Phytochemical Effects on FcepsilonRI and MrgprX2-mediated Activation of Human Mast Cells

Abstract

Abstract Phytochemicals and herbal extracts are currently used in food supplements as a means of preventing and treating disease. Although phytochemicals have been studied for their potentially beneficial effects on coronary heart disease and their ability to prevent atherosclerosis, certain cancers and inflammatory disease, very little attention has been focused on the potential health benefits of phytochemicals in atopic disease. Mast cells synthesize and store several proinflammatory mediators and are centrally important in atopic diseases such as asthma. Our team has been characterizing the effect of several phytochemicals (flavonoids and polysaccharides) on mast cell activation and pro-inflammatory mediator production when mast cells were activated via the high affinity Fc epsilon receptor I (FceRI) or mas-related G protein coupled receptor, MrgprX2. We show that quercetin and resveratrol decrease mast cell degranulation of both bone marrow-derived mast cells and the human mast cell line (LAD2) by at least 50% (at 10 ug/mL) when the cells were activated via FceRI with IgE and antigen. However, these flavonoids had no effect on LAD2 cells activated via MrgprX2. Polysaccharides isolated from seaweed inhibited IgE/Ag and MrgprX2 activated degranulation of LAD2 cells (by 50%, p<0.01) with some polysaccharides specific to only MrgprX2 activation. These results suggest that mast cell activation can be differentially modulated by phytochemicals.