• Natural Product Sciences
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• v.10 no.5
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• pp.211-216
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• 2004

Citrus unshiu (Rutaceae) has long been known as an anti-inflammatory and anti-allergic agent. In the present study, the inhibitory effect of CUWE (Citus unshiu water extract) on the production of $TNF-{\alpha}$ and tryptase was examined. In addition, a possible mechanism for the inhibition of trypsin-stimulated human leukemic mast cell-1 (HMC- 1 ) activation was determined. To do so, $TNF-{\alpha}$ production from the HMC-1 cells that were stimulated by trypsin (100 nM) in the presence or absence of CUWE $(10,\;100,\;and\;100\;{\mu}g/ml)$ was measured by enzyme-linked immunosorbent assay (ELISA) and reverse transcription-PCR. The tryptase production was evaluated by reverse transcription-PCR. Extracellular signal-regulated kinase (ERK) activation was analyzed by Western blot. Trypsin activity was measured by using Bz-DL-Arg-p-nitroanilide (BAPNA) as substrate. Results showed that the CUWE inhibited production of both $TNF-{\alpha}$ and tryptase from the trypsin-stimulated HMC-1 in a dose-dependent manner. The CUWE a1so inhibited the ERK phosphorylation and trysin activity. These results indicate that the CUWE had an inhibitory effect on $TNF-{\alpha}$ and the tryptase productions by blocking the ERK phosphorylation and trypsin activity.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.3
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• pp.281-286
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• 2012

The present study was designed to investigate the effect of Rehmannia glutinosa on phosphorylation of extracellular signal-regulated kinase(ERK) and cAMP response element-binding protein(CREB) in the acute cocaine-treated rats. Rats orally received vehicle or extract of Rehmannia glutinosa 1 h prior to saline (1 ml/kg, i.p.) or cocaine hydrochloride (20 mg/kg, i.p.) treatment. Rats were sacrificed 15 min after a single intraperitoneal injection of saline or cocaine. Rehmannia glutinosa at dose of 50 mg/kg significantly decreased phosphorylation of ERK, CREB and Elk-1 in the nucleus accumbens and striatum of the cocaine-treated rat brain by immunocytochemistry. These results suggest that Rehmannia glutinosa may contribute to the effects of cocaine on gene expression and on behaviors.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.20 no.3
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• pp.1-13
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• 2007

Objective : This study was performed to assess the whitening effect of Bombysis Corpus on melanin synthesis. Methods : The whitening effects of Bombysis Corpus were examined by in vitro melanin production assay. We assessed inhibitory effects of Bombysis Corpus on melanin-release from B16F10, on melanin production in B16F10, on mushroom tyrosinase activity in vitro, on tyrosinase activity in B16F10, effect of Bombysis Corpus on the expression tyrosinase, TRP-1, PKA, ERK-1 ERK-2, AKT-1, MITF in B16F10. Results : 1. Bombysis Corpus inhibited melanin-release, melanin production in B16F10. 2. Bombysis Corpus inhibited tyrosinase activity in vitro and in B16F10. 3. Bombysis Corpus suppressed the expression of tyrosinase, TRP-1 in B16F10. 4. Bombysis Corpus suppressed the expression of PKA in B16F10. 5. Bombysis Corpus suppressed the expression of ERK-1, ERK-2, AKT-1 in B16F10. 6. Bombysis Corpus suppressed the expression of MITF in B16F10. Conclusion : The study shows that Bombysis Corpus inhibited melanin production on the melanogenesis.

• Biomolecules & Therapeutics
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• v.18 no.1
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• pp.24-31
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• 2010

Taurine, 2-aminoethanesulfonic acid, is an abundant free amino acid present in brain cells and exerts many important biological functions such as anti-convulsant, modulation of neuronal excitability, regulation of learning and memory, anti-aggressiveness and anti-alcoholic effects. In the present study, we investigated to explore whether taurine has any protective actions against oxidative stress-induced damages in neuronal cells. ERK I/II regulates signaling pathways involved in nitric oxide (NO) and reactive oxygen species (ROS) production and plays a role in the regulation of cell growth, and apoptosis. We have found that taurine significantly inhibited AMPA induced cortical depolarization in the Grease Gap assays using rat cortical slices. Taurine also inhibited AMPA-induced neuronal cell damage in MTT assays in the differentiated SH-SY5Y cells. When the neuronal cells were treated with $H_2O_2$, levels of NO were increased; however, taurine pretreatment decreased the NO production induced by $H_2O_2$ to approximately normal levels. Interestingly, taurine treatment stimulated ERK I/II activity in the presence of AMPA or $H_2O_2$, suggesting the potential role of ERK I/II in the neuroprotection of taurine. Taken together, taurine has significant neuroprotective actions against AMPA or $H_2O_2$ induced damages in neuronal cells, possibly via activation of ERK I/II.

