Inhibitory Effects of Anthocyanins Isolated from Black Soybean (Glycine max L.) Seed Coat on Degranulation and Cytokine Generation in RBL-2H3 Cells

Anthocyanins belong to a group of flavonoid compounds and are well known for their various health beneficial effects, which include antioxidative activities. Among them, the major anthocyanins isolated from seed coat of black soybean (Glycine max L.) were previously characterized as glycosides containing glucopyranose. Asthma is an allergic disease that is strongly associated with various immune cells, including basophils and mast cells. Eosinophils, basophils, and mast cells play important roles in allergic asthma through the release of inflammatory mediators such as asthma-specific T-helper 2 (Th2) cytokines and subsequent amplification of asthma symptoms via degranulation. Rat basophilic leukemia RBL-2H3 cells are the most common in vitro models for evaluating allergic reactions. In this study, we examined the effects of anthocyanin from seed coat of black soybean on antigen-stimulated degranulation and Th2 cytokine production in RBL-2H3 cells. Cell degranulation was evaluated by measuring the release of -hexosaminidase. -Hexosaminidase release and Th2 cytokine production in RBL-2H3 cells was much higher upon stimulation with IgE-antigen complex than those in untreated control cells. Anthocyanins significantly suppressed IgE-antigen complex-induced degranulation of RBL-2H3 cells and inhibited IgE-antigen complex-mediated interleukin (IL)-4, IL-13, and tumor necrosis factor (TNF-) production in RBL-2H3 cells. These findings suggest that anthocyanins from seed coat of black soybean effectively inhibit allergic reactions and may have beneficial effects against allergic asthma.