Hyuncheol Oh

Wonkwang University, Riri, Jeollabuk-do, South Korea

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Publications (134)319.15 Total impact

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    ABSTRACT: Objective. Studies have shown that dipeptidyl peptidase-4 (DPP-4) inhibitors have anti- inflammatory effects. Soluble DPP-4 (sDPP-4) has been considered as an adipokine of which actions need to be further characterized. Methods. We investigated the pro-inflammatory actions of sDPP-4 and the anti- inflammatory effects of DPP-4 inhibition, using vildagliptin, as an enzymatic inhibitor, and mannose-6-phosphate (M6P) as a competitive binding inhibitor. Results. In lipopolysaccharide (LPS)-stimulated RAW264.7 cells, vildagliptin suppressed the increased expression of inducible nitric oxide synthase (iNOS) and phosphorylated JNK (pJNK), activation of the NF-κB pathway, and the resultant NO and proinflammatory cytokine production. Although sDPP-4 alone did not affect the protein level of iNOS or pJNK or the production of NO in RAW264.7 cells, it did amplify iNOS expression, NO responses, and proinflammatory cytokine production in LPS-stimulated RAW264 cells. As a probable mechanism, we found that sDPP-4 caused dose-dependent increases in the expression levels of toll-like receptor 4 (TLR4) and TLR2 in RAW264.7 cells, and that these alterations were inhibited by vildagliptin, M6P, or bisindolylmaleimide II, a protein kinase C inhibitor. Either vildagliptin or M6P suppressed iNOS expression and NO and cytokine production in LPS + DPP-4-co-stimulated macrophages, while combined treatment of the co-stimulated cells with both agents had increased anti-inflammatory effects compared with either treatment alone. Intravenous injection of sDPP-4 to C57BL/6J mice increased the expression of both TLRs in kidney and white adipose tissues. Conclusion. Our findings suggest that sDPP-4 enhances inflammatory actions via TLR pathway, while DPP-4 inhibition with either an enzymatic or binding inhibitor has anti- inflammatory effects.
    No preview · Article · Feb 2016 · Metabolism: clinical and experimental
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    ABSTRACT: Although the heartwood of Dalbergia odorifera T. Chen (Leguminosae) is an important source of traditional Korean and Chinese medicines, the effects of novel compound methoxydalbergione (4-MD) isolated from Dalbergia odorifera was not reported. Herein, we investigated the effects of the 4-MD in vitro and in vivo against osteosarcoma cells and its molecular mechanisms. 4-MD inhibited the proliferation of osteosarcoma cells and induced apoptosis as evidenced by Annexin V + and TUNEL + cells. This apoptosis was accompanied by upregulation of apoptotic proteins (procaspase-3 and PARP), but downregulation of anti-apoptotic proteins (Bcl-2, Bcl-xL, and Survivin). 4-MD inhibited phosphorylation of JAK2 and STAT3 with the inactivation of mitogen-activated protein kinases (MAPKs) and CREB, and the upregulation of PTEN in osteosarcoma cells. Importantly, 4-MD reduced colony formation in soft agar and inhibited tumor growth in mice xenograft model in association with the reduced expression of PCNA, Ki67, p-STAT3, and Survivin. Taken together, the present study for the first time demonstrates that 4-MD exerts in vitro and in vivo anti-proliferative effects against osteosarcoma cells through the inhibition of the JAK2/STAT3 pathway, and suggest the potential for therapeutic application of 4-MD in the treatment of osteosarcoma.
