A critical review of Astragalus polysaccharides: From therapeutic mechanisms to pharmaceutics

As the important active ingredients of Astragali Radix (AR), Astragalus polysaccharides (APs) have therapeutic potential for multiple diseases including nervous system diseases, cardiovascular diseases, diabetes mellitus, and cancer. A large number of cell experiments combined with animal experiments have shed light on the therapeutic mechanisms and therapeutic effects of APs on a variety of diseases. However, the clinical application of APs is not widespread, except for the use of injected APs in the clinical adjuvant therapy of cancer. Due to the excessive molecular weight, bulky, low solubility and negatively charged characteristics, APs have low bioavailability which limits their clinical application. With the deepening of researches on the pharmaceutics of APs, the nanocrystals and moderate structural modification enormously boost the bioavailability, which may expand the application of APs. This review summarizes the studies in pharmacodynamic properties and pharmaceutics of APs, with the purpose of providing experimental researches and clinical application data for expanding the clinical development through expounding the therapeutic mechanisms and pharmaceutical researches of APs.