Abstract:Row polysaccharide (ACP) was extracted from air part of Abrus cantoniensis Hance by ethanol precipitation and further purified by DEAE anion exchange chromatography to obtain fractions ACPa and ACPb, for investigation of their antioxidant activity and preliminary characterization. Weight-average molar mass (MW) and monosaccharide composition of the polysaccharide were determined by gel permeation chromatography (GPC and High-performance liquid chromatography with evaporative light-scattering detection (HPLC-ELSD), respectively. A cellular antioxidant activity (CAA) assay was used to quantify the antioxidant activity of purified fractions by conducting in human liver carcinoma HepG2 cells. The results showed that weight-average molar mass (MW) of ACPa and ACPb were 1.24×105 Da and 2.15×105 Da, respectively. Infrared (IR) spectra analysis demonstrated that both of them had the typical characteristic absorption of polysaccharides, ACPa only contained glucose, while ACPb was a heteropolysaccharde, composed of rhamnose, arabinose, galactose and glucose in a molar ratio of 1:3.4:3.6:10.9. Moreover, cellular antioxidant activity (CAA) assay suggested a positive relationship between antioxidant effect and dose of ACPa and ACPb. In a certain concentration range，antioxidant effect of ACPa and ACPb increased with increasing their concentration. When concentration of ACPa and ACPb were 6.25 μg/mL and 100.00 μg/mL, respectively, CAA value reached 20. Further increasing their dose showed little effects on the antioxidant effects.