    Preview · Article · Jan 2016 · Oncotarget
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    ABSTRACT: Dojuksan is a traditional herbal medicine used in Korea and China to treat urinary diseases. In the present study, we aimed to examine the anti-inflammatory effects of an ethanol solvent extract of Dojuksan and a fraction (by bioassay-guided fractionation) derived from this extract, and to elucidate the specific mechanisms involved. The Dojuksan 30% ethanol extract (DEE) had a more significant and potent anti-inflammatory effect than the Dojuksan water extract (DWE). DEE markedly inhibited the production of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), as well as nuclear factor-κB (NF-κB) binding activity. We found that the anti-inflammatory effects of DEE were mediated by the induction of nuclear factor E2-related factor 2 (Nrf2)-dependent heme oxygenase-1 (HO-1). To further explore the anti-inflammatory effects of DEE, we generated 6 different fractions of DEE. Of these, DEE-5 decreased the production of NO more significantly than the other fractions. DEE-5 also significantly decreased the expression of iNOS and COX-2, and the production of NO, PGE2, TNF-α and IL-1β. In addition, DEE-5 also significantly increased HO-1 levels; HO-1 significanlty contributed to the inhibitory effects of DEE-5 on the production of pro-inflammatory mediators. In this study, we determined whether the choice of extraction solvent affects the biological activity of Dojuksan, a traditional herbal formula. Our findings demonstrate that DEE and a fraction derived from this extract exerts anti-inflammatory effects through Nrf2‑dependent HO-1 expression, and that DEE may thus have greater potential therapeutic application than DWE.
    No preview · Article · Dec 2015 · International Journal of Molecular Medicine
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    ABSTRACT: Chemical investigation of the EtOAc extracts of marine-derived fungal isolates Aspergillus sp. SF-5974 and Aspergillus sp. SF-5976 yielded a new dihydroisocoumarin derivative (1) and 12 known metabolites. The structures of the isolated metabolites were established by extensive spectroscopic analyses, including 1D and 2D NMR spectra and MS data. Among the metabolites, the absolute configuration of 5'-hydroxyasperentin (6) was determined by single-crystal X-ray diffraction analysis. The in vitro antineuroinflammatory effects of the metabolites were also evaluated in lipopolysaccharide (LPS)-stimulated microglial cells. Among the isolated metabolites, dihydroisocoumarin derivatives 1-6 (10-80 μM) were shown to inhibit LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production by suppressing the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2), respectively, in LPS-stimulated BV2 microglia. Further, 1 (20-80 μM) was found to suppress the phosphorylation of the inhibitor of nuclear factor kappa B-α (IκB-α), interrupt the nuclear translocation of nuclear factor kappa B (NF-κB), and decrease the activation of p38 mitogen-activated protein kinase (MAPK).
    No preview · Article · Dec 2015 · Journal of Natural Products
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    ABSTRACT: Twelve metabolites, including five highly oxygenated azaphilones, geumsanols A-E, along with seven known analogues were isolated from Penicillium sp. KCB11A109, a fungus derived from a ginseng field. Their structures were assigned by spectroscopic means (NMR and MS), and stereochemistries were determined by extensive spectroscopic analyses ((1)H-(1)H coupling constants, NOESY, and HETLOC) and chemical derivatizations (modified Mosher's method and acetonide formation). The isolates were evaluated for their anticancer, antimicrobial, antimalarial activities, and phenotypic effects in zebrafish development. Of these compounds possessing no pyranoquinone core, only geumsanol E exhibited cytotoxic activities and toxic effects on zebrafish embryos, suggesting that a double bond at C-11 and C-12 is important for biological activity.
    No preview · Article · Dec 2015 · Phytochemistry
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    ABSTRACT: In the course of searching for anti-neuroinflammatory metabolites from marine fungi, citreohybridonol was isolated from marine-derived fungal strain Toxicocladosporium sp. SF-5699. Citreohybridonol inhibited production of nitric oxide (NO) and prostaglandin E2 (PGE2) in BV2 cells stimulated by lipopolysaccharide (LPS). Citreohybridonol also suppressed the expression of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), and other pro-inflammatory cytokines including interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the LPS-stimulated cells. In the further study, citreohybridonol disturbed nuclear translocation of nuclear factor-kappa B (NF-κB) in LPS-stimulated BV2 cells by inhibiting the phosphorylation of the inhibitor kappa B-α (IκB-α). Citreohybridonol also had inhibitory effect on the LPS-stimulated phosphorylation of p38 mitogen-activated protein kinase (MAPK). Finally, citreohybridonol suppressed the protein expression of Toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88) in LPS-induced BV2 cells. These results suggest that citreohybridonol has anti-neuroinflammatory effect in LPS-stimulated BV2 cells by modulating TLR4-mediated several inflammatory pathways such as NF-κB and p38 MAPK pathways.
