Influence of Different Extraction and Purification Methods on Astragalus Polysaccharides and Pharmacological Evaluation / 中草药·英文版

ABSTRACT

Objective To clarify the influence on component and pharmacological action of Astragalus polysaccharides (APS) as complementary therapeutic agents prepared by different extraction and purification techniques. Methods Components of APS prepared by different extraction and purification techniques were analyzed, and these APS were used for synergy and attenuation of chemotherapy, radiotherapy treatment with H22 liver cancer and Lewis lung cancer of tumor-bearing mice, and also used for the regulation of immune function to immunosuppression mice. Results Experimental data were analyzed by means of statistical method to get pharmaco-result: A3 (extracted by microwave assistance and purified by membrane separation) > A4 (extracted by refluxing and purified by membrane separation) > A1 (extracted by refluxing and no purification)≈ A2 (extracted by microwave assistance and no purification). There were no significant differences on pharmacodynamic action between A1 and A2. However, compared with A1 and A2,it was worth noting that A3 and A4 exhibited good pharmacodynamic action. Then A3-in and A4-in, the samples in dialyzer after dialysis, were separated and purified to get homogeneous APS, which were the principal constituents of APS in dialyzer, with the molecular weight (Mw) of 7669 and 14 142 determined by HPGPC, respectively. The average Mw of APS outside of the dialyzer, A3-out was 3102 and A4-out 3256, which were the main compositions of A3 and A4, accounted for 79.63% and 53.92%, respectively. Conclusion APS with Mw about 5000 Da exhibit better antitumor effect and immunological activity. Refluxing, microwave assistance extractions, and membrane enrichment techniques bring different cases on Mw distribution, components and pharmacodynamic action, and obviously exhibit relationship among component, Mw distribution, and pharmacological action.