Astragalus (Astragalus membranaceus) as a tool for helping with Immune support

The Astragalus polysaccharide is an important bioactive component derived from the dry root of Astragalus membranaceus. This review aims to provide a comprehensive overview of the research progress on the immunomodulatory effect of Astragalus polysaccharide and provide valuable reference information. We review the immunomodulatory effect of Astragalus polysaccharide on central and peripheral immune organs, including bone marrow, thymus, lymph nodes, spleen, and mucosal tissues. Furthermore, the immunomodulatory effect of Astragalus polysaccharide on a variety of immune cells is summarized. Studies have shown that Astragalus polysaccharide can promote the activities of macrophages, natural killer cells, dendritic cells, T lymphocytes, B lymphocytes and microglia and induce the expression of a variety of cytokines and chemokines. The immunomodulatory effect of Astragalus polysaccharide makes it promising for the treatment of many diseases, including cancer, infection, type 1 diabetes, asthma, and autoimmune disease. Among them, the anticancer effect is the most prominent. In short, Astragalus polysaccharide is a valuable immunomodulatory medicine, but further high-quality studies are warranted to corroborate its clinical efficacy.

Decoctions prepared from the roots of Astragali Radix are known as "Huangqi" and are widely used in traditional Chinese medicine for treatment of viral and bacterial infections, inflammation, as well as cancer. Astragaloside IV (AS-IV), one of the major compounds from the aqueous extract of Astragalus membranaceus, is a cycloartane-type triterpene glycoside chemical. To date, many studies in cellular and animal models have demonstrated that AS-IV possesses potent protective effects in cardiovascular, lung, kidney and brain. Based on studies over the past several decades, this review systematically summarizes the pharmacological effects, pharmacokinetics and the toxicity of AS-IV. We analyze in detail the pharmacological effects of AS-IV on neuroprotection, liver protection, anti-cancer and anti-diabetes, attributable to its antioxidant, anti-inflammatory, anti-apoptotic properties, and the roles in enhancement of immunity, attenuation of the migration and invasion of cancer cells and improvement of chemosensitivity of chemotherapy drugs. In addition, the latest developments in the combination of AS-IV and other active ingredients of traditional Chinese medicine or chemical drugs are detailed. These pharmacological effects are associated with multiple signaling pathways, including the Raf-MEK-ERK pathway, EGFR-Nrf2 signaling pathway, Akt/PDE3B signaling pathway, AMPK signaling pathway, NF-κB signaling pathway, Nrf2 antioxidant signaling pathways, PI3K/Akt/mTOR signaling pathway, PKC-α-ERK1/2-NF-κB pathway, IL-11/STAT3 signaling pathway, Akt/GSK-3β/β-catenin pathway, JNK/c-Jun/AP-1 signaling pathway, PI3K/Akt/NF-κB pathway, miRNA-34a/LDHA pathway, Nox4/Smad2 pathway, JNK pathway and NF-kB/PPARγ pathway. This review will provide an overall understanding of the pharmacological functions of astragaloside IV on neuroprotection, liver protection, anti-cancer and anti-diabetes. In light of this, AS-IV will be a potent alternative therapeutic agent for treatment of the above mentioned diseases.