Structural Characterization of APSN from <i>Astragalus membranaceus</i> and Its Potential Therapeutic Effect on Immune Dysregulation and Tissue Damage

Addressing the global health impact of inflammatory and immune-mediated diseases, this study focused on purifying and characterizing a neutral polysaccharide, APSN, from the <i>Astragalus membranaceus</i>. Employing high-performance gel permeation chromatography (HPGPC), Fourier-transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR) spectroscopy, we elucidated APSN's structural features, revealing a highly branched glucan with a 1,4-α-d-glucopyranosyl main chain and side chains at the O-6 position. Separately, we assessed APSN's biological activity, finding that it significantly modulates immune responses by inhibiting the NF-κB pathway in RAW264.7 macrophages and promotes endothelial cell proliferation and angiogenesis-related gene expression in HUVECs. These results position APSN as a potential therapeutic for diseases characterized by immune dysregulation and tissue damage, warranting further investigation of its mechanisms and clinical efficacy.