Inhibition of mast cell histamine release by flavonoids and biflavonoids.

The effect of 11 flavonoids and 4 biflavonoids on the release of histamine from peritoneal rat mast cells induced by compound 48/80 and calcium ionophore A23187 was studied. Dihydroflavonoids (flavanones) and (+)-catechin did not modify histamine release induced by both secretagogues. Flavone, apigenin and cromoglycate inhibited the secretion elicited by compound 48/80 but did not modify the A23187-induced secretion. The effect of kaempferol on the compound 48/80-induced histamine release was biphasic. Low doses (10 (-6) to 10 (-5)M) of the compound potentiated secretion whereas higher doses inhibited histamine secretion. Some of the drugs tested revealed a higher potency as referred to quercetin. Luteolin, a tetrahydroxyflavone and amentoflavone, a biapigenin, exhibited the highest inhibitory effects of mast cell histamine secretion.