Neuroprotective effects of resveratrol derivatives from the roots of Vitis thunbergii var. sinuate against glutamate-induced neurotoxicity in primary cultured rat cortical cells

We observed that an aqueous extract of this medicinal plant exhibited significant neuroprotection against glutamate-induced toxicity in primary cultured rat cortical cells from methanol extracts of the roots of Vitis thunbergii var. sinuate (Vitaceae). To further clarify the underlying neuroprotective mechanisms of this observed effect, we isolated and identified various active fractions and components. By using such fractionation procedures, five resveratrol derivatives - vitisinols A (1), B (2), C (3), (+)-vitisin A (4), and (+)-vitisin C (5) - were isolated from the methanol extracts from the roots of V. thunbergii var. sinuate. Among these five resveratrol derivatives, 3 exhibited most significant neuroprotective activity against glutamate-induced neurotoxicity, as indicated by a cell viability of approximately 75%-85%, at concentrations ranging from 0.1 mu M to 10 mu M. These findings indicate that the neuroprotective effects of V. thunbergii var. sinuate might be due to the inhibition of glutamate-induced toxicity by resveratrol derivatives present in the plant.