Myungsuk Kim

Apigenin isolated from Daphne genkwa Siebold et Zucc. inhibits 3T3-L1 preadipocyte differentiation through a modulation of mitotic clonal expansion.

AIMS Obesity develops when energy intake chronically exceeds total energy expenditure. We sought to assess whether the flavonoid-rich fraction of crude extracts from Daphne genkwa Siebold et Zuccarini (GFF) might inhibit adipogenesis of 3T3-L1 cells. MAIN METHODS Cell viability of 3T3-L1 preadipocytes was assessed by MTT assays, and lipid accumulation was measured by Oil Red O. Adipogenesis related factors were checked by Western blot analysis. Flow cytometry was used to analyze the mitotic cell cycle during the mitotic clonal expansion phase. KEY FINDINGS Among five flavonoids isolated from GFF, only apigenin potently inhibited the differentiation of 3T3-L1 cells. Apigenin reduced CCAAT/enhancer binding protein (C/EBP) α and peroxisome proliferator-activated receptor γ levels. Apigenin-treated 3T3-L1 cells failed to undergo clonal expansion during the early phase of adipocyte differentiation. Apigenin arrested cell cycle progression at the G0/G1 phase. This effect was associated with a marked decrease in cyclin D1 and cyclin-dependent kinase 4 expression, with the concomitant and sustained expression of p27(Kip1). In addition, apigenin inhibited the DNA-binding activity of C/EBPβ in differentiating 3T3-L1 cells by down-regulating the 35kDa isoform of C/EBPβ (liver-enriched activating protein) and up-regulating the expression of two different sets of C/EBP inhibitors: C/EBP homologous protein and the phospho-liver-enriched inhibitory protein isoform of C/EBPβ. SIGNIFICANCE These findings suggest that apigenin can prevent 3T3-L1 preadipocyte differentiation by the inhibition of the mitotic clonal expansion and the adipogenesis related factors and upregulation of the expression of multiple C/EBPβ inhibitors.

Youngiasides A and C Isolated from Youngia denticulatum Inhibit UVB-Induced MMP Expression and Promote Type I Procollagen Production via Repression of MAPK/AP-1/NF-κB and Activation of AMPK/Nrf2 in HaCaT Cells and Human Dermal Fibroblasts

This study investigated the effects of youngiaside A (YA), youngiaside C (YC), and Youngia denticulatum extract (YDE) on extrinsic aging and assessed its molecular mechanisms in UVB-irradiated HaCaT keratinocytes and human dermal fibroblasts (HDFs). The results showed that YA, YC, and YDE decreased matrix metalloproteinase (MMP) expression and production in HaCaT cell and HDFs and increased collagen expression and production in HDFs. In addition, YA, YC, and YDE significantly increased antioxidant enzyme expression, thereby down-regulating UVB-induced reactive oxygen species (ROS) production and ROS-induced mitogen-activated protein kinase (MAPK) and activator protein-1 (AP-1) signaling in HaCaT cells. Furthermore, YA, YC, and YDE reduced phosphorylation of IκBα and IKKα/β, blocked nuclear factor-κB (NF-κB) p65 nuclear translocation, and strongly suppressed pro-inflammatory mediators. Finally, YA, YC, and YDE augmented UVB-induced adenosine monophosphate activated protein kinase (AMPK) phosphorylation and YA and YC did not inhibit MMP-1 production in AMPK inhibitor or nuclear factor-erythroid 2-related factor-2 (Nrf2) siRNA-treated HaCaT cells. The results suggest that these compounds could be potential therapeutic agents for prevention and treatment of skin photoaging.

Aceriphyllum rossii Extract and Its Active Compounds, Quercetin and Kaempferol Inhibit IgE-mediated Mast Cell Activation and Passive Cutaneous Anaphylaxis

Aceriphyllum rossii contains an abundant source of natural flavonoids with potential antioxidant, anticancer and anti-inflammatory properties. However, the effect of A. rossii extract (ARE) on immunoglobulin E(IgE)-mediated allergic responses remains unknown. In the present study, the effects of ARE and its active compounds, quercetin and kaempferol, on IgE-mediated rat basophilic leukemia mast cell activation and passive cutaneous anaphylaxis (PCA) were investigated. ARE, quercetin, and kaempferol inhibited secretion of β-hexosaminidase and histamine, and reduced the production and mRNA expression of interleukin-4 and tumor necrosis factor-α. ARE also decreased the production of prostaglandin E2 and leukotriene B4 and expression of cyclooxygenase 2 and 5-lipoxygenase. Furthermore, ARE, quercetin, and kaempferol inhibited IgE-mediated phosphorylation of Syk, phospholipase Cγ, protein kinase C (PKC)μ, and the mitogen-activated protein kinases, extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinase. ARE, quercetin, and kaempferol markedly suppressed mast cell-dependent PCA in IgE-sensitized mice. These results indicate that ARE and its active constituents, quercetin and kaempferol, may be a useful therapy for immediate-type hypersensitivity.

