The effect of 13 flavonoids on the contraction of guinea-pig isolated ileum induced by prostaglandin E2 (PGE2) and leukotriene D4 (LTD4) have been investigated. Apigenin, quercetin and kaempferol at a concentration of 10-mu-M significantly (p < 0.001) reduced the contraction to either agonist. Crysin and flavone antagonized only PGE2 (p < 0.01). The other flavonoids were inactive. The blocking effect of apigenin, quercetin and kaempferol against PGE2 was also concentration- and time-dependent, and was augmented by the calcium channel blocker verapamil or by lowering the extracellular calcium to 25%, consistent with a calcium-mediated mechanism of protection which these flavonoids, at the same concentration, also showed against barium chloride (BaCl2)- or acetylcholine (ACh)-induced contraction (p < 0.05-0.001).
Reduction of agonist-induced contractions of guinea-pig isolated ileum by flavonoids
CAPASSO, Anna;PINTO, Aldo;AUTORE, Giuseppina;
1991-01-01
Abstract
The effect of 13 flavonoids on the contraction of guinea-pig isolated ileum induced by prostaglandin E2 (PGE2) and leukotriene D4 (LTD4) have been investigated. Apigenin, quercetin and kaempferol at a concentration of 10-mu-M significantly (p < 0.001) reduced the contraction to either agonist. Crysin and flavone antagonized only PGE2 (p < 0.01). The other flavonoids were inactive. The blocking effect of apigenin, quercetin and kaempferol against PGE2 was also concentration- and time-dependent, and was augmented by the calcium channel blocker verapamil or by lowering the extracellular calcium to 25%, consistent with a calcium-mediated mechanism of protection which these flavonoids, at the same concentration, also showed against barium chloride (BaCl2)- or acetylcholine (ACh)-induced contraction (p < 0.05-0.001).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
