Characterization of a Novel Alkali-Soluble Heteropolysaccharide from Tetraploid Gynostemma pentaphyllum Makino and Its Potential Anti-inflammatory and Antioxidant Properties

A novel polysaccharide (GPP-S), with a molecular mass of 1.2 x 10(6) Da, was isolated from the tetraploid Gynostemma pentaphyllum Makino by alkali extraction followed by purifications using DEAE and Sephacryl S-400 column chromatographies. The monosaccharide composition of GPP-S was determined as rhamnose, arabinose, glucose, and galactose with a molar ratio of 1.00:3.72:19.49:7.82. The structural analysis suggested that the backbone of GPP-S is (1 -> 4)-linked-glucose and (1 -> 6)-linked-galactose with a (1 -> 4,6)-linked-glucose branch every six monosaccharide residues. The terminals were 1-)-alpha-arabinose, glucuronic acid, and other monosaccharides. GPP-S exhibited scavenging capacities against hydroxyl, peroxyl, and DPPH* radicals in vitro. GPP-S also had inhibitory activities on IL-1 beta, IL-6, and COX-2 gene expressions in RAW 264.7 mouse macrophage cells. These results suggested that GPP-S could be developed as a bioactive ingredient for functional foods and dietary supplements.