Achyranthes bidentata Polysaccharides (AbPS) was carboxymethylated by ClCH_2COOH in aqueous NaOH and the crude product was purified by successive DEAE-Cellulose and Sephadex G-25 column chromatography to yield homogeneous carboxymethylated product (CM-AbPS), which was detected by high performance liquid chromatography (HPLC) and capillary electrophoresis (CE). By the methylation method and GC-MS analysis, we studied the distribution of carboxymethyl groups in the sugar backbone of CM-AbPS and conclude that the carboxymethyl groups mainly substitute on 4-position of the fructofuranose of the sugar backbone. The product has anti-tumor activity.

Key words: achyranthes bidentata, POLYSACCHARIDE, CARBOXYMETHYL GROUP, HPLC, ANTITUMOR DRUGS