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Cheongwon, South Korea

Jun H.,Korean University of Science and Technology | Lee J.H.,Korean University of Science and Technology | Cho B.-R.,Korean University of Science and Technology | Seo W.-D.,South Korean National Institute of Crop Science | And 3 more authors.
European Food Research and Technology | Year: 2012

We investigated the in vitro effects of p-coumaric acid on melanogenesis. The melanin content in B16F1 cells stimulated with p-coumaric acid significantly decreased (68 % vs. control) through inhibition of tyrosinase enzyme activity assessed using both cell-free and cell-based assays (46 and 27 % compared with control, respectively). In addition, stimulating B16F1 cells with p-coumaric acid reduced cyclic adenosine monophosphate (cAMP)-responsive element-binding protein (CREB) protein phosphorylation (26 % vs. control), which in turn downregulated the expression of the microphthalmia-associated transcription factor (MITF) and its target gene tyrosinase (27 and 20 % vs. control, respectively). p-Coumaric acid has a hypopigmentation effect in melanocytes by both directly inhibiting tyrosinase enzyme activity and reducing CREB phosphorylation, which inhibits MITF and tyrosinase expression. © 2012 Springer-Verlag Berlin Heidelberg. Source


Jung H.Y.,Seoul National University | Yoo D.Y.,Seoul National University | Kim W.,Seoul National University | Nam S.M.,Seoul National University | And 5 more authors.
BMC Complementary and Alternative Medicine | Year: 2015

Background: In this study, we investigate the effects of valerian root extracts (VE) on physical and psychological stress responses by utilizing a communication box. Methods: Eight-week-old ICR mice received oral administration of VE (100 mg/kg/0.5 ml) or equal volume of distilled water in every day for 3 weeks prior to being subjected to physical or psychological stress for 3 days, which are induced by communication box developed for physical electric shock and psychological stress by nociceptive stimulation-evoked responses. The stress condition was assessed by forced swimming test and serum corticosterone levels. In addition, norepinephrine (NE), serotonin (5-HT), and their metabolites such as 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MHPG-SO4) and 5-hydroxyindoleacetic acid (5-HIAA) were measured in the hippocampus and amygdala at 1 h after final stress condition, respectively. Results: Immobility time and corticosterone levels were significantly increased in both the physical and psychological stress groups compared to the control group. The administration of VE significantly reduced these parameters in both the physical and psychological stress groups. In addition, compared to the control group, physical and psychological stress groups showed significantly increased levels of MHPG-SO4 and 5-HIAA in the hippocampus and amygdala, respectively. The administration of VE significantly suppressed the increase of MHPG-SO4 and 5-HIAA in the two stress groups. Conclusion: These results suggest that VE can suppress physical and psychological stress responses by modulating the changes in 5-HT and NE turnover in the hippocampus and amygdala. © 2014 Jung et al.; licensee BioMed Central. Source


Yoo D.Y.,Seoul National University | Jung H.Y.,Seoul National University | Nam S.M.,Seoul National University | Kim J.W.,Seoul National University | And 6 more authors.
Journal of Medicinal Food | Year: 2015

As a medicinal plant, the roots of Valeriana officinalis have been used as a sedative and tranquilizer. In the present study, we evaluated the neuroprotective effects of valerian root extracts (VE) on the hippocampal CA1 region of gerbils after 5min of transient cerebral ischemia. Gerbils were administered VE orally once a day for 3 weeks, subjected to ischemia/reperfusion injury, and continued on VE for 3 weeks. The administration of 100mg/kg VE (VE100 group) significantly reduced the ischemia-induced spontaneous motor hyperactivity 1 day after ischemia/reperfusion. Four days after ischemia/reperfusion, animals treated with VE showed abundant cresyl violet-positive neurons in the hippocampal CA1 region when compared to the vehicle or 25mg/kg VE-treated groups. In addition, the VE treatment markedly decreased microglial activation in the hippocampal CA1 region 4 days after ischemia. Compared to the other groups, the VE100 group showed the lowest level of lipid peroxidation during the first 24h after ischemia/reperfusion. In summary, the findings in this study suggest that pretreatment with VE has protective effects against ischemic injury in the hippocampal pyramidal neurons by decreasing microglial activation and lipid peroxidation. © Copyright 2015, Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition 2015. Source


Hwang I.K.,Seoul National University | Yoo K.-Y.,Kangwon National University | Yoo D.Y.,Seoul National University | Choi J.H.,Kangwon National University | And 7 more authors.
Journal of Medicinal Food | Year: 2011

Zizyphus jujuba is considered to have various physiological functions in the brain. We obtained a Z. jujuba methanol extract (ZJE) and observed its effects on neurogenesis in middle-aged mice. Twelve-month-old mice received repeated oral administrations of ZJE for 30 days. The administration of ZJE significantly increased the number of Ki67 (a marker for cell proliferation)-positive cells in the subgranular zone of the dentate gyrus of middle-aged mice. Furthermore, ZJE significantly increased doublecortin (a marker for neuroblast differentiation)-immunoreactive neuroblasts with tertiary dendrites, but not those without tertiary dendrites, in the dentate gyrus. In addition, doublecortin protein levels in the ZJE-treated groups tended to increase dose-dependently. These results suggest that the repeated supplement of ZJE may increase the hippocampal plasticity in middle-aged mice. Copyright 2011, Mary Ann Liebert, Inc. Source


Jun H.-J.,Korean University of Science and Technology | Lee J.H.,Korean University of Science and Technology | Cho B.-R.,Korean University of Science and Technology | Seo W.-D.,South Korean National Institute of Crop Science | And 4 more authors.
Journal of Natural Products | Year: 2012

The in vitro effects on melanogenesis of γ-oryzanol (1), a rice bran-derived phytosterol, were investigated. The melanin content in B16F1 cells was significantly and dose-dependently reduced (-13% and -28% at 3 and 30 μM, respectively). Tyrosinase enzyme activity was inhibited by 1 both in a cell-free assay and when analyzed based on the measurement of cellular tyrosinase activity. Transcriptome analysis was performed to investigate the biological pathways altered by 1, and it was found that gene expression involving protein kinase A (PKA) signaling was markedly altered. Subsequent analyses revealed that 1 stimulation in B16 cells reduced cytosolic cAMP concentrations, PKA activity (-13% for cAMP levels and -40% for PKA activity), and phosphorylation of the cAMP-response element binding protein (-57%), which, in turn, downregulated the expression of microphthalmia-associated transcription factor (MITF; -59% for mRNA and -64% for protein), a key melanogenic gene transcription factor. Accordingly, tyrosinase-related protein 1 (TRP-1; -69% for mRNA and -82% for protein) and dopachrome tautomerase (-51% for mRNA and -92% for protein) in 1-stimulated B16F1 cells were also downregulated. These results suggest that 1 has dual inhibitory activities for cellular melanogenesis by inhibiting tyrosinase enzyme activity and reducing MITF and target genes in the PKA-dependent pathway. © 2012 The American Chemical Society and American Society of Pharmacognosy. Source

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