Regulation of wheat bran feruloyl oligosaccharides in the intestinal antioxidative capacity of rats associated with the p38/JNK-Nrf2 signaling pathway and gut microbiota

BACKGROUND Feruloyl oligosaccharides (FOs), the ferulic acid ester of oligosaccharides, may possess the physiological functions of both ferulic acid and oligosaccharides, including antioxidative activity and gut microbiota modulation capacity. The present study aimed to investigate whether FOs could regulate the intestinal antioxidative capacity of rats by modulating the MAPKs/Nrf2 signaling pathway and gut microbiota. Thirty Wistar rats were randomly divided into five groups. Rats received a standard diet and were gavaged once daily with 0.85% normal saline, 100 mg kg(-1) body weight vitamin C or FOs solution at doses of 20, 40 and 80 mg kg(-1) body weight for 21 days. RESULTS FOs strengthened the antioxidative capacity of the jejunum, as indicated by increased in contents of catalase, superoxide dismutase and glutathione peroxidase, as well as glutathione. Moreover, FOs administration upregulated the mRNA expression level of antioxidant-related genes (glutamate-cysteine ligase catalytic subunit, glutamate-cysteine ligase modifier subunit and heme oxygenase-1) in the jejunum. Increases in phosphorylation levels of Nrf2, p38 and JNK were also observed. Administration with 40 mg kg(-1) FOs altered the structure and composition of the cecal microbiota, which was indicated by the increased the relative abundances of Actinobacteria, Proteobacteria and Acidobacteriota, and the decreased the relative abundances of Firmicutes, Lachnospiraceae_NK4A136_group and Blautia. Furthermore, Spearman correlation analysis revealed that the altered cecal microbiota closely correlated with jejunal antioxidative capacity of rats. CONCLUSION FOs could be used as an antioxidant for gut heath improvement through modulating the p38/JNK-Nrf2 signaling pathway and gut microbiota. (c) 2022 Society of Chemical Industry.

Automated summary

This study found that feruloyl oligosaccharides (FOs) can enhance the intestinal antioxidative capacity of rats by modulating the MAPKs/Nrf2 signaling pathway and gut microbiota. FOs increased the activity of antioxidative enzymes and the content of glutathione in the jejunum, and upregulated the expression of antioxidant-related genes. Additionally, FOs administration altered the composition of the cecal microbiota, which was closely correlated with the jejunal antioxidative capacity of rats.