• Korean Journal of Food Science and Technology
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• v.51 no.1
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• pp.81-89
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• 2019

This study was performed to confirm the influence of chlorogenic acid (CGA) and 3,5-dicaffeyolquinic acid (3,5-diCQA) intake on problems caused by high-fat diet. CGA was more effective in suppressing weight gain than 3,5-diCQA. In contrast, 3,5-diCQA was more effective in improving glucose tolerance than CGA. In the biopsy, it was confirmed that CGA inhibited visceral fat and liver fat accumulation. 3,5-diCQA also inhibited visceral fat accumulation, but 3,5-diCQA increased liver fat accumulation. The liver fat accumulation induced oxidative stress, but 3,5-diCQA reduced oxidative damage through its antioxidant activity. The increased liver fat accumulation was because a 3,5-diCQA greatly increased Akt phosphorylation and decreased AMPK phosphorylation in the liver. Consequently, CGA was effective in alleviating the problems caused by high-fat diets, while maintaining normal balance. 3,5-diCQA also showed a positive effect on problems caused by high-fat diets, but it increased liver fat accumulation and thereby had negative consequences.

• Journal of Life Science
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• v.28 no.10
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• pp.1233-1243
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• 2018

Sterol regulatory-element binding proteins (SREBPs) are a family of transcription factors that regulate lipid homeostasis and metabolism by controlling the expression of enzymes required for endogenous cholesterol, fatty acid (FA), triacylglycerol, and phospholipid synthesis. The three SREBPs are encoded by two different genes. The SREBP1 gene gives rise to SREBP-1a and SREBP-1c, which are derived from utilization of alternate promoters that yield transcripts in which distinct first exons are spliced to a common second exon. SREBP-2 is derived from a separate gene. Additionally, SREBPs are implicated in numerous pathogenic processes, such as endoplasmic reticulum stress, inflammation, autophagy, and apoptosis. They also contribute to obesity, dyslipidemia, diabetes mellitus, and nonalcoholic fatty liver diseases. Genome-wide analyses have revealed that these versatile transcription factors act as important nodes of biological signaling networks. Changes in cell metabolism and growth are reciprocally linked through SREBPs. Anabolic and growth signaling pathways branch off and connect to multiple steps of SREBP activation and form complex regulatory networks. SREBPs are activated through the PI3K-Akt-mTOR pathway in these processes, but the molecular mechanism remains to be understood. This review aims to provide a comprehensive understanding of the role of SREBPs in physiology and pathophysiology at the cell, organ, and organism levels.

• The Korean Journal of Mycology
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• v.46 no.2
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• pp.161-176
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• 2018

Fungal ${\beta}$-glucan, known to have immunostimulatory and antitumor activities, can be recognized by host immune cells as one of the pathogen-associated molecular patterns (PAMPs). Although there are several reports on the diverse immunostimulatory activities of ${\beta}$-glucan, little is known about the intracellular signal transduction of ${\beta}$-glucan. Stimulation of RAW264.7 macrophage cells with ${\beta}$-glucan from Ganoderma lucidum induced the expressions of dectin-1, toll-like receptor 2 (TLR2), TLR4, and TLR6 at the transcription stage. Treatment with ${\beta}$-glucan also induced inflammatory mediators such as macrophage inflammatory proteins (MIP)-$1{\alpha}$, MIP-$1{\beta}$, MIP-$1{\gamma}$, interleukin (IL)-$1{\beta}$, and tumor necrosis factor (TNF)-${\alpha}$. Treatment of the cells with polymyxin B, an inhibitor of lipopolysaccharides (LPS), blocked the induction of inflammatory mediators in LPS- or ${\beta}$-glucan-stimulated systems. Pretreatment of the cells in our cell culture system with LY294002, a phosphoinositide 3-kinase (PI3K) inhibitor, or U0126, a mitogen-activated protein kinase/extracellular-signal-regulated kinase (MAPK/ERK) kinase (MEK)1/MEK2 inhibitor, led to a reduction in the induction of inflammatory mediators in a concentration-dependent manner. These results show that stimulation of the macrophage cells by ${\beta}$-glucan induced the expressions of both dectin-1 and TLRs. We also found that the PI3K/Akt and MEK pathways were involved in the induction of inflammatory mediators in macrophage cells during intracellular signal transduction of ${\beta}$-glucan.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.122-127
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• 2023

