Efeito de Plathymenia reticulata sobre a toxicidade induzida por metilmercúrio, em ratos

Abstract

Mercury (Hg) is a known metal high toxicity been described over the years. Methylmercury (MeHg) is one of organic forms of this metal that has a higher toxicity find it easier to penetrate the cell membranes of organs and blood-brain and placental barriers causing numerous systemic consequences in the contaminated organism. One of the mechanisms underlying the toxicity of MeHg is to generate in excess of reactive oxygen species (ROS) causing oxidative stress. P.reticulata is a species commonly known as mahogany whose use in folk medicine is widespread mainly in northern and central-western Brazil. The P. reticulata bark extract has in its composition tannins, flavonoids and other phenolic groups of compounds of structure responsible in large part by the antioxidant effect of the plant. The aim of this study was to investigate the effect of aqueous extract of P. reticulata by contamination MeHg for 21 days in mice through behavioral tests and Hg dosages in liver, kidney, brain and cerebellum. In vitro testing was also carried out to evaluate antioxidant activity of the aqueous extract through the superoxide radical test. They were selected for the 64 mice experiments Wistar weighing males between 150 and 200g from the Vivarium of Bioprospecting Laboratory and Experimental Biology (LabbBex) of the Federal University of Western Pará. The animals were separated into the following groups (G) with n = 6 in each: G1 Water, G2 - P.reticulata 60 mg / kg, G3 - P. reticulata 120mg / kg, G4 - P. reticulata 240mg / kg, G5 - MeHg 4 mg / kg, G6 - P. reticulata 60mg / kg + MeHg , G7 - P. reticulata 120mg / kg + MeHg, G8 - P. reticulata 240 mg / kg + MeHg. After 21 days of daily administration animals were subjected to behavioral testing (Y maze, Box Light-dark and Rota-Rod) subsequently euthanized and finally collecting made brain, liver and kidneys for analysis. The results of the behavioral tests showed that the groups that had received MeHg short and long term memory plus motor function affected. In the Y maze, the switching% of G1, G2, G3, G4, G5, G6, G7 and G8 were on average 65; 62; 71; 62; 33; 75; 41; 20% respectively. In the rotating rod test it was observed that the animals G5, G6 spent less time on the swivel bar, averaging 65.75. G7 and G8 animals were not able to remain on the swivel bar. Hg dosages showed higher concentration of metal respectively in liver, kidney, brain and cerebellum. The dose of P. reticulata 60 mg / kg proved to be more effective overall in protecting the damage caused by metal to organs and memory and learning assessed in behavioral tests. The in vitro evaluation of the extract demonstrated antioxidant activity through inhibition of superoxide radicals (its% inhibition: 25.6%, 50.92% 68% 93% for 5 mg / mL concentrations, 10 mg / mL, 20 ug / ml and 50 ug / ml.