Characterization of an antioxidant pectic polysaccharide from Platycodon grandiflorus.

Platycodonis Radix is widely used as homology of medicine and food in China; polysaccharides are thought to be one of its functional constituents. In this study, a pectic polysaccharide, PGP-I-I, was obtained from the root of the traditional medicine plant Platycodon grandiflorus through ion exchange chromatography and gel filtration. This was characterized being mainly composed of 1,5-α-L-arabinan and both arabinogalactan type I (AG-I) and II chains linked to rhamnogalacturonan I (RG-I) backbone linked to longer galacturonan chains. In vitro bioactivity study showed that PGP-I-I could restore the intestinal cellular antioxidant defense under the condition of hydrogen peroxide (H 2 O 2) treatment through promoting the expressions of cellular antioxidant genes and protect against oxidative damages. • A pectic polysaccharide PGP-I-I was purified from Platycodon grandiflorus. • PGP-I-I contains long HG regions and AG side chains, with Mw of 27.9 kDa. • PGP-I-I promotes antioxidant defense of the intestinal porcine epithelial cells in vitro. [ABSTRACT FROM AUTHOR]