IJCS | Volume 32, Nº2, May/June 2019

245 1. Chong MF, MacDonald R, Lovegrove JA. Fruit polyphenols and CVD risk: a review of human intervention studies. Br J Nutr. 2010;104(S3):S28-39. 2. Mudnic I, Budimir D, Modun D, Gunjaca G, Generalic I, Skroza D, et al. Antioxidant and vasodilatory effects of blackberry and grape wines. J Med Food. 2012;15(3):315-21. 3. Stoclet JC, Chataigneau T, Ndiaye M, OakMH, El Bedoui J, Chataigneau M, et al. Vascular protection by dietary polyphenols. Eur J Pharmacol. 2004;500(1-3):299-313. 4. Burns J, Gardner PT, O’Neil J, Crawford S, Morecroft I, McPhail DB, et al. Relationship among antioxidantactivity, vasodilation capacity, and phenolic content ofred wines. J Agric Food Chem. 2000;48:220-30. 5. Stein JH, Keevil JG, Wiebe DA, Aeschlimann S, Folts JD. Purple grape juice improves endothelial function and reduces the susceptibility of LDL cholesterol to oxidation in patients with coronary artery disease. Circulation. 1999;100(10):1050-5. 6. Anselm E, Chataigneau M, Ndiaye M, Chataigneau T, Schini-Kerth VB. Grape juice causes endothelium-dependent relaxation via a redox- References Britto Junior et al. Antioxidant and vasodilatory action of grape juices Int J Cardiovasc Sci. 2019;32(3)238-246 Original Article endothelial cells. 25 In the blood vessels, endothelial cells play a critical role in maintaining local homeostasis by producing various autacoids that act on neighboring vascular cells. Among these endothelial-derived factors, NO, which is synthesized by the endothelial NO synthase, is the main one and produces a potent vasodilator action. Some studies have shown that NO can be stimulated by red wine in isolated arteries. 18,26 In contrast, other studies have shown that inhibition of NO synthase has no effect on red wine-induced relaxation. 25 In this study, the inhibition of NO synthase with L-NAME significantly inhibited the relaxation of almost all samples, revealing the important role of endothelial NO in the vasodilator effect of grape juices. Only the RS (2) sample showed no difference in the vascular relaxation effect when NO production was inhibited. This shows that the mechanism of induction of vasodilation in this sample is little effective and is not related to the endothelial NO release stimulus, like most of the samples tested. Conclusion This study shows that the grape juices analyzed have different levels of antioxidant activity. Besides, the vasodilatory effect also presented a varying intensity from one sample to another. The mechanism of vasodilatory action seems to be related to the release of endothelial NO, except for one of the samples (RS (2) ). Only one sample (RJ) has a vasodilator activity comparable to that of red wine. Finally, these findings help understanding that the functional qualities of grape juice can vary greatly across different regions of Brazil. Even though all the samples meet the eligibility criteria, not all of them have functional effects as an appreciable antioxidant and vasodilator activity, some of which are probably incapable of providing protection against cardiovascular diseases. Acknowledgements CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) awarded a Masters’ Grant to José Britto Junior. Matheus L. Rocha receives financial support for research productivity (PQ2) from CNPq. Author contributions Conception and design of the research:Britto Junior J, Rocha ML. Acquisition of data: Britto Junior J, Leite KCS. Analysis and interpretation of the data: Britto Junior J, Leite KCS, Gil ES, Rocha ML. Statistical analysis: Rocha ML. Writing of themanuscript: Gil ES, RochaML. Critical revision of the manuscript for intellectual content: Gil ES, Rocha ML. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This article is part of the thesis of master submitted by José Britto Junior, from Universidade Federal de Goiás . Ethics approval and consent to participate This study was approved by the Ethics Committee on Animal Experiments of the Universidade Federal de Goiás under the protocol number 044/17.