Estudo sobre os efeitos cardiovasculares do extrato hidroalcoólico de folhas de Colônia (Alpinia zerumbet) em ratos espontaneamente hipertensos

Abstract

Alpinia zerumbet is a plant originally from West Asia and abundant in the northeast and southeast of Brazil, where it is commonly known as Colony. This plant is widely used in folk medicine, and its antihypertensive, diuretic and anxiolytic properties can be highlighted. This study aims to investigate the effects of chronic treatment with hydroalcoholic colony leaf extract (AZE) on cardiovascular changes in spontaneously hypertensive rats (SHR). SHRs with 90 days of age treated or not with AZE (50mg / Kg / day in drinking water) for 6 weeks were used. Wistar-Kyoto rats were used as controls. Blood pressure, assessed by tail plethysmography, and weight were assessed weekly. At the end of the treatment, the 24-hour urine was collected and, subsequently, the animals were anesthetized with thiopental (70mg / Kg ip) and the blood collected through the puncture of the abdominal aorta. The thoracic aorta was isolated for morphological analysis and the mesenteric arterial bed (LAM) was isolated and coupled to an organ perfusion system to assess vascular function. Plasma levels of urea, creatinine and nitrite were evaluated by colorimetric and angiotensin assays (AngII) by the ELISA method. Protein carbonylation, lipid peroxidation and antioxidant enzyme activity were evaluated in plasma by spectrophotometry. In the 24-hour urine, urinary volume, creatinine, urea and lipid peroxidation levels were evaluated. Results: Treatment with AZE normalized blood pressure in SHR, but was not able to improve vascular dysfunction, characterized by a reduction in the vasodilator response of acetylcholine and an increase in the norepinephrine vasoconstrictor response in LAM. There was no difference between the experimental groups in parameters such as weight, urinary volume, proteinuria and plasma levels of AngII and nitrite. In the urine of SHRs, lower levels of urea and creatinine were observed compared to controls, and AZE was able to increase their excretion. In the plasma of SHRs an increased level of urea was observed in relation to the controls, without alteration by the treatment, in contrast to the level of creatinine, which was reduced by AZE. Levels of lipid peroxidation were higher in the urine of SHRs compared to controls and normalized by treatment, but in plasma there was no difference between groups. There was an increase in protein damage in the plasma of SHRs compared to controls, and AZE was able to decrease the same. A reduction in the activity of the enzymes catalase and glutathione peroxidase was observed in the plasma of SHRs compared to controls. However, there was an increase in the activity of these enzymes in the SHR group treated with AZE. There was hypertrophy of the intima-media layer, as well as a reduction in the lumen of the thoracic aorta of SHR animals when compared to controls. AZE treatment reversed the remodeling of the aorta in this model of hypertension. Conclusion: The results showed that AZE reduces blood pressure and remodeling of the thoracic aorta in SHR animals, which could be related, in part, to increased antioxidant activity and reduced oxidative damage