Rutin from Buckwheat Flowers and Leaves Exerts Vasodilatation and Myocardial Preservation through Inhibiting the Elevation of Intracellular Free Calcium Concentration

The aim of this study was to investigate the cardiovascular effects of rutin from buckwheat flowers and leaves (RBFL) on rats and its mechanisms. The study was performed on isolated vascular rings and a rat model of myocardial infarction. RBFL (0.1-1.6 mg/L) induced a concentration-dependent relaxant effect on the phenylephrine (PE, 10(-5) mol/L) and KCl (60 mmol/L) contracted aortic rings with or without intact endothelium. This effect was attenuated by pretreated with N-G-nitro-L-arginine-methy lester (L-NAME, 10(-5) mol/L). The Ca2+-induced contraction and PE-induced contraction were obviously attenuated after pretreated with RBFL (0.8 mg/L) for 30 min in Krebs solution without Ca2+. KCl (60 mmol/L) significantly increased the intracellular free Ca2+ concentration ([Ca2+](i)) and RBFL inhibited the increase of [Ca2+]i induced by KCl on single cardiac myocyte scanned by laser scanning confocal microscope. RBFL obviously prolonged the survival time of hypoxic mice pretreated with isoprenaline and decreased the myocardial infarction size in rat coronary artery ligation. These findings suggest that RBFL induces concentration-dependent vasodilatation and myocardial preservation and the mechanism maybe related to decrease the intracellular free Ca2+ concentration.