Avaliação dos extratos etanólico e acetato de etila da casca do caule da Copaifera multijuga Hayne (Fabaceae) sobre o estresse oxidativo induzido por paracetamol em camundongos

Abstract

The human organism is subject to the oxidative stress caused by reactive oxygen species (ROS) and reactive nitrogen species (RNS) from the environment, generated by the organism itself or through contact with xenobiotics or toxic metabolites of drugs, such as paracetamol (PCM). PCM is an analgesic widely used by the population, however, overdosage or intoxication leads to severe toxicity. The toxicity occurs by the formation of excessive N-acetyl-p-benzoquinoneimine (NAPQI), the product of this metabolism, which causes depletion of reduced glutathione (GSH) and hence oxidative stress. The aim of this work was to evaluate the antioxidant effect exerted by the ethanolic and ethyl acetate crude extract from the stem bark of the Copaifera multijuga on oxidative stress induced by paracetanol in Swiss mice. The mice were subjected to acute poisoning with PCM (250 mg/ kg) and then treated with ethanolic and ethyl acetate extracts (EE and EA, 250 mg/ kg) or rutin (6 mg/ kg) by gavage. It was analysed alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in plasma, protein carbonyls, lipid peroxidation (reaction products with thiobarbituric acid - TBARS), reduced glutathione (GSH), ascorbic acid (ASA), catalase (CAT), superoxide dismutase (SOD) and glutathione-s-transferase (GST) of tissues (liver, brain and kidney). CAT and GST in the hepatic tissue had their diminished activity in the PCM group in 22.8 % and 30.2 %, respectively. In this group, there was an increase of protein carbonyls in the liver (53.5 %), renal (71.3 %) and brain (28.5%). However, there was a decrease in the carbonylation in the groups treated PCM + EE (44,1 %) in the liver and PCM + EA, PCM + Rutina in the kidneys about 50,7 % e 30,4 %, respectively. Hepatic GSH decreased (22.8%) in the PCM group and the animals treated with PCM + EE increased by 35%. Furthermore, it was shown an increase in ALT (25.8%) and AST (64.5%) aminotransferases in the plasma and PCM + Rutin, PCM + EE and PCM + EA groups had a decrease of 35%, 21.7%, 28.6%, respectively. In addition, AST decreased 55.9% only in PCM + Rutin group. However, the extracts showed a positive effect on the non-enzymatic antioxidants GSH and ASA, as they were able to restore the levels of these parameters changed by the PCM. The best antioxidant effect on oxidative stress induced model PCM gave to the EE, due to the high content of phenolic compounds shown by analysis of DPPH. and total phenols concentration.