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Polygalae Radix (PR) from Polygala tenuifolia (Polygalaceae) is traditionally used in China and Korea, as this herb has a sedative, anti-inflammatory and antibacterial agent. To extend our understanding of the pharmacological actions of PR in the CNS on the basis of its CNS inhibitory effect, the present study examined whether PR has the neuroprotective action against N-methyl-D-aspartate (NMDA)-induced cell death in primarily cultured rat cerebellar granule neurons. PR, over a concentration range of 0.05 to 5 μg/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-diphenyl-tetrazolium bromide (MTT) assay. PR (0.5 μg/ml) inhibited glutamate release into medium induced by NMDA (1 mM), which was measured by HPLC. Pre-treatment of PR (0.5 μg/ml) inhibited NMDA (1 mM)-induced elevation of intracellular Ca²⁺ concentration ([Ca²⁺]_i), which was measured by a fluorescent dye, Fura 2-AM, and generation of reactive oxygen species (ROS). These results suggest that PR prevents NMDA-induced neuronal cell damage in vitro.

BNG-1, a novel mixture of traditional Chinese medicines with a long history in the treatment of stroke, exhibited acute neuroprotection effect on rats with middle cerebral artery occlusion (MCAO). Anti-ischemic effects were seen in both animals receiving BNG-1 before the ischemic insult as well as in animals receiving the drug formulation after surgical occlusion of the artery. Anti-thrombic activity was seen in vitro to inhibit arachidonic acid-induced platelet aggregation and in vivo to prolong bleeding time in mice. BNG-1 was also found to inhibit several phosphodiesterase (PDE) isoforms with potency order of the following rank: PDE 1>PDE 3>PDE 6>PDE 2>PDE 4>PDE 5. Other pre-clinical results and emerging clinical data coupled with the present findings suggest that BNG-1 may be a safe and effective therapy for both the prevention and treatment of cerebral stroke. Moreover, the fundamental cellular mechanism underlying its therapeutic effects may result from phosphodiesterase inhibition.

In this study, the effects of Polygala tenuifolia root extract on brain ischemia/reperfusion injury in Mongolian gerbils were investigated. The gerbils were administered ethanol extract of P. tenuifolia and its four sub-fractions orally 2 hours prior to ischemia, and were subjected to a 20-minute no-flow cerebral ischemia in vivo. Thirty minutes and 72 hours after reperfusion, the brain was removed and the ATP, lactate and lipid peroxide levels were determined, and the neurons in the hippocampal CA1 subfield were examined. In the vehicle-treated ischemic gerbils, the brain ATP levels decreased significantly, but this decrease was prevented by pre-treatment with an n-butanol fraction of P. tenuifolia. In contrast, both the lactate content and lipid peroxidation levels were elevated in the vehicle-treated ischemic animals, but this elevation was inhibited by ethanol extract and n-butanol fraction of P. tenuifolia, respectively. Both the ethanol extract and n-butanol fraction of P. tenuifolia attenuated post-ischemic neuronal necrosis in the hippocampal CA1 subfield. Our findings suggest that both ethanol extract and n-butanol fraction of P. tenuifolia root can reduce brain damage during ischemia and reperfusion, and prevent lipid peroxidation and preserve the energy metabolism.

