raw material to simultaneously extract polysaccharides and total flavonoids by hot water extraction.Based on single factor experiments,a central composite design(CCD) involving three variables such as material/liquid ratio and extraction time and temperature at three levels was employed for establishing a quadratic regression model describing weighted extraction yield(at 1:1 weight ratio) of polysaccharides and total flavonoids at different levels of the above variables.The optimal values of these variables were determined by response surface analysis.Moreover,the validity of the established model was verified.Results showed that both extraction temperature and time had a significant effect on polysaccharide yield,whereas no significant effect of material/liquid ratio was observed.The predicted and observed values of weighted extraction yield of polysaccharides and total flavonoids were achieved under the following optimal conditions:extraction for 2.2 h at a material/liquid ratio of 1:25.2 and 98.4 ℃.