Myocardial infarction (MI) is a major public health problem and the leading cause of human mortality in both developed and developing countries. MI is an acute condition of myocardial necrosis, which is caused by an imbalance between the coronary blood supply and myocardial demand. This condition is regularly followed by several biochemical alterations to the body, including lipid peroxidation, hyperlipidemia, free radical damage, and hyperglycemia, leading to qualitative and quantitative changes to the myocardium . Treatment of ischemic injury includes restoration of the blood supply to ischemic tissue and prevention of damage inflicted at the time of injury.
Reactive oxygen species (ROS) play an important role in oxidative stress and related myocardial damage. Increasing numbers of ROS-like hydroxyl radicals and superoxide anions during heart ischemia lead to destruction of the cell membrane, development of lipid peroxides, and damage to the antioxidative defense system [2, 3]. Experimental and clinical studies have shown that the infarct size of myocardial necrosis may be limited by the development of endogenous antioxidant enzymes and the suppression of free radical generation .
Post-MI myocardial damage is attenuated by anti-inflammatory, anti-fibrotic, and vasodilator agents. MI causes inflammation and leukocyte recruitment to the injured myocardium and renal glomerulus . After MI, myofibroblast persistence may contribute to fibrosis and adverse myocardial remodeling, particularly if the myofibroblasts remain active in healthy areas of the heart that are located at a distance from the original site of injury (reactive fibrosis). Fibrosis in the remote myocardium inevitably leads to increased myocardial stiffness, resulting in systolic and diastolic dysfunction, left ventricular (LV) hypertrophy, arrhythmia, neurohormonal activation, and, ultimately, heart failure .
Recently, there has been growing interest toward establishing the therapeutic potential of natural products against several diseases. For instance, the consumption of plant items, such as antioxidant supplements or antioxidant-containing foods, might be used to protect against various diseases, including cardiovascular diseases . Euterpe oleracea Mart., popularly known as “açaí,” is widely cultivated in the Amazon region of Brazil. Chemical studies have shown that this purple fruit contains hydroxybenzoic acids, antioxidant polyphenolics, flavan-3-ols, and anthocyanins, predominantly cyanidin 3-O-rutinoside and cyanidin 3-O-glucuronide [8–10]. Açaí exhibits anti-inflammatory action through the inhibition of cyclooxygenases 1 and 2 , vasodilator effect , inhibition of nitric oxide (NO) production, as well as inducible nitric oxide synthase (iNOS) activity and expression , and antioxidant properties in acute lung inflammation .
Although E. oleracea is an important medicinal plant that has antioxidant, anti-inflammatory, and vasodilator properties, its cardioprotective activity against MI has not been studied. Therefore, in this study, we investigated the effects of the oral administration of hydroalcoholic extract from the seeds of E. oleracea fruit on cardiac dysfunction and exercise intolerance of rats subjected to MI.