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

Jie Gao,Myoung-Sook Shin,Sullim Lee,Ji-Hwan Lee,Ki-Sung Kang

doi:10.3390/app11157111

Abstract

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.

Highlights

Radioimmunoprecipitation assay (RIPA) buffer and polyvinylidene difluoride (PVDF) membranes were obtained from Millipore (Burlington, MA, USA) and the protease inhibitor cocktail and Enhanced Chemiluminescence (ECL) solution were purchased from Roche Diagnostics Corporation (SIN, USA) and Thermo Fisher Scientific (Waltham, MI, USA), respectively
Analysis of monosaccharides revealed that glucose is the major sugar component (60.5%), which may be related to the starch-like polysaccharide, though its structure warrants further analysis
Korean red ginseng (KRG)-P contained large amounts of galacturonic acid, galactose, and arabinose, which are probably derived from the RG-I structure of the pectin polysaccharides of ginseng extracts

Summary

Introduction

P. ginseng has been shown to have anti-inflammatory [1], anti-oxidant [2], anti-cancer [3,4], anti-stress [5], cognitive function enhancement [6], anti-fatigue [7], and anti-wrinkle [8,9] activities. It is composed of ginsenosides, phenolic compounds, polysaccharides, peptides, polyacetylenes, fatty acids, and other ingredients [10]. KRG-P 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

Methods

Results

Conclusion