Efeito do extrato bruto e da fração alcaloídica de Erythrina velutina em camundongos submetidos ao labirinto em cruz elevado e ao modelo de esquiva inibitória do tipo descida da plataforma

Abstract

In the popular therapy Erythrina velutina (EV), plant family Fabaceae, is used as an analgesic, anticonvulsant, anxiolytic or sedative and combating insomnia. Previous studies performed in rodents suggest that extracts of EV have anxiolytic and amnesic effect. In this context, the objective of this study was to investigate the effect of gross extract and alkaloid fraction of EV in mice submitted to elevated plus-maze (EPM) and inhibitory avoidance test. For this we conducted two experiments: for Experiment 1, Swiss albino mice were randomly assigned in 10 groups according to the treatment midazolam (MDZ- 0, 2.0 mg/Kg, i.p.); gross extract (50, 100, 200, 400 e 800 mg/Kg, p.o.) and alkaloid extract (3.0, 10 e 30 mg/Kg, p.o.). Thirty minutes after drug administration they were exposed to the EPM. For Experiment 2, animals were assigned in 2 groups: no footshock (NFS) and with footshock (WFS). The first exposure, thirty min. after saline administration (p.o) mice were exposed to the footshock (0.3mA, 15 s) or not. Twenty-four hours after the first exposure, animals received MDZ, gross extract or alkaloid extract. Thirty min. after the drugs being administrated, they were reexposed over the platform (no shock) to evaluate the latency (L2). In Experiment 1, one-way independent analysis of variance (ANOVA) shows that EV (50 mg/kg), enhanced the percentage open arm entries and percentage open time, but the doses (100 and 800 mg/kg) only resulted on significant increase of percentage open arm entries in EPM. In experiment 2, the two-way independent ANOVA (Factor 1: shock x Factor 2: treatment) shows significant effect to aversive stimuli exposure (P < 0.05), treatment (P < 0.05) and interaction between factors (P < 0.05). The post hoc shows that the treatment with gross extract of EV (400 mg/Kg) and alkaloid fraction (30 mg/Kg) resulted on significant decrease of latency on animals previously exposed to aversive stimuli. In this sense, we demonstrated that gross extract and alkaloid extract of EV had anxiolitic-like effect on the anxiety of mice submitted to EPM and inhibitory avoidance test.