Youngwan Seo

Korea Maritime University, Tsau-liang-hai, Busan, South Korea

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Publications (64)92.92 Total impact

  • Chang‐Suk Kong, Haejin Kim, Youngwan Seo
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    ABSTRACT: The present study performed the bioactivity-monitored isolation of anti-adipogenic phlorotannins from Ecklonia cava as a part of the ongoing research to develop antiobesity nutraceuticals from natural origin. Extracts were partitioned into n-hexane, 85% aqueous MeOH, n-BuOH and water fractions. Their adipogenic activities were examined by measuring glycerol release level and adipogenic-related gene expression in differentiating 3T3-L1 preadipocytes. Among them, n-BuOH fractions significantly increased glycerol secretion and reduced the regulation of adipogenic transcription factors, peroxisome proliferator-activated receptor-γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), as well as tumor necrosis factor α (TNFα). Further separation from n-BuOH fraction led to the isolation of phlorotannins, triphlorethol-A, eckol and dieckol. Phlorotannins increased the glycerol secretion and reduced the glucose consumption levels of 3T3-L1 adipocytes. Moreover, the phlorotannins reduced the expression levels of PPARγ, C/EBPα and differentiation-dependent factor 1/sterol regulatory element-binding protein 1c, as well as downstream genes such as fatty acid binding protein-4, fatty acid transport protein-1, fatty acid synthase, Leptin and acyl-CoA synthetase 1. In addition, phlorotannins increased the mRNA expression of hormone-sensitive lipase while suppressing perilipin and TNFα expressions.Practical ApplicationsBrown alga, Ecklonia cava, is one of the most common edible algae in East Asian countries and widely consumed throughout Korea and Japan because of its nutritional importance along with its medicinal value. Constituents of E. cava, especially phenolic compounds, are considered to possess several bioactivities against various complications and diseases. In this regard, this study provides valuable insights concerning the antiobesity potential of E. cava and effective ingredients. Results indicate that the isolated phlorotannins act as antiobesity agents and suggest possible mechanisms of action. Following this study, a better utilization of E. cava via proper extraction of antiobesity constituents will pave the way for future nutraceuticals with antiobesity value.
    Journal of Food Biochemistry 12/2014; · 0.76 Impact Factor
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    ABSTRACT: isolation and structure of new labdane-type diterpene (I) together with five known diterpenes
    ChemInform 05/2014; 45(18).
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    ABSTRACT: The (2'S,7'S)-O-(2-methylbutanoyl)-columbianetin (OMC) is a novel secondary metabolite extracted from Corydalis heterocarpa, which has long been used as a folk medicine for various inflammatory diseases in Korea. We examined the effect of OMC on allergic rhinitis (AR). We assessed the therapeutic effects and regulatory mechanisms of OMC on the phorbol 12-myristate 13-acetate plus A23187-stimulated mast cell line, HMC-1cells and ovalbumin (OVA)-induced AR models. OMC significantly decreased the releases of histamine and tryptase from stimulated HMC-1 cells. The degranulation process, characterized by morphological extension of the filopodia on the surface and membrane ruffling, was strongly induced in the stimulated-HMC-1 cell, however OMC suppressed the morphological changes in stimulated-HMC-1 cells. OMC reduced the production and mRNA expression of inflammatory cytokines. These inhibitory actions by OMC were dependent on the regulation of mitogen-activated protein kinases, nuclear factor-κB, and caspapase-1 signaling pathways. In the AR animal model, the increased rub scores and AR biomarkers (histamine and IgE) in ovalbumin (OVA)-sensitized mice were significantly reduced by the administration of OMC. Furthermore, eosinophils and mast cells infiltrations in nasal mucosa tissue were also blocked through the regulation of macrophage-inflammatory protein and intercellular adhesion molecule-1 levels. OMC showed the possibility to regulate AR in activated mast cells and OVA-induced AR models. Hence, we suggest that OMC is a powerful and feasible new agent to suppress AR.
