Jehun Choi

Dr. Jehun Choi


Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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25 March 2013 in Molecules
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Journal Article
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Dae Young LeeDae Young Lee
Dae Young Lee
HNHyung-Jun Noh
Hyung-Jun Noh
JCJehun Choi
Jehun Choi
KLKyeong-Hee Lee
Kyeong-Hee Lee
MLMin-Ho Lee
Min-Ho Lee
GKGeum-Soog Kim
Geum-Soog Kim
A new cycloartane-type triterpene glycoside, agroastragaloside V (1) was isolated from the roots of Astragalus membranaceus. The structure was identified as 3-O-β-(2'-O-acetyl)-D-xylopyranosyl-6-O-β-D-glucopyranosyl-(24S)-3β,6α,24α,25-tetrahydroxy- 9,19-cyclolanostane, by means of spectroscopic methods, including HR-FAB/MS, 1D NMR (1H, 13C, DEPT), 2D NMR (gCOSY, gHSQC, gHMBC, NOESY), and IR spectroscopy. Four known cycloartane glycosides, namely, agroastragaloside I (2), agroastragaloside II (3), isoastragaloside II (4) and astragaloside IV (5) were also isolated. All isolated compounds were tested for the ability to inhibit LPS-induced nitric oxide production in RAW264.7 macrophages.

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JLJae Won Lee
Jae Won Lee
HMHyuck Jun Mok
Hyuck Jun Mok
Dae Young LeeDae Young Lee
Dae Young Lee
SPSeung Cheol Park
Seung Cheol Park
MBMyeong Soon Ban
Myeong Soon Ban
HKHyung Don Kim
Hyung Don Kim
While both the pro- and anti-inflammatory effects of several eicosanoids have been widely studied, the degree of inflammation in cells that results from various eicosanoids has yet to be comprehensively studied. The objective of this study was to assess the effect of lipopolysaccharide (LPS) treatment on eicosanoid content in RAW264.7 cells. An Ultra performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS)-based profiling method was used to analyze the eicosanoid contents of RAW264.7 cells treated with different LPS concentrations. The profiling data were subjected to statistical analyses, such as principal component analysis (PCA) and hierarchical clustering analysis. LPS treatment increased nitric oxide production and secretion of pro-inflammatory cytokines, such as tumor necrosis factor-α and interleukin-6, in a concentration-dependent manner. In total, 79 eicosanoids were identified in the cells. RAW264.7 cells treated with different LPS concentrations were well differentiated in the PCA score plot. A heatmap was used to identify the eicosanoids that were up- or down-regulated according to the degree of inflammation and LPS concentration. Thirty-nine eicosanoids were upregulated and seven were down-regulated by LPS treatment in a concentration-dependent manner. Our novel UPLC-MS/MS technique can profile eicosanoids, and can evaluate the correlations between inflammation and eicosanoid metabolism.

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SLSeung-Eun Lee
Seung-Eun Lee
SPSaetbyeol Park
Saetbyeol Park
GJGwi Yeong Jang
Gwi Yeong Jang
JLJeonghoon Lee
Jeonghoon Lee
MMMinho Moon
Minho Moon
DKDong Hwi Kim
Dong Hwi Kim
Aster koraiensis Nakai (AK) leaf reportedly ameliorates health problems, such as diabetes. However, the effects of AK on cognitive dysfunction or memory impairment remain unclear. This study investigated whether AK leaf extract could attenuate cognitive impairment. We found that AK extract reduced the production of nitric oxide (NO), tumour necrosis factor (TNF)-α, phosphorylated-tau (p-tau), and the expression of inflammatory proteins in lipopolysaccharide- or amyloid-β-treated cells. AK extract exhibited inhibitory activity of control specific binding on N-methyl-D-aspartate (NMDA) receptors. Scopolamine-induced AD models were used chronically in rats and acutely in mice. Relative to negative controls (NC), hippocampal choline acetyltransferase (ChAT) and B-cell lymphoma 2 (Bcl2) activity was increased in rats chronically treated with scopolamine and fed an AK extract-containing diet. In the Y-maze test, spontaneous alterations were increased in the AK extract-fed groups compared to NC. Rats administered AK extract showed increased escape latency in the passive avoidance test. In the hippocampus of rats fed a high-AK extract diet (AKH), the expression of neuroactive ligand–receptor interaction-related genes, including Npy2r, Htr2c, and Rxfp1, was significantly altered. In the Morris water maze assay of mice acutely treated with scopolamine, the swimming times in the target quadrant of AK extract-treated groups increased significantly to the levels of the Donepezil and normal groups. We used Tg6799 Aβ-overexpressing 5XFAD transgenic mice to investigate Aβ accumulation in animals. In the AD model using 5XFAD, the administration of AK extract decreased amyloid-β (Aβ) accumulation and increased the number of NeuN antibody-reactive cells in the subiculum relative to the control group. In conclusion, AK extract ameliorated memory dysfunction by modulating ChAT activity and Bcl2-related anti-apoptotic pathways, affecting the expression of neuroactive ligand–receptor interaction-related genes and inhibiting Aβ accumulation. Therefore, AK extract could be a functional material improving cognition and memory.

