This study examined the ability of Aronia melanocarpa (chokeberry) juice, a rich source of polyphenols, to cause NO-mediated endothelium-dependent relaxations of isolated coronary arteries and, if so, to determine the underlying mechanism and the active polyphenols. A. melanocarpa juice caused potent endothelium-dependent relaxations in porcine coronary artery rings. Relaxations to A. melanocarpa juice were minimally affected by inhibition of the formation of vasoactive prostanoids and endothelium-derived hyperpolarizing factor-mediated responses, and markedly reduced by N(ω)-nitro-l-arginine (endothelial NO synthase (eNOS) inhibitor), membrane permeant analogs of superoxide dismutase and catalase, PP2 (Src kinase inhibitor), and wortmannin (PI3-kinase inhibitor). In cultured endothelial cells, A. melanocarpa juice increased the formation of NO as assessed by electron paramagnetic resonance spectroscopy using the spin trap iron(II)diethyldithiocarbamate, and reactive oxygen species using dihydroethidium. These responses were associated with the redox-sensitive phosphorylation of Src, Akt and eNOS. A. melanocarpa juice-derived fractions containing conjugated cyanidins and chlorogenic acids induced the phosphorylation of Akt and eNOS. The present findings indicate that A. melanocarpa juice is a potent stimulator of the endothelial formation of NO in coronary arteries; this effect involves the phosphorylation of eNOS via the redox-sensitive activation of the Src/PI3-kinase/Akt pathway mostly by conjugated cyanidins and chlorogenic acids.
Keywords: AKT; AUC; Aronia melanocarpa (chokeberry) juice; DHE; EDH; EPR; Endothelial function; Endothelial nitric oxide synthase; GAE; HBSS; Hanks balanced salt solution; L-NA; N(ω)-nitro-l-arginine; NO; Nitric oxide; PEG-catalase; ROS; Reactive oxygen species; SOD; TIC; area under the curve; dihydroethidium; eNOS; electron paramagnetic resonance spectroscopy; endothelial nitric oxide synthase; endothelium-dependent hyperpolarization; gallic acid equivalents; nitric oxide; polyethyleneglycol-catalase; protein kinase B; reactive oxygen species; superoxide dismutase; total ion current.
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