Publications by authors named "Won-Keun Oh"

As part of our ongoing research on new anti-diabetic compounds from ethnopharmacologically consumed plants, two previously undescribed lupane-type triterpenoids ( and ) with dicarboxylic groups, an undescribed nor-taraxastane-type triterpenoid (), and 14 known compounds (-) were isolated from the leaves of . Extensive spectroscopic analysis (IR, HRESIMS, 1D, and 2D NMR) was used for structure elucidation, while the known compounds were compared to reference data reported in the scientific literature. All the isolates (-) were evaluated for their inhibitory effects on the protein tyrosine phosphatase 1B (PTP1B) enzyme.

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During the search for protein tyrosine phosphatase 1B (PTP1B) inhibitory compounds from the natural resources, two new serratane triterpenes, 3-O-dihydro-p-coumaroyltohogenol (1) and 21-O-acetyltohogenol (2), along with four known serratane triterpenes (3-6), were isolated from the whole plant of Huperzia serrata. The chemical structures of compounds 1 and 2 were determined by NMR study, HRMS analysis, and chemical modification. All isolates were evaluated for their PTP1B inhibitory activities.

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Article Synopsis
  • * The synthesis of compounds involved a Diels-Alder reaction guided by biomimetic studies, leading to the creation of various unnatural chalcone-monoterpene derivatives.
  • * Some compounds demonstrated significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), suggesting their potential use as antidiabetic agents due to the enzyme inhibition.
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The isolation of previously undescribed 12 compounds from the MeOH extract of Jacobaea vulgaris whole plants is disclosed, comprising 11 dihydrostilbenes (1-11) and one flavanone (12), and eight known compounds (six flavonoids, one dihydrostilbene, and one caffeoylquinic acid). Structural elucidation employed spectroscopic methods, including 1D and 2D NMR spectroscopy, HRESIMS, and ECD calculations. Evaluation of the compounds' effects on PCSK9 and LDLR mRNA expression revealed that compounds 1 and 3 downregulated PCSK9 mRNA while increasing LDLR mRNA expression, suggesting potential cholesterol-lowering properties.

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Article Synopsis
  • The plant studied has a long history of use in cooking and medicine, and shows potential for antioxidant and anti-inflammatory benefits.
  • A metabolomic analysis identified ten compounds, including one new flavonoid and nine known compounds, that were isolated through advanced NMR techniques.
  • The research found that --feruloyltyramine is particularly effective at inhibiting markers associated with aging-related cellular processes, highlighting the plant's potential for developing treatments for age-related diseases.
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Mill. (Lauraceae), commonly known as avocado, is a well-known food because of its nutrition and health benefits. The seeds of avocado are major byproducts, and thus their phytochemicals and bioactivities have been of interest for study.

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Autophagy is a crucial process for maintaining cellular homeostasis by degrading and recycling unnecessary or damaged cellular components. In the process of exploring autophagy regulators in plants, unique nine oligomeric flavonoids linked by the bonding of C-3 and C-4, consisting of three pairs of biflavonoids, linderanidins A-C [(+)-1/(-)-1, (+)-2/(-)-2, and (+)-3/(-)-3], and three trimeric A-type proanthocyanidins, linderanidins D-F (4-6), were isolated from the roots of Lindera erythrocarpa. The structures and absolute configurations of these compounds were determined using various techniques, such as 1D and 2D NMR, mass spectrometry, X-ray crystallography, and electronic circular dichroism.

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Article Synopsis
  • Irritant contact dermatitis (ICD) is a skin inflammation caused by irritants like soap, while the herbal medicine HJ is known for its anti-inflammatory, antimicrobial, and antioxidant properties.
  • A study tested the effect of HJ and its key compound, luteolin, on ICD using mice and specific immune cells, finding that both reduced symptoms of dermatitis and inflammation.
  • Results showed that HJ and luteolin decreased inflammation-related gene expression, suggesting that HJ could be an effective treatment for ICD by suppressing inflammatory responses.
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Seven undescribed compounds, dentipellinones A‒D (1, 2, 5, and 6), dentipellinol (3), methoxyerinaceolactone B (4), and erinaceolactomer A (7), were isolated from the culture broth of Dentipellis fragilis. Chemical structures of these isolated compounds were determined by analyses of 1D and 2D-NMR and MS data in comparison with data reported in the literature. Absolute configurations of 1‒7 were also determined by Electronic Circular Dichroism calculations.

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While screening senotherapeutics from natural products, seven undescribed chemicals, two syringylglycerol derivatives, two cyclopeptides, one tigliane analogue, and two chromone derivatives, as well as six known compounds were isolated from the stems of Limacia scandens. The structures of compounds were elucidated through spectroscopic data analysis, including 1D and 2D NMR, HRESIMS, and CD data. All compounds were tested in replicative senescent human dermal fibroblasts (HDFs) to determine their potential as senotherapeutic agents to specifically target senescent cells.

