• The Korean Journal of Physiology and Pharmacology
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• v.19 no.3
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• pp.219-228
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• 2015

Excessive microglial activation and subsequent neuroinflammation lead to synaptic loss and dysfunction as well as neuronal cell death, which are involved in the pathogenesis and progression of several neurodegenerative diseases. Thus, the regulation of microglial activation has been evaluated as effective therapeutic strategies. Although dieckol (DEK), one of the phlorotannins isolated from marine brown alga Ecklonia cava, has been previously reported to inhibit microglial activation, the molecular mechanism is still unclear. Therefore, we investigated here molecular mechanism of DEK via extracellular signal-regulated kinase (ERK), Akt and nicotinamide adenine dinuclelotide phosphate (NADPH) oxidase-mediated pathways. In addition, the neuroprotective mechanism of DEK was investigated in microglia-mediated neurotoxicity models such as neuron-microglia co-culture and microglial conditioned media system. Our results demonstrated that treatment of anti-oxidant DEK potently suppressed phosphorylation of ERK in lipopolysaccharide (LPS, $1{\mu}g/ml$)-stimulated BV-2 microglia. In addition, DEK markedly attenuated Akt phosphorylation and increased expression of $gp91^{phox}$, which is the catalytic component of NADPH oxidase complex responsible for microglial reactive oxygen species (ROS) generation. Finally, DEK significantly attenuated neuronal cell death that is induced by treatment of microglial conditioned media containing neurotoxic secretary molecules. These neuroprotective effects of DEK were also confirmed in a neuron-microglia co-culture system using enhanced green fluorescent protein (EGFP)-transfected B35 neuroblastoma cell line. Taken together, these results suggest that DEK suppresses excessive microglial activation and microglia-mediated neuronal cell death via downregulation of ERK, Akt and NADPH oxidase-mediated pathways.

• Archives of Pharmacal Research
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• v.28 no.2
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• pp.216-219
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• 2005

Wogonin (5,7-dihydroxy-8-methoxyflavone) has been reported to exhibit a variety of biological properties including anti-inflammatory and neuroprotective functions. In this study, biological activities of diverse synthetic wogonin derivatives have been evaluated in two experimental cell culture models. Inhibitory activities of wogonin derivatives on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV2 microglial cells and on hydrogen peroxide ($H_{2}O_2$)-induced neuronal cell death in SH-SY5Y human neuroblastoma were examined. Wogonin derivatives such as WS2 and WS3 showed more potent suppressive activities on LPS-induced NO production and $H_{2}O_2$-induced cytotoxicity than wogonin itself. In addition, thiol substitution played a minor role in enhancing the activities of the derivatives. These findings may contribute to the development of novel anti-inflammatory and neuroprotective agents derived from wogonin.

• The Korea Journal of Herbology
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• v.25 no.1
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• pp.83-91
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• 2010

Objectives : In this study, we compared the anti-oxidant and anti-inflammatory activities of Curcumae longae Radix (CLRa) and Curcumae longae Rhizoma (CLRh). Methods : We performed 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) cation scavenging assays, and determined total polyphenolic content to examine the anti-oxidant effects of CLRa and CLRh. We also evaluated the anti-oxidant effects of CLRa and CLRh against hydrogen peroxide ($H_2O_2$)-induced toxicity in PC12 cells using thiazolyl blue tetrazolium bromide (MTT) and reactive oxygen species (ROS) assays. Next, to compare the anti-inflammatory effects of CLRa and CLRh against lipopolysaccharide (LPS)-induced inflammation in microglia BV2 cells, we measured nitric oxide (NO) assay and inducible nitrite synthase (iNOS) using Western blotting analysis. Results : CLRa showed higher activity in DPPH and ABTS assays and lower total polyphenolic contents compared with CLRh. In PC12 cells, CLRa and CLRh showed no difference in H2O2-induced cell toxicity and ROS overproduction. In BV2 cells, CLRa showed higher effect than CLRh in NO and iNOS production induced by LPS. Conclusions : These results demonstrate that CLRa has higher radical scavenging activities and anti-inflammatory effect in BV2 cells comparing CLRh. However, CLRa and CLRh have no effect and no difference in $H_2O_2$-induced toxicity.

• Herbal Formula Science
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• v.25 no.4
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• pp.537-551
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• 2017

