Identificação de flavonoides por LC-MS/MS em extratos de folhas da Protium heptaphyllum (Aubl.) Mach. e atividade antioxidante sobre lesão hepática induzida por paracetamol em camundongos

Abstract

Protium heptaphyllum (Aubl.) March. is a plant used in popular medicine as a potent therapeutic agent being distributed throughout Brazil, widely found in the Amazon region. The objective of the research was to identify the chemical composition and biological activity of the crude ethanolic extract (EE) and the ethyl acetate fraction (EA) from the ethanolic extract of P. heptaphyllum leaves under oxidative stress induced by paracetamol in mice. The extract and the fraction were evaluated by different in vivo and in vitro assays such as HPLC-UV and LC-MS / MS fractionation. The animals were acutely intoxicated with paracetamol (PCM) (250 mg / kg) and subsequently treated with EE and EA (100 mg / kg) of P. heptaphyllum for 7 days via gavage. The following animal plasma determinations were performed: alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), glucose, total cholesterol and triglycerides. In the liver of the animals, the dosages of superoxide dismutase (SOD), catalase (CAT) glutathiones-transferase (GST), reduced glutathione (GSH), ascorbic acid (ASA), protein carbonyl (PC), and lipid peroxidation (TBARS). For the kidneys, the dosages of CAT, GST, GSH, ASA and PC were determined. The extract and fraction showed the presence of phenols and flavonoids. Three main flavonoids were identified, being quercetin-3-β-D-glucoside, myricetin and quercetin. In the tests of total antioxidant potential, EE presented EC50 of 75 μg / mL and EA, EC50 of 100 μg / mL. There was an increase in plasma ALT, AST and ALP enzymes in the group exposed to PCM, but EA decreased these levels to control levels for ALT and AST and EE decreased this index to control levels only for AST. The glycemic levels of the animals had a decrease with EE and EA which may be due to a possible hypoglycemic effect of the plant under study. In the hepatic tissue it was observed that SOD did not change, but CAT, GSH and ASA had their levels decreased in the PCM group, but EA, was able to promote an increase of these levels. GST was shown to be decreased in the animals treated with PCM and the studied plant did not influence the results. Damage markers such as TBARS and PC also raised in the PCM group in the liver of these animals and both treatments (EE and EA) reduced this increase. In the same way, in the renal tissue the increase of PC was reduced by the treatment with both EE and EA. In addition, the GST decreased in this tissue in the PCM group and the EA promoted increase of its levels. GSH also decreased, and the extract and fraction increased their levels in renal tissue. In view of the findings, the antioxidant activity of P. heptaphyllum leaf extract in this model of oxidative stress is evident. This antioxidant effect may be due to the presence of flavonoids such as quercetin-3-β-D-glucoside, myricetin and quercetin which are already well known for their antioxidant properties.