Signaling Pathways Associated with Macrophage-Activating Polysaccharide Isolated from Korea Red Ginseng

Background and Objectives: Korean red ginseng (KRG) is known as an immune-enhancing health food and has been approved by the Korea Food and Drug Administration. We analyzed the immune-enhancing activity of KRG and its polysaccharide (KRG-P) using RAW264.7 murine macrophage cells. Materials and Methods: The protein and mRNA expression levels of IL-6 and TNF-α were measured using ELISA and qRT-PCR, respectively. Nitric oxide levels were measured using the Griess reagent. The phosphorylation and total protein levels of ERK, p38, JNK, p65, and GAPDH were determined by immunoblot assay. Results: The polysaccharide (KRG-P), but not KRG, produced nitric oxide, interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α) in RAW264.7 cells. KRG-P increased nitric oxide synthase 2 (NOS2), IL-6, and TNF-α expression in RAW264.7 cells. KRG-P also increased phosphorylation of MAPKs (mitogen-activate protein kinases) including ERK, p38, JNK, and NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) in a concentration-dependent manner in RAW264.7 cells. Conclusions: The polysaccharide KRG-P is the active component responsible for the immune-enhancing activity of Korean red ginseng and may modulate the systemic immune system in vivo.