EGb761 protects against nigrostriatal dopaminergic neurotoxicity in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinsonism in mice: role of oxidative stress.

1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) causes nigrostriatal dopaminergic neurotoxicity and behavioral impairment in rodents. Previous studies suggest that oxidative stress, via free radical production, is involved in MPTP-induced neurotoxicity. The MPTP-treated mouse has been the most widely used model for assessing neuroprotective agents for Parkinson's disease. It has been reported previously that EGb761 prevents dopaminergic neurotoxicity of MPTP. This compound is multifunctional via different mechanisms. Here, we report the neuroprotective effect of EGb761 against oxidative stress induced by MPTP in C57BL/6J mice. EGb761 is a patented and well-defined mixture of active compounds extracted from Ginkgo biloba leaves, with neuroprotective effects, exerted probably via its antioxidant or free radical scavenger action. MPTP administration resulted in a significant decrease in striatal dopamine levels and tyrosine hydroxylase immunostaining in the striatum and substantia nigra pars compacta. Mice receiving EGb761 had significantly attenuated MPTP-induced loss of striatal dopamine levels and tyrosine hydroxylase immunostaining in the striatum and substantia nigra pars compacta. The neuroprotective effect of EGb761 against MPTP neurotoxicity is associated with blockade of lipid peroxidation and reduction of superoxide radical production (indicated by a down-regulation of Mn-superoxide dismutase activity), both of which are indices of oxidative stress. Behavioral analyses showed that EGb761 improved MPTP-induced impairment of locomotion in a manner that correlated with enhancement of striatal dopamine levels. These findings suggest that, in mice, EGb761 attenuates MPTP-induced neurodegeneration of the nigrostriatal pathway and that an inhibitory effect against oxidative stress may be partly responsible for its observed neuroprotective effects.

Spirulina maxima pretreatment partially protects against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine neurotoxicity.

Spirulina is an alga that has a high nutritional value and some of its biological activities are attributed to the presence of antioxidants. Oxidative stress is involved in Parkinson's disease. This study aims at evaluating the neuroprotective role of Spirulina maxima (Sp.) against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxicity, used as a model of Parkinson's disease. Ninety-six male C-57 black mice were pretreated with Spirulina for 14 days (25, 50, 100, 150 or 200 mg/kg, oral), followed by three MPTP administrations (30 mg/kg, intraperitoneal, i.p.). Animals were given Sp. for 8 additional days. After the treatment, the striatal dopamine (DA) content was analysed by high performance liquid chromatography, and lipid peroxidation was studied as an index of oxidative stress. Sp. pretreatment at 150 mg/kg partially prevented (51%) the DA-depleting effect of MPTP and blocked oxidative stress. Spirulina partially prevents MPTP neurotoxicity and oxidative stress, suggesting it could be a possible alternative in experimental therapy.