Cassia tora Seed Extract and Its Active Compound Aurantio-obtusin Inhibit Allergic Responses in IgE-Mediated Mast Cells and Anaphylactic Models

Cassia tora seed is widely used due to its various biological properties including anticancer, antidiabetic, and anti-inflammatory effects. However, there has been no report of the effects of C. tora seed extract (CTE) on immunoglobulin E (IgE)-mediated allergic responses. In this research, we demonstrated the effects of CTE and its active compound aurantio-obtusin on IgE-sensitized allergic reactions in mast cells and passive cutaneous anaphylaxis (PCA). CTE and aurantio-obtusin suppressed degranulation, histamine production, and reactive oxygen species generation and inhibited the production and mRNA expression of tumor necrosis factor-α and interleukin-4. CTE and aurantio-obtusin also suppressed the prostaglandin E2 production and expression of cyclooxygenase 2. Furthermore, CTE and aurantio-obtusin suppressed IgE-mediated FcεRI signaling such as phosphorylation of Syk, protein kinase Cμ, phospholipase Cγ, and extracellular signal-regulated kinases. CTE and aurantio-obtusin blocked mast cell-dependent PCA in IgE-mediated mice. These results suggest that CTE and aurantio-obtusin are a beneficial treatment for allergy-related diseases.

Gnetin H isolated from Paeonia anomala inhibits FcεRI-mediated mast cell signaling and degranulation

ETHNOPHARMACOLOGICAL RELEVANCE Paeonia anomala L. is used in Mongolian traditional medicine to treat various diseases including indigestion, abdominal pain, kidney disorders, inflammation, and female diseases. In this study we examined the effects of Paeonia anomala extract (PAE) and compounds derived from Paeonia anomala on immunoglobulin E (IgE)-mediated type I hypersensitivity responses in vitro. MATERIALS AND METHODS Degranulation assay, reverse transcription PCR, enzyme-lined immunosorbent assays, western blot analyses were performed to measure allergic and proinflammatory mediators in IgE-stimulated rat basophilic leukemia (RBL)-2H3 mast cells treated with or without PAE or gnetin H. RESULTS Seventeen compounds were isolated, and β-hexosaminidase release from IgE-stimulated RBL-2H3 mast cells was measured. Of the seventeen isolated compounds, gnetin H, a resveratrol derivative, significantly inhibited β-hexosaminidase release from RBL-2H3 cells with an IC50 value of 0.3 μM. Notably, Gnetin H reduced β-hexosaminidase release at lower concentrations than resveratrol. Furthermore, PAE and gnetin H inhibited histamine secretion, decreased the production and mRNA expression of tumor necrosis factor-α and interleukin-4 and suppressed translocation of nuclear factor κB. PAE and gnetin H also reduced the expression of cyclooxygenase-2 and production of prostaglandin E2. PAE and gnetin H suppressed the phosphorylation of Syk, protein kinase C (PKC)μ, phospholipase Cγ, and the mitogen-activated protein kinases, c-Jun N-terminal kinase, p38, and extracellular signal-regulated kinase. CONCLUSIONS These results suggest that PAE and its active compound gnetin H could be promising therapeutic agents for allergic disorders.

Gomisin J Inhibits Oleic Acid-Induced Hepatic Lipogenesis by Activation of the AMPK-Dependent Pathway and Inhibition of the Hepatokine Fetuin-A in HepG2 Cells

The aim of our study is to investigate the molecular mechanism of gomisin J from Schisandra chinensis on the oleic acid (OA)-induced lipid accumulation in HepG2 cells. Gomisin J attenuated lipid accumulation in OA-induced HepG2 cells. It also suppressed the expression of lipogenic enzymes and inflammatory mediators and increased the expression of lipolytic enzymes in OA-induced HepG2 cells. Furthermore, the use of specific inhibitors and fetuin-A siRNA and liver kinase B1 (LKB1) siRNA transfected cells demonstrated that gomisin J regulated lipogenesis and lipolysis via inhibition of fetuin-A and activation of an AMP-activated protein kinase (AMPK)-dependent pathway in HepG2 cells. Our results showed that gomisin J suppressed lipid accumulation by regulating the expression of lipogenic and lipolytic enzymes and inflammatory molecules through activation of AMPK, LKB1, and Ca(2+)/calmodulin-dependent protein kinase II and inhibition of fetuin-A in HepG2 cells. This suggested that gomisin J has potential benefits in treating nonalcoholic fatty liver disease.

Stellera chamaejasme and its constituents induce cutaneous wound healing and anti-inflammatory activities.