Ginkgo biloba exerts many pharmacological actions. It possesses antioxidant properties, the ability of neurotransmitter/receptor modulation and antiplatelet activation factor. This research is designed to investigate the neuroprotective effects of long-term treatment with EGb761 (a standard form of the extract of Ginkgo biloba leaf) in combination with MgSO₄, FK506, or MK-801 on the infarct volume of male gerbils' brain induced by unilateral middle cerebral artery occlusion (MCAO). Thirty-five gerbils fed a standard diet were intragastrically given water or EGb761 (100 mg/kg/day) for one week. Five randomized groups were established: control (n = 7), EGb761 (n = 8), EGb761 + MgSO₄ (n = 7), EGb761 + FK506 (n = 7), and EGb761 + MK-801 (n = 6). The three drug-combination groups were injected with MgSO₄ (90 mg/kg), FK506 (0.5 mg/kg), or MK-801 (1 mg/kg), respectively 30 min before MCAO. Gerbils were anesthetized and craniectomized to expose the right middle cerebral artery (MCA). The right MCA was constricted with an 8-0 suture to produce a permanent ligation for 24 hours. Postmortem infarct volumes were determined by quantitative image analysis of 2,3,5-triphenyltetrazolium chloride (TTC)-stained brain sections. Results showed that the total infarct volumes of the four treated groups either EGb761 alone or in combination with drugs were lower than the control group by 36.1% (EGb761 alone), 40.3% (EGb761 + MgSO₄), 35.3% (EGb761 + FK506), and 56.4% (EGb761 + MK-801), respectively (p < 0.01). The main affected areas of the brain in the four treated groups were significantly focused between 4 and 6 mm from the frontal pole, when compared to the control group (p < 0.01). All animals in the five groups had infarctions in both cortex and subcortex. These results indicate that long-term pre-treatment of EGb761 administered either alone or in combination with drugs significantly effective neuroprotection on infarct volume in gerbil ischemic brains.

Picroside II is an active constituent extracted from the traditional Chinese medicine (TCM) Hu-Huang-Lian. To evaluate the neuroprotective effect of picroside II, PC12 cells were treated with glutamate in vitro and male ICR mice were treated with AlCl₃in vivo. Pre-treatment of PC12 cells with picroside II could enhance the cell viability and decrease the level of intracellular reactive oxygen species (ROS) induced by glutamate. By DNA fragmentation and flow cytometry assay, picroside II (1.2 mg/ml) significantly prevented glutamate-induced cell apoptosis. In the animal study, amnesia was induced in mice by AlCl₃ (100 mg/kg/d, i.v.). Pricroside II, at the dose of 20 and 40 mg/kg/d (i.g.), markedly ameliorated AlCl₃-induced learning and memory dysfunctions and attenuated AlCl₃-induced histological changes. This was associated with the significant increased superoxide dismutase (SOD) activity in the brain of experimental mice. All these results indicated that picroside II possessed the therapeutic potential in protecting against neurological injuries damaged by oxidative stress.

To investigate whether HT008-1, a prescription used in traditional Korean medicine to treat mental and physical weakness, has a neuroprotective effect on a rat model of global brain ischemia and an enhancing effect against memory deficit following ischemia. Global brain ischemia was induced for 10 min by using 4-vessel occlusion (4-VO). HT008-1 was orally administered at doses of 30, 100, and 300 mg/kg respectively twice at 0 and 90 min after ischemia. The effect on memory deficit was investigated by using a Y-maze neurobehavioral test 4 days after brain ischemia, and the effect on neuronal damage was measured 7 days after ischemia. The mechanism of action was studied immunohistochemically using an anti-CD11b (OX-42) antibody. The oral administration of HT008-1 at 100 and 300 mg/kg significantly reduced hippocampal neuronal cell death by 49% and 53%, respectively, compared with a vehicle-treated group, and also improved spatial memory function in the Y-maze test. Immunohistochemically, HT008-1 inhibited OX-42 expression in the hippocampus. The effects of HT008-1 were more pronounced than those of its individual herb components. The herbal mixture HT008-1 protects the most vulnerable CA1 pyramidal cells of the hippocampus and enhances spatial memory function against global brain ischemia; an anti-inflammatory effect may be one of the mechanisms of action.

EGb 761 is a standardized extract of Gingko biloba that exerts protective effects against ischemic brain injury. This study investigated whether EGb 761 modulates the neuroprotective effects through Akt and its downstream targets, Bad and FKHR. Adult male rats were treated with EGb 761 (100 mg/kg) or vehicle prior to middle cerebral artery occlusion (MCAO). Brains were collected 24 hours after MCAO and infarct volumes were analyzed. EGb 761 significantly reduced infarct volume. Potential activation was mearsured by phosphorylation of Akt at Ser⁴⁷³, Bad at Ser¹³⁶, and FKHR at Ser²⁵⁶ using Western blot analysis. EGb 761 prevented the injury-induced decrease of pAkt and its down stream targets, pBad and pFKHR. Furthermore, EGb 761 prevented the injury-induced increase of cleaved caspase-3 levels. In conclusion, this study suggests that EGb 761 prevents cell death due to brain injury and that EGb 761 protection is affected by preventing the injury-induce decrease of Akt phosphorylation.

