EGb761 pretreatment reduces monoamine oxidase activity in mouse corpus striatum during 1-methyl-4-phenylpyridinium neurotoxicity.

EGb761 produces reversible inhibition of both monoamine oxidase (MAO) isoforms in the central nervous system. 1-Methyl-4-phenylpyridinium (MPP+) neurotoxicity is prevented by treatment with the MAO inhibitor pargyline. We investigated EGb761's effect on striatal MAO activity during MPP+ neurotoxicity. C-57 black mice were pretreated with EGb761 (10 mg/kg) daily for 17 days followed by administration of MPP+ (0.72 mg/kg). MPP+ enhanced striatal MAO (30%) activity at 6 h, and EGb761 prevented this effect. MAO-B activity in striatum was enhanced (70%) 6 h after MPP+ administration and was reduced to almost normal levels in EGb761 + MPP+ group compared to MPP+ group. Pretreatment with EGb761 partially prevented (32%) the striatal dopamine-depleting effect of MPP+ and prevented the reduction in striatal tyrosine hydroxylase activity (100%). Results suggest that EGb761 supplements may be effective in reducing MAO activity as well as enhancement in dopamine metabolism, thereby preventing MPP+-neurotoxicity.