Ilex asprella-derived polysaccharide activates macrophage via TLR4-mediated NF-κB and MAPK signaling pathways

• The polysaccharide in Ilex asprella was isolated and purified (IAP). • IAP was mainly composed of arabinose, galactose, glucose, and mannose. • IAP treatment enhanced cytokines and ROS production in RAW264.7 macrophages. • IAP exerted immunomodulation via TLR4-mediated NF-κB and MAPK signaling pathways. Ilex asprella , a valued herb in China, is recognized for its medicinal and dietary benefits, yet its active components and mechanisms of action have been largely unknown. This study focused on the polysaccharide extracted from Ilex asprella (IAP) and to investigate its structural characteristics and immunomodulatory effects. The results indicated IAP had a molecular weight of 3324 Da and was mainly composed of arabinose, galactose, glucose, and mannose. In vitro study showed 10, 50, and 100 μg/mL of IAP significantly increased the mRNA expression of inducible nitric-oxide synthase, cyclooxygenase-2, reactive oxygen, and cytokines in RAW264.7 macrophages. According to the results, IAP also facilitated the nucleus translocation of NF-κB p65 and activated the phosphorylation of p38, JNK, and ERK, revealing IAP activated RAW264.7 cells via NF-κB and MAPK signaling pathways. Furthermore, the results of membranes receptor inhibitor administration suggested toll-like receptor 4 might be the action target of IAP.