In order to investigate the mechanisms underlying the neuroprotective effect of ginsenoside Rb₃, rat hippocampal neurons were primarily cultured, and exposed to 1 mM N-methyl-D-aspartate (NMDA), cell viability and lactate dehydrogenase leakage were measured. Ca²⁺ influx was determined by calcium imaging with a laser confocal microscopy. The influences of ginsenoside Rb₃ on these variables were examined. Patch-clamp technique was used to observe the effects of ginsenoside Rb₃ on NMDA-evoked current. The results show that treatment of Rb₃ raised the neuronal viability, reduced the leakage of lactate dehydrogenase, and inhibited NMDA-elicited Ca²⁺ influx in a dose-dependent manner. In the presence of Rb₃, NMDA-evoked peak current was inhibited, and Ca²⁺-induced desensitization of NMDA current was facilitated. It is suggested that ginsenoside Rb₃ could exert a neuroprotective role on hippocampal neurons, a role which was partly mediated by the facilitation of Ca²⁺-dependent deactivation of NMDA receptors, and the resultant reduction of intracellular free Ca²⁺ level.

A standardized extract of Gingko biloba, EGb 761, has been shown to exert a neuroprotective effect against permanent and transient focal cerebral ischemia. This study investigated whether EGb 761 modulates Bcl-2 family proteins in ischemic brain injury. Male adult rats were treated with EGb 761 (100 mg/kg) or vehicle prior to middle cerebral artery occlusion (MCAO), brain tissues were collected 24 hours after MCAO. EGb761 administration significantly decreased the number of TUNEL-positive cells in the cerebral cortex. Ischemic brain injury induced decrease of Bcl-2 and Bcl-X_L levels. EGb 761 prevented not only the injury-induced decrease of Bcl-2 and Bcl-X_L levels, but also the injury-induced increase of Bax. Moreover, in the presence of EGb 761, the interaction of Bad and Bcl-X_L decreased compared to that of vehicle-treated animals. In addition, EGb 761 prevented the injury-induced increase of cleaved PARP. The finding suggests that EGb 761 prevents cell death against ischemic brain injury and EGb 761 neuroprotection is affected by preventing the injury-induced increase of Bad and Bcl-X_L interaction.

EGb 761 is an extract of Gingko biloba that exhibits neuroprotective effects against cerebral ischemia. The mammalian target of rapamycin (mTOR) is a critical downstream effector of Akt and a central regulator of ribosomal biogenesis and protein synthesis. We investigated whether EGb 761 regulates Akt downstream targets, including mTOR, p70S6 kinase, and S6 phosphorylation. Adult male rats were treated with vehicle or EGb 761 (100 mg/kg) prior to middle cerebral artery occlusion (MCAO). Brains were collected at 24 hours after MCAO and the cerebral cortex regions were examined. We previously showed that EGb 761 significantly reduces infarct volume and decreases the number of TUNEL-positive cells in the cerebral cortex. Ischemic brain injury induces a decrease in Akt up-stream target, PDK1 phosphorylation. The levels of phospho-mTOR, phospho-p70S6 kinase, and phospho-S6 are subsequently decreased in regions affected by ischemic injury. However, EGb 761 prevented injury-induced decreases in these protein levels. We confirmed that EGb 761 inhibits injury-induced decreases in the number of positive cells for phospho-p70S6 kinase and phospho-S6. The results of this study provide evidence that EGb 761 protects neuronal cells against ischemic brain injury by preventing injury-induced decreases in p70S6 kinase and S6 phosphorylation.

