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Immunoglobulin E (IgE) is involved in the onset of allergic reaction, and the suppression of IgE production leads to alleviation of allergic symptoms. We found that mango peel ethanol extract (MPE) significantly suppresses IgE production by human myeloma cell line U266 cells, suggesting that MPE has an anti-allergic effect by inhibiting the production of IgE. Although mangiferin is contained in mango, which suppresses IgE production by U266 cells, it was not contained in MPE. We investigated the suppressive effect of MPE in 2,4-dinitrofluorobenzene (DNFB)-induced allergic contact dermatitis model mice. The elevation of serum IgE level was significantly suppressed by oral administration of MPE. Intake of MPE also suppressed the expression level of IL-4 in the DNFB-challenged ears, suggesting that MPE suppresses the IL-4-mediated maturation into IgE-producing cells. Our findings indicate that MPE has a potential to alleviate the increase in serum IgE level that is feature of type I allergy. [ABSTRACT FROM AUTHOR]

An array of foodstuffs was screened for the suppressive effect on production of IgE, a key molecule in the type I allergic reaction, using U266 cells. An ethanol extract from passion fruit seeds (PFS) has emerged as a food material with the IgE production-suppressive effect as the result of screening. Real-time RT-PCR analysis revealed that the IgE production-suppressive effect was caused by downregulated IgE gene expression. In addition, PFS selectively suppressed IgE production and did not affect the production of IgG, IgA, or IgM by mouse splenocytes. Resveratrol and piceatannol were identified as bioactive ingredients contained in passion fruit seeds. The effect of oral administration of PFS, resveratrol, and piceatannol was evaluated using a mouse model of allergic contact dermatitis. Both stilbenoids significantly suppressed IgE production in orally administered mice. Overall results indicated that passion fruit seeds are a promising candidate with the antiallergy effect for development of functional foods. [ABSTRACT FROM AUTHOR]

We herein report the immunostimulatory effect of spinach aqueous extract (SAE) on mouse macrophage-like J774.1 cells and mouse primary peritoneal macrophages. SAE significantly enhanced the production of interleukin (IL)-6 and tumor necrosis factor-α by both J774.1 cells and peritoneal macrophages by enhancing the expression levels of these cytokine genes. In addition, the phagocytosis activity of J774.1 cells was facilitated by SAE. Immunoblot analysis revealed that SAE activates mitogen-activated protein kinase and nuclear factor-κB cascades. It was found that SAE activates macrophages through not only TLR4, but also other receptors. The production of IL-6 was significantly enhanced by peritoneal macrophages from SAE-administered BALB/c mice, suggesting that SAE has a potential to stimulate macrophage activityin vivo. Taken together, these data indicate that SAE would be a beneficial functional food with immunostimulatory effects on macrophages. [ABSTRACT FROM AUTHOR]

Chlorophyll c2 in a Sargassum horneri extract suppressed the degranulation of rat basophilic leukaemia RBL-2H3 cells. In this contribution, the mode of action of S. horneri extract was revealed. The extract inhibited the elevation of intracellular Ca 2+ concentration induced by the antigen. Immunoblot analysis showed that S. horneri extract down-regulated the phosphorylation of both Syk and PI3K in the signalling pathways involved in degranulation triggered by antigen–antibody interaction. In addition, oral administration of S. horneri extract inhibited mice nasal rubbing behaviour sensitized with anti-DNP IgE. These findings suggest that S. horneri extract has anti-allergic activity via the suppression of degranulation of mast cells and basophils. [ABSTRACT FROM AUTHOR]

• Caffeine suppressed antigen-mediated degranulation of RBL-2H3 cells. • Caffeine suppressed degranulation by decreased Ca2+ influx into the cells. • Caffeine inhibits the degranulation caused by Ca2+ influx from the endoplasmic reticulum. • Suppressed Ca2+ influx seems to result from decreased phosphorylation of Syk, Btk, PLCγ1, PI3K, and Akt. • Caffeine showed the effect on in vivo study after oral administration. Based on some studies, moderate caffeine consumption provides several benefits to human health. However, there are few reports on the anti-degranulation activity of caffeine. Allergy is a global healthcare problem that is drastically increasing in both developed and developing countries. Meanwhile, allergic reactions are triggered by the presence of chemical mediators released from the granules in mast cells, which are called the degranulation process. In this study, caffeine was evaluated for anti-degranulation activity using basophilic cell line RBL-2H3 cells as the in vitro model and the passive cutaneous anaphylaxis (PCA) model mice in vivo. As a result, caffeine effectively suppressed antigen-induced degranulation by RBL-2H3 cells in a dose-dependent manner without cytotoxicity. Besides, caffeine also inhibited FcεRI-mediated intracellular signaling pathways, such as phosphorylation of Syk, Btk, PLCγ1, PI3K, and Akt in antigen-stimulated RBL-2H3 cells. Caffeine also suppressed PCA response in mice. [ABSTRACT FROM AUTHOR]