Feruloylated Oligosaccharides from Maize Bran Modulated the Gut Microbiota in Rats.

Corn bran is a byproduct produced from corn milling; it is rich in ferulic acid and hemicellulose. In this research, the effects of feruloylated oligosaccharides (FOs) from maize bran on the microbial diversity and profiles in rat feces were investigated through 16S rRNA sequencing. FOs significantly increased bacterial richness and diversity compared with the control and xylooligosaccharides (XOS) alone. In comparison with the control group and the group administrated with XOS, FOs orally administered at 300 mg/kg increased OTU in feces by 57.0 and 24.8 %, and Chao value by 93.4 and 37.6 %, respectively. FOs also influenced obesity- and diabetes-associated bacteria. Oral administration of FOs at 300 mg/kg decreased the ratio of Firmicutes to Bacteroidetes from 477.7:1 to 55.1:1; greatly increased the reads of bacteria that were previously found resistant against diabetes in rats, such as Actinobacteria, Bacteroides, and Lactobacillus; whereas decreased diabetes-prone bacteria, such as Clostridium and Firmicutes.

Maize bran feruloylated oligosaccharides inhibited AGEs formation in glucose/amino acids and glucose/BSA models.

Various Maillard reaction systems were established to investigate the effect of maize bran feruloylated oligosaccharides (FOs) on the formation of both endogenous and exogenous advanced glycation end-products (AGEs) under different pH values. The formation of AGEs and four kinds of dicarbonyl compounds (glyoxal, methylglyoxal, 3-deoxyglucosulose, 2,3-butanedione) were determined by fluorescence spectrophotometry and HPLC, respectively. Results showed that maize bran FOs effectively inhibited the production of fluorescent AGEs. Moreover, increase in pH, temperature and concentration of FOs in reaction systems elevated the inhibition effects of feruloylated oligosaccharides, fluorescent AGEs and dicarbonyl compounds. Mainly because of the ester bond of FOs at high pH and/or temperature systems are readily to be hydrolyzed, resulting in the release of ferulic acid.

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-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-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 µM for DPPH and an ORAC value of 4.77 versus 2.62 µmol Trolox/µmol. Tetrazolium blue assay showed that the addition of FOs with an FA concentration >50 µM significantly increased cell viability after treatment with H2O2. Flow cytometry analysis showed that the addition of FOs at concentrations of 800, 200, and 50 µM significantly decreased the apoptosis rate at the sub-G0 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 H2O2 and prevented the damage of cellular membranes by decreasing the release of LDH to the cultures. The addition of FA at 800 µM showed an effect similar to that of FOs at 200 µM. Therefore, the FOs prepared from corn bran are potential functional ingredients for protection against oxidative stress.