• The Journal of Korean Medicine
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• v.30 no.6
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• pp.17-26
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• 2009

Objectives: Little information is available regarding the effect of Lycii cortex radicis (LCR) on cell viability in glioma cells. This study was therefore undertaken to examine the effect of LCR on cell survival in U87MG human glioma cells. Methods: Cell viability and cell death were estimated by MTT assay and trypan blue exclusion assay, respectively. Reactive oxygen species (ROS) generation was measured using the fluorescence probe DCFH-DA. Activation of Akt and extracellular signal-regulated kinase (ERK) and activation of caspase-3 were estimated by Western blot analysis. Results: LCR resulted in apoptotic cell death in a dose- and time-dependent manner. LCR increased reactive oxygen species (ROS) generation and LCR-induced cell death was also prevented by antioxidants, suggesting that ROS generation played a critical role in LCR-induced cell death. Western blot analysis showed that LCR treatment caused down-regulation of Akt and ERK. The LCR-induced cell death was increased by the inhibitors of Akt and ERK. Activation of caspase-3 was stimulated by LCR and caspase inhibitors prevented the LCR-induced cell death. Conclusion: These findings suggest that LCR results in human glioma cell death through a mechanism involving ROS generation, down-regulation of Akt and ERK, and caspase activation.

• Molecules and Cells
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• v.23 no.2
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• pp.138-144
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• 2007

Previously we showed that the human GM3 synthase gene was expressed during the induction of megakaryocytic differentiation in human leukemia K562 cells by phorbol 12-myristate 13-acetate (PMA). In this study we found that treatment of PMA-induced K562 cells with $G{\ddot{o}}6976$, a specific inhibitor of PKC, and U0126, an inhibitor of the extracellular signal-regulated kinase (ERK) reduced expression of GM3 synthase, whereas wortmannin, an inhibitor of phosphoinositide 3-kinase (PI3K) did not. Moreover, activation of ERK and cAMP response element binding protein (CREB) was prevented by pretreatment with $G{\ddot{o}}6976$ and U0126. PMA stimulated the promoter activity of the 5'-flanking region from -177 to -83 region of the GM3 synthase gene, and mutation or deletion of a CREB site located around -143 of the promoter reduced PMA-stimulated promoter activity, as did the inhibitors $G{\ddot{o}}6976$ and U0126. Our results demonstrate that induction of GM3 synthase during megakaryocytic differentiation in PMA-stimulated human leukemia K562 cells depends upon the PKC/ERK/CREB pathway.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.3
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• pp.263-268
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• 2015

The purpose of this study was to investigate anti-melanogenesis effects of mulberry seed extracts (MSE). MSE inhibited melanogenesis in melan-a cells at $10{\mu}g/mL$ without cytotoxicity. Also, MSE decreased tyrosinase, tyrosinase-related protein-1 (TRP-1) protein expression in the melan-a cells. To identify the signaling pathway of MSE, the ability of MSE to influence extracellular signal-regulated protein kinase (ERK) activation was investigated. MSE induced ERK protein expression in a dose-dependent manner. In addition, MSE presented inhibition of the body pigmentation in vivo zebrafish model. These results suggest that MSE may be an effective anti-melanogenesis agent regulating the expression of ERK protein and melanogenic enzymes.

• Korean Journal of Plant Resources
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• v.27 no.3
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• pp.209-214
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• 2014

In this study, we investigated whether A. distichum decreases the production of inflammatory mediators through downregulation of the NF-${\kappa}B$ and ERK pathway. Our data indicated that A. distichum leaf inhibits the overexpression of iNOS in protein and mRNA levels, and subsequently blocked LPS-mediated NO overproduction in RAW264.7 cells. A. distichum leaf inhibited $I{\kappa}B-{\alpha}$ degradation and p65 nuclear translocation, and subsequently suppressed transcriptional activity of NF-${\kappa}B$ in LPS-stimulated RAW264.7 cells. In addition, A. distichum leaf suppressed LPS-induced ERK1/2 activation by decreasing phosphorylation of ERK1/2. These findings suggest that A. distichum leaf shows anti-inflammatory activities through suppressing ERK-mediated NF-${\kappa}B$ activation in mouse macrophage.

• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.1063-1066
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• 2016

Longan (Dimocarpus longan Lour.) has been used as a traditional oriental medicine and possesses a number of physiological activities. In this study, we used cell-based herbal extract screening to identify longan fruit extract (LFE) as an activator of osteoblast differentiation. LFE up-regulated alkaline phosphatase (ALP) activity, induced mineralization, and activated Runx2 gene expression in MC3T3-E1 cells. Furthermore, treatment of MC3T3-E1 cells with LFE promoted the phosphorylation of extracellular signal-regulated kinase1/2 (Erk1/2); however, abrogation of Erk1/2 activation with PD98059 resulted in down-regulation of the phospho-SMAD1/5/8 and Runx2 levels, which in turn reduced the ALP activity. Our findings suggest that LFE exerts its osteogenic activity through activation of the ERK signaling pathway and may have potential as an herbal therapeutic or a preventive agent for the treatment of osteoporosis.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.1
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• pp.29-34
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• 2015

Fucoidan, a fucose-rich sulfated polysaccharide derived from brown seaweed in the class Phaeophyceae, has been widely studied for its possible health benefits. However, the potential of fucoidan as a possible treatment for hyperpigmentation is not fully understood. This study investigated the effects of fucoidan on melanogenesis and related signaling pathways using Mel-Ab cells. Fucoidan significantly decreased melanin content. While fucoidan treatment decreased tyrosinase activity, it did not do so directly. Western blot analysis indicated that fucoidan downregulated microphthalmia-associated transcription factor and reduced tyrosinase protein expression. Further investigation showed that fucoidan activated the extracellular signal-regulated kinase (ERK) pathway, suggesting a possible mechanism for the inhibition of melanin synthesis. Treatment with PD98059, a specific ERK inhibitor, resulted in the recovery of melanin production. Taken together, these findings suggest that fucoidan inhibits melanogenesis via ERK phosphorylation.