    Life sciences 01/2014; · 2.56 Impact Factor
  • You Ah Kim, Hojun Kim, Youngwan Seo
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    ABSTRACT: Three flavonoids, luteolin (1), vitexicarpin (2) and artemetin (3), from the salt marsh plant Vitex rotundifolia, were tested for their anti-proliferative activities in AGS, MCF-7 and HT-29 human cancer cell lines and compared with the control using MTT assay. Among them, 2 was most effective with an IC50 of 6.9 and 22.8 microM against AGS and HT-29 cells, respectively. Inaddition, mRNA expression levels of major apoptosis-related genes such as p21, p53, Bcl-2 andBax in AGS cells were evaluated by reverse-transcription polymerase chain reaction (RT-PCR). Compound 2 not only enhanced most remarkably the expression level of tumor suppressor genes p53 and p21, and pro-apoptotic gene Bax at a concentration of 25 microM, but also suppressed the expression level of antiapoptotic gene Bcl-2 to 20% at the same concentration, thus shifting the Bax/Bcl-2 ratio in favor of apoptosis.
    Natural product communications 10/2013; 8(10):1405-8. · 0.96 Impact Factor
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    ABSTRACT: In the present study, methanolic extract of Ecklonia cava and its solvent-partitioned fractions were evaluated for their antiadipogenic effect in 3T3-L1 adipocytes. One of them, n-BuOH fraction, effectively reduced lipid accumulation and glucose consumption. In addition, the presence of n-BuOH fraction in adipocytes suppressed the regulations of adipogenic transcription factors, PPARγ and SREBP1c and adipogenic specific genes, FABP4, FABP1, FAS, LPL, HSL and ACS1. Further purification of n-BuOH fractions led to the isolation of six phlorotannins (1-6). The six phlorotannins effectively suppressed triglyceride accumulation Comparative analysis showed that lipid accumulation in adipocytes was dramatically attenuated in the presence of eckstolonol (4).
    Journal of Agricultural and Food Chemistry 08/2013; · 3.11 Impact Factor
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    ABSTRACT: The cytotoxicity of the brown alga Sargassum siliquastrum on human cancer cells (AGS, HT-29, HT-1080, and MCF-7) was investigated. Bioassay-guided fractionation of the crude extracts showed that the 85% aq. methanol (MeOH) fraction was the most toxic. Seven known meroterpenoids (1-7) were isolated from this cytotoxic fraction. Each compound was evaluated for its cytotoxic effect on human cancer cells. Compounds 1, 2, and 4 showed strong cytotoxicity against AGS, HT-29, and HT-1080 cell lines, with IC50 values ranging from 0.5 to 5.7 microg/mL.
    Natural product communications 04/2013; 8(4):431-2. · 0.96 Impact Factor
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    ABSTRACT: Ultraviolet-B (UVB) irradiation acts primarily on the epidermal basal cell layer of the skin, inducing harmful biological effects. In this study, we have investigated the effect of libanoridin isolated from Corydalis heterocarpa against UVB-induced damage in human keratinocyte (HaCaT) cells and the molecular mechanism underlying those effects. Treatment with libanoridin inhibited the cell cytotoxicity and LDH induced by UVB exposure at 40 mJ/cm(2) . Additionally, expression levels of type IV collagenases (MMP-2, MMP-9) were decreased by libanoridin. Furthermore, MMP tissue inhibitors were enhanced followed by treatment with libanoridin. Moreover, UVB-induced activation of phosphorylation of three MAPKs such as JNK, ERK, p38 and AP-1 transcription factor were decreased by treatment with libanoridin. Our present study demonstrates that libanoridin has the abilities to inhibit UVB-induced cellular damage via ASK1-MAPK and AP-1 signalling pathways. Therefore, libanoridin may be used as an effective natural compound to prevent skin damage due to UVB exposure.
    Experimental Dermatology 02/2013; 22(2):155-7. · 3.58 Impact Factor
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    ABSTRACT: A bacterium CGH18 exhibiting antioxidizing and chitin-degrading activities in the colloidal chitin culture medium was isolated from salt-fermented crab. This strain was identified as Bacillus idriensis based on 16S rDNA sequence homology search. Its crude extract was partitioned between n-BuOH and . The organic layer was further partitioned between and . Antioxidant activities of crude extract and its solvent fractions were evaluated using five different bioassay methods, including the degree of occurrence of intracellular reactive oxygen species (ROS), peroxynitrite scavenging (ONOO), and oxidative damage of genomic DNA. All fractions exhibited significant antioxidant activity in bioassay systems used.
