Immunomodulatory mechanism of α-D-(1→6)-glucan isolated from banana

Banana is a delicious fruit with potent immunomodulatory function. In this study, -d-(16)-glucan was purified from banana pulp. It could significantly promote pinocytic activity and production of nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor- (TNF-). The mRNA expression of nitric oxide synthase (iNOS), IL-6 and TNF- was increased in RAW264.7 macrophages. -d-(16)-glucan could not only increase the expression levels of p-p65 and p-IB, but also induce the translocation of nuclear factor-kappa B (NF-B) p65 into the nucleus. Moreover, mitogen-activated protein kinases (MAPKs), including p-ERK, p-JNK and p-p38, were upregulated. These results suggested that NF-B and MAPK signaling pathways were involved in the immunomodulatory mechanisms of -d-(16)-glucan. The results revealed that -d-(16)-glucan might be the critical component responsible for the health benefits of banana.