• YAKHAK HOEJI
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• v.40 no.6
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• pp.720-726
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• 1996

The neurotoxicity induced by L-glutamate in primary cultures of rat cortical cells could be attenuated by diterpene constituents of Ginkgo biloba leaves, ginkgolides A, B and C. At the concentration of 100 nM, ginkgolides up-regulated the activity of glutathione reductase in primary cultures of rat cortical cells exposed to 100 ${\mu}$M glutamate. Furthermore, ginkgolides increased the content of reduced glutathione in glutamate-treated cortical cells. However, ginkgolides showed little effect in reducing superoxide dismutase activity. Ginkgolides did, however, markedly block the production of malondialdehyde, a byproduct of lipid peroxidation in glutamate-treated rat cortical cells.

• YAKHAK HOEJI
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• v.39 no.4
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• pp.444-449
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• 1995

Primary cultures of rat cortical and chicken embryonic brain cells were employed to establish a reliable screening method for natural products blocldng or enhancing glutamate-induced neurotoxicity. Exposure of primary cultured rat cortical cells or chicken embryonic brain cells to high dose of glutamate resulted in the fragmentation of neutites and consequent neuronal death. The level of cytoplasmic lactate dehydrogenase(LDH), indicator for cell survival in cultures, was significantly reduced at exposure to glutamate. For the practical application of the methods, series of concentrations of plants extracts and positive control were applied prior to the glutamate insult on primary cultures of rat cortical and chicken embryonic, brain cells. Relative LDH level in cells was measured for the estimation of the effect of the test materials on the glutamatergic neurons. The validity of the present screening method for natural products acting on glutamatergic neurons was examined with dextromethorphan, a known glutamatergic antagonist. The treatment of 100 $\mu{M}$ dextromethorphan prevented the reduction of LDH in rat cortical and chicken embryonic brain cells caused by glutamate insult keeping 60% and 90% of LDH level in normal control, respectively. Above results indicate that primary cultures of rat cortical and chicken embryonic brain cells could be proper systems for the screening of potential natural agents acting on glutamatergic, neurons. Between the two types of cultures, primary culture of chicken embryonic brain cells seemed to be a better system for the primary screening, since it is technically easier and economical compared to that of rat cortical cells.

• YAKHAK HOEJI
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• v.41 no.1
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• pp.111-116
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• 1997

The neurotoxicity induced by L-glutamate in primary cultures of rat cortical cells could be attenuated by sesquiterpene constituent of Ginkgo biloba leaves, bilobalide. At the c oncentration of 100 nM, Bilobalide elevated the combined levels of reduced/oxidized glutathione in rat cortical cells exposed to 100 ${\mu}$M glutamate. Furthermore, bilobalide promoted a reduction in superoxide dismutase activity in glutamate-treated cells. Finally, bilobalide markedly inhibited the production of malondialdehyde. a measure of lipid peroxidation, in glutamate-treated rat cortical cells.

• Natural Product Sciences
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• v.15 no.3
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• pp.125-129
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• 2009

Neurodegenerative diseases such as Alzheimer's disease, stroke, and Parkinson's disease, are caused by neuronal cell death. Apoptosis, oxidative stress, inflammation, excitotoxicity or ischemia are discussed to play a role of neuronal cell death. In order to find the candidate of neuroprotective agent, neuroprotective activity of some medicinal plants was investigated with in vitro assay system using glutamate-induced neurotoxicity in primary cultures of rat cortical cells. The aqueous methanolic extracts of twenty-seven medicinal plants were evaluated the protective effects against glutamate-injured excitotoxicity in rat cortical cells at the concentration of 50 $\mu$g/ml and 100 $\mu$g/ml, respectively. Among them, extracts of Lonicera japonica, Taraxacum platycarpum, Polygonum aviculare, Gardenia jasminoides, Forsythia viridissima, Lygodium japonicum, Panax notoginseng, Akebia quinata, Anemarrhena asphodeloides and Phellodendron amurense showed significantly neuroprotective activities against glutamate-induced neurotoxicity in primary rat cortical cells.

• Natural Product Sciences
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• v.14 no.3
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• pp.156-160
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• 2008

The methanolic extract of Rhus verniciflua Stokes (RVS-T) and its fractions (RVS-H, RVS-C, RVS-E and RVS-B) showed significant neuroprotective activity against glutamate-induced toxicity in primary cultures of rat cortical cells. RVS-B, which showed the most potent neuroprotective activity, was further fractionated to yield RVS-B5. Treatment of cortical cells with the RVS-T, RVS-B and RVS-B5 reduced the cellular ROS level and restored the reduced activities of glutathione reductase and SOD induced by glutamate. Although, the activity of glutathione peroxidase was not virtually changed by glutamate, RVS-B5 increased the glutathione peroxidase activity. In addition, these three tested fractions significantly restored the content of GSH which was decreased by glutamate insult in our cultures. Taken together, it could be postulated that RVS extract, in particular its fraction RVS-B5, protected neuronal cells against glutamate-induced neurotoxicity through acting on the antioxidative defense system.