    No preview · Article · Dec 2015 · Neurochemistry International
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    ABSTRACT: Myrrh has been used since ancient times for the treatment of various diseases such as inflammatory diseases, gynecological diseases, and hemiplegia. In the present study, we investigated the effects of aqueous extracts of myrrh resin (AEM) on scopolamine-induced memory impairments in mice. AEM was estimated with (2 E ,5 E )-6-hydroxy-2,6-dimethylhepta-2,4-dienal as a representative constituent by HPLC. The oral administration of AEM for 7 days significantly reversed scopolamine-induced reduction of spontaneous alternation in the Y -maze test. In the passive avoidance task, AEM also restored the decreased latency time of the retention trial by scopolamine treatment. In addition, Western blot analysis and Immunohistochemistry revealed that AEM reversed scopolamine-decreased phosphorylation of Akt and extracellular signal-regulated kinase (ERK). Our study demonstrates for the first time that AEM ameliorates the scopolamine-induced memory impairments in mice and increases the phosphorylation of Akt and ERK in the hippocampus of mice brain. These results suggest that AEM has the therapeutic potential in memory impairments.
    Full-text · Article · Nov 2015 · Evidence-based Complementary and Alternative Medicine
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    ABSTRACT: Objective: To investigate the effects of Gastrodiae rhizoma, a dried root of Gastrodia elata Blume, on proliferation and differentiation of human NSCs derived from embryonic stem cells. Methods: A 70% ethanol extract of Gastrodiae rhizoma (EEGR) was estimated with 4-hydroxybenzyl alcohol as a representative constituent by HPLC. Results: MTT assay showed that the treatment with EEGR increased the viability of NSCs in growth media. Compared to control, EEGR increased the number of dendrites and denritic spines extended from a differentiated NSC. Whereas EEGR decreased the mRNA expression of Nestin, it increased that of Tuj1 and MAP2 in NSCs grown in differentiation media. Immunocytochemical analysis using confocal microscopy also revealed the increased expression of MAP2 in dendrites of EEGR-treated NSCs. Furthermore, EEGR decreased mRNA expression of Sox2 in NSCs grown even in growth media. Conclusions: In conclusion, our study demonstrates for the first time that EEGR induced proliferation and neuronal differentiation of NSCs, suggesting its potential benefits on NSC-based therapies and neuroregeneration in various neurodegenerative diseases and brain injuries.
    No preview · Article · Nov 2015 · Asian Pacific Journal of Tropical Medicine
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    ABSTRACT: Alternaramide (1), a novel lipophilic depsipeptide, has been isolated from the extract of the marine-derived fungus Alternaria sp. SF-5016. In the course of extensive biological evaluation of 1, its anti-inflammatory effects in lipopolysaccharide (LPS)-stimulated RAW264.7 and BV2 cells were observed. In our initial study of the anti-inflammatory effects of 1, the compound suppressed production of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-stimulated RAW264.7 and BV2 cells. Suppression of NO and PGE2 production was correlated with the inhibitory effect of 1 on expression of LPS-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the protein level in RAW264.7 and BV2 cells. In addition, 1 reduced production of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and IL-12 in LPS-stimulated RAW264.7 and BV2 cells. In the evaluation of the molecular mechanisms underlying the anti-inflammatory effects of 1, the compound was found to suppress the nuclear factor-kappa B (NF-κB) signaling pathway in RAW264.7 and BV2 cells stimulated with LPS. This suppression was mediated by disruption of phosphorylation and degradation of IκBα, an inhibitor of NF-κB, in the cytoplasm, and blocking of nuclear translocation of the NF-κB p50-p65 heterodimer. Furthermore, 1 inhibited phosphorylation of c-Jun N-terminal kinases (JNKs) and p38 mitogen-activated protein kinase (MAPK), demonstrating its capacity to inhibit MAPK signaling. Finally, 1 markedly reduced expression of Toll-like receptor 4 (TLR4) and myeloid differentiation primary response gene 88 (MyD88) at the mRNA and protein levels in LPS-stimulated RAW264.7 and BV2 cells. Taken together, the results of the present study suggest that 1 modulates several TLR4-mediated inflammatory pathways, demonstrating its potential in the treatment of inflammatory and neuroinflammatory conditions.
