A zinc-modified Anemarrhena asphodeloides polysaccharide complex enhances immune activity via the NF-κB and MAPK signaling pathways

Anemarrhena asphodeloides polysaccharide (AAP70–1) was reported to have immunomodulatory effects in our previous report. To further improve the immunomodulatory effects of AAP70–1, an A. asphodeloides polysaccharide-zinc complex (AAP-Zn) was synthesized using a ZnCl 2 modification method, and the potential mechanisms by which AAP-Zn activates macrophages were investigated. The results showed that the structural features of AAP-Zn were similar to those of AAP70–1 with a Zn content of 0.2 %, confirming that Zn mainly interacted with AAP70–1 by forming Zn O coordination bonds and Zn…OH bonds. In addition, the administration of AAP70–1 and AAP-Zn effectively improved the immunomodulatory effects by enhancing phagocytosis and upregulating the mRNA expression of cytokines (TNF- α , IL-6, IL-1 β , and IL-18), as well as increasing the production levels of nitric oxide (NO) and reactive oxygen species (ROS) in zebrafish embryos. The intracellular mechanism by which AAP-Zn activates macrophages was found to involve activation of the NF- κ B and MAPK signaling pathways. Our findings suggest that AAP-Zn may be a potential immunopotentiator in the field of biomedicine or functional foods.