Immunostimulatory action of high-content active arabinoxylan in rice bran. - GreenMedInfo Summary

Immunostimulatory activity comprises specific and nonspecific immune responses stimulated by internal and external factors. Arabinoxylan is well known for its immunostimulatory activityand, although the biological activities of arabinoxylan oligosaccharides depend on their structural features. In this study, we aimed to evaluateandthe immunostimulatory activity of high-content active arabinoxylan (HCAA) obtained from rice bran through bioconversion by microorganisms and acid hydrolysis. Three microorganisms,,, and, and three different acid concentrations of hydrochloric acid (5, 10, and 20%) and acetic acid (25, 50, and 75%) were used for producing HCAA. HPLC analysis of arabinose and xylose content revealed that fermentation withfollowed by hydrolysis with 5% hydrochloric acid was the most efficient to produce HCAA. GPC analysis of HCAA indicates that HCAA is a complex of various forms of saccharides and shows an average molecular weight of 625. Further,evaluation disclosed that exposure to HCAA (10-200μg/mL) increased cell viability in mice splenic cells and RAW 264.7 cells. Additionally, exposure of mice to oral administration of HCAA (100 mg/kg) for 4-7 days increased lymphokine-activated killer (LAK)- and macrophage-mediated cytotoxic activity in cancer cells (YAC-1). Furthermore,exposure to HCAA and oral administrations in mice revealed increased interferon-γ (IFN-γ) and interleukin-10 (IL-10) protein expression through western blot analysis in RAW 264.7 cells and isolated splenic cells. Our results suggest that HCAA developed by bioconversion and acid hydrolysis may enhance immune responsesand.