Comparison of Anti-allergenic Activities of Various Polyphenols in Cell Assays

Abstract

The inhibitory effects of 25 polyphenols against in vitro allergic reactions were compared using biochemical and cell assays. Three polyphenols including curcumin, gallic acid, and quercetin suppressed the release of -hexosaminidase from ionophore A23187-stimulated RBL-2H3 cells more effectively (>50% inhibition at concentration). They were found to have potencies in suppressing the release of histamine not only from ionophore A23187-, but also from immunoglobulin E (IgE)-stimulated RBL-2H3 cells. Moreover, such suppressive effects of the three polyphenols were also observed in A23187 plus PMA-costimulated rat peritoneal mast cells. The extent of inhibition were quantified as the respective polyphenol concentration that inhibit 50% () of -hexosaminidase or histamine release, showing an inhibition tendency with decreasing order of curcumin>gallic acid>quercetin. Down-regulation of influx was suggested as the cause of the inhibition of -hexosaminidase and histamine releases in these cells. The immune process inhibition was confirmed by the observed reduction in the gene expressions and release of pro-inflammatory cytokine tumor necrosis factor (TNF)-, interleukin (IL)-, and IL-4, due probably to antioxidant activity of the polyphenols. These findings illustrate that curcumin, gallic acid, and quercetin may be beneficial against allergic inflammatory diseases.