Abstract
The potency, structure-activity relationship, and mechanism of vasorelaxation of a series of flavonoids, representing different subclasses (flavonols: fisetin, rutin, quercetin; flavones: chrysin, flavone, baicalein; flavanones: naringenin, naringin; isoflavones: diadzein and flavanes: epigallo catechin gallate), were examined in the isolated rat aorta. Most of the flavonoids tested showed concentration dependent relaxant effects against K+ (80 mM) and phenylephrine (PE, 0.1 microM)-induced contractions with a greater inhibition of the responses to the alpha1-adrenoceptor agonist. The relaxant effects of most of the flavonoids involve in part the release of nitric oxide and prostaglandins from the endothelium as pretreatment with L-NAME and indomethacin attenuated the responses. In addition, the relaxant action of the flavonoids includes inhibition of Ca+2 influx and release of Ca+2 from intracellular stores. A structure-activity relationship amongst the flavonoids was suggested.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Aorta, Thoracic / drug effects*
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Cyclooxygenase Inhibitors / pharmacology
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Enzyme Inhibitors / pharmacology
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Flavonoids / pharmacology*
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In Vitro Techniques
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Indomethacin / pharmacology
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Male
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Muscle Contraction / drug effects
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Muscle Relaxation / drug effects
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Muscle, Smooth, Vascular / drug effects*
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NG-Nitroarginine Methyl Ester / pharmacology
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Nitric Oxide Synthase / antagonists & inhibitors
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Nitric Oxide Synthase Type III
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Phenylephrine / antagonists & inhibitors
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Phenylephrine / pharmacology
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Potassium / antagonists & inhibitors
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Potassium / pharmacology
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Rats
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Rats, Inbred WKY
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Structure-Activity Relationship
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Vasoconstrictor Agents / antagonists & inhibitors
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Vasoconstrictor Agents / pharmacology
Substances
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Cyclooxygenase Inhibitors
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Enzyme Inhibitors
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Flavonoids
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Vasoconstrictor Agents
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Phenylephrine
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Nitric Oxide Synthase
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Nitric Oxide Synthase Type III
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Nos3 protein, rat
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Potassium
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NG-Nitroarginine Methyl Ester
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Indomethacin