• 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.

• 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.

• Archives of Pharmacal Research
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• v.27 no.4
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• pp.454-459
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• 2004

The present study investigated the effects of gossypin, 3,3',4',5,7,8-hexahydroxyflavone 8-glucoside, on the toxicity induced by oxidative stress or $\beta$-amyloid ($A_{\beta}$) in primary cultured rat cortical cells. The antioxidant properties of gossypin were also evaluated by cell-free assays. Gossypin was found to inhibit the oxidative neuronal damage induced by xanthinelxanthine oxidase or by a glutathione depleting agent, D,L-buthionine (S,R)-sulfoximine. In addition, gossypin significantly attenuated the neurotoxicity induced by $A_{{\beta}(25-35)}$. Furthermore, gossypin dramatically inhibited lipid peroxidation initiated by $Fe^{2+}$ and ascorbic acid in rat brain homogenates. It also exhibited potent radical scavenging activity generated from 1 ,1-diphenyl-2-picrylhydrazyl. These results indicate that gossypin exerts neuroprotective effects in the cultured cortical cells by inhibiting oxidative stress- and $A_{\beta}$-induced toxicity, and that the antioxidant properties of gossypin may contribute to its neuroprotective actions.

• Archives of Pharmacal Research
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• v.29 no.8
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• pp.699-706
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• 2006

The present study evaluated antioxidant and neuroprotective activities of hesperidin, a flavanone mainly isolated from citrus fruits, and its aglycone hesperetin using cell-free bioassay system and primary cultured rat cortical cells. Both hesperidin and hesperetin exhibited similar patterns of 1,1-diphenyl-2-picrylhydrazyl radical scavenging activities. While hesperidin was inactive, hesperetin was found to be a potent antioxidant, inhibiting lipid peroxidation initiated in rat brain homogenates by $Fe^{2+}$ and L-ascorbic acid. In consistence with these findings, hesperetin protected primary cultured cortical cells against the oxidative neuronal damage induced by $H_2O_2$ or xanthine and xanthine oxidase. In addition, it was shown to attenuate the excitotoxic neuronal damage induced by excess glutamate in the cortical cultures. When the excitotoxicity was induced by the glutamate receptor subtype-selective ligands, only the N-methyl-D-aspartic acid-induced toxicity was selectively and markedly inhibited by hesperetin. Furthermore, hesperetin protected cultured cells against the $A_{{\beta}(25-35)}-induced$ neuronal damage. Hesperidin, however, exerted minimal or no protective effects on the neuronal damage tested in this study. Taken together, these results demonstrate potent antioxidant and neuroprotective effects of hesperetin, implying its potential role in protecting neurons against various types of insults associated with many neurodegenerative diseases.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.302.2-303
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• 2002

Oxidative stress has been implicated in the pathophysiology of many neurodegenerative disorders including Alzheimer's and Parkinson's diseases. Baicalein. baicalin and wogonin. the major constituents of Scutellaria baicalensis. have been reported to exhibit antioxidant properties in many different bioassay systems. The present study evaluated neuroprotective effects of these flavonoids on various neuronal injuries induced in primary cultured rat cortical cells by oxidative stress. NMDA. oxygen-glucose deprivation. and $A{\beta}$(25-35). (omitted)

• YAKHAK HOEJI
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• v.47 no.6
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• pp.369-375
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• 2003

Xiaoshuan Zaizao Wan (XZW) has been used in China to improve hemiplegia, deviation of eye and mouth, and dysphasia due to cerebral thrombosis. To characterize pharmacological actions of XZW, we evaluated its effects on neuronal cell damage induced in primary cultured rat cortical cells by various oxidative insults, glutamate or N-methyl-D-aspartate (NMDA), and $\beta$-amyloid fragment ($A_{\beta(25-35)}$). XZW was found to inhibit the oxidative neuronal damage induced by $H_2O_2$, xanthine/xanthine oxidase, or $Fe^{2+}$/ascorbic acid. It also attenuated the excitotoxic damage induced by glutamate or NMDA. The NMDA-induced neurotoxicity was more effectively inhibited than the glutamate-induced toxicity. In addition, we found that XZW protected neurons against the $A_{\beta(25-35)}$-induced toxicity. Moreover; XZW exhibited dramatic inhibition of lipid peroxidation in rat brain homogenates and mild 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. Taken together; these results demonstrate that XZW exerts neuroprotective effects against oxidative, excitotoxic, or $A_{\beta(25-35)}$-induced neuronal damage. These findings may provide pharmacological basis for its clinical usage treating the sequelae caused by cerebral thrombosis. Furthermore, XZW may exert beneficial effects on Alzheimer's disease and other oxidative stress-related neurodegenerative disorders.

