Optimization of two-phase aqueous extraction for Astragali Radix by central composite design-response surface method / 中成药

ABSTRACT

AIM To optimize the two-phase (ethanol-dipotassium phosphate) aqueous extraction for Astragali Radix by central composite design-response surface method.METHODS With ethanol concentration,dipotassium hydrogen phosphate solution concentration and Astragali Radix feed ratio as influencing factors,together with extraction rates of total flavonoids and total saponins as evaluation indices,the technology optimization was accomplished by central composite design-response surface method.RESULTS The optimal conditions were determined to be 27.97％ for ethanol concentration,22.03％ for dipotassium hydrogen phosphate solution concentration,and 1 ∶ 58.85 for Astragali Radix feed ratio.The extraction rate of total flavonoids reached 74.13％ (concentrated in the upper layer),while that of total saponins reached 81.34％ (concentrated in the lower layer).CONCLUSION With good predictability,this simple and accurate method can be used for the extraction of total flavonoids and total saponins in Astragali Radix.