Two arabinans APRP70-1-1 and APRP70-1-2 from Angelica pubescens: structural characterization and immunomodulatory mechanism.

Immunomodulation plays a key role in maintaining organismal health, and precise molecular mechanisms that control immune activation are key to achieving this balance. Angelica pubescens is in high demand in the Chinese herbal medicine market due to its effective properties in dispelling dampness and relieving pain. Nevertheless, the immunological activity of A. pubescens has not been fully elucidated. This study focuses on exploring the structural characterization and immunomodulatory activities of two homogeneous arabinans (APRP70-1-1 and APRP70-1-2) isolated from A. pubescens. Structural analysis revealed that APRP70-1-1 possesses a higher degree of branching compared to APRP70-1-2. In vitro experiments showed that despite activating macrophages, APRP70-1-2 was less effective than APRP70-1-1 at promoting nitric oxide (NO) release. APRP70-1-1 demonstrated superior immunomodulatory effects, as evidenced by its significantly enhancing macrophage phagocytic capacity and upregulation of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 mRNA expression. Mechanistic studies indicated that APRP70-1-1 activated the JAK2/STAT3 and NF-κB signaling pathways. In summary, these results indicate that APRP70-1-1 had good immunomodulatory activity.