Cardiovascular disease (CVD) is increasingly increasing as the main cause of death worldwide, and activation of platelet in vascular damage is one of the important causes of CVD. In recent, there is a growing interest in anti-thrombotic materials through platelet suppression, and efforts are being made to reduce side effects by using natural bioactive compounds. Known as one of the Flavonoids, hydroxygenkwanin (HGK) is a purified substance in Daphne Genkwa, which is known to have antibacterial, anti-inflammatory and anti-cancer effects, and has been reported to serve as an inhibitor of tissue factor that prevents thrombosis, but its anti-platelet effects and the action mechanisms is not known. In this study, we confirmed that the effects of HGK on the collagen-induced human platelets activation. HGK suppressed phosphorylation of PI3K/AKT and mitogen-activated protein kinases during platelet signaling, and reduced granule secretion in platelets such as ATP and serotonin. In addition, HGK inhibited the phosphorylation of cPLA₂ and strongly undermined the production of TXA₂, which is a powerful aggregation amplifier. As a result, the platelet aggregation derived by Collagen, a cohesive induced substance, was strongly suppressed by HGK to an IC₅₀ of 86.36 µM. Therefore, HGK might be worth the antithrombotic substance that inhibits the activation and aggregation of human platelets that occur through blood vessel damage.

• Korean Journal of Food Science and Technology
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• v.52 no.1
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• pp.81-88
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• 2020

The biological activities of Platycodon grandiflorum (PG) root extracts have been studied intensively, whereas there are limited number of studies on PG seed extract (PGSE). PGSE was prepared by ethanol extraction, and its antidiabetic effect was evaluated in mice with type 2 diabetes (C57BLKS/J-db/db). Results indicated that the administration of high-dose PGSE (600 mg/kg, wb) significantly stabilized the blood glucose levels, as evidenced by the results of the oral glucose tolerance test. Mice treated with high-dose PGSE exhibited significantly lower serum hemoglobin A1c, insulin, and leptin levels after eight weeks of feeding trial (p<0.05). High-dose PGSE administration significantly improved glucose uptake in the femoral muscle of db/db mice by activating both IRS-1/PI3K/AKT/AS160 and AMPK phosphorylation pathways. GLUT4 translocation from the cytosol to the plasma membrane increased 1.7-fold in the PGSE high-dose group. These results suggest that PGSE has potential for development as an antidiabetic agent.

• The Korean Journal of Mycology
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• v.48 no.1
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• pp.1-13
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• 2020

Mushrooms have been extensively used as traditional medicines to treat cancer and inflammatory diseases. In this study, we examined whether Trametes cubensis extract (TCE) exerted beneficial effects on cardiovascular function. First, we demonstrated that TCE was non-cytotoxic and enhanced cell proliferation of bovine aortic endothelial cells (BAEC). Moreover, TCE induced cell migration and blocked lipopolysaccharide-induced adhesion of monocytes to BAEC. We performed a variety of cell signaling studies, showing that TCE activates p38 MAPK and generates reactive oxygen species (ROS). Our results showed that TCE-induced vascular functions were mediated by p38 MAPK, but not by ROS. These results provide insights into bio-medical applications of TCE as a preventive or therapeutic agent for treating cardiovascular diseases including atherosclerosis.

• YAKHAK HOEJI
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• v.51 no.6
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• pp.482-489
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• 2007

Kaempferitrin, isolated from Kenaf (Hibiscus cannabinus), was examined to evaluate its modulatory effects on antigen-presenting cell functions of macrophages/monocytes such as phagocytosis of foreign materials, up-regulation of costimulatory molecules (CD40, CD80 and CD86), adhesion molecule activation, and antigen processing and presentation. Kaempferitrin strongly blocked up-regulation of CD40, CD80 and CD86, but not pattern recognition receptor (PRR) (e.g., TLR2). It also suppressed functional activation of CD29 (${\beta}1$-integrins), as assessed by cell-cell adhesion assay, required for T cell-antigen-presenting cell (APC) interaction. Furthermore, this compound did not block a simple activation of CD29, as assessed by cell-fibronectin adhesion assay. However, the compound did not diminish phagocytic uptake, an initial step for antigen processing, and ROS generation in RAW264.7 cells. In particular, to understand molecular mechanism of kaempferitrin-mediated inhibition, the regulatory role of LPS-induced signaling events was examined using immunoblotting analysis. Interestingly, this compound dose dependently suppressed the phosphorylation of $I{\kappa}B{\alpha}$, Src, Akt and Syk, demonstrating that it can negatively modulate the activation of these signaling enzymes. Therefore, our data suggested that kaempferitrin may be involved in regulating APC function-relevant immune responses of macrophages and monocytes by regulating intracellular signaling.

