Calcium-antagonist effect of quercetin and its relation with the spasmolytic properties of Psidium guajava L

ABSTRACT

The antidiarrheal properties of water ad methanolic extracts of Psidium guajava leaves have been demonstrated with anteriority and their spasmolytic effect was attributed to quercetin, a flavonoid conatined in this plant. The present paper reports the intestinal smooth muscle relaxation produced by quercetin on isolated guinea pig ileum previously contracted by a depolarizing KCl solution. Quercetin also inhibited intestinal contraction induced by different concentrations of calcium, shifting the contraction curve to the right showing a clear clacium-antagonistic efecct. Quercetin effect on ileal and aortic smooth muscles ar compared, the ileum being more sensitive to this flavonoid. The clacium antagonist property of quercetin is discussed and also its contribution to explain the spasmolytic effect of this popular herbal remedy