4 January 2023 in Processes
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Journal Article
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SLSeung-Eun Lee
Seung-Eun Lee
GJGwi Yeong Jang
Gwi Yeong Jang
JJJi Wook Jung
Ji Wook Jung
SPSaetbyeol Park
Saetbyeol Park
JLJeong-Hoon LEE
Jeong-Hoon LEE
GKGeumsoog Kim
Geumsoog Kim
One of the factors related to the pathogenesis of Alzheimer’s disease, a disease characterized by gradual cognitive and memory impairment, is an inflammatory process induced by the amyloid-β-mediated activation of microglia. In the present study, an extract of the Chrysanthemum boreale (Makino) Makino (CB) flower, which has inhibitory effects on inflammation and the production of phosphorylated tau in cells, was investigated for its ameliorative effect on memory dysfunction in scopolamine-treated Alzheimer’s disease models. The CB-extract-diet-administered groups, which were treated chronically with scopolamine (intraperitoneal), showed increased spontaneous alterations (12.5–15.5% increase) in the Y-maze test and latency to escape (3.7–6.7-fold increase) in the passive avoidance test, compared to the negative control (NC) group. Rats administered the CB extract also showed a higher tendency (66–86% increase) of hippocampal brain-derived neurotrophic factor expression than NC rats. Moreover, the ratio of phosphorylated extracellular signal-regulated kinase/extracellular signal-regulated kinase in the CB-extract-administered group was lower (48.0–52.2%) than that (100%) in the NC group. In the Morris water maze test conducted on the fifth day, the free-swimming times of the CB-extract-administered mice that were also treated with scopolamine for a short time (5 d) increased (51.7–56.1%) significantly compared to those of the NC mice. Finally, high-performance liquid chromatography analysis confirmed that isochlorogenic acid A, linarin, and chlorogenic acid are the major phenolic components of the CB extract. These results suggest that the extract of CB flowers might be useful as a functional material with memory-enhancing effects.

2 May 2021 in Processes
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Journal Article
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JCJehun Choi
Jehun Choi
GJGwi Yeong Jang
Gwi Yeong Jang
JLJeong-Hoon LEE
Jeong-Hoon LEE
HCHae Young Chung
Hae Young Chung
HNHyung-Jun Noh
Hyung-Jun Noh
SLSeung-Eun Lee
Seung-Eun Lee
Senescence is the phenomenon by which physiological functions of organisms degenerate with time. Cellular senescence is marked by an inhibition of cell cycle progression. Beta-galactosidase accumulates in the lysosomes of aged cells. In this study, human dermal fibroblast cells (HDFs) were treated with 0.5 μM doxorubicin for 4 h to induce cellular senescence. Senescence-associated beta-galactosidase (SA-β-gal) activity was then measured 72 h after treatment with aerial parts of Dendranthema zawadskii var. lucidum (Nakai) J.H. Park (DZ) extract. Treatment with DZ extract significantly decreased SA-β-gal activity in a dose-dependent manner in HDFs. Additionally, DZ extract treatment reduced age-related oxidative stress and inflammation in the aortas of aged rats. The reactive oxygen species (ROS) levels in aortas of aged control rats were higher than those in young rats. However, DZ extract-fed aged rats showed significantly lower ROS levels than the aged control rats. When the aged rats were treated with DZ extract at either 0.2 or 1.0 mg∙kg−1∙day−1, NF-κB levels in aorta tissue decreased significantly compared to those in aorta tissue of the aged control rats without DZ treatment. In addition, DZ extract-fed aged rat aortas showed significant reductions in expression of iNOS and COX-2 induced by NF-κB translocation. Therefore, these results suggest that DZ effectively inhibited senescence-related NF-κB activation and inflammation. DZ extract may have a role in the prevention of the vascular inflammatory responses that occur during vascular aging.

31 December 2014 in Journal of Applied Biological Chemistry
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Journal Article
Closed access
KLKyeong-Hee Lee
Kyeong-Hee Lee
Dae Young LeeDae Young Lee
Dae Young Lee
SLSeung-Eun Lee
Seung-Eun Lee
HNHyung-Jun Noh
Hyung-Jun Noh
JLJeong-Hoon Lee
Jeong-Hoon Lee
GKGeum-Soog Kim
Geum-Soog Kim