Effects of intravenous administration of polysaccharide purified from fermented barley on tumor metastasis inhibition via immunostimulating activities

The present study was aimed that determine the effects of polysaccharide isolated from fermented barley about tumor metastasis inhibition via immune related factors such as complementary system, macrophages, natural killer (NK) cells, and cytotoxic T lymphocyte (CTL). To characterize the tumor inhibition effects through immunostimulation of polysaccharides purified from fermented barley, the active crude polysaccharide (BF-CP) was isolated from fermented barley and further fractionated into three purified polysaccharides (BF-I, –II, and –III) with different molecular weights through gel permeation chromatography. BF-I was mainly composed of four monosaccharides, including xylose (32.90%), arabinose (26.71%), and glucose (33.43%). BF-I augmented the secretion of cytokines, such as interleukin (IL)-6, IL-12, and tumor necrosis factor-α, through peritoneal macrophages and potently activated the complement system. In the experiment for NK cells and CTL activities, intravenous ( i.v. ) administration of BF-I significantly augmented the cytotoxicity of NK cells and CTL-mediated cytotoxicity against tumor cells. In addition, i.v. administration of BF-I potently inhibited tumor metastasis in a mouse model of lung cancer and tumor metastasis in mice with suppressed NK cell function through anti-asialo GM1. Consequently, BF-I shows potent tumor inhibition effects, and these effects are related to various immune factors such as macrophages, the complement system, NK cells, and CTL. Therefore, BF-I, the polysaccharide purified from fermented barley possess the new possibility for developing functional foods and medical ingredients. • Study aimed to present a new pharmacological potential of barley. • Immunostimulatory activities of polysaccharides purified from barley evaluated. • BF-I enhanced cytokine secretion and activated complement system. • Intravenously administered BF-I inhibited tumor in lung cancer animal model. • BF-I shows potent tumor inhibition effects related to various immune factors.