Studies On The Extraction Of Active Components In Radix Astragali And Different Drying Methods

Taking the medical herb Radix Astragali as material, this research established the methods for the quantitative determination of Astragalus Polysaccharides(APS) and Astragalus Saponin(AS),furthermore investigated the optimum technological parameters of extracting conditions for APS and AS separately, then discussed the different drying methods for fresh Radix Astragali root, and indicated the separation and purification technology of APS crude samples finally. The conclusions of this research were as follows:1 The methods for the quantitative determination of active components in Radix Astragali were established.The content of total sugar was phenol- oil of vitriol mensuration, while the content of reductive sugar was 3, 5-Dinitrosalicylic Acid mensuration, however the content of Astragalus Polysaccharides depended on their concentration difference.On the other hand, the content of Astragalus Saponin was vanilla aldehyde - acetic acid.2 The optimum technological parameters of two extracting conditions for APS were compared.At first, traditional hot water extraction for APS were studied, wich the optimum technological conditions were disintegrating the dry roots by 40 granularity sieve, the ratio of water to solid was 20, extracting at 100℃for 2 hours twice respectively, and the average final content of APS was 9.45%. However, thanks to the cellulase could accelerate the APS dissolving into the solvent during extracting process, the extraction of APS by cellulase was brought into effect.In this paper, Box-Behnken center-united experiment design attached to Response Surface Method and the Design Expert 7.0.3 software were applied to optimize the extraction conditions for APS by cellulase. How the parameters such as pH value, reaction temperature and enzymatic quantity influenced the content of APS was discussed. The results indicated that the optimal parameters of extraction technology for the content of APS by cellulase were: pH value 4.0, reaction temperature 56.5℃, enzymatic quantity 61U/g, while the maximal content of APS in average was 20.31%, the effect of extraction of APS improved significantly. The analysis of variance for model regression equation indicated significance, the R² value of model was 0.9962, also the independent variable had significant linear relations with attributive variables. Therefore this model could forecast the final content of APS by cellulase during extraction abstractly. After regression analysis, factors which influenced response variables (the content of APS) significantly wew selected. Consequently multinomial regression equation which the content of APS as response variables versus coded attributive factors (pH value of cellulase degradation, treatment temperature and cellulase dosage) used in the extraction of APS by cellulase was as follows: Y = 20.0042+0.46775x₁0.20663x₂+0.158625x₃+0.01025x₁x₂+1.47025x₁x₃+ 0.593x₂x₃-2.0111x₁²-1.48085x₂²-1.17485x₃².Aaccording to the multinomial regression equation of RSM, the response surface plot and their contour plot were drawed respectively.3 The optimum technological parameters of extracting conditions for AS were established. When these parameters of extracting conditions were adopted, which the percent of ethanol volume was 80%, the ratio of solvent to Astragalus was 20 and 1.5 hours as time length, the content of AS would achieve the maximum.4 The different drying methods for fresh Radix Astragali root were compared. After respective drying methods, the contents of active components in Radix Astragali were different. Comparing with other drying methods, vacuum freeze drying method could preserve the maximum content of active components in fresh Radix Astragali roots more effectively.5 The separation and purification technology of APS crude samples. The extracting solution of APS concentrated by vacuum rotary evaporator, then eliminated protein using sevag reagent and dialysed by distilled water.When ethanol of certain concentration added, many white deposit were formed. Then the deposit dried by vacuum freeze drier. Above all, purification was achieved by DEAE-Sepharose Fast Flow Ion Exchange Chromatography. Furthermore the grads elution diagrams of the APS samples on Sephadex G-200 Gel Chromatography were also received. In the end, the separated compositions were analysed by High Performance Liquid Chromatography.