Stellera chamaejasme L. (Thymelaeaceae) is a perennial herb that is widely used in traditional Chinese medicine to treat tumours, tuberculosis and psoriasis. S. chamaejasme extract (SCE) possesses anti-inflammatory, analgesic and wound healing activities; however, the effect of S. chamaejasme and its active compounds on cutaneous wound healing has not been investigated. We assessed full-thickness wounds of Sprague-Dawley (SD) rats and topically applied SCE for 2 weeks. In vitro studies were performed using HaCaT keratinocytes, Hs68 dermal fibroblasts and RAW 264.7 macrophages to determine cell viability (MTT assay), cell migration, collagen expression, nitric oxide (NO) production, prostaglandin E2 (PGE2) production, inflammatory cytokine expression and β-catenin activation. In vivo, wound size was reduced and epithelisation was improved in SCE-treated SD rats. In vitro, SCE and its active compounds induced keratinocyte migration by regulating the β-catenin, extracellular signal-regulated kinase and Akt signalling pathways. Furthermore, SCE and its active compounds increased mRNA expression of type I and III collagen in Hs68 fibroblasts. SCE and chamechromone inhibited NO and PGE2 release and mRNA expression of inflammatory mediators in RAW 264.7 macrophages. SCE enhances the motility of HaCaT keratinocytes and improves cutaneous wound healing in SD rats.

Effects of Hovenia dulcis Thunb. extract and methyl vanillate on atopic dermatitis‐like skin lesions and TNF‐α/IFN‐γ‐induced chemokines production in HaCaT cells

Here, we hypothesized that Hovenia dulcis branch extract (HDB) and its active constituents ameliorates 2,4‐dinitrochlorobenzene‐induced atopic dermatitis (AD)‐like skin lesions by modulating the T helper Th1/Th2 balance in NC/Nga mice and TNF‐α‐ and IFN‐γ‐induced production of thymus and activation‐regulated chemokine (TARC) and macrophage‐derived chemokine (MDC) in HaCaT cells.

Achillea asiatica extract and its active compounds induce cutaneous wound healing

ETHNOPHARMACOLOGICAL RELEVANCE Achillea asiatica Serg. is a perennial herb belonging to the Asteraceae family that has long been traditionally used to treat acute intestinal and stomach inflammation, persistent fever, ulcers, wounds, and rheumatism. AIM OF THE STUDY We investigated the effect of A. asiatica extract (AAE) on cutaneous wound healing. MATERIALS AND METHODS To assess the effect of AAE on wounds, an incisional Sprague-Dawley (SD) rat model was topically treated with AAE for 2 weeks. HaCaT keratinocytes, Hs68 dermal fibroblasts, and RAW 264.7 macrophages were used for in vitro experiments. After treatment with AAE, cell viability, cell migration, and production of nitric oxide (NO) and prostaglandin E2 (PGE2) were investigated. mRNA expression of collagen type I and III and inflammatory cytokines was measured by RT-PCR. The effect of AAE on activation of β-catenin and other markers was determined by Western blot analysis. RESULTS AAE treatment significantly increased epithelialization and accelerated wound healing in SD rats. Meanwhile, AAE and its active compounds reduced NO and PGE2 release and mRNA expression of inflammatory cytokines in RAW 264.7 macrophages, reflecting anti-inflammatory activity. Furthermore, AAE and its constituents stimulated collagen expression in Hs68 fibroblasts by activating transforming growth factor-β and stimulated keratinocyte differentiation and motility by inducing β-catenin, Akt, and keratinocyte differentiation markers. CONCLUSIONS AAE improves skin wounds in SD rats and supports keratinocyte development.

Chicoric acid attenuate a nonalcoholic steatohepatitis by inhibiting key regulators of lipid metabolism, fibrosis, oxidation and inflammation in mice with methionine and choline deficiency

Scope: Nonalcoholic fatty liver diseases (NAFLD) range histopathologically from hepatic steatosis to steatohepatitis. Chicoric acid has beneficial effects on obesity and liver injury, but its effects on nonalcoholic steatohepatitis (NASH) have not yet been determined. This study examined the effects of Crepidiastrum denticulatum extract (CDE) and its active compound chicoric acid in a mouse model of NASH and fibrosis. Methods: CDE and chicoric acid were orally administrated to mice fed a methionine‐ and choline‐deficient (MCD) diet. HepG2 and AML‐12 cells in MCD medium were incubated with chicoric acid. MCD‐fed mice developed the histopathological characteristics of human NASH, including altered regulation of lipid metabolism, inflammation, fibrosis, and oxidation‐associated expression, along with augmented lipoperoxidation. Administration of CDE or chicoric acid to MCD‐fed mice and HepG2 and AML‐12 cells in MCD medium reduced oxidative stress by upregulating antioxidant enzymes and decreased inflammation by inhibiting proinflammatory cytokines and nuclear factor‐κB activation. In addition, CDE or chicoric acid reduced fibrosis, apoptosis, and lipogenesis‐related gene expression and increased AMP Kinase activation both in vivo and in vitro. Conclusions: CDE and chicoric acid may be effective in the treatment of NAFLD and NASH.