    KSBB Journal. 01/2013; 28(4).
  • Ocean and Polar Research 12/2012; 34(4):385-394.
  • Chang-Suk Kong, Youngwan Seo
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    ABSTRACT: In the present study, effect of flavonoid glucopyranoside, isorhamnetin 3-О-β-D-glucopyranoside, from Salicornia herbacea on adipogenic differentiation were evaluated in 3T3-L1 adipocytes. Confluent 3T3-L1 preadipocytes in medium (0.5 mM methylisobutylxanthine, 0.25 µM dexamethasone, 5 µg/mL insulin, and 10% fetal bovine serum [FBS]) were differentiated into adipocytes for 6 days with/without isorhamnetin 3-О-β-D-glucopyranoside. The presence of isorhamnetin 3-О-β-D-glucopyranoside effectively suppressed adipogenic differentiation by downregulation of peroxisome proliferator-activated receptor-γ (PPARγ), CCAAT/enhancer-binding proteins (C/EBPα), sterol regulatory element-binding protein 1 (SREBP1), and the adipocyte-specific proteins. Moreover, the specific mechanism mediating the effects of isorhamnetin 3-О-β-D-glucopyranoside was confirmed by activation of AMP-activated protein kinase (AMPK). These findings suggest that isorhamnetin 3-О-β-D-glucopyranoside exerts antiadipogenic activity through AMPK activation. This study should find the nutraceutical value of S. herbacea-derived glucopyranoside, isorhamnetin 3-О-β-D-glucopyranoside, as potent candidate of antiobesity agent via alleviation of lipid accumulation.
    Immunopharmacology and Immunotoxicology 09/2012; · 1.36 Impact Factor
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    ABSTRACT: In the present study, the bioactivity-monitored isolation of flavonoid glucopyranosides from the salt-marsh plant Salicornia herbacea was performed, and their effects on adipogenic differentiation were evaluated in 3T3-L1 adipocytes. Among the solvent-partitioned fractions from S. herbacea, the 85% aq. MeOH and n-BuOH fractions effectively reduced the levels of triglyceride accumulation, glucose consumption and adipogenic transcription factor peroxisome proliferator-activated receptor-γ (PPARγ) expression. Further purification of the n-BuOH fraction led to the isolation of two flavonoid glucopyranosides, isorhamnetin 3-O-β-d-glucopyranoside (A) and quercetin 3-O-β-d-glucopyranoside (B), as the active principles. The presence of glucopyranosides A and B in adipocyte cells effectively suppressed adipogenic differentiation. Comparative analysis indicated that adipogenic differentiation was dramatically attenuated in the presence of glucopyranoside B rather than glucopyranoside A. The anti-adipogenic activity of glucopyranosides B was confirmed by down-regulation of sterol regulatory element-binding protein 1 (SREBP1), CCAAT/enhancer-binding proteins (C/EBPα), PPARγ and the adipocyte-specific proteins. Moreover, the specific mechanism mediating the effects of glucopyranosides B was confirmed by activation of AMP-activated protein kinase (AMPK). Findings from this study should underscore the nutraceutical value of S. herbacea-derived glucopyranosides as potent anti-obesity agents via alleviation of lipid accumulation.
    PROCESS BIOCHEMISTRY 07/2012; 47(7):1073–1078. · 2.41 Impact Factor
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    ABSTRACT: As a part of an ongoing search for novel antioxidants from the salt marsh plants, bioactivity-isolation and structure determination of constituents from Salicornia herbacea were performed. One new triterpenoid saponin (4), along with three known saponins (1-3), has been isolated from n-BuOH fraction of S. herbacea. On the basis of the spectroscopic methods, the structure of the new saponin 4 was elucidated as 3β-hydroxy-23-oxo-30-noroleana-12, 20(29)-diene-28-oic acid 3-O-β-D-glucuronopyranosyl-28-O-β-d-glucopyranoside. Scavenging effects of saponins 1-4 were examined on 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical and peroxynitrite. Particularly, saponin 3 exerted significant antioxidant activity on both authentic peroxynitrite and peroxynitrite generated from morpholinosydnonimine (SIN-1).
