Inhibitory effects of fermented grape marc from Vitis vinifera Negroamaro on antigen-induced degranulation

To investigate the antiallergic effects of fermented grape marc from Negroamaro (N-FGM), we examined antigen (Ag)-induced degranulation of rat basophilic leukemia (RBL-2H3) cells. Among supernatants of N-FGM suspensions in water, ethanol, and dimethyl sulfoxide (DMSO), supernatants of DMSO-suspended N-FGM but not of nonfermented Negroamaro grape marc (N-GM) markedly suppressed the Ag-induced degranulation and phosphorylation of Syk in RBL-2H3 cells. Supernatants of DMSO-suspended N-FGM did not reduce the expression of Fc epsilon RI on RBL-2H3 cells. Analyses of supernatants of N-FGM suspensions in water, ethanol, and DMSO by high-performance liquid chromatography revealed higher amounts of quercetin in supernatants of DMSO-suspended N-FGM than those in the other supernatants. Quercetin also suppressed the Ag-induced degranulation and phosphorylation of Syk but did not reduce the expression of Fc epsilon RI on RBL-2H3 cells. These results suggest that inhibition of the Ag-induced degranulation and Syk phosphorylation by N-FGM might be due to the action of quercetin, as an active component in N-FGM.