Phenolic acid bound arabinoxylans extracted from Little and Kodo millets modulate immune system mediators and pathways in RAW 264.7 cells.

The immunomodulating effect of Phenolic acid bound arabinoxylans (PCA‐AXs) extracted from Little (PCA‐AX‐L) and Kodo (PCA‐AX‐K) millet seeds in RAW 264.7 cells were investigated. The PCA‐AXs were extracted from millets and their chemical characterization were carried out by GC‐MS, HPLC, and FT‐IR. The immunomodulatory effect of PCA‐AXs in RAW 264.7 cells were investigated by estimating ROS, NO, and cytokines TNF‐α, IL‐1β, IL‐6, and evaluation of molecular mechanism by q‐PCR & western blotting techniques. The xylose: arabinose ratio of PCA‐AX‐L and PCA‐AX‐K were 1.48:1.0 and 2.26:1.0, respectively. The phenolic acids content was higher in PCA‐AX‐K than PCA‐AX‐L determined by HPLC. FT‐IR analysis confirms the presence of α‐glucosidic linkage with the degree of substitution of xylan backbone by arabinose residues. The evaluation of immunomodulating effect of PCA‐AXs revealed that the PCA‐AX‐L–treated cells showed higher release of NO, ROS and cytokines than PCA‐AX‐K–treated cells. The mRNA expressions of TNF‐α, iNOS and COX‐2 were upregulated by PCA‐AX‐L and downregulated by PCA‐AX‐K in dose‐dependent manner. Furthermore, in western blotting, the ERK and NF‐κB were found to be activated by PCA‐AX‐L and inhibited by PCA‐AX‐K. Our findings suggest that the high branched arabinoxylans of PCA‐AX‐L could modulate the immune response in RAW 264.7 cells through activation of ERK and NF‐κB signaling pathways and acts as an immunostimulant. The higher phenolic content in PCA‐AX‐K could modulate the immune response by downregulation of ERK and NF‐κB signaling pathways and thus, it could act as an immunomodulator. Practical applications: Millets are the richest source of arabinoxylans in which they are known to be bound with phenolic acids (PCA‐AX). Arabinoxylans derived from rice and wheat is known immunomodulators. This study was focused to evaluate the immunomodulatory property of PCA‐AX derived from two different millets little and kodo. The study results clearly indicated the immune stimulatory action of PCA‐AX‐L and immunomodulatory action of PCA‐AX‐K. The explored mechanism indicated that the PCA‐AXs modulate NF‐κB & ERK pathways for their immunomodulatory action. [ABSTRACT FROM AUTHOR]