A Polysaccharide Extracted from Rice Bran Fermented with Lentinus edodes Enhances Natural Killer Cell Activity and Exhibits Anticancer Effects

Department of Food Science and Biotechnology, Kyonggi University, Sŏul, Seoul, South Korea
Journal of Medicinal Food (Impact Factor: 1.63). 04/2007; 10(1):25-31. DOI: 10.1089/jmf.2006.116
Source: PubMed


The objective of this study was to investigate the activation of natural killer (NK) cells and anticancer effects of exo-biopolymer from rice bran cultured with Lentinus edodes [rice bran exo-biopolymer (RBEP)]. Oral administration of RBEP induced the activation of NK cells in a dose-dependent manner. RBEP also prolonged the life spans of mice transplanted with Sarcoma-180 cells and inhibited growing Sarcoma-180 cells in intraperitoneum. Solid tumor growth was also suppressed by oral administration of RBEP in C57/Bl6 mice transplanted with B16/Bl6 melanoma. Intraperitoneal injection of RBEP was more effective than oral administration at the same dosage in mice with transplanted tumor cells. According to this result, when RBEP directly contacts immune cells, the anticancer activity is higher than by indirectly inducing an immune response through oral administration. Therefore, we suggest that the administration of RBEP may be effective for preventing and/or treating cancer through NK cell activation. However, further studies are needed to elucidate the possible mechanisms of the anticancer activity and to investigate the other beneficial effects of RBEP for the development of a new biological response modifier.

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    • "Rice bran fermented with Lentinus edodes (rice bran exo-biopolymer, RBEP) is a food supplement that is obtained by reacting rice bran with Shiitake mushroom-derived carbohydrates [8]. Furthermore, RBEP has been shown to suppress the growth of melanoma cancer cells by enhancing natural killer (NK) cell activity in mice [2] and by activating macrophage cells both in vivo and in vitro[5,8]. Different products derived from rice bran and mushroom cocultures have also been reported to increase NK cell activity in patients with multiple myeloma [9], cancerous mice [10], and lymphocytes [11,12]. "
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    ABSTRACT: The purpose of this study was to investigate the hypothesis that dietary supplementation with rice bran fermented with Lentinus edodes (rice bran exo-biopolymer, RBEP), a substance known to contain arabinoxylan, enhances natural killer (NK) cell activity and modulates cytokine production in healthy adults. This study was designed in a randomized, double-blind, placebo-controlled, and parallel-group format. Eighty healthy participants with white blood cell counts of 4,000-8,000cells/muL were randomly assigned to take six capsules per day of either 3 g RBEP or 3 g placebo for 8 weeks. Three participants in the placebo group were excluded after initiation of the protocol; no severe adverse effects from RBEP supplementation were reported. NK cell activity of peripheral blood mononuclear cells was measured using nonradioactive cytotoxicity assay kits and serum cytokine concentrations included interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, interleukin (IL)-2, IL-4, IL-10, and IL-12 were measured by Bio-Plex cytokine assay kit. This study was registered with the Clinical Research Information Service (KCT0000536). Supplementation of RBEP significantly increased IFN-gamma production compared with the placebo group (P = 0.012). However, RBEP supplementation did not affect either NK cell activity or cytokine levels, including IL-2, IL-4, IL-10, IL-12, and TNF-alpha, compared with the placebo group. The data obtained in this study indicate that RBEP supplementation increases IFN-gamma secretion without causing significant adverse effects, and thus may be beneficial to healthy individuals. This new rice bran-derived product may therefore be potentially useful to include in the formulation of solid and liquid foods designed for treatment and prevention of pathological states associated with defective immune responses.
    Full-text · Article · Apr 2014 · Nutrition Journal
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    • "NK cells play a central role in the immune defence system. The immunotherapy of cancer was dependent on the activation of NK cells (Kim et al., 2007). Therefore, the results suggested that splenic NK cells were activated by AG treatment and had beneficial anticancer effects. "
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    ABSTRACT: In this study, the innate immuno-modulatory effects and anti-cancer action of arabinogalactan (AG), a derivative of a well-known orchid, Anoectochilus formosanus, were investigated. The innate immuno-modulatory effects of AG were determined in vitro using RAW 264.7 cells for microarray analysis, and in vivo using BALB/c mice administrated with AG at 5 and 15mg/kg intra-peritoneally for 3 weeks. The anti-cancer activity of AG was evaluated by CT26 colon cancer-bearing BALB/c mice. The microarray analysis was performed to evaluate the innate immunity and demonstrated that AG significantly induced the expression of cytokines, chemokines, and co-stimulatory receptors, such as IL-1α, CXCL2, and CD69. An intraperitoneal injection of AG in mice increased the spleen weight, but not the body weight. The treatment of mitogen, LPS significantly stimulated splenocyte proliferation in AG treated groups. The AG treatment also promoted splenocyte cytotoxicity against YAC-1 cells and increased the percentage of CD3(+)CD8(+) cytotoxic T cells in innate immunity test. Our experiments revealed that AG significantly decreased both tumour size and tumour weight. Besides, AG increased the percentage of DC, CD3(+)CD8(+) T cells, CD49b(+)CD3(-) NK cells among splenocytes, and cytotoxicity activity in tumour-bearing mice. In addition, the immunohistochemistry of the tumour demonstrated that the AG treatments increased the tumour-filtrating NK and cytotoxic T-cell. These results demonstrated that AG, a polysaccharide derived from a plant source, has potent innate immuno-modulatory and anti-cancer activity. AG may therefore be used for cancer immunotherapy.
    Full-text · Article · Dec 2013 · Phytomedicine: international journal of phytotherapy and phytopharmacology
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    • "Cereals have been reported to possess beneficial health effects such as lipid lowering (Delaney et al. 2003), anticancer (Kim et al. 2007), neuroprotective (Jang et al. 2010), cardioprotective (Harris and Kris-Etherton 2010), and wound healing (Akkol et al. 2011). "
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    ABSTRACT: The ethyl acetate and ethanol extracts obtained from eight varieties (Faikbey, Y-1779, CI-8357, Cheokota, Seydişehir, Y-330, Sivas and YVD-18) of oat (Avena sativa L.), one variety (Larende) of barley (Hordeum vulgare L.), one variety (Tatlicak 97) of triticale (Triticale sp.) and one rye variety (Aslim 95) (Secale cereale L.) were investigated for their antioxidant effects in seven test systems. Anticholinesterase activity of the extracts was examined by enzyme-linked immunosorbent assay (ELISA) microplate reader. Total phenol and flavonoid contents were calculated using Folin Ciocalteau and AlCl₃ reagents, respectively. All of the extracts were ineffective in cholinesterase inhibition assays and had weak-to-moderate activity in antioxidant assays. The extracts exerted better activity in iron-chelation capacity ranging between 43.17 ± 2.04 and 62.97 ± 1.29%. Triticale extracts showed higher activity in reducing power experiments. A notable difference in the results of the antioxidant activity assays was observed among the oat varieties.
    Full-text · Article · Dec 2011 · International Journal of Food Sciences and Nutrition
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