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Phenols are significant environmental endocrine disruptors that can have adverse health effects on exposed individuals. Correlating phenol exposure to potential health implications requires the development of a comprehensive and sensitive analytical method capable of analyzing multiple phenols in a single sample preparation and analytical run. Currently, no such method is available for multiple classes of phenols due to electrospray ionization (ESI) limitations in concurrent ionization and lack of sensitivity to certain phenols, particularly alkylphenols.

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Three different medicinal plants that consisted of the formulated mixture (CAVAC-1901) have been traditionally used for distinct medicinal purposes in different areas. Angelica dahurica has been used as an important ingredient of a prescription, Gumiganghwal-tang, for the common cold and influenza. Curcuma longa has been utilized for the treatment of asthma, and jaundice.

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Natural guanidines, molecules that contain the guanidine moiety, are structurally unique and often exhibit potent biological activities. A phytochemical investigation of the leaves of Alchornea rugosa (Lour.) Müll.

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Chemical investigation of the plant Gymnema latifolium led to the isolation of seven undescribed 23-glycosyl oleanane triterpenoids, gymlatinosides GLF1-GLF7, and two known compounds, gymnemosides D and E. The structures of the isolated compounds were elucidated using diverse spectroscopic methods. The extract of G.

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is traditionally used to treat depression and affective disorders in Malaysia. The chemical compositions have been reported to include bisbenzylisoquinoline and aporphine-type alkaloids in the genus Lour., but studies on the components of have rarely been reported.

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Ten phenolic constituents, including three new macrocyclic glycosides (-), a new phenolic glycoside (), a new biphenyl glycoside (), and five known compounds (, -), were isolated from a 70% MeOH extract of the leaves of by liquid chromatography-tandem mass spectrometry (LC-MS/MS)-guided molecular networking. The chemical structures of new compounds -, and were established based on comprehensive spectroscopic data analysis, including 1D and 2D NMR and HRESIMS techniques. All isolated compounds (-) were evaluated for their stimulation of glucose uptake in differentiated 3T3-L1 adipocytes using 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-d-glucose (2-NBDG) as a fluorescent glucose analog.

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Melicoptelines, natural cyclopeptides containing a 3a-hydroxy hexahydropyrrolo[2,3-]indole (HPI) moiety, exhibit anti-influenza activity. Herein, we report the first total synthesis of melicoptelines C-E (, respectively). The core 3a-hydroxy HPIs were synthesized in a diastereoselective manner from l-tryptophan using dimethyldioxirane-mediated oxidation.

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Background: Neuroinflammation plays an important role in cognitive decline and memory impairment in neurodegenerative disorders. Previously, we demonstrated that Humulus japonicus (HJ) has anti-inflammatory effects in rodent models of Alzheimer's disease and Parkinson's disease. The present study aimed to examine the protective potential of HJ extracts against lipopolysaccharide (LPS)-induced cognitive impairment and scopolamine-induced amnesia in mouse models.

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Although several vaccines and antiviral drugs against SARS-CoV-2 are currently available, control and prevention of COVID-19 through these interventions is limited due to inaccessibility and economic issues in some regions and countries. Moreover, incomplete viral clearance by ineffective therapeutics may lead to rapid genetic evolution, resulting in the emergence of new SARS-CoV-2 variants that may escape the host immune system as well as currently available COVID-19 vaccines. Here, we report that phytochemicals extracted from Chlorella spp.

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Two undescribed sesquiterpene lactone-proaporphine hybrid skeletons, two undescribed sesquiterpenes, and four known compounds were isolated from the aerial part of Magnolia grandiflora L. The structures of isolated compounds were unambiguously determined based on the interpretation of a combination of NMR spectroscopy, HRESIMS, DP4+ probability calculation of carbon data, X-ray crystallographic analyses, and ECD calculation. The isolated compounds were investigated for their anti-inflammatory activity against nitric oxide production and the protein expression of COX-2 in LPS-stimulated RAW 264.

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Background: Cancer is a representative geriatric disease closely related to senescent cells and cell aging in tissues. Senescent cells that surround cancer tissues reduce the effects of various cancer treatments and induce cancer recurrence through senescence-associated secretory phenotype (SASP) secretion. Thus, for good therapeutic effect, candidate drugs should be selective for both cancer and senescent cells.

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Emerging evidence indicates that the accretion of senescent cells is linked to metabolic disorders. However, the underlying mechanisms and metabolic consequences of cellular senescence in obesity remain obscure. In this study, we found that obese adipocytes are senescence-susceptible cells accompanied with genome instability.

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Human lung organoids (hLOs) are useful for disease modelling and drug screening. However, a lack of immune cells in hLOs limits the recapitulation of in vivo cellular physiology. Here, we generated hLOs containing alveolar macrophage (AMφ)-like cells derived from pluripotent stem cells (PSC).

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Microbial cocultivation has been applied as a strategy to induce the biosynthesis of specialized metabolites. However, most previous studies have focused on competitive interactions between test strains. During our LC-MS-based chemical screening of randomized cocultures of Basidiomycetous fungi, we discovered that the coculture of (Hymenochaetaceae) and (Schizoporaceae) induces multiple metabolites, although they did not show any competitive morphology.

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