Polysaccharides were extracted from corn bran (CBPs) and then modified by a sulfating reaction to obtain sulfated corn bran polysaccharides (SCBPs). Synthesized sulfated polysaccharides were located in the equatorial bonds of monosaccharide residues. A more orderly and smooth surface of SCBPs was observed. Single factor experiment results showed 2.0 g of aminosulfonic acid, 60 mL of N-dimethylformamide and 2.5 h of reaction time were the optimum conditions for SCBPs preparation. Phenolic content of SCBPs significantly decreased with increasing concentration of aminosulfonic acid, while it increased with increasing DMF concentration and reaction time. SCBPs had higher DPPH, ABTS and iron chelating capacity under the optimum conditions. SCBPs significantly inhibited the proliferation of A549 and HepG2 cell lines, which was associated with the up-regulation at the mRNA expression level of pro-apoptotic genes CASP3, CASP8, CASP9 and reduced expression of p53, gene Bcl-2 and gene iNOS.
Summary Corn bran polysaccharides were extracted using an ultrasonic-assisted method with a yield of 33.50% and then carboxymethylated. The occurrence of modification was confirmed using Fourier transform infrared spectral analysis. The surface of polysaccharide particles became loosened following the carboxymethylation. The effect of sodium hydroxide concentration, reaction temperature, and the reaction time on the degree of substitution was investigated, and the relationship among the substitution degree, total phenolic content and antioxidant activity were studied. With sodium hydroxide concentration of 6.0 mol L −1 , keeping the reaction temperature of 60 °C and reaction time of 5.0 h, the modified polysaccharides possessed the highest degree of substitution and antioxidant activity. Cell culture model indicated that the carboxymethylated polysaccharide significantly inhibited the proliferation of A549 and HepG-2 cells, and these antitumour characteristics may be associated with the elevated expression of CASP3 , CASP8 , CASP9 , and p53 , as well as the significantly decreased expression of Bcl-2 and iNOS genes. The excellent antioxidant capacity and strong antitumour activity of these polysaccharides might provide a potential application as a naturally functional ingredient.
危险品化学品经营许可证（带存储）