• YAKHAK HOEJI
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• v.49 no.1
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• pp.30-37
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• 2005

Xuesaitong Ruanjiaonang (XR), a soft capsule containing Panax notoginseng saponins as main ingredients, is believed to remove extravasated blood and increase cerebral blood flow by improving blood circulation, and therefore, has been used in China to treat ischemic stroke or hemiplegia caused by cerebral thrombosis. To characterize pharmacological actions of XR, the present study evaluated its effects on neuronal cell damage induced by various oxidative insults or excitotoxic amino acids in primary cultured rat cortical cells. The neuronal cell viability was not affected by XR with the exposure for 2 h at the concentrations tested in this study ($10{\sim}1000\;{\mu}g/ml$). However, significant reduction of the cell viability was observed when the cultured cells were exposed to XR at $1000\;{\mu}g/ml$ for 24 h. XR was found to concentration-dependently inhibit the oxidative neuronal damage induced by $H_{2}O_2$, xanthine/xanthine oxidase or $Fe^{2+}$/ascorbic acid. In addition, it dramatically inhibited the excitotoxic damage induced by glutamate or N-methyl-D-aspartate (NMDA). We found that the NMDA-induced neurotoxicity was inhibited more effectively and potently than the glutamate-induced toxicity. Moreover, XR was found to exert mild inhibition of lipid peroxidation induced by $Fe^{2+}$/ascorbic acid in rat brain homogenates and some 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. Taken together, these results demonstrate neuroprotective and antioxidant effects of XR, showing inhibition of oxidative and excitotoxic damage in the cultured cortical neurons, as well as inhibition of lipid peroxidation and its radical scavenging activity. Considering that excitotoxicity and oxidative stress pl ay crucial roles in neuronal cell damage during ischemia and reperfusion, these results may provide pharmacological basis for its clinical usage to treat ischemic stroke.

• Proceedings of the PSK Conference
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• 2002.04a
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• pp.114.1-114.1
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• 2002

• YAKHAK HOEJI
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• v.46 no.3
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• pp.185-191
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• 2002

Alzheimer's disease (AD) involves neuronal degeneration with impaired cholinergic transmission, particularly in areas of the brain associated with learning and memory. Several cholinesterase inhibitors are widely prescribed to ameliorate the cognitive deficits in AD patients. In an attempt to examine if tacrine and donepezil, two well-known cholinesterase inhibitors, exhibit additional pharmacological actions in primary cultured rat cortical cells, we investigated the effects on neuronal injuries induced by glutamate or N-methyl-D-aspartate (NMDA), $\beta$-amyloid fragment ( $A_{{beta}25-35)}$), and various oxidative insults. Both tacrine and donepezil did not significantly inhibit the excitotoxic neuronal damage induced by glutamate. However, tacrine inhibited the toxicity induced by NMDA in a concentration-dependent fashion. In addition, tacrine significantly inhibited the $A_{{beta}25-35)}$-induced neuronal injury at the concentration of 50 $\mu$M. In contrast, donepezil did not reduce the NMDA- nor $A_{{beta}25-35)}$-induced neuronal injury. Tacrine and donepezil had no effects on oxidative neuronal injuries in cultures nor on lipid peroxidation in vitro. These results suggest that, in addition to its anticholinesterase activity, the neuroprotective effects by tacrine against the NMDA- and $A_{{beta}25-35)$-induced toxicity may be beneficial for the treatment of AD. In contrast, the potent and selective inhibition of central acetylcholinesterase appears to be the major action mechanism of donepezil.

• YAKHAK HOEJI
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• v.52 no.2
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• pp.117-124
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• 2008

The leaves of Perilla frutescens Britt. var. japonica Hara (Labiatae) are often used in gourmet food in several Asian countries. Two kinds of perilla cultivars, Namcheon (NC) and Bora (BR), have been respectively developed in Korea by the pure line of 'deulkkae' from the local variety and by the cross of 'deulkkae' and 'chajogi'. The present study evaluated and compared antioxidant and neuroprotective effects of the fractions prepared from the leaves of the two cultivars using cell-free bioassay systems and primary cultured rat cortical cells. We found that the spirit, chloroform, hexane and butanol fractions from NC and BR leaves inhibited lipid peroxidation initiated in rat brain homogenates by $Fe^{2+}$ and L-ascorbic acid. In contrast, only the spirit and butanol fractions from both cultivars exhibited 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. Among the fractions tested, the butanol fractions from NC and BR leaves exhibited the most potent antioxidant properties, and the butanol fraction from BR was more potent than the NC fraction. In consistence with these findings, the butanol fractions from both cultivars protected primary cultured cortical cells from the oxidative damage induced by $H_2O_2$ or xanthine and xanthine oxidase, with the BR butanol fraction being more active. The butanol fractions from NC and BR did not produce cytotoxicity in our cultures treated for 24 h at the concentrations of up to $100\;{\mu}g/ml$. Taken together, these results indicate that the leaves of the two cultivars of Perilla frutescens exert antioxidant and neuroprotective effects, and that the butanol fraction from BR leaves exhibits the most potent antioxidative neuroprotection among the fractions tested in this study.