kaempferol and Leukemia

Toona sinensis is a traditional Chinese medicine belonging to the Meliaceae family. The aim of this study was to identify the potential compounds responsible for anticancer activity of T. sinensis. The EtOAc extracts of leaves and woods of T. sinensis inhibited cell proliferation and induced apoptosis in human leukemia HL-60 cells. Our phytochemical research of these extracts led to the isolation of various polyphenolic constituents. The chemical structures were determined by spectroscopic analyses. Among isolates, gallic acid and loropetalin D showed inhibition of cell proliferation and possible induction of apoptosis in these cells. Overall, our results revealed the importance of T. sinensis as a chemopreventive medicinal plant. In addition, an analysis of structure-activity relationship indicated that the number of galloyl groups affects their antileukemic potency.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; HL-60 Cells; Humans; Leukemia; Meliaceae; Molecular Conformation; Phytochemicals; Phytotherapy; Plant Extracts; Plant Leaves; Structure-Activity Relationship; Wood

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