Differential neuroprotective activity of two different grape seed extracts

Area of Science:

• Neuroscience
• Pharmacology
• Plant Science

Background:

• Glutamate excitotoxicity is a key factor in neurotoxic injuries like brain ischemia.
• Grape seed extracts (GSEs) are rich in polyphenols with potential therapeutic benefits.

Purpose of the Study:

• To investigate the neuroprotective effects of GSEs from two different grape varieties against glutamate excitotoxicity.
• To identify the polyphenol composition associated with neuroprotection.

Main Methods:

• Primary cultures of neonatal mouse hippocampal neurons were exposed to excitotoxic glutamate.
• Neuroprotective effects of Koshu and Muscat Bailey A GSEs were assessed by measuring Erk1/2 inactivation, dendrite retraction, Akt phosphorylation, and neuron survival.
• Polyphenol profiles were analyzed using liquid chromatography/time-of-flight mass spectrometry.

Main Results:

• Koshu GSE significantly alleviated glutamate-induced Erk1/2 inactivation and dendrite retraction.
• Koshu GSE enhanced neuron survival 24 hours post-glutamate exposure.
• Muscat Bailey A GSE showed no significant neuroprotective effects.
• Koshu GSE did not induce Akt phosphorylation, unlike brain-derived neurotrophic factor.
• Koshu GSE was characterized by higher levels of low molecular weight polyphenols and specific procyanidin oligomers.

Conclusions:

• Koshu GSE exhibits potent neuroprotective properties against glutamate excitotoxicity in hippocampal neurons.
• The neuroprotection mechanism differs from that of BDNF and may involve specific low molecular weight polyphenols and procyanidin oligomers.
• These findings highlight the therapeutic potential of specific grape varietals for neuroprotection.