Objectives : Jinnoe-san (JNS) is a novel herbal formula consisting of five oriental medicinal herbs including Polygalae Radix, Prunellae Spica, Perillae Herba, Betulae Cortex, and Lonicerae Flos. In this study, we investigated the effects and molecular mechanism of JNS on Parkinson's disease in vitro model. Methods : The effects of JNS on 1-methyl-4-phenylpyridinium ($MPP^+$)-induced cell death in SH-SY5Y cells were evaluated with a cell viability assay, flow cytometry, and western blots analysis. The effects of JNS on lipopolysaccharide (LPS)-stimulated BV2 microglia were determined with a nitric oxide (NO) assay, enzyme linked immunosorbent assays, and western blots analysis. Result : $MPP^+$-induced cell death in SH-SY5Y cells was significantly reduced by JNS pre-treatment in a dose-dependent manner. JNS inhibited the production of reactive oxygen species, mitochondria dysfunction, and apoptosis induced by $MPP^+$ in SH-SY5Y cells. Furthermore, JNS significantly activated Akt and ERK in SH-SY5Y cells and the ability of JNS to prevent mitochondria dysfunction by $MPP^+$ was antagonized by pre-treatment of LY294002 and PD98059, an Akt and ERK inhibitor, respectively. In addition, JNS inhibited LPS-induced NO and $PGE_2$ production as well as iNOS expression and secretion of TNF-${\alpha}$, pro-inflammatory cytokines without affecting the cell viability. JNS also suppressed LPS-induced ERK activation. Conclusions : These results demonstrate that JNS has a protective effect on the dopaminergic neurons against $MPP^+$-induced neurotoxicity and anti-inflammatory effect on the LPS-stimulated microglia. These findings provide evidences for JNS to be considered as a new prescription for treating Parkinson's disease.

• BMB Reports
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• v.52 no.10
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• pp.613-618
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• 2019

Microglial cells are known as the main immune cells in the central nervous system, both regulating its immune response and maintaining its homeostasis. Furthermore, the antioxidant ${\alpha}-lipoic$ acid (LA) is a recognized therapeutic drug for diabetes because it can easily invade the blood-brain barrier. This study investigated the effect of ${\alpha}-LA$ on the inflammatory response in lipopolysaccharide (LPS)-treated BV-2 microglial cells. Our results revealed that ${\alpha}-LA$ significantly attenuated several inflammatory responses in BV-2 microglial cells, including pro-inflammatory cytokines, such as tumor necrosis $factor-{\alpha}$ and interleukin (IL)-6, and other cytotoxic molecules, such as nitric oxide and reactive oxygen species. In addition, ${\alpha}-LA$ inhibited the LPS-induced phosphorylation of ERK and p38 and its pharmacological properties were facilitated via the inhibition of the nuclear factor kappa B signaling pathway. Moreover, ${\alpha}-LA$ suppressed the activation of NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasomes, multiprotein complexes consisting of NLRP3 and caspase-1, which are involved in the innate immune response. Finally, ${\alpha}-LA$ decreased the genes accountable for the M1 phenotype, $IL-1{\beta}$ and ICAM1, whereas it increased the genes responsible for the M2 phenotype, MRC1 and ARG1. These findings suggest that ${\alpha}-LA$ alleviates the neuroinflammatory response by regulating microglial polarization.

• The Korea Journal of Herbology
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• v.28 no.6
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• pp.79-86
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• 2013

Objectives : The purpose of this study is to investigate neuroprotective effects and molecular mechanisms of luteolin against ${\beta}$-amyloid ($A{\beta}_{25-35}$)-induced oxidative cell death in BV-2 cells. Methods : The protective effects of luteolin against $A{\beta}_{25-35}$-induced cytotoxicity and apoptotic cell death were determined by MTT dye reduction assay and TUNEL staining, respectively. The apoptotic cell death was further analyzed by measuring mitochondrial transmembrane potential and expression of pro- and/or anti-apoptotic proteins. To elucidate the molecular mechanisms underlying the protective effects of luteolin, intracellular accumulation of reactive oxygen species, oxidative damages, and expression of antioxidant enzymes were examined. Results : Luteolin pretreatment effectively attenuated $A{\beta}_{25-35}$-induced apoptotic cell death indices such as DNA fragmentation, dissipation of mitochondrial transmembrane potential, increased Bax/Bcl-2 ratio, and activation of c-Jun N-terminal kinase and caspase-3 in BV-2 cells. Furthermore, $A{\beta}_{25-35}$-induced intracellular formation of reactive oxygen species and subsequent oxidative damages such as lipid peroxidation and depletion of endogenous antioxidant glutathione were suppressed by luteolin treatment. The neuroprotective effects of luteolin might be mediated by up-regulation of cellular antioxidant defense system via up-regulation of ${\gamma}$-glutamylcysteine ligase, a rate-limiting enzyme in the glutathione biosynthesis and superoxide dismutase, an enzyme involved in dismutation of superoxide anion into oxygen and hydrogen peroxide. Conclusions : These findings suggest that luteolin has a potential to protect against $A{\beta}_{25-35}$-induced neuronal cell death and damages thereby exhibiting therapeutic utilization for the prevention and/or treatment of Alzheimer's disease.

