Immunomodulatory, antioxidant, antiangiogenic, and antiproliferative effects of rice bran arabinoxylan

Rice bran arabinoxylan compound (RBAC) is a functional food produced from hydrolysed rice bran denatured with shiitake mushroom enzymes. RBAC demonstrates strong immunomodulatory properties, particularly for enhancing the natural killer cell activity. Additionally, RBAC can augment phagocytic cellular functions by promoting the growth of macrophage and neutrophil antimicrobial/ antitumour phenotypes. Research has also shown that RBAC can modulate the production of many cytokines, including tumour necrosis factoralpha (TNF-α), interferons (IFN-γ and IFN-λ), and interleukins (IL-2 and IL-12) which have antitumour applications. Moreover, RBAC is an inducer for the maturation and activation of dendritic cells (DCs), which plays a crucial role in priming the adaptive immune response against invading pathogens and cell mutations. As DCs are antigen-presenting cells that activate the T lymphocytes, stimulation of DCs by RBAC can induce CD4+ T cell proliferation and inhibit the immunosuppressing Treg cells in patients with underactive immune responses. While not an antioxidant in its own right, RBAC has also been shown to augment the body’s natural antioxidant defence mechanisms against free radicals. RBAC also shows antiangiogenesis effects in blocking the vascular endothelial growth factor pathway and thus inhibiting tumour development. Overall, RBAC is a potent antiproliferative food supplement with strong evidence showing that it can arrest tumour proliferation.