Different mechanisms of actions of genistein and quercetin on spontaneous contractions of rabbit duodenum

Abstract

Flavonoids are known to relax precontracted intestinal smooth muscle and delay intestinal transit or intestinal peristalsis. The aim of this study was to determine the effects of genistein and quercetin on spontaneous contractions of rabbit duodenum in vitro in an organ bath. Genistein and quercetin (0.1-10 µM) reduced the amplitude of spontaneous contractions in the longitudinal and circular smooth muscle of rabbit duodenum, but they did not modify the frequency. Bay K8644 (L-type Ca 2+ channel activator), apamin, charybdotoxin, and tetraetylammonium (K + channel blockers) reverted the inhibition of amplitude of spontaneous contractions induced by genistein in longitudinal and circular smooth muscle. H-89 (protein kinase A inhibitor) antagonized the reduction of the amplitude of spontaneous contractions induced by quercetin in longitudinal and circular smooth muscle of duodenum, while 2,5-dideoxiadenosine (adenylyl cyclase inhibitor) reverted only the reduction of the amplitude in circular smooth muscle. In conclusion, genistein and quercetin reduce the spontaneous contractions in the duodenum by different mechanisms of actions. The effect of genistein would be mediated by Ca 2+ and K + channels, while the effect of quercetin would be mediated by cAMP and protein kinase A.

Antispasmodic Effect of Blackcurrant (<b><i>Ribes nigrum</i></b> L.) Juice and Its Potential Use as Functional Food in Gastrointestinal Disorders

“…The spasmolytic effect of flavonoids has been demonstrated on the ileum [17][18][19][20], bronchi, and the uterus of rats [33] in vitro and in vivo. Quercetin, one of the flavonoids found in blackcurrant juice, has been shown to have an inhibitory effect on the spontaneous contractions of rabbit duodenum [34]. Quercetin has produced a relaxant effect on isolated guinea pig ileum previously contracted by high concentrations of K + , and has inhibited intestinal contraction induced by different concentrations of calcium, showing a calcium-antagonistic effect [35].…”

Antispasmodic Effects and Action Mechanism of Essential Oil of Chrysactinia mexicana A. Gray on Rabbit Ileum

“…Flavonoids such as genistein and quercetin reduced the amplitude of spontaneous contractions in the smooth muscle of rabbit duodenum, but they did not modify the frequency, these effects being similar to those found for EOCM. The effect of genistein is mediated by Ca 2+ and K + channels, while the effect of quercetin is mediated by cAMP and protein kinase A [15]. Trolox decreases the amplitude and frequency of spontaneous contractions and the acetylcholine-induced contractions [14].…”

“…The spontaneous motility and contractility of rabbit intestine is mediated by the influx of extracellular Ca 2+ , intracellular Ca 2+ release [11] and K + channels [12]. Different agents induce relaxing responses in the rabbit intestine as sodium nitroprusside (nitric oxide donor), trolox (analogue of vitamin E) or quercetin and genistein (flavonoids) [13,14,15].…”