Down-Regulation of FcRI Expression by Houttuynia cordata Thunb Extract in Human Basophilic KU812F Cells

Human basophilic KU812F cells express a high-affinity immunoglobulin (Ig) E receptor, FcRI, which plays an important role in IgE-mediated allergic reactions. Houttuynia cordata Thunb (Family Saururaceae), which is rich in polyphenols, has been shown to have various physiological properties, including antiviral, antioxidative, anticancer, and anti-inflammatory activities. The effect of H. cordata extract on the expression of FcRI in human KU812F cells was examined. Flow cytometric analysis showed that the FcRI expression and the IgE binding activity were suppressed when the cells were cultured with H. cordata extract. Reverse transcription-polymerase chain reaction analysis showed that levels of the mRNAs for FcRI α- and γ-chains were decreased by the treatment of H. cordata extract. Addition of H. cordata extract to culture medium was also observed to result in a reduction in the release of histamine from the cells. These results suggest that H. cordata extract may exert its anti-allergic activity through down-regulation of FcRI expression and a subsequent decrease in histamine release. KCI Citation Count: 14