ABC | Volume 114, Nº1, January 2019

Original Article Euterpe Oleracea Mart. ( Açaí ) Reduces Oxidative Stress and Improves Energetic Metabolism in Myocardial Ischemia-Reperfusion Injury in Rats Patricia Alegre, 1 Livia Mathias, 1 Maria Angelica Lourenço, 1 Priscila Portugal dos Santos, 1 Andrea Gonçalves, 1 Ana Angélica Fernandes, 1 Paula Schmidt Azevedo Gaiolla, 1 Marcos Ferreira Minicucci, 1 L eonardo Zornoff, 1 Sergio Alberto Rupp Paiva, 1 B ertha Furlan Polegato 1 Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP, 1 São Paulo, SP – Brazil Mailing Address: Bertha Furlan Polegato • Universidade Estadual Paulista Júlio de Mesquita Filho - Faculdade de Medicina Campus de Botucatu - Rubiao Jr s/n. Postal Code 18618-970, Botucatu, SP – Brazil E-mail: bertha.polegato@unesp.br Manuscript received August 14, 2018, revised manuscript February 15, 2019, accepted March 10, 2019 DOI: https://doi.org/10.36660/abc.20180140 Abstract Background: Euterpe oleracea Mart. ( açaí ) is a fruit with high antioxidant capacity and could be an adjuvant strategy to attenuate ischemia-reperfusion injury. Objective: To evaluate the influence of açaí in global ischemia-reperfusion model in rats. Methods: Wistar rats were assigned to 2 groups: Control (C: receiving standard chow; n = 9) and Açaí (A: receiving standard chow supplemented with 5% açaí; n = 10). After six weeks, the animals were subjected to the global ischemia-reperfusion protocol and an isolated heart study to evaluate left ventricular function. Level of significance adopted: 5%. Results: There was no difference between the groups in initial body weight, final body weight and daily feed intake. Group A presented lower lipid hydroperoxide myocardial concentration and higher catalase activity, superoxide dismutase and glutathione peroxidase than group C. We also observed increased myocardial activity of β -hydroxyacyl coenzyme-A dehydrogenase, pyruvate dehydrogenase, citrate synthase, complex I, complex II and ATP synthase in the A group as well as lower activity of the lactate dehydrogenase and phosphofructokinase enzymes. The systolic function was similar between the groups, and the A group presented poorer diastolic function than the C group. We did not observe any difference between the groups in relation to myocardial infarction area, total and phosphorylated NF- κ B, total and acetylated FOXO1, SIRT1 and Nrf-2 protein expression. Conclusion: despite improving energy metabolism and attenuating oxidative stress, açai supplementation did not decrease the infarcted area or improve left ventricular function in the global ischemia-reperfusion model. (Arq Bras Cardiol. 2020; 114(1):78-86) Keywords: Euterpe Olerácea; Oxidative Stress; Energy Metabolism; Chemical Reactions; Myocardial Ischemia; Myocardial Reperfusion Injury; Rats. Introduction Although the mortality attributed to ischemic heart disease is declining in some countries, it still presents high morbidity, decreasing the quality of life and increasing healthcare spending. 1 Cardiac ischemic events may be due to partial or total tissue ischemia, with reversible or irreversible myocardial dysfunction and cell death. Ischemic periods of more than 20 minutes cause irreversible damage of the cardiomyocytes and inability to functionally recover, even with the restoration of blood flow. 2,3 During ischemia, to meet the myocardial energy demand, cellular ATP is generated by glycolysis, leading to intracellular pH reduction. 1,4 In parallel, reduced ATP levels interrupt important active pumps in ionic homeostasis, which results in overloaded cytosolic Na + and Ca 2+ , making cell repolarization unfeasible and leading to myocardial dysfunction. In addition, it is possible to observe elevated Ca 2+ levels in cytosol, which activate enzymes (phospholipases, proteases, endonucleases and ATPases) associated with lipid peroxidation, production of reactive oxygen species (ROS), dysfunction of contractile proteins, and loss of cellular function. 4 Although necessary to reverse ischemia, the restoration of blood flow may ultimately be more harmful than the ischemic process itself. 1,4,5 During reperfusion, ischemia damages are worsened due to an additional discharge of ROS generated in the mitochondria by the restoration of oxygen flow. 5,6 To improve myocardial protection during procedures involving reperfusion injury, attention has been focused on the research of drugs and substances that can prevent cardiac cell damage. 7 In this context, we observe great interest in the antioxidant action of natural products such as açaí. 8 Açaí (Euterpe oleracea Mart.) is a typical northern Brazilian fruit recently made popular for its high antioxidant capacity related to the presence of phenolic acids, flavonoids and anthocyanins. 9-12 Açaí pulp compounds consist of 31% flavonoids, 23% phenolic compounds, 11% lignoids and 9% anthocyanins. 13 The main anthocyanins in açaí pulp are 78