Ferulic acid mediates prebiotic responses of cereal-derived arabinoxylans on host health.

Dietary fiber is named as "the 7th nutrient" for humans, which is beneficial to improve intestinal health and prevent metabolic disease of the host. Mechanisms of dietary fiber administration on improved host health are mediated by short chain fatty acids (SCFA), which are reported to activate G protein-coupled receptors (GPR) and suppress activity of histone deacetylase (HDAC) to down-regulate expression of nuclear factor-к-gene binding (NF-кB) signaling. Arabinoxylan is fermented by gut microbiota to produce SCFA and improved microbial community composition, intestinal barrier functions and host health. Interestingly, the latest publications have observed that ferulic acid combined with the arabinose in arabinoxylans from various cereal grains can be released through gut microbial fermentation. Ferulic acid can improve antioxidase activity and decrease reactive oxygen species (ROS) concentration by activating the signaling pathway of Kelch-like ECH-associated protein-1 and nuclear factor E2-related factor-2 (Keap1-Nrf2). However, the role of ferulic acid in cooperation with SCFA produced from microbial fermentation of cereal-derived arabinoxylan to regulate the intestinal health and host metabolisms, has been widely unclear. This review summarizes the potential mechanisms of ferulic acid from microbial fermentation of cereal-derived arabinoxylans on immunological functions and physiological metabolisms of the host. The evidence presented in the review indicates that dietary supplementation with cereal-derived arabinoxylans improves antioxidant capacity of intestinal epithelial cells due to the production of ferulic acid and SCFA from microbial fermentation. Ferulic acid can cooperate with SCFA to regulate intestinal integrity and immunological functions of the host. Peroxisome proliferator activated-receptor γ (PPARγ) may play an important role in integrating ferulic acid and SCFA to regulate host health and metabolism.