Identification of an immunostimulatory polysaccharide in banana.

Banana is a fruit widely accepted by people over the world. Besides having delicious taste, it shows multiple health benefits. In this work, the major polysaccharide was isolated from banana and purified. It was identified to be α-(1 → 6)-d-glucan. The in vivo immunomodulatory activity assay indicated that α-(1 → 6)-d-glucan could improve the immune status by elevating T cell proliferation, phagocytic function of macrophage, CD3⁺ T cell level, CD4⁺/CD8⁺ ratio, IL-6, IgG, IgM, TNF-α and hemolysin antibody levels. The immunostimulatory activities of α-(1 → 6)-d-glucan were similar to β-(1 → 3)-d-glucan, a clinical immunostimulatory drug. This work revealed that α-(1 → 6)-d-glucan was an important bioactive chemical for the immunostimulatory activity of banana. It could be used as a nutraceuticals candidate.