Comparison of different extraction and separation methods on the effective sections of Radix Astragali

Key words: 
• astragalus membranceus polysaccharide /
• total saponins of astragalus /
• ultrasonic waves /
• superfine comminution /
• ultrafiltration

Abstract: Objective: To select optimal diameter of the powder of Radix Astragali and extraction method by four methods of extracting astragalus polysaccharide and total astragalus saponins in three Radix Astragali powders of different diameter. Methods: The water-alcohol co-distillation, cellulose degradation technology, calcarea solution technology, ultrasonic waves technology were used to three Radix Astragali powders of different diameter respectively.The astragalus polysaccharide and total astragalus saponins were separated with combined techniques hollow fiber membrane and D21 macro absorbing resin. According to the contents of astragalus polysaccharide and total astragalus saponins,the extraction methods were compared. Results: The most effective way of extracting astragalus polysaccharide was the ultrasonic waves technology with the yield rate of 1.73%, while the most effective method of distilling total astragalus saponins was ultrasonic waves technology on prepared slice of herbal drug, with the yield of 1.82. Conclusion: Ultrasonic waves technology was a much better way of extracting both astragalus polysaccharide and total astragalus saponins. The shorter the diameter of Radix Astragali powder, the higher the yield of extracting astragalus polysaccharide. The yield of extracting total astragalus saponins turned out contray.