• Journal of Life Science
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• v.21 no.9
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• pp.1234-1243
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• 2011

Liriope platyphylla has been used in oriental medicine as an effective medical plant to improve symptoms of cough, sputum production, neurodegenerative disorders, obesity and diabetes for long time. In order to investigate the effects of novel extracts on nerve growth factors (NGF)-stimulated neuritic outgrowth, the alteration of NGF expression and NGF receptor signaling pathway were detected in neuroblastoma cells and C57BL/6 mice. Of a total of 13 novel extracts, 4 extracts (LP-E, LP-M, LP-M50, LP2E17PJ) showed high viability on MTT assay. Also, all of these extracts induced NGF secretion and NGF mRNA expression in neuroblastoma cells. However, the NGF-induced neuritic outgrowth from PC12 cells was only stimulated by LP-E, LP-M and LP-M50. Furthermore, we selected LP-M as a best candidate, based on method and amounts of extraction, in order to verify its effect in mice. C57BL/6 mice were treated with 50 mg/kg of LP-M for 2 weeks and the effects on NGF regulation were analyzed with various methods. The expression of NGF mRNA was significantly increased in LP-M treated mice compared to vehicle treated mice. Also, the signaling pathway of p75NTR was inhibited in the cortex by LP-M treatment, with no change in the hippocampus of brain. However, the signaling pathway of TrkA was dramatically activated in only hippocampus via LP-M treatment. Therefore, these results suggest that the novel four extracts of L. platyphylla may contribute to the regulation of NGF expression and secretion in neuronal cells. LP-M was especially considered to be an excellent candidate for a neurodegenerative disease-therapeutic drug.

• Clinical and Experimental Pediatrics
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• v.52 no.2
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• pp.213-219
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• 2009

Purpose:Iron is a critical nutritional element that is essential for a variety of important biological processes, including cell growth and differentiation, electron transfer reactions, and oxygen transport, activation, and detoxification. Iron is also required for neoplastic cell growth due to its catalytic effects on the formation of hydroxyl radicals, suppression of host defense cell activities, and promotion of cancer cell multiplication. Chronic transfusion-dependent patients receiving chemotherapy may have iron overload, which requires iron-chelating therapy. We performed this study to demonstrate whether the iron chelating agent deferoxamine induces apoptosis in Saos-2 osteosarcoma cells, and to investigate the underlying apoptotic mechanism. Methods:To analyze the apoptotic effects of an iron chelator, cultured Saos-2 cells were treated with deferoxamine. We analyzed cell survival by trypan blue and crystal violet analysis, apoptosis by nuclear condensation, DNA fragmentation, and cell cycle analysis, and the expression of apoptotic related proteins by Western immunoblot analysis. Results:Deferoxamine inhibited the growth of Saos-2 cell in a time- and dose-dependent manner. The major mechanism for growth inhibition with the deferoxamine treatment was by the induction of apoptosis, which was supported by nuclear staining, DNA fragmentation analysis, and flow cytometric analysis. Furthermore, bcl-2 expression decreased, while bax, caspase-3, caspase-9, and PARP expression increased in Saos-2 cells treated with deferoxamine. Conclusion:These results demonstrated that the iron chelating agent deferoxamine induced growth inhibition and mitochondrial-dependent apoptosis in osteosarcoma Saos-2 cells, suggesting that iron chelating agents used in controlling neoplastic cell fate can be potentially developed as an adjuvant agent enhancing the anti-tumor effect for the treatment of osteosarcoma.

• Korean Journal of Food Science and Technology
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• v.53 no.4
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• pp.423-433
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• 2021

This study was performed to examine the neuroprotective effect of the ethyl acetate fraction from Eucommia ulmoides oliver leaf (EFEL) on PM_2.5-induced cytotoxicity. EFEL had higher total phenolic and flavonoid contents than the other fractions. In ABTS and DPPH radical scavenging activities, the IC₅₀ of EFEL was measured as 212.80 and 359.13 ㎍/mL, respectively. To investigate the neuroprotective effect of EFEL, MTT and DCF-DA assays were performed on HT22, MC-IXC, and BV-2 cells. EFEL effectively decreased PM_2.5-induced intercellular reactive oxygen species (ROS) content and inhibited PM_2.5-induced cell death. In the results of protein expression related to cellular cytotoxicity on microglial cells (BV-2), EFEL had an improvement effect on