Optimization of extraction technology of Astragalus polysaccharides by response surface methodology and its effect on CD40

Astragali is a herbal medicine used as an adjuvant extensively in the treatment of various cancers of lung, digestive tract, urinary system, etc. Statistics-based experimental designs were applied to optimize the extraction conditions for Astragalus polysaccharides (AP). The optimum conditions were found to be: the values of extraction time 3 h, ratio of liquid to solid 4 and particle size 33.8 mesh. Under these optimized conditions, the maximum AP extraction rate was 16.32 (%), which well matches with the predicted value. Furthermore, the chemical composition was analyzed with HPLC, and the pharmacological effect of the AP was evaluated. Results showed that AP could significantly decreased CD40 expression rate and protein expression in rats with stomach cancer.