Protection of NMDA-induced neuronal cell damage by methanol extract of Zizyphi Spinosi Semen in cultured rat cerebellar granule cells

Zizypus is one of the herbs widely used in Korea and China due to the CNS calming effect. The present study aims to investigate the effect of the methanol extract of Zizyphi Spinosi Semen (ZSS), the seeds of Zizyphus jujuba Mill var. spinosa, on N-methyl-D-aspartate (NMDA)-induced neurotoxicity in cultured rat cerebellar granule neuron. ZSS, over a concentration range of 0.05-5 mug/ml, inhibited NMDA (1 mM)-induced neuronal cell death, which was measured by a trypan blue exclusion test and a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. ZSS (0.5 mug/ml) inhibited glutamate release into medium induced by NMDA (1 mM), which was measured by HPLC. Pretreatment of ZSS (0.5 p,g/ml) inhibited NMDA (1 mM)-induced elevation of cytosolic calcium concentration ([Ca2+](c)), which was measured by a fluorescent dye, Fura 2-AM, and generation of reactive oxygen species (ROS). These results suggest that ZSS prevents NMDA-induced neuronal cell damage in vitro. (C) 2004 Elsevier Ireland Ltd. All rights reserved.