title: Differential neuroprotective activity of two different grape seed extracts.
abstract: Glutamate excitotoxicity is one of the major events that takes place during various neurotoxic injuries such as brain ischemia. We prepared grape seed extracts, from two different varieties, containing high amounts of polyphenols but little resveratrol. Their neuroprotective effects were investigated using primary culture of neonatal mouse hippocampal neurons treated with an excitotoxic concentration of glutamate. Koshu, a white, local variety of V. vinifera, alleviated the acute inactivation of Erk1/2 and dendrite retraction in cultured hippocampal neurons exposed to a toxic concentration of glutamate (1.0 ng/ml). By contrast, Muscat Bailey A, a red, hybrid variety (Muscat Humburg × Bailey), failed to show any neuroprotective effect. Unlike brain-derived neurotrophic factor and other neuroprotective cytokines, Koshu extract did not induce Akt phosphorylation. Koshu extract also augmented neuron survival rate 24 hours after glutamate toxicity. The comparison of polyphenols between the two samples by liquid chromatography/time-of-flight mass spectrometry demonstrated that Koshu had higher amounts of low molecular weight polyphenols along with several Koshu-specific procyanidin oligomers. These data suggest the presence of high affinity molecular targets for polyphenols in hippocampal neurons, which induce neuroprotective effects in a manner different from BDNF, and the importance of low molecular weight polyphenols and/or procyanidin oligomers for neuroprotection.
authors.affiliation: Department of Anatomy and Cell Biology, Interdisciplinary Graduate School of Medicine & Engineering, University of Yamanashi, Yamanashi, Japan.
authors.forename: Keishi
authors.initials: K
authors.lastname: Narita
authors.forename: Masashi
authors.initials: M
authors.lastname: Hisamoto
authors.forename: Tohru
authors.initials: T
authors.lastname: Okuda
authors.forename: Sen
authors.initials: S
authors.lastname: Takeda
mesh_terms: D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D003116:Color; D005419:Flavonoids / Q000032:analysis / Q000737:chemistry; D018698:Glutamic Acid / Q000633:toxicity; D056604:Grape Seed Extract / Q000494:pharmacology*; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects*; D051379:Mice; D008970:Molecular Weight; D009474:Neurons / Q000166:cytology / Q000187:drug effects; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010636:Phenols / Q000032:analysis / Q000737:chemistry; D059808:Polyphenols; D027843:Vitis
chemical_list: D005419:Flavonoids; D056604:Grape Seed Extract; D018696:Neuroprotective Agents; D010636:Phenols; D059808:Polyphenols; D018698:Glutamic Acid