title: Effects of baicalein on leukotriene biosynthesis and degranulation in human polymorphonuclear leukocytes.
abstract: Studies were made on the effects of baicalein (5,6,7-trihydroxyflavone) on leukotrienes B4 and C4 biosyntheses and degranulation induced by calcium ionophore A23187 (A23187) in human polymorphonuclear leukocytes. Baicalein inhibited A23187-induced biosynthesis of leukotrienes B4 and C4 in human polymorphonuclear leukocytes. The concentration of baicalein required for 50% inhibition (IC50) of leukotrienes B4 and C4 formations was 1.46.10(-6) and 6.00.10(-7) M, respectively, using 1.0 microgram/ml of A23187. In addition, baicalein dose-dependently inhibited beta-glucuronidase and lysozyme releases induced by A23187, leukotriene B4 plus cytochalasin B and platelet-activating factor plus cytochalasin B. Furthermore, baicalein was found to inhibit dose-dependently Ca2+ uptake into the cells and Ca2+ mobilization from the intracellular stores.
authors.affiliation: Second Department of Medical Biochemistry, School of Medicine, Ehime University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kimura
authors.forename: H
authors.initials: H
authors.lastname: Okuda
authors.forename: S
authors.initials: S
authors.lastname: Arichi
mesh_terms: D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D003571:Cytochalasin B / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D044950:Flavanones; D005419:Flavonoids / Q000494:pharmacology*; D005966:Glucuronidase / Q000378:metabolism; D006801:Humans; D009113:Muramidase / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D010972:Platelet Activating Factor / Q000494:pharmacology; D013189:SRS-A / Q000096:biosynthesis*
chemical_list: D044950:Flavanones; D005419:Flavonoids; D010972:Platelet Activating Factor; D013189:SRS-A; D000001:Calcimycin; D003571:Cytochalasin B; C006680:baicalein; D000242:Cyclic AMP; D009113:Muramidase; D005966:Glucuronidase; D002118:Calcium