Neuroprotective effect of Allium hookeri against H₂O₂-induced PC12 cell cytotoxicity by reducing oxidative stress

In this study, the anti-oxidative and neuro-protective effects of ethanolic extracts of the dried roots of Allium hookeri were investigated. Total phenolic contents and total flavonoid contents of A. hookeri extract depended on the ethanol concentrations used (50, 70 and 95%). In order to evaluate radical scavenging activity, DPPH and ABTS radical scavenging assays and ferric reducing powers were evaluated. The results showed the 95% ethanol extract of A. hookeri (95AH) had higher phenolic and flavonoid contents, and greater radical scavenging activities than 50 or 70% ethanol extracts of A. hookeri. The neuro-protective effects of 95AH were evaluated using H₂O₂-treated PC12 neuronal cells. Treatment of 95AH increased cell viability and superoxide dismutase and glutathione peroxidase activities, reduced lactate dehydrogenate release, reduced reactive oxygen species production, and increased Bcl-2/Bax ratio. HPLC revealed 95AH was rich in phenolics, especially catechin. These results demonstrate 95AH has substantial anti-oxidative and neuro-protective effects against H₂O₂-induced oxidative stress.