Structural characterization and in vitro antitumor activity of an acidic polysaccharide from Angelica sinensis (Oliv.) Diels

• Structure of the polysaccharide was established by NMR and chemical approaches.
• ASP is an acidic heteropolysaccharide with backbone consisting of Galp and Glcp.
• ASP contained 2-OMe-galactose and glucuronic acid.
• ASP showed cytotoxicity against HepG2 cells, MCF-7 cells and A549 cells.

A water-soluble polysaccharide extracted from the roots of Angelica sinensis (Oliv.) Diels, which is a traditional Chinese medicine herb, was fractioned and purified by Sephadex G-50 gel filtration chromatography. The structural characterization and antitumor activities of the purified polysaccharide fraction, named as ASP, were evaluated in the present study. ASP, which molecular weight was determined to be 80 kDa by high-performance gel-permeation chromatography, is an acidic heteropolysaccharide consisting of glucuronic acid, glucose, arabinose and galactose in ratio of 1.00:1.70:1.85:5.02. It has a backbone composed of (1 → 3)-linked Galp, (1 → 6)-linked Galp and 2-OMe-(1 → 6)-linked Galp with three branches attached to O-3 of 2-OMe-(1 → 6)-linked Galp and terminated with GlcpA and Araf, and all of Araf and the majority of Glcp are distributed in branches. Moreover, all of GlcpA were presented as (1 → )-linked GlcpA in branches. In in vitro antitumor assays, ASP displayed cytotoxicity against HepG2 cells (34.32 ± 3.50% at the concentration of 1 mg/mL) and MCF-7 cells (28.90 ± 1.50% at the concentration of 1 mg/mL) in a dose-dependent manner, and ASP also showed mild inhibitory activity against A549 cells.