ome diet components, such as certain indigestible polysaccharides from edible plants, may interact with the
gut-associated lymphoid tissue and improve the host immune response to pathogens. The non-starch polysac-
charides (NSP) from bananas are non-digestible carbohydrates that resemble some immunomodulatory polysac-
charides occurring in the cell wall of cereals. Based on this similarity, the effects of the water-soluble NSP from
two banana cultivars (Nanicão and Thap Maeo) on the phagocytic activity, nitric oxide (NO) and cytokines pro-
duced by cultured macrophages were investigated. An investigation into the monosaccharide composition and
the oligomers released by enzymatic hydrolysis of the ultra-
fi
ltered fraction above 50 kDa and the heat-treated
fraction of water-soluble NSP from both cultivars revealed they are mostly composed of mannan and
galacturonans (homogalacturonan, xylogalacturonan and rhamnogalacturonan). The NSP tested were able to ac-
tivate the macrophages, but the effects on the phagocytic activity and the release of tumor necrosis factor alpha
(TNF-
α
), interleukin-6 (IL-6) and nitric oxide production were dependent on the polysaccharide concentration
and the cultivar origin. Despite some speci
fi
c differences, the NSP from Nanicão and Thap Maeo banana fruits
may be considered prospective food immunomodulators, which contribute to the promotion of a more respon-
sive immune system.