Investigação do papel protetor de Eugenia uniflora e Psidium cattleianum sobre alterações metabólicas e oxidativas em modelo animal de resistência à insulina

Abstract

The insulin resistance (IR) plays an important role in the development of various diseases, such as diabetes mellitus, hypertension, dyslipidemia, cardiovascular diseases. Studies show beneficial effects of plants rich in phenolic compounds in the treatment of diseases as diabetes mellitus, mainly by the antioxidant activity of these compounds. So, the aim of the present study was to evaluate the effects of the Brazilian native fruit (Eugenia uniflora and Psidium cattleianum) extracts on body weight gain and pancreatic weight, serum biochemical parameters as well as on hepatic oxidative markers in an animal model of insulin resistance induced by dexamethasone (DEX). Wistar rats were received water, E. uniflora extract (200 mg/Kg) or P. cattleianum extract (200 mg/Kg), once a day by gavage for 21 days. In the last 5 days, the animals received an intraperitoneal injection of saline or DEX (1 mg/Kg). Our results demonstrated that DEX caused a reduction in body weight gain and relative pancreatic weight, as well as glucose intolerance, and an increase in serum glucose and triacylglycerols levels. The extracts were able to prevent the hyperglycemia and hypertriglyceridemia induced by DEX. With regard to hepatic oxidative stress parameters, DEX caused an increase in the levels of thiobarbituric acid reactive substances and reactive oxygen species production and both extracts prevented these changes. Besides, GPx activity was reduced by DEX. However, total thiol content and activities of the catalase, superoxide dismutase and delta-aminolevulinate dehydratase were not altered in any of the tested groups. Thus, extracts of Eugenia uniflora and Psidium cattleianum elicited important antihyperglycemic, antidyslipidemic and antioxidant effects, and may be useful in the therapeutic management of alterations due to IR.