• Clinical and Experimental Pediatrics
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• v.55 no.7
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• pp.238-248
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• 2012

Purpose: Hypoxic-ischemic encephalopathy is an important cause of neonatal mortality, as this brain injury disrupts normal mitochondrial respiratory activity. Carnitine plays an essential role in mitochondrial fatty acid transport and modulates excess acyl coenzyme A levels. In this study, we investigated whether treatment of primary cultures of rat cortical neurons with L-carnitine was able to prevent neurotoxicity resulting from oxygen-glucose deprivation (OGD). Methods: Cortical neurons were prepared from Sprague-Dawley rat embryos. L-Carnitine was applied to cultures just prior to OGD and subsequent reoxygenation. The numbers of cells that stained with acridine orange (AO) and propidium iodide (PI) were counted, and lactate dehydrogenase (LDH) activity and reactive oxygen species (ROS) levels were measured. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and the terminal uridine deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling assay were performed to evaluate the effect of L-carnitine (1 ${\mu}M$, 10 ${\mu}M$, and 100 ${\mu}M$) on OGD-induced neurotoxicity. Results: Treatment of primary cultures of rat cortical neurons with L-carnitine significantly reduced cell necrosis and prevented apoptosis after OGD. L-Carnitine application significantly reduced the number of cells that died, as assessed by the PI/AO ratio, and also reduced ROS release in the OGD groups treated with 10 ${\mu}M$ and 100 ${\mu}M$ of L-carnitine compared with the untreated OGD group (P<0.05). The application of L-carnitine at 100 ${\mu}M$ significantly decreased cytotoxicity, LDH release, and inhibited apoptosis compared to the untreated OGD group (P<0.05). Conclusion: L-Carnitine has neuroprotective benefits against OGD in rat primary cortical neurons in vitro.

• Archives of Pharmacal Research
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• v.17 no.5
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• pp.343-347
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• 1994

Effects of betaine on glutamate-induced neurotoxicity were examined on primary culturs of chicken embryonic brain cells and on rat cortical cultures. Betaine was found to attenuate glutamate-induced neurotoxicity both morphologically and biochemically. A 30 min exposure of chicken embryonic brain cells cultured for 12 days to 500 .mu.M glutamate produced wide-spread acute neuronal swelling and neurtic fragmentation. A 2-h pretreatment of cultured chicken embryonic brain cells with i mM betaine prior to a 30 min exposure to 500 , mu, M glutamate significantly raised the survival rate of neurons in the culture. When chicken embryonic brain cells were pretreated for 2 h with i mM betaine followed by exposure to 100 .mu.M glutamate for 42 h, lactate dehydrogenase levels within the cells remained at 62% of .mu.M untreated control values while glutamate-treated control fell to 0% lactate dehydrogenase. Betaine also exerted attenuating effects on N-methyl-D-asparte-, kainate-and quisqualate-induced neurotoxicity in a similar manner to that observed with glutamate. Similar neuroprotective effects of betaine with rat cortical cultures.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.195.2-195.2
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• 2003

The CH$_2$Cl$_2$ fraction of the bark of Machilus thunbergii Sieb. et Zucc. (Lauraceae) significantly protected primary cultures of rat cortical cells exposed to the excitotoxic amino acid, L-glutamate. Several lignans including (-)-isoguaiacin, meso- dihydroguaiaretic acid, machilin A, (+)-galbelgin, licarin A, (-)-sesamin, and (+)-guaiacin were isolated from the CH$_2$Cl$_2$ fraction using by bioactivity-guided isolation techniques. Among these lignans, (-)-isoguaiacin, meso-dihydroguaiaretic acid, licarin A and (+)-guaiacin had significant neuroprotective activities against glutamate-induced toxicity in primary cultures of rat cortical cells at concentration ranging from 0.1 ${\mu}$M to 10.0 ${\mu}$M. (omitted)

• Natural Product Sciences
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• v.14 no.3
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• pp.167-170
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• 2008

We previously reported that 90% MeOH fraction of Biota orientalis leaves (L.) ENDL. had significant neuroprotective activity against glutamate-induced neurotoxicity in primary cultures of rat cortical cells. In the present study, (-)-savinin (1), (-)-hinokinin (2), dehydroheliobuphthalmin (3) were isolated by bioactivity-guided fractionation from the 90% MeOH fraction. All three lignans had significant neuroprotective activities against glutamate-induced neurotoxicity at the concentrations ranging from 0.1 to 10.0 ${\mu}M$.

• Proceedings of the Ginseng society Conference
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• 1998.06a
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• pp.47-56
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• 1998

In the present study, we assayed a number of compounds isolated from Panax ginseng C. A. Meyer (Araliaceae) for an ability to protect rat cortical cell cultures from the deleterious effects of the neurotoxicant, glutamate. We found that ginsenosides Rbl and Rg3 significantly attenuated glutamate-induced neurotoxicity. Brief exposure of cultures to excess glutamate caused extensive neuronal death. Glutamate-induced neuronal cell damage was significantly reduced by pretreatment with Rbl and Rgl. Ginsenosides Rbl and Rg3 inhibited the overproduction of nitric oxide which routinely follows glutamate neurotoxicity and preserved the level of superoxide dismutase in glutamate-treated cells. Furthermore, in cultures treated with glutamate, these ginsenosides inhibited the formation of malondialdehyde, a compound produced during lipid peroxidation, and diminished the influx of calcium. These results show that ginsenosides Rbl and Rg1 exerted significant neuroprotective effects on cultured cortical cells. As such, these compounds may be efficacious in protecting neurons from oxidative damage produced by exposure to excess glutamate.