    No preview · Article · Nov 2015 · Chemico-biological interactions
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    ABSTRACT: During the chemical investigation of marine-derived fungus, an unusual diketopiperazine (DKP) alkaloid, haenamindole (1), was isolated from a culture of the marine-derived fungus Penicillium sp. KCB12F005. The structure of 1, which possesses benzyl-hydroxypiperazindione and phenyl-pyrimidoindole rings system in the molecule, was elucidated by analysis of NMR and MS data. The stereochemistry of 1 was determined by ROESY and advanced Marfey's method.
    No preview · Article · Sep 2015 · Bioorganic & medicinal chemistry letters
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    ABSTRACT: We previously reported that Nardostachys jatamansi (NJ) exhibits anti-inflammatory activity against lipopolysaccharide (LPS). However, the active compound in NJ is unknown. Therefore, here, we examined the effects of desoxo-narchinol-A (DN) isolated from NJ against LPS-induced inflammation. To demonstrate the anti-inflammatory effect of DN against LPS, we used two models; murine endotoxin shock model for in vivo model, and peritoneal macrophage responses for in vitro. In endotoxin shock model, DN was administrated intraperitoneally 1h before LPS challenge, then we evaluated mice survival rates and organ damages. Pretreatment with DN (0.05mg/kg, 0.1mg/kg, or 0.5mg/kg) dramatically reduced mortality in a murine LPS-induced endotoxin shock model. Furthermore, DN inhibited tissue injury and production of pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor alpha (TNF-α), in the liver and lung. In in vitro macrophage model, we examined the inflammatory mediators and regulatory mechanisms such as mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B (NF-κB). DN inhibited the production of inflammatory mediators, such as inducible nitric oxide synthase (iNOS) and its derivative nitric oxide (NO), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), IL-1β, IL-6 and TNF-α and H3 protein acetylation in murine peritoneal macrophages. DN also inhibited p38 activation, but not extracellular signal-regulated kinase (ERK), c-jun NH2-terminal kinase (JNK), and NF-κB. These results suggest that DN from NJ exhibits protective effects against LPS-induced endotoxin shock and inflammation through p38 deactivation.
    No preview · Article · Sep 2015 · International immunopharmacology
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    ABSTRACT: Two novel cyclic depsipeptides, ulleungamides A (1) and B (2), were isolated from cultures of terrestrial Streptomyces sp. Their structures were determined by analyses of spectroscopic data and various chemical transformations, including modified Mosher's method, advanced Marfey's method, PGME, GITC derivatizations, and Snatzke's method. Ulleungamides were determined to be a new class of peptides bearing unprecedented units, such as 5-hydroxy-6-methyl-2,3-dehydropipecolic acid, 4,5-dihydroxy-6-methyl-2,3-dehydropipecolic acid, and amino-linked 2-isopropylsuccinic acid. Ulleungamide A displayed growth inhibitory activity against Staphylococcus aureus and Salmonella typhimurium without cytotoxicity.
