eNOS Activation Induced by a Polyphenol-Rich Grape Skin Extract in Porcine Coronary Arteries

Abstract

Background/Aims: Drinking red wine is associated with a decreased mortality from coronary heart diseases. This study examined whether polyphenols contained in a grape skin extract (GSE) triggered the endothelial formation of nitric oxide (NO) and investigated the underlying mechanism. Methods: Vascular reactivity was assessed in organ chambers using porcine coronary artery rings in the presence of indomethacin (a cyclooxygenase inhibitor) and charybdotoxin plus apamin (inhibitors of endothelium-derived hyperpolarizing factor-mediated responses). The phosphorylation level of Src, Akt and endothelial NO synthase (eNOS) were assessed by Western blot analysis, and the formation of reactive oxygen species (ROS) was investigated using dihydroethidine and dichlorodihydrofluorescein. Results: GSE-induced endothelium-dependent relaxations were abolished by N^G-nitro-L-arginine (an eNOS inhibitor) and ODQ (a soluble guanylyl cyclase inhibitor), and they were reduced by MnTMPyP, polyethyleneglycol catalase, PP2 (an inhibitor of Src kinase) and wortmannin (an inhibitor of phosphoinositide 3-kinase). GSE caused phosphorylation of Src, which was prevented by MnTMPyP. It also caused phosphorylation of Akt and eNOS, which were prevented by MnTMPyP, polyethyleneglycol catalase, PP2, wortmannin and LY294002. GSE elicited the formation of ROS in native and cultured endothelial cells, which was prevented by MnTMPyP. Conclusions: GSE causes endothelium-dependent NO-mediated relaxations of coronary arteries. This effect involves the intracellular formation of ROS in endothelial cells leading to the Src kinase/phosphoinositide 3-kinase/Akt-dependent phosphorylation of eNOS.

Antihypertensive and Vasorelaxant Effects of Water-Soluble Proanthocyanidins from Persimmon Leaf Tea in Spontaneously Hypertensive Rats

“…12) Phosphorylation of eNOS at Ser-1177 has been found to be associated with increases in enzyme activation and NO production. 15) Furthermore, several studies have reported that polyphenols such as epigallocatechin-3-gallate, 21) delphinidin, 22) resveratrol, 23) and PAs from grape skin extract 24) increased the phosphorylation of eNOS. Evaluation of persimmon leaf PA-stimulated phosphorylation in HUVECs revealed that ex vivo persimmon leaf PAs at the maximal relaxation concentration caused time-dependent phosphorylation not only of eNOS (Ser-1177), but also of its upstream kinase Akt (Ser-473) (Fig.…”

Nutritional improvement of the endothelial control of vascular tone by polyphenols: role of NO and EDHF

“…The PI3-kinase/ Akt signaling pathway is triggered by the polyphenolinduced intracellular formation of reactive oxygen species predominantly superoxide anions in endothelial cells [5, 68,77]. A similar mechanism of eNOS activation has been observed in response to a grape seed extract [35], grape skin extract [68], purple grape juice [5], strawberry powder rich in polyphenols [36], and epigallocatechin-3-gallate [67], a major flavonoid from the flavan-3-ol subclass found in green tea. In addition, polyphenols cause within minutes the phosphorylation of eNOS, and this effect persists for several hours indicating a sustained activation of eNOS.…”

In vitro preventive effects of nitrate tolerance by a polyphenol-enriched extract of Hibiscus sabdariffa

“…Indeed, it is now accepted that polyphenols could prevent many diseases such as cancers (Yang et al, 2009;Korkina et al, 2009;Khan et al, 2009;Bracke et al, 2008;Franklin and McCubrey, 2007), cardiovascular (Madeira et al, 2009;Jones et al, 2011;Kumar et al, 2008;Agouni et al, 2009;Walter et al, 2008;SchiniKerth et al, 2011;Sall Diallo et al, 2008;Sarr et al, 2006 ; and degenerative diseases (Mollnau et al, 2006;Chen et al, 2007;Berrino, 2002;Meydani, 2002;Meydani, 2001). Encouraging the consumption of fruits and vegetables is now a major public health recommendation.…”