EGb761 Pretreatment Reduces Monoamine Oxidase Activity in Mouse Corpus Striatum During 1-Methyl-4-Phenylpyridinium Neurotoxicity

Abstract

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.

Ginkgo biloba extract (EGb 761) modulates the expression of dopamine-related genes in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinsonism in mice

“…This effect could be the result of an enhancement of its transcription that could increase DA synthesis. Consistent with this, we previously reported that EGb 761 upregulates Th activity in conditions of MPTP/MPP + neurotoxicity (Rojas et al, 2004).…”

“…In that study, EGb 761 also improved the MPTP-induced impairment of locomotion in a manner that correlated with an enhancement of striatal DA content. We have also reported that EGb 761 regulates MAO activity and enhances Th content in MPTP neurotoxicity (Rojas et al, 2004). This finding shows that the EGb 761 neuroprotective effect is, in part, acting on the DA system.…”

“…In that study the neuroprotective effects of EGb 761 against MPTP neurotoxicity were associated with reduced oxidative stress. We also reported that EGb 761 regulates monoamine oxidase (MAO) activity and enhances tyrosine hydroxylase content in MPTP neurotoxicity (Rojas et al, 2004). Moreover, EGb 761 improved the MPTP-induced impairment of locomotion (Rojas et al, 2008), showing that the EGb 761 neuroprotective effect is, in part, acting on the DA system.…”

Improving the oral bioavailability of beneficial polyphenols through designed synergies

“…A peripheral decarboxylase inhibitor which does not cross the BBB to prevent peripheral serotonin production from dietary tryptophan (currently unknown) 4. A centrally acting MAO inhibitor which may modulate serotonin deamination within the brain (e.g., Ginkgo biloba extract [68]). …”

Hyperforin prevents β-amyloid neurotoxicity and spatial memory impairments by disaggregation of Alzheimer's amyloid-β-deposits

“…Weak inhibitor of monoamine oxidase-A and -B in vitro 66 Inhibition of monoamine oxidase activity in mouse brain 53 Inhibition of monoamine oxidase activity in mouse corpus striatum 67 Stimulation of Ach release in vivo 62 …”