    No preview · Article · Aug 2015 · Organic Letters
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    ABSTRACT: A chemical investigation of the methanol extract from the roots of Cudrania tricuspidata resulted in the isolation of 16 compounds, including prenylated xanthones 1-9 and flavonoids 10-16. Their structures were identified by NMR spectroscopy and mass spectrometry and comparisons with published data. Compounds 1-9 and 13-16 significantly inhibited PTP1B activity in a dose dependent manner, with IC50 values ranging from 1.9-13.6 μM. Prenylated xanthones showed stronger PTP1B inhibitory effects than the flavonoids, suggesting that they may be promising targets for the future discovery of novel PTP1B inhibitors. Furthermore, kinetic analyses indicated that compounds 1 and 13 inhibited PTP1B in a noncompetitive manner; therefore, they may be potential lead compounds in the development of anti-obesity and -diabetic agents.
    No preview · Article · Jun 2015 · Molecules
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    ABSTRACT: Journal of Antibiotics, official journal of the Japan Antibiotics Research Association, is a print and online publication that focuses on research on antibiotics and related types of medicinal substances
    No preview · Article · May 2015 · The Journal of Antibiotics
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    ABSTRACT: The new tanzawaic acid derivative, 2E,4Z-tanzawaic acid D (I), is isolated along with four known analogues from the marine-derived fungus Penicillium sp.
    No preview · Article · May 2015 · ChemInform
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    ABSTRACT: isolation and structure elucidation of a new sesquiterpene, longanone A (I), showing nitrite inhibitory effects
    No preview · Article · Jan 2015 · ChemInform
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    Wonmin Ko · Jae Hak Sohn · Youn-Chul Kim · Hyuncheol Oh
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    ABSTRACT: Viridicatol (1) has previously been isolated from the extract of the marine-derived fungus Penicillium sp. SF-5295. In the course of further biological evaluation of this quinolone alkaloid, anti-inflammatory effect of 1 in RAW264.7 and BV2 cells stimulated with lipopolysaccharide (LPS) was observed. In this study, our data indicated that 1 suppressed the expression of well-known pro-inflammatory mediators such as inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, and consequently inhibited the production of iNOS-derived nitric oxide (NO) and COX-2-derived prostaglandin E2 (PGE2) in LPS stimulated RAW264.7 and BV2 cells. Compound 1 also reduced mRNA expression of pro-inflammatory cytokines such as interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). In the further evaluation of the mechanisms of these anti-inflammatory effects, 1 was shown to inhibit nuclear factor-kappa B (NF-κB) pathway in LPS-stimulated RAW264.7 and BV2 cells. Compound 1 blocked the phosphorylation and degradation of inhibitor kappa B (IκB)-α in the cytoplasm, and suppressed the translocation of NF-κB p65 and p50 heterodimer in nucleus. In addition, viridicatol (1) attenuated the DNA-binding activity of NF-κB in LPS-stimulated RAW264.7 and BV2 cells.
    Preview · Article · Jan 2015 · Natural Product Sciences
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    ABSTRACT: Chemical investigation on the methanol extract of the starfish Ctenodiscus crispatus resulted in the isolation of five steroids, (22E,24 xi)-26,27-bisnor-24-methyl-5 alpha-cholest-22-en-3 beta,5,6 beta,15 alpha,25-pentol 25-O-sulfate (1), (22E,24R,25R)-24-methyl-5 alpha-cholest-22-en-3 beta,5,6 beta,15 alpha,25,26-hexol 26-O-sulfate (2), (28R)-24-ethy1-5 alpha-cholesta-3 beta,5,6 beta,8,15 alpha,28,29-heptaol-24-sulfate (3), (25S)-5 alpha-cholestane-3 beta,5,6 beta,15 alpha,16 beta,26-hexaol (4), and Delta 7-sitosterol (5). Their structures were identified by extensive spectroscopic analyses, including 1D, 2D NMR and MS and chemical methods. Compound 4 showed cytotoxicity against human hepatoma HepG2 and glioblastoma U87MG cells via inhibition of cell growth and induction of apoptosis. Induction of apoptosis by 4 was demonstrated by cell death, DNA fragmentation, increased Bax/Bcl-2 protein ratio and the activation of caspase-3, caspase-9 and poly (ADP-ribose) polymerase (PARP).
