The comparison of the relaxant effects of two methoxylated flavones in rat aortic rings


UYDES-DOGAN B., TAKIR S., OZDEMIR O., KOLAK U., Topcu G. , ULUBELEN A.

VASCULAR PHARMACOLOGY, cilt.43, ss.220-226, 2005 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Cilt numarası: 43 Konu: 4
  • Basım Tarihi: 2005
  • Doi Numarası: 10.1016/j.vph.2005.07.002
  • Dergi Adı: VASCULAR PHARMACOLOGY
  • Sayfa Sayısı: ss.220-226

Özet

The vascular effect of salvigenin (6-hydroxyapigenin 6,7,4'-trimethyl other) (1), a natural flavone, was investigated in comparison with another flavone, 6-hydroxyluteolin 6,7,3', 4'-tetramethyl ether (2) in rat aotic rings. Cumulative addition of their increasing concentrations (10(-9)-10(-4)M) produced graded relaxations on rings precontracted with noradrenaline (10(-6) M) and KCl (40 mM). The maximal relaxations induced by flavones were similar, however, based on their pEC(50) values salvigenin displayed a higher potency than 6-hydroxyluteolin 6,7,3',4'-tetramethyl ether. Endothelium removal markedly reduced the relaxations to salvigenin while the responses to 6-hydroxyluteolin 6,7,3',4'-tetramethyl ether were partially affected. In addition, a significant decrease was observed in maximal responsiveness and sensitivity to flavones in the presence of L-NOARG, a NO synthase inhibitor. The cyclooxygenase inhibitor indomethacin significantly inhibited the relaxations to salvigenin, but not altered the responses to 6-hydroxyluteolin 6,7,3',4'-tetramethyl ether. Our results provide evidence that salvigenin is an effective flavone in causing vasorelaxation which appears to be mediated by endothelium derived NO and prostacyclin. Whereas, the other flavone, 6-hydroxyluteolin 6,7,3',4'-tetramethyt ether induced relaxant responses are partially endothelium, presumably NO mediated. (c) 2005 Published by Elsevier Inc.