Jeong-Ro Park

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

Human basophilic KU812F cells express a high-affinity immunoglobulin (Ig) E receptor, FcepsilonRI, 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 FcepsilonRI in human KU812F cells was examined. Flow cytometric analysis showed that the FcepsilonRI 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 FcepsilonRI alpha- and gamma-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 FcepsilonRI expression and a subsequent decrease in histamine release.

Isolation and identification of flavonoids from Gujeolcho (Chrysanthemum zawadskii var. latilobum) as inhibitor of histamine release

In an ongoing search of compounds from natural sources that exhibit anti-allergic properties, 3 flavonoids were isolated from the ethyl acetatefraction of methanol extracts of gujeolcho (Chrysanthemum zawadskii var. latilobum), with guided histamine release inhibitory effects. The isolated compounds were identified as eriodictyol-7-O-β-d-glucuronide, 5,7-dihydroxy-4-chromene, and 6-methoxyluteolin based on spectroscopic evidences including NMR and MS spectra. These results suggest that gujeolcho extracts and 3 compounds would be candidates as therapeutic or preventive agents for allergic reaction.

Kaempferol isolated from Nelumbo nucifera stamens inhibits phosphorylation of ERK 1/2, Syk, and Lyn in FcεRI-mediated allergic reaction

Cross-linking of FcεRI with multivalent allergen and specific IgE on mast cells and initiates activation of signal cascades that lead to IgE-mediated allergic responses. Kaempferol is a phenolic compound contained in natural substances including the stamens of flavonoid-rich Nelumbo nucifera stamens. In this study, the effects of kaempferol on allergic reaction induced by an FcεRI α chain antibody were investigated. Western blot analysis revealed that the protein expression of FcεRI and the phosphorylation of Syk, Lyn, and extracellular signal-regulated kinases (ERK) 1/2 were dose-dependently inhibited by kaempferol. β-Hexosaminidase was reduced to 97.9, 89.1, 75.1, and 55.8% when treated with 5, 10, 20, and 40 μM kaempferol, respectively. From the results, the negative regulation of basophil activation with kaempferol via the suppression of FcεRI expression and degranulation may be suggested to be through inhibition of Lyn and Syk, and ERK 1/2 activation.