Structural characterization of an alkali-soluble polysaccharide from Angelica sinensis and its antitumor activity in vivo.

A novel alkali-soluble polysaccharide (AASP) was isolated from Angelica sinensis (Oliv.) Diels under aqueous alkali treatment, and its structural characterization and antitumor activity in vivo were evaluated in present study. Results of HPGPC and IC revealed that AASP was a neutral polysaccharide containing Ara, Gal and Glc in the mole ratio of 1.00: 2.26: 24.43, with the average molecular weight of 4.7 kDa. Periodate oxidation, Smith degradation, methylation, FT-IR and NMR analyses further demonstrated that a preliminary structure of AASP was proposed as follows: (1→3)-linked arabinose, (1→6)-linked galactose, and (1→), (1→4), (1→6), (1→3,6)-linked glucose with α- and β-configuration. In vivo antitumor assays, AASP exhibited prominent antitumor effects on H22 hepatoma cells with an inhibitory ratio of 48.57% and effectively protected thymuses and spleens of tumor bearing mice. Besides, AASP displayed a  proliferation stimulating activity of immunocytes (splenocytes, peritoneal macrophages and natural killer cells), and an auxo-action release of cytokines (TNF-α, IL-2 and IFN-γ), leading to the apoptosis of H22 solid tumors cells in vivo via G0/G1 phase arrested. The above data demonstrated that AASP holds great application prospects to be a safe and effective antitumor supplement in the future.