Free radical-scavenging capacity and inhibitory activity on rat erythrocyte hemolysis of feruloyl oligosaccharides from wheat bran insoluble dietary fiber

Water-soluble feruloyl oligosaccharides, which were released from wheat bran insoluble dietary fiber treated with xylanase from Bacillus subtilis and further purified with Amberlite XAD-2, were evaluated for their 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity and their capacity in inhibition of rat erythrocyte hemolysis mediated by 2,2′-azobis-2-amidinopropane dihydrochloride (AAPH) under in vitro conditions. The EC₅₀ value of the water-soluble feruloyl oligosaccharides against the DPPH radical was 0.52 mg/ml. The oxidative hemolysis of rat erythrocytes induced by AAPH was suppressed by the water-soluble feruloyl oligosaccharides in a concentration- and time-dependent manner. The water-soluble feruloyl oligosaccharides, at a concentration of 4 mg/ml, showed 91.7% of inhibition of rat erythrocytes hemolysis, and the erythrocyte hemolysis could be retarded for more than 120 min. These data indicated that the water-soluble feruloyl oligosaccharides from wheat bran insoluble dietary fiber might have potential as natural antioxidants.