Purification, structural characterization, and antioxidant activity of the COP-W1 polysaccharide from Codonopsis tangshen Oliv.

•COP-W1 is a new polysaccharide extracted from the root of Codonopsis tangshen Oliv.•The structure of COP-W1 was elucidated using several complementary methods.•COP-W1 has a molecular weight of 2.34 × 10−4 Da.•COP-W1 is composed of mannose, rhamnose, glucose and galactose sugars.•COP-W1 may have strong anti-oxidant properties.