Immunomodulatory activities of proteins from Astragalus membranaceus waste

BACKGROUND Astragalus membranaceus is a traditional Chinese medicine that has a long history of medical applications. It is of interest to investigate the functional components of A. membranaceus waste with regard to its development and utilization and increasing resource utilization. RESULTS The protein AMWP was isolated from the A. membranaceus waste. This protein was further purified by DEAE-cellulose-52 chromatography and Sephadex G-200 size-exclusion chromatography to obtain three fractions, named AMWPDG2, AMWPDG4 and AMWPDG6. Then, their immunomodulatory activities were evaluated by using cell model experiments. The results indicated that the protein fractions could significantly increase the proliferation of splenic lymphocytes, peritoneal macrophages and bone-marrow-derived cells (BMDCs). AMWPDG2 showed the highest immunocompetence. AMWPDG2, AMWPDG4 and AMWPDG6 not only significantly improved the phagocytosis and immunomodulatory factors (interleukin (IL)-6, tumor necrosis factor-alpha, nitric oxide, hydrogen peroxide) secretion of peritoneal macrophages, but also promoted the expression of inflammatory cytokines (IL-6, IL-12 p40, IL-1 beta, IL-1 alpha) and chemokines (CXCL1, CCL3) in BMDCs. CONCLUSION Taken together, these results indicated that three protein fractions from the A. membranaceus waste might be a potential natural immunomodulator. Moreover, it also provided the theoretical basis for further researching the mechanism of AMWPDG2, AMWPDG4 and AMWPDG6 on improving the immune response. (c) 2019 Society of Chemical Industry