Chemical structural elucidation of a new polysaccharide from ginseng radix and preliminary evaluation of its immunomodulatory activity.

A novel polysaccharide, designated as GP6001502, was isolated from Ginseng Radix, with a molecular weight (Mw) of 9.21 × 103 Da. Monosaccharide composition analysis revealed that GP6001502 was mainly composed of mannose (Man), glucuronic acid (GlcA), galacturonic acid (GalA), glucose (Glc), galactose (Gal), and arabinose (Ara), with glycosidic linkages including terminal (T)-linked Ara, (1 → 3)-linked Man, (1 → 2,4)-linked Man, (1 → 3,4)-linked Man, (1 → 4)-linked GalA, (1 → 4)-linked GlcA, (1 → 4)-linked Gal, (1 → 3)-linked Gal, (1 → 3,4)-linked Gal, and (1 → 4)-linked Glc. The putative average structural model of GP6001502 was reasonably deduced. The backbone of GP6001502 is mainly composed of mannan, while its side chains contain Man, Gal, GalA, Glc, GlcA, and Ara. The immunomodulatory activity of GP6001502 was evaluated by in vitro cell experiments using RAW264.7 macrophages. The results demonstrated that GP6001502 significantly enhanced the proliferation and phagocytic capacity of macrophages, and promoted the secretion of nitric oxide (NO). Collectively, these findings suggest that GP6001502, a polysaccharide derived from Ginseng Radix, possesses potent immunomodulatory activity, providing a scientific basis for the further exploitation and utilization of ginseng polysaccharides.