Chemistry Behind the Immunomodulatory Activity of Astragalus membranaceus

Abstract

Huang Qi (黄芪 Astragalus membranaceus) is a well-known and widely used herb in traditional Chinese medicine (TCM) tonic preparations. It has been used for many ailments over the last 2000 years. Flavonoids, saponins, and polysaccharides have been shown to be the main compounds responsible for the biological and pharmacological activities, especially the immunomodulatory properties, of such tonic preparations. This review summarizes the published data on Astragalus extracts and fractions and the natural compounds responsible for the immunomodulatory activity with special reference to the modulation of nuclear factor-kappa B and related pathways (e.g., Nrf2). In addition, this review highlights the importance of Astragalus membranaceus in TCM for treating patients with diseases related to immunocompromised conditions, such as cancer and diabetes.