Structural and anti-inflammatory characterization of a novel neutral polysaccharide from North American ginseng (Panax quinquefolius)

Neutral polysaccharides are one of the active components in the American ginseng roots. Recently, the studies about American ginseng polysaccharides are mainly centered on acidic polysaccharides, while there is relatively limited research that explores neutral polysaccharides. In this study a novel neutral polysaccharide (PPQN) was isolated from American ginseng roots and its structure and anti-inflammatory activity were investigated. The average molecular weight (Mw) of PPQN was 3.1 kDa. Monosaccharide components' analysis indicated that PPQN was composed of glucose (Glc) and galactose (Gal) in a molar ratio of 1:1.15. Secretions of nitric oxide (NO), TNF-α, IL-6, and IL-1β after lipopolysaccharide (LPS) stimulation were detected in PPQN pre-treatment RAW264.7 macrophages. PPQN (150 μg/mL) exhibited more effective inhibition of TNF-α, IL-1β, and IL-6 secretions, followed by NO production with respective values of 40.5%, 41.1%, 34.4%, and 11.1% suppression. These results indicated that PPQN may have therapeutic implications in treatment of inflammation and inflammatory-related diseases.