title: Red ginseng extract attenuates kainate-induced excitotoxicity by antioxidative effects.
abstract: This study investigated the neuroprotective activity of red ginseng extract (RGE, Panax ginseng, C. A. Meyer) against kainic acid- (KA-) induced excitotoxicity in vitro and in vivo. In hippocampal cells, RGE inhibited KA-induced excitotoxicity in a dose-dependent manner as measured by the MTT assay. To study the possible mechanisms of the RGE-mediated neuroprotective effect against KA-induced cytotoxicity, we examined the levels of intracellular reactive oxygen species (ROS) and [Ca(2+)](i) in cultured hippocampal neurons and found that RGE treatment dose-dependently inhibited intracellular ROS and [Ca(2+)](i) elevation. Oral administration of RGE (30 and 200 mg/kg) in mice decreased the malondialdehyde (MDA) level induced by KA injection (30 mg/kg, i.p.). In addition, similar results were obtained after pretreatment with the radical scavengers Trolox and N, N'-dimethylthiourea (DMTU). Finally, after confirming the protective effect of RGE on hippocampal brain-derived neurotropic factor (BDNF) protein levels, we found that RGE is active compounds mixture in KA-induced hippocampal mossy-fiber function improvement. Furthermore, RGE eliminated 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, and the IC(50) was approximately 10 mg/ml. The reductive activity of RGE, as measured by reaction with hydroxyl radical ((•)OH), was similar to trolox. The second-order rate constant of RGE for (•)OH was 3.5-4.5 × 10(9) M(-1)·S(-1). Therefore, these results indicate that RGE possesses radical reduction activity and alleviates KA-induced excitotoxicity by quenching ROS in hippocampal neurons.
authors.affiliation: Research Institute of Veterinary Medicine, Chungbuk National University, Cheongju 361-763, Republic of Korea.
authors.forename: Jin-Yi
authors.initials: JY
authors.lastname: Han
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Ahn
authors.forename: Eun-Hye
authors.initials: EH
authors.lastname: Oh
authors.forename: Sang-Yoon
authors.initials: SY
authors.lastname: Nam
authors.forename: Jin Tae
authors.initials: JT
authors.lastname: Hong
authors.forename: Ki-Wan
authors.initials: KW
authors.lastname: Oh
authors.forename: Mi Kyeong
authors.initials: MK
authors.lastname: Lee