Protection of Feruloylated Oligosaccharides from Corn Bran against Oxidative Stress in PC 12 Cells

Feruloylated oligosaccharides (FOs) were prepared by autoclaving corn bran in oxalic acid (0.6%) solution, and their protection effects against oxidative stress in pheochromocytoma cells (PC 12) cells were investigated. The FOs samples, which comprised a mixture of feruloylated mono- and dipentoses with 4.88% bound ferulic acid (FA), as well as xylose, arabinose, galactose, and glucose amounting to 46.43, 40.46, 3.76, and 8.68% of the total sugars, respectively, were prepared by autoclaving the pretreated corn bran in 0.6% oxalic acid and then further separated. Antioxidant activity was tested by 1,1-dipheny1-2-picrylhydrazyl radical 2,2-dipheny1-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH) scavenging and oxygen radical absorbance capacity (ORAC) methods. Oxidative stress was induced by H2O2 in PC 12 neuronal cell culture model. The results showed that FOs exhibited higher antioxidant activity than free ferulic acid, with an IC50 value of 11 versus 128 mu M for DPPH and an ORAC value of 4.77 versus 2.62 mu mol Trolox/pmol. Tetrazolium blue assay showed that the addition of FOs with an FA concentration >50 mu M significantly increased cell viability after treatment with H202. Flow cytometry analysis showed that the addition of FOs at concentrations of 800, 200, and 50 mu M significantly decreased the apoptosis rate at the sub-GO phase from 37.5 to 12.7, 16.2, and 20.9% (P < 0.01), respectively. FOs also significantly decreased the malonic dialdehyde content and lactate dehydrogenase (LDH) activity, but increased superoxide dismutase activity in PC 12 cells treated with H202 and prevented the damage of cellular membranes by decreasing the release of LDH to the cultures. The addition of FA at 800 HM showed an effect similar to that of FOs at 200 pM. Therefore, the FOs prepared from corn bran are potential functional ingredients for protection against oxidative stress.