    Bioorganic & medicinal chemistry letters 05/2012; 22(13):4318-22. · 2.65 Impact Factor
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    ABSTRACT: A salt tolerant plant, Corydalis heterocarpa has been used as a folk medicine to treat travail and spasm. Recent studies have also reported antioxidant and antiinflammatory activities of compounds isolated from C. heterocarpa. In this study, the protective effect of (2'S)-columbianetin isolated from C. heterocarpa on UVB-induced human keratinocyte (HaCaT) damage was investigated. First, the appropriate energy level of UVB irradiation was determined using MTT and LDH assays. And then the protective effect of (2'S)-columbianetin on UVB induced HaCaT damage was evaluated by measuring; the changes in cell viability, LDH release level, ROS generation, cell cycle arrest and MMP expression levels. Finally, the effect of compound on MAPK and AP-1 signaling pathways were studied to understand the underlying signaling mechanisms. Result demonstrated that the presence of (2'S)-columbianetin suppressed the reactive oxygen species (ROS) generation, cell cycle arrest at sub-G1 phase and down regulation of MMP expression in UVB treated HaCaT cells. Furthermore, stress activated signaling pathways (ASK1-MAPK) and AP-1 signaling pathway were regulated by (2'S)-columbianetin treatment. These results suggest that (2'S)-columbianetin could be effectively used to protect human keratinocytes from UVB induced damage.
    Journal of photochemistry and photobiology. B, Biology 04/2012; 109:20-7. · 3.11 Impact Factor
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    Jung Im Lee, Youngwan Seo
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    ABSTRACT: Six meroterpenoids (compounds 1-6) of chromene class, including three known compounds (1-3), were isolated from Sargassum siliquastrum. The structure of these compounds was established by extensive 2D-NMR experiments such as (1)H gradient double quantum filtered correlation spectroscopy (gDQCOSY), total correlation spectroscopy (TOCSY), nuclear Overhauser effect spectroscopy (NOESY), gradient heteronuclear multiple quantum coherence (gHMQC), and gradient heteronuclear multiple bond correlation (gHMBC), and by comparison with published spectral data. The antioxidant activity of these compounds was evaluated by various antioxidant tests, such as scavenging effects on generation of intracellular reactive oxygen species (ROS), increments of intracellular glutathione (GSH) level, and inhibitory effects on lipid peroxidation in human fibrosarcoma HT 1080 cells. Compounds (1-6) significantly decreased generation of intracellular ROS and inhibited lipid peroxidation while they increased levels of intracellular GSH at a concentration of 5 µg/ml.
    Chemical & pharmaceutical bulletin 11/2011; 59(6):757-61. · 1.70 Impact Factor
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    ABSTRACT: In the present study, an attempt has been made to isolate antiobesity components from crude extracts of the flower buds of Magnolia denudata by CH(2)Cl(2) and MeOH solvents. The crude extracts were partitioned into n-hexane, 85% aqueous MeOH, n-butanol, and water fractions. Their antiobesity effects were evaluated by measuring the effect on adipogenic differentiation using 3T3-L1 cells. Among the fractions, n-hexane and 85% aqueous MeOH fractions effectively reduced the lipid accumulation and the regulation of the adipogenic transcription factor. Both n-hexane and 85% aqueous MeOH fractions were further separated by diverse chromatographic methods to give four lignans (A-D). In comparative analysis, the presence of the lignans during adipogenic differentiation reduced the absorbance values of eluted Oil Red O solution in the order of potency C > D > B > A. Moreover, C and D effectively downregulated SREBP1, PPARγ, and C/EBPα.
