Ellagic acid exerts protective effect in intrastriatal 6-hydroxydopamine rat model of Parkinson's disease: Possible involvement of ERβ/Nrf2/HO-1 signaling

Parkinson's disease (PD) is a prevalent movement disorder in the elderly with progressive loss of mesencephalic dopaminergic neurons and incapacitating motor and non-motor complications. Ellagic acid is a natural phenolic compound with potent antioxidant and anti-inflammatory properties. In this study, we investigated its possible neuroprotective effect in 6-hydroxydopamine (6-OHDA) rat model of PD. Intrastriatal 6-OHDA-lesioned rats were pretreated with ellagic acid at a dose of 50 mg/kg/day for 1 week. Results showed that ellagic acid attenuates apomorphine-induced rotational bias and lowers the latency to initiate and the total time in the narrow beam task and this beneficial effect was partially abrogated following intracerebroventricular microinjection of estrogen receptor β (ERβ) antagonist. Furthermore, ellagic acid reduced striatal malondialdehyde (MDA), reactive oxygen species (ROS), and DNA fragmentation, and improved monoamine oxidase B (MAO-B), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), and heme oxygenase 1 (HO-1). Meanwhile, ellagic acid prevented loss of tyrosine hydroxylase (TH)-positive neurons within substantia nigra pars compacta (SNC). These findings indicate neuroprotective potential of ellagic acid in 6-OHDA rat model of PD via amelioration of apoptosis and oxidative stress, suppression of MAO-B, and its favorable influence is partly reliant on ERβ/Nrf2/HO-1 signaling cascade.