    No preview · Article · Jan 2015 · ChemInform
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    ABSTRACT: Chemical investigation of a marine-derived fungus Penicillium sp. SF-6013 resulted in the discovery of a new tanzawaic acid derivative, 2E,4Z-tanzawaic acid D (1), together with four known analogues, tanzawaic acids A (2) and D (3), a salt form of tanzawaic acid E (4), and tanzawaic acid B (5). Their structures were mainly determined by analysis of NMR and MS data, along with chemical methods. Preliminary screening for anti-inflammatory effects in lipopolysaccharide (LPS)-activated microglial BV-2 cells showed that compounds 1, 2, and 5 inhibited the production of nitric oxide (NO) with IC50 values of 37.8, 7.1, and 42.5μM, respectively. Compound 2 also inhibited NO production in LPS-stimulated RAW264.7 murine macrophages with an IC50 value of 27.0μM. Moreover, these inhibitory effects correlated with the suppressive effect of compound 2 on inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in LPS-stimulated RAW264.7 and BV2 cells. In addition, compounds 2 and 5 significantly inhibited the activity of protein tyrosine phosphatase 1B (PTP1B) with the same IC50 value (8.2μM). Copyright © 2014 Elsevier Ltd. All rights reserved.
    No preview · Article · Dec 2014 · Bioorganic & Medicinal Chemistry Letters
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    ABSTRACT: The brain is vulnerable to oxidative stress and inflammation that can occur as a result of aging or neurodegenerative diseases. Our work has sought to identify natural products that regulate heme oxygenase (HO)-1 and to determine their mechanism of action in neurodegenerative diseases. KCHO-1 is a novel herbal therapeutic containing 30% ethanol (EtOH) extracts from nine plants. In this study, we investigated the antineuroinflammatory effects of KCHO-1 in lipopolysaccharide- (LPS-) treated mouse BV2 microglia. KCHO-1 inhibited the protein expression of inducible nitric oxide synthase (iNOS), iNOS-derived nitric oxide (NO), cyclooxygenase- (COX-) 2, and COX-2-derived prostaglandin E2 (PGE2) in LPS-stimulated BV2 microglia. It also reduced tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 production. This effect was correlated with the suppression of inhibitor of nuclear factor kappa B-α (IκB-α) phosphorylation and degradation and nuclear factor kappa B (NF-κB) translocation and DNA binding. Additionally, KCHO-1 upregulated HO-1 expression by promoting nuclear translocation of nuclear factor E2-related factor 2 (Nrf2) in mouse BV2 microglia. Tin protoporphyrin (SnPP), an HO activity inhibitor, was used to verify the inhibitory effects of KCHO-1 on proinflammatory mediators and proteins associated with HO-1 expression. Our data suggest that KCHO-1 has therapeutic potential in neurodegenerative diseases caused by neuroinflammation.
    Full-text · Article · Dec 2014 · Evidence-based Complementary and Alternative Medicine

Publication Stats

2k Citations
319.15 Total Impact Points


  • 2001-2015
    • Wonkwang University
      • • College of Pharmacy
      • • Professional Graduate School of Oriental Medicine
      Riri, Jeollabuk-do, South Korea
  • 2005-2012
    • Silla University
      Tsau-liang-hai, Busan, South Korea
  • 1998-2010
    • University of Iowa
      • Department of Chemistry
      Iowa City, Iowa, United States
  • 2004-2005
    • Korea Research Institute of Bioscience and Biotechnology KRIBB
      • Chemical Biology Research Center
      안산시, Gyeonggi-do, South Korea