Extraction, structural elucidation and immunostimulating properties of water-soluble polysaccharides from wheat bran

A water-soluble polysaccharide was extracted from wheat bran (WBP) and investigate their structural characteristics and immunostimulatory activities. The chemical composition of WBP and purified fraction (WBP-F) mainly consists of neutral sugars (91.2 ± 1.2 and 98.7 ± 1.2%), proteins (8.6 ± 0.3 and 0.2 ± 0.1%) and uronic acids (0.7 ± 0.1 and 0.6 ± 0.1%). The molecular weight (M_w ) of WBP and WBP-F was calculated as 911.7 and 510.2 × 10³  g/mol, respectively. The WBP-F stimulates the RAW264.7 cells through the production of nitric oxide and various cytokines. The treatment of WBP-F facilitated the phosphorylation of P38, JNK, ERK, and NF-ƘB in RAW264.7 cells suggesting that they might stimulate RAW264.7 cells through the activation of NF-ƙB and MAPKs pathways. Furthermore, the structural details of WBP-F were studied by GC-MS and NMR spectrum, which confirms that the main backbone consists of 4-α-D-linked glucopyranosyl residues with branching points at C-6. PRACTICAL APPLICATIONS: Wheat bran is a potential source of health-promoting compounds. It has been reported that polysaccharides of wheat bran containing numerous beneficial activities. In this study, the wheat bran polysaccharide was extracted, fractionated and investigated their immunostimulatory activities. The results found in this study revealed that the purified polysaccharide from wheat bran potentially enhanced the RAW264.7 cells activation. Hence, these polysaccharides could be utilized as a potent immunity-enhancing agent in food and pharmaceutical industries.