Polysaccharide isolated from fermented barley activates innate immune system and anti-tumor metastasis in mice

To develop novel functional ingredients, a polysaccharide called BF-E2-P was purified from fermented barley and its antitumor activity was investigated. In the experimental lung metastasis model of colon 26-M3.1 carcinoma cells, intravenous administration of BF-E2-P (500 μg/mouse) 2 days before inoculation resulted in inhibition of metastasis by about 76%, and the extent of inhibition was dose-dependent. To demonstrate the anti-metastatic activity of BF-E2-P, we tested whether BF-E2-P could activate the innate immune system. Stimulation of macrophages by BF-E2-P resulted in cytokine production. In a co-culture of macrophages and cancer cells, BF-E2-P altered the pattern of cytokine production, suggesting that BF-E2-P affects the polarization of macrophages. In addition, intravenous administration of BF-E2-P augmented the natural killer (NK) cell-mediated cytotoxicity against cancer cells. It also increased the production of IFN- γ and granzyme B. In conclusion, BF-E2-P activates NK cells and macrophages, resulting in the enhancement of host-defense against tumor growth.