Endothelium-dependent vasorelaxation effect of rutin-free tartary buckwheat extract in isolated rat thoracic aorta.
The aim of this study was to point out the potential of tartary buckwheat on vascular functions. A nonabsorbed fraction of hot-water extract of tartary buckwheat on a SP70 column (TBSP-T), which was free from rutin, was used for this aim. In a contractile experiment using Sprague-Dawley rat thoracic aorta rings contracted by 1.0 microM phenylephrine (PE) or 50 mM KCl, TBSP-T evoked a significant vasorelaxation [EC50 (mg/ml): PE; 2.2; KCl, 1.9]. By a further fractionation of TBSP-T by liquid-liquid partitioning into basic, neutral and acidic fractions, a marked enhancement of vasorelaxation effect was observed only for acidic fraction (EC50, 0.25 mg/ml). The action of acidic fraction was significantly attenuated in endothelium-denuded aortic rings and in the presence of nitric oxide synthase inhibitor, NG-monomethyl-L-arginine (100 microM). The fraction also enhanced the cyclic guanosine monophosphate (cGMP) production in aortic rings contracted with PE [cGMP (pmol/mg protein): PE, 7.2+/-2.3; PE+Acidic fraction, 35+/-8]. These results indicate that acidic fraction could mediate NO/cGMP pathways, thereby exerting endothelium-dependent vasorelaxation action. In conclusion, tartary buckwheat was proven to regulate vascular tones and have latent acidic candidates except for rutin.
Ushida
Yusuke
Y
Faculty of Agriculture, Graduate School of Kyushu University, Higashi-ku, Fukuoka 812-8581 Japan.
Matsui
Toshiro
T
Tanaka
Mitsuru
M
Matsumoto
Kiyoshi
K
Hosoyama
Hirokazu
H
Mitomi
Atsuhiro
A
Sagesaka
Yuko
Y
Kakuda
Takami
T
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000502:physiology; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D019612:Fagopyrum / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology; D066298:In Vitro Techniques; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D012431:Rutin / Q000737:chemistry*; D014664:Vasodilation / Q000187:drug effects*
D016166:Free Radical Scavengers; D010936:Plant Extracts; D012431:Rutin