Avaliação do efeito do tratamento com o extrato de Passiflora alata no modelo animal de doença de Parkinson induzido por 6-hidroxidopamina

Abstract

Parkinson’s disease (PD) is a chronic and neurodegenerative disease with an unknown etiology. Studies have shown that oxidative processes may be involved in this neuronal death. Thus, studies have been focused on medicinal plants and substances with antioxidant properties that may inhibit such oxidative processes. Passiflora alata is a Brazilian native plant with an antioxidant and neuroprotective activity, described on literature. In addition, there is evidences that species of the genus Passiflora can act against neurodegenerative diseases, such as PD. Hence, the aim of present investigation was to evaluate the neuroprotective effect of ethanolic extract of Passiflora alata (EEPA) in an animal model of PD, induced by the neurotoxin 6-Hydroxidopamine (6-OHDA). The extract of P. alata’s leaves was prepared by extraction with ethanolic solution (95%), and characterized by its phenolic compounds, flavonoids and the scavenger activity against DPPH• and ABTS•+ radicals. To evaluate the effect per se of EEPA, an evaluation of the behavioral effect was carried out on non-injured animals, with different doses of the extract. For the identification of the possible neuroprotective effect of the plant, male Wistar rats were used, which were separated into 5 experimental groups: SHAM (false-operated), 6-OHDA control, 6-OHDA + 100mg/kg/day of EEPA, 6-OHDA + 200mg/kg/day of EEPA and 6-OHDA + 300mg/kg/day of EEPA. After the division of these groups, the animals were submited to the stereotaxic surgery for bilateral administration of 6-OHDA neurotoxin or saline solution (SHAM) in the medial forebrain bundle. On following day, the treatment with the extracts started and continued for 14 days. After the treatment was finished, all the animals were submitted to the following behavioral tests: Social recognition, Open field, Object recognition, Elevated plus maze and Forced swimming. The non-injured animals, the same treatment protocol and tests were followed. Subsequently, the animals were sacrificed and blood and brain (striatum) were collected for the determination of GSH, catalase, hematological and biochemical parameters. The present results demonstrate a neuroprotective effect resulting from treatment with the EEPA on rats with 6-OHDA injury, indicating a reversal of cognitive deficit and depressive and anxious behaviors. However, no behavioral effects were observed in the non-injured rats. In addition, the extract exhibited a good scavenger activity against the ABTS•+ radical, indicating its antioxidant activity. No differences were observed between groups on GSH concentrations and catalase activity, on blood and striatal tissue. However, hematological changes were identified in the injured animals. In conclusion, the treatment with EEPA reversed the cognitive, anxious and depressive impairments caused by the intracerebral infusion of 6-OHDA, an animal model of PD.