Effect of sulfation on the antioxidant properties and in vitro cell proliferation characteristics of polysaccharides isolated from corn bran

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.