Structural characterization of a water-soluble polysaccharide from the Roots of Codonopsis pilosula and its immunity activity

The water-soluble polysaccharide (CPP), with a molecular mass of 1.1 × 104 Da, was obtained from the roots of Codonopsis pilosula. Structure feature investigation by a combination of chemical and instrumental analysis revealed that CPP had a backbone consisting of (1 → 3)-linked-β-d-galactopyranosyl, (1 → 2, 3)-linked-β-d-galactopyranosyl and (1 → 3)-linked-α-d-rhamnopyranosyl residues, which were branched with two glycosyl residues composed of α-l-arabinose-(1 → 5)-α-l-arabinose(1 → linked residues at the O-2 position of galactosyl along the main chain in the ratio of 1:1:2:1:1. Preliminary immunological tests in vitro showed CPP could stimulate concanavalin A (ConA)- or lipopolysaccharide (LPS)-induced lymphocyte proliferation in a dose-dependent manner.