    Journal of Agricultural and Food Chemistry 04/2011; 59(10):5665-70. · 3.11 Impact Factor
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    ABSTRACT: In this study, the antioxidant potentials of crude extracts and solvent-partitioned fractions of Limonium tetragonum were assessed by measuring their ability to scavenge intracellular reactive oxygen species (ROS) generated in HT-1080 cells. Following activity-oriented separation, four flavonol glycosides were isolated as active principles and their chemical structures were determined by 2 D NMR and by comparison with reported spectral data. The isolated compounds (1–4) were evaluated for their antioxidant capacity using three different activity tests; degree of occurrence of intracellular ROS, lipid peroxidation in HT-1080 cells and the extent of oxidative damage of genomic DNA purified from HT-1080 cells. All compounds exhibited significantly inhibited the generation of intracellular ROS and lipid peroxidation in HT-1080 cells, and significantly inhibited DNA oxidation. In addition, direct free radical scavenging effects of these compounds were investigated using the electron spin resonance (ESR) spin-trap technique. Keywords Limonium tetragonum –antioxidant activity–reactive oxygen species–ESR
    Biotechnology and Bioprocess Engineering 01/2011; 16(5):992-999. · 1.28 Impact Factor
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    ABSTRACT: Crude extract and solvent-partitioned fraction of Glehnia littoralis were found to possess different anti-proliferative effects against AGS, HT1080 and U937 human cancer cells. The crude extracts and solvent fractions dose-dependently inhibited cell proliferation. Especially, n-hexane and 85% aqueous MeOH fractions exhibited comparatively higher anti-proliferative effects and reduced expressions of Bcl-2, COX-2 and iNOS genes. Systematic separation of all solvent fractions by chromatographic methods led to the isolation of three glucopyranosides, four furanocoumarins and two polyacetylenic alcohols. All the nine compounds were evaluated for their inhibitory effects against both proliferation of human cancer cells and expressions of MMP-2 and -9 in HT1080 cells. Two polyacetylenic alcohols exerted the highest inhibitory activity against both human cancer cell lines, and MMP-2 and -9. These results suggest that G. littoralis may possibly be used as a valuable chemopreventive agent or food supplement for reducing cancer risk.
    Food Chemistry. 01/2010; 120(2):385-394.
  • ChemInform 01/2010; 32(29).
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    ABSTRACT: In order to investigate the potential of Glehnia littoralis as a cancer chemopreventive food, antiproliferative effects of both its crude extracts and solvent-partitioned fractions (n-hexane, 85% aq. MeOH, n-BuOH, and water) were evaluated in HT-29 human colon cancer cells. Its crude extracts and solvent-partitioned fractions exhibited dose-dependent inhibitory effects on the cell proliferation. Especially, n-hexane and 85% aq. MeOH fractions exhibited a high antiproliferative effect, induced apoptosis as determined by 4,6-diamidino-2-phenylindole (DAPI) staining, and reduced mRNA expression of Bcl-2, cyclooxygenase (COX-2) and inducible nitric oxide synthase (iNOS). Systematic separation of n-hexane and 85% aq. MeOH fractions by diverse chromatographic methods led to the isolation of furanocoumarins (1–4) and polyacetylene alcohols (5–7). All compounds exhibited dose-dependent inhibitory effects on the cell proliferation. These results indicated that potent inhibitory activity of G. littoralis on proliferation of cancer cells can be significantly traceable to furanocoumarines and polyacetylenic alcohols contained in G. littoralis.
    Process Biochemistry. 01/2010; 45(1):114-119.
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 01/2010; 32(23).

Publication Stats

316 Citations
92.92 Total Impact Points


  • 2004–2014
    • Korea Maritime University
      • Division of Marine Environment and Bioscience
      Tsau-liang-hai, Busan, South Korea
  • 2013
    • National Fisheries Research and Development Institution
      Sŏul, Seoul, South Korea
  • 2011–2012
    • Silla University
      Tsau-liang-hai, Busan, South Korea
  • 2009
    • Pukyong National University
      • Marine Bioprocess Research Center
      Pusan, Busan, South Korea
  • 2005
    • Kyung Hee University
      • College of Oriental Medicine
      Seoul, Seoul, South Korea
    • Wonkwang University
      • College of Pharmacy
      Iksan, North Jeolla, South Korea
  • 2001
    • Hannam University
      • Department of Biological Sciences
      Sŏul, Seoul, South Korea
  • 1995
    • Ewha Womans University
      • College of Natural Sciences
      Sŏul, Seoul, South Korea