• Biomolecules & Therapeutics
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• v.30 no.5
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• pp.455-464
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• 2022

Efonidipine, a calcium channel blocker, is widely used for the treatment of hypertension and cardiovascular diseases. In our preliminary study using structure-based virtual screening, efonidipine was identified as a potential inhibitor of c-Jun N-terminal kinase 3 (JNK3). Although its antihypertensive effect is widely known, the role of efonidipine in the central nervous system has remained elusive. The present study investigated the effects of efonidipine on the inflammation and cell migration induced by lipopolysaccharide (LPS) using murine BV2 and human HMC3 microglial cell lines and elucidated signaling molecules mediating its effects. We found that the phosphorylations of JNK and its downstream molecule c-Jun in LPS-treated BV2 cells were declined by efonidipine, confirming the finding from virtual screening. In addition, efonidipine inhibited the LPS-induced production of pro-inflammatory factors, including interleukin-1β (IL-1β) and nitric oxide. Similarly, the IL-1β production in LPS-treated HMC3 cells was also inhibited by efonidipine. Efonidipine markedly impeded cell migration stimulated by LPS in both cells. Furthermore, it inhibited the phosphorylation of inhibitor kappa B, thereby suppressing nuclear translocation of nuclear factor-κB (NF-κB) in LPS-treated BV2 cells. Taken together, efonidipine exerts anti-inflammatory and anti-migratory effects in LPS-treated microglial cells through inhibition of the JNK/NF-κB pathway. These findings imply that efonidipine may be a potential candidate for drug repositioning, with beneficial impacts on brain disorders associated with neuroinflammation.

• Korean Journal of Pharmacognosy
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• v.47 no.1
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• pp.7-11
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• 2016

The aerial part of Trichosanthes kirilowii Maxim. (Cucurbitaceae), has long been used in traditional Korean and Chinese medicines for the treatment of heatstroke. We isolated and identified three flavones, luteolin-7-O-${\beta}$-D-glucopyranoside(1), luteolin-4'-O-${\beta}$-D-glucopyranoside(2), luteolin(3) from its methanolic extract. In the present study, we found that luteolin attenuates the lipopolysaccharide(LPS)-induced inflammation in BV2 microglial cells. Luteolin significantly inhibited LPS-induced production of pro-inflammatory mediators such as nitric oxide(NO) and prostaglandin $E_2(PGE_2)$ in BV2 microglia in a concentration-dependent manner without cytotoxic effect. Luteolin dose-dependently suppressed the protein expression of inducible nitric oxide synthase(iNOS) and cyclooxygenase-2(COX-2). In addition, luteolin also showed significant induction of heme oxygenase(HO)-1. These results suggest that both the aerial part of T. kirilowii and luteolin may be good candidates to regulate LPS-induced inflammatory response.

• Biomolecules & Therapeutics
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• v.19 no.4
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• pp.425-430
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• 2011

In this study, we found that Forsythiae fructus (FF) and one of its main compounds, arctigenin, significantly inhibited nitric oxide production in lipopolysaccharide (LPS)-stimulated BV-2 microglial cells. Arctigenin also suppressed the expression of inducible nitric oxide synthase and cyclooxygenase-2, and inhibited the activation of extracellular signal-regulated kinase, c-Jun N-terminal kinase and p38. Moreover, it also reduced levels of proinflammatory cytokines, interleukin $1{\beta}$, tumor necrosis factor ${\alpha}$ and prostaglandin E2, and inhibited neuronal death in LPS-treated organotypic hippocampal cultures. Therefore, we suggest that arctigenin may confer a neuroprotective effect via the inhibition of neuroinflammation.

• Journal of Nutrition and Health
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• v.50 no.1
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• pp.25-31
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• 2017

Purpose: Neuroinflammation is mediated by activation of microglia implicated in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. Inhibition of neuroinflammation may be an effective solution to treat these brain disorders. Petalonia binghamiae is known as a traditional food, based on multiple biological activities such as anti-oxidant and anti-obesity. In present study, the anti-neuroinflammatory potential of Petalonia binghamiae was investigated in LPS-stimulated BV2 microglial cells. Methods: Cell viability was measured by MTT assay. Production of nitric oxide (NO) was examined using Griess reagent. Expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) was detected by Western blot analysis. Activation of nuclear factor ${\kappa}B$ ($NF-{\kappa}B$) signaling was examined by nuclear translocation of $NF-{\kappa}B$ p65 subunit and phosphorylation of $I{\kappa}B$. Results: Extract of Petalonia binghamiae significantly inhibited LPS-stimulated NO production and iNOS/COX-2 protein expression in a dose-dependent manner without cytotoxicity. Pretreatment with Petalonia binghamiae suppressed LPS-induced $NF-{\kappa}B$ p65 nuclear translocation and phosphorylation of $I{\kappa}B$. Co-treatment with Petalonia binghamiae and pyrrolidine duthiocarbamate (PDTC), an $NF-{\kappa}B$ inhibitor, reduced LPS-stimulated NO release compared to that in PB-treated or PDTC-treated cells. Conclusion: The present results indicate that extract of Petalonia binghamiae exerts anti-neuroinflammation activities, partly through inhibition of $NF-{\kappa}B$ signaling. These findings suggest that Petalonia binghamiae might have therapeutic potential in relation to neuroinflammation and neurodegenerative diseases.