chrysoeriol and Leukemia

Quercetin, luteolin and chrysoeriol were identified from rooibos tea as degranulation inhibitors in rat basophilic leukaemia cells. The degranulation inhibitory activity of chrysoeriol was first discovered in the present study. When quercetin, luteolin and chrysoeriol were mixed in the ratio that occurs in rooibos tea extract, the mixture inhibited antigen- and calcium ionophore-stimulated degranulation to the same degree as that by the whole rooibos tea extract. These findings indicate that these three flavonoids are the key factors underlying the degranulation inhibitory activity of rooibos tea.

Topics: Animals; Anti-Allergic Agents; Aspalathus; Basophils; Calcium Ionophores; Cell Degranulation; Cell Line, Tumor; Flavones; Leukemia; Luteolin; Plant Extracts; Quercetin; Rats; Teas, Herbal

Flavonoids are widely occurring polyphenols that are found in plants. The aim of this study was to investigate the structure-activity relationships of 5,7-dihydroxyflavones, with a focus on the effect of B ring structure substitution on the antiproliferative effects of the compounds in human leukemia HL-60 cells. We prepared a series of 5,7-dihydroxyflavones and evaluated their ability to inhibit the proliferation of HL-60 cells by using the MTT assay. The apoptosis- and cell differentiation-inducing ability of the most potent flavones were investigated using staining and morphological analyses. This study explored the antileukemic and chemopreventive potency of 5,7-dihydroxyflavones, particularly diosmetin and chrysoeriol, which have both hydroxy and methoxy groups on the B ring.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Cell Differentiation; Cell Proliferation; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Flavones; Flavonoids; HL-60 Cells; Humans; Leukemia; Molecular Structure; Structure-Activity Relationship