Studies On Method Of Extracting Of Effective Components From Radix Astragali

Objective:The purpose of this paper is to search for the optimum extract methods of effective components in Radix Astragali, with the content of astragaloside Ⅳ, total astragalosides and astragalus polysaccharides (APS) as evaluation indicator.Methods:1. This study established quantitative methods for determining astragaloside IV by HPLC-ELSD, determining total astragalosides and APS by UV-VIS spectrophoto-metry.2. Application of sodium hydroxide solution to hydrolysis the extract of astragalus. The optimum conditions of extraction process for astragaloside Ⅳ was confirmed by single-factor test and orthogonal design.3. By comparing different extraction methods, the optimum condition was confirmed with total astragalosides and APS as indexes.4. Comparision of AB-8and D101macroporous adsorption resin in purification of total astragalosides, and study the purification process parameters with the selected resin.5. Comparision of cellulase, hemicellulase, xylanase and pectinase on extraction yield of total astragalosides and APS, taken single-factor test and orthogonal design with selected enzyme, and used a multi-index integrated assessment method to confirm the optimum enzyme aided extraction, then examined whether enzyme assisted extraction has an impact on the structure of the main effective components in Radix Astragali.Results:1. Methods with high accuracy, stability and reliable for determination of astraga-loside IV, total astragalosides and APS were established.2. The optimum preparative procedure were as follows:the concentration of sodium hydroxide was0.4%, hydro-lysis at room temperature for2hours and the solid-to-liquid ratio was1:12, the content of astragaloside IV was nearly16.4times compared with the extraction before hydrolysis.3. The optimum process for extracting total astragalosides was as follows:with10,8,8volume of70%ethanol as solvent, extracted3times at90℃ and1h for each time. The extraction of APS was as follows:with10,8,8volume of distilled water as solvent, circumfluence extraction3times and1h for each time. The extraction rate of total astragalosides as high as97.05%compared to the method in2005version of chinese pharmacopoeia.4. The purification of D101was better than AB-8macroporous adsorption resin. The purification process by D101resin were:the extracting solution containing0.5g crude drug·mL-1was loaded onto the chromatography column of pretreated D101macroporous adsorption resin, washed with3BV of water and then eluted with5BV of70%ethanol, the purity of total astragalosides was up to83.44%.5. The optimal enzyme assisted extraction were as follows:the pH of extracting media was4.5, the amounts of cellulose was1.0%, the enzymolysis temperature was55℃and enzymolysis for2.5hours. The content of total astragalosides and APS increased by27.26%and40.91%, respectively. By analysing the enzymatic and untreated extract-ion of APS, total astragalosides and astraisoflavan (AF), the primary prediction was that enzymatic hydrolysis has little impact on the chemical composition of effect components in Radix Astragali.Conclusion:In this research, the determination methods of astragaloside IV, total astragalosides and APS were simple, accurate and can be used to control the quality of Radix astragali and Jinqi Jiangtang Tablet. Sodium hydroxide can effectively increase the content of astragaloside Ⅳ, the method was simple with high conversion efficiency and high practical value, which provided a basis of study for the develop-ment of monomer preparations of astragaloside IV and the improvement of the quality of astragalus compound preparation. Enzyme assisted extraction can increase the extract rate of effective components for root and stem class of medicinal materials and do not require special equipment, it also can reduce energy consumption cost for the benefit of industry production, it provides an experimental basis for the further development and utilization of Radix Astragali.