Activation of microglia is a critical pathological marker of Parkinson's disease. Activated microglia produces proinflammatory and neurotoxic factors, which cause neurons to induce neurodegeneration. Although it is believed that Chinese herbs, such as Tripterygium wilfordii Hook F, can ease inflammatory diseases, little is known about its benefit to neurodegenerative disease, like Parkinson's disease. In this study, we report the extract of Tripterygium wilfordii Hook F with a novel extraction method significantly protected dopaminergic neurons from LPS-induced degeneration in rat mesencephalic neuron-glia cultures. Cells pretreated with the extract have shown dose-dependent inhibition of LPS-induced TNFα and excessive NO production. More importantly, the total number of activated microglia was greatly reduced in these pretreated cells. Our results suggest that the extract of Tripterygium wilfordii Hook F has a strong bioactive function to diminish the pro-inflammatory factors, such as TNFα and NO. These data might also shed light for future neurodegenerative disease therapy.

EGb 761 is a standardized extract of Ginkgo biloba that appears to have a neuroprotective effect against neurodegenerative diseases. Adult male rats were treated with EGb 761 (100 mg/kg) or vehicle prior to middle cerebral artery occlusion (MCAO), and brains were collected 24 h after MCAO. Proteins that were differentially expressed after EGb 761 treatment during cerebral ischemia were detected using two-dimensional gel electrophoresis. Protein spots with more than a 2.5-fold change in intensity between vehicle- and EGb 761-treated groups were identified by mass spectrometry. The levels of peroxiredoxin-2 and protein phosphatase 2A subunit B were significantly decreased in the vehicle-treated group in comparison to the EGb 761-treated group. In contrast, levels of the collapsing response mediator protein 2 (CRMP2) were significantly increased in vehicle-treated animals, while EGb 761 prevented the injury-induced increase of CRMP2. These results suggest that EGb 761 protects neuronal cells against ischemic brain injury through the specific up- and down-modulation of various proteins.

EGb 761 is an extract of Gingko biloba that is neuroprotective against focal cerebral ischemic injury. PEA-15 (phosphoprotein enriched in astrocytes 15) modulates cell proliferation and apoptosis. In this study, we investigated whether EGb 761 regulates the expression of PEA-15 and two phosphorylated forms of PEA-15 (Ser 104 and Ser 116) in middle cerebral artery occlusion (MCAO)-induced injury. Adult male rats were treated with vehicle or EGb 761 (100 mg/kg) prior to MCAO and cerebral cortices were collected 24 h after MCAO. A reduction in expression of PEA-15 and its phosphorylated forms induced by MCAO injury was detected using a proteomic approach. EGb 761 pretreatment prevented the ischemic injury-induced decrease in PEA-15 expression. Western blot analysis demonstrated that EGb 761 attenuates the injury-induced reduction in PEA-15, phospho-PEA-15 (Ser 104), phospho-PEA-15 (Ser 116). Phosphorylation of PEA-15 influences its anti-apoptotic function; a decrease in PEA-15 phosphorylation induces apoptotic cell death. The maintenance of PEA-15 phosphorylation by EGb 761 pretreatment during cerebral ischemic injury indicates that EGb 761 is a neuroprotective against cerebral ischemic injury.

Disruption of the blood-brain barrier (BBB) contributes to the inflammatory response and edema formation in the brain, exacerbating brain damage. The present study evaluated the effects of Scutellaria baicalensis (SR) water extracts on BBB disruption after intracerebral hemorrhage (ICH) in rats. ICH was induced by stereotaxic intrastriatal injection of bacterial type VII collagenase, and SR was administrated orally three times (50 mg/ml/kg) during the 48 h after ICH onset. SR treatment significantly reduced the degree of (1) hemorrhage volume and edema percentage of the ipsilateral hemisphere, (2) brain water content, (3) MPO-positive neutrophil infiltration in the peri-hematoma, and (4) BBB permeability measured by Evans blue leakage. In addition, expression of matrix metalloproteinase (MMP)-9, MMP-12, and tissue inhibitor of MMPs (TIMP)-1 were investigated with immunohistochemistry. SR treatment reduced MMP-9 and MMP-12 expression in the peri-hematoma after ICH. These results indicate that SR attenuates the BBB disruption through anti-inflammatory effects and suppression of MMP expression. These findings provide a pharmacological basis for the use of SR in the treatment of the BBB disruption following stroke and trauma.

Rotenone, an inhibitor of mitochondrial complex I, has been widely regarded as a neurotoxin because it induces a Parkinson's disease-like syndrome. The fruit and root bark of Lycium chinense Miller have been used as traditional medicines in Asia to treat neurodegenerative diseases. In this study, we examined the neuroprotective effects of Lycium chinense Miller extracts in rotenone-treated PC12 cells. Treatment with rotenone reduced PC12 cell viability and cellular ATP levels. Conversely, caspase 3/7 activity, the ratio of Bax:Bcl-2 expression levels, mitochondrial superoxide level, and intracellular calcium (Ca²⁺) concentration were elevated. Pretreatment with Lycium chinense Miller extracts significantly increased cell viability and ATP levels. Additionally, they attenuated caspase activation, mitochondrial membrane depolarization and mitochondrial superoxide production. Moreover, confocal microscopy showed that the mitochondrial staining pattern was restored from that of extracts treated cells and that the increase in intracellular Ca²⁺ level was blunted by treatment with the extracts. Our results suggest that Lycium chinense Miller extracts may have the possible beneficial effects in Parkinson's disease by attenuating rotenone induced toxicity.

A variety of flavonoids are suggested to be useful for the treatment of brain-related disorders, including dementia and depression. An investigation on the characteristics of the extracted compounds of Iris tenuifolia Pall. (IT) is of much interest, as this plant has been used as a traditional medicine. In the present study, we examined the effect of total flavonoids obtained from IT on cultured cortical neurons under oxidative-stress and found that pretreatment with IT flavonoids significantly inhibited H₂O₂-induced cell death in cortical neurons. Such a survival-promoting effect by IT flavonoids was partially blocked by inhibitors for extracellular signal-regulated kinase (ERK) and phosphoinositide 3-kinase/Akt (PI3K/Akt) cascades, both of which are known as survival-promoting signaling molecules. Furthermore, the phosphorylation of Src homology-2 (SH2) domain-containing phosphatase2 (Shp2) was induced by IT flavonoids, and the protective effect of IT flavonoids was abolished by NSC87877, an inhibitor for Shp2, suggesting the involvement of Shp2-mediated intracellular signaling in flavonoid-dependent neuroprotection.

The rhizome of Coptis chinensis is commonly used in traditional Chinese medicine alone or in combination with other herbs to treat diseases characterized by causing oxidative stress including inflammatory diseases, diabetes mellitus and neurodegenerative diseases. In particular, there is emerging evidence that Coptis chinensis is effective in the treatment of neurodegenerative diseases associated with oxidative stress. Hence, the aim of this study was to investigate the neuroprotective effect of Coptis chinensis in vitro and in vivo using MPP${}^{+}$ and MPTP models of Parkinson’s disease. MPP${}^{+}$ treated human SH-SY5Y neuroblastoma cells were used as a cell model of Parkinson’s disease. A 24h pre-treatment of the cells with the watery extract of Coptis chinensis significantly increased cell viability, as well as the intracellular ATP concentration and attenuated apoptosis compared to the MPP${}^{+}$ control. Further experiments with the main alkaloids of Coptidis chinensis, berberine, coptisine, jaterorrhizine and palmatine revealed that berberine and coptisine were the main active compounds responsible for the observed neuroprotective effect. However, the full extract of Coptis chinensis was more effective than the tested single alkaloids. In the MPTP-induced animal model of Parkinson’s disease, Coptis chinensis dose-dependently improved motor functions and increased tyrosine hydroxylase-positive neurons in the substantia nigra compared to the MPTP control. Based on the results of this work, Coptis chinensis and its main alkaloids could be considered potential candidates for the development of new treatment options for Parkinson’s disease.

Interest in the health benefits of flavonoids, particularly their effects on neurodegenerative disease, is increasing. This study evaluated the role of baicalein, a flavonoid compound isolated from the traditional Chinese medicine Scutellaria baicalensis, in glutamate release and glutamate neurotoxicity in the rat hippocampus. In the rat hippocampal nerve terminals (synaptosomes), baicalein inhibits depolarization-induced glutamate release, and this phenomenon is prevented by chelating the extracellular Ca${}^{2+}$ ions and blocking presynaptic Cav2.2 (N-type) and Cav2.1 (P/Q-type) channel activity. In slice preparations, whole cell patch-clamp experiments revealed that baicalein reduced the frequency of miniature excitatory postsynaptic currents, without affecting their amplitude. In a kainic acid rat model, intraperitoneally administering baicalein to rats before the kainic acid intraperitoneal injection substantially attenuated kainic acid-induced neuronal cell death, c-Fos expression, and the activation of the mammalian target of rapamycin in the hippocampus. This study is the first to demonstrate that the natural compound baicalein inhibits glutamate release from hippocampal nerve terminals, and executes a protective action against kainic acid-induced excitotoxicity in vivo. The findings enhance the understanding of baicalein’s action in the brain, and suggest that this natural compound is valuable for treating brain disorders related to glutamate excitotoxicity.

We previously reported a novel danshensu derivative ($R$)-(3,5,6-Trimethylpyrazinyl) methyl-2-acetoxy-3-(3,4-diacetoxyphenyl) propanoate (ADTM), which conferred cardioprotective and anti-thrombotic effects in vitro and in vivo. Here, we examined the neuroprotective actions of ADTM on 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in PC12 cells 1 in vitro and zebrafish in vivo. Pretreatment with ADTM significantly inhibited 6-OHDA-induced cytotoxicity and production of reactive oxygen species (ROS) in PC12 cells through Akt signaling. Moreover, treatment with ADTM also inhibited expression of inducible nitric oxide synthase (iNOS) and production of intracellular nitric oxide (NO), which are associated with inflammation. In addition, ADTM exhibited significant protection against 6-OHDA-induced loss of tyrosine hydroxylase-positive dopaminergic neurons in a zebrafish model. Taken together, our findings suggest that ADTM is also a potential effective therapeutic agent for neurodegenerative conditions such as Parkinson’s disease (PD) through anti-oxidant cytoprotective and anti-inflammatory actions.

The fruit of Vaccinium bracteatum Thunb. (VBF) is commonly known as the oriental blueberry in Korea. The aim of this study was to evaluate the antidepressant-like effects of water VBF extract (VBFW) in a mouse model of chronic restraint stress (CRS) and to identify the underlying mechanisms of its action. The behavioral effects of VBFW were assessed in the forced swim test (FST) and open field test (OFT). The levels of serum corticosterone (CORT), brain monoamines, in addition to the extracellular signal-regulated kinases (ERKs)/protein kinase B (Akt) signaling pathway were evaluated. VBFW treatment significantly reduced the immobility time and increased swimming time in FST without altering the locomotor activity in unstressed mice. Furthermore, CRS mice treated with VBFW exhibited a significantly decreased immobility time in FST and serum CORT, increased locomotor activity in OFT, and enhanced brain monoamine neurotransmitters. Similarly, VBFW significantly upregulated the ERKs/Akt signaling pathway in the hippocampus and PFC. In addition, VBFW may reverse CORT-induced cell death by enhancing cyclic AMP-responsive element-binding protein expression through the up-regulation of ERKs/Akt signaling pathways. In addition, VBFW showed the strong antagonistic effect of the 5-HT${}_{2\mathrm{\text{A}}}$ receptor by inhibiting 5-HT-induced intracellular Ca${}^{2+}$ and ERK1/2 phosphorylation. Our study provides evidence that antidepressant-like effects of VBFW might be mediated by the regulation of monoaminergic systems and glucocorticoids, which is possibly associated with neuroprotective effects and antagonism of 5-HT${}_{2\mathrm{\text{A}}}$ receptor.