tiliroside and Leukemia

We isolated the 4 kinds of flavonoids from strawberry 'Nohime' and examined the effect of these flavonoids on the degranulation in RBL-2H3 cells. The flavonoids were found to suppress the degranulation from Ag-stimulated RBL-2H3 cells to different extents. To disclose the inhibitory mechanism of degranulation by flavonoids, we examined their effects on the intracellular free Ca(2+) concentration ([Ca(2+)]i) and the intracellular signaling pathway such as Lyn, Syk, and PLCgammas. The intracellular free Ca(2+) concentration ([Ca(2+)]i) was elevated by Fc epsilonRI activation, but these flavonoid treatments reduced the elevation of [Ca(2+)]i by suppressing Ca(2+) influx. Kaempferol strongly suppressed the activation of Syk and PLCgammas. It was thus suggested that suppression of Ag-stimulated degranulation by the flavonoids is mainly due to suppression of [Ca(2+)]i elevation and Syk activation. These results suggested that strawberry would be of some ameliorative benefit for the allergic symptoms.

Topics: Animals; Anti-Allergic Agents; Basophil Degranulation Test; Basophils; beta-N-Acetylhexosaminidases; Calcium; Cell Degranulation; Cell Line, Tumor; Flavonoids; Fragaria; Fruit; Immunoglobulin E; Intracellular Signaling Peptides and Proteins; Leukemia; Molecular Structure; Protein-Tyrosine Kinases; Rats; Reactive Oxygen Species; Receptors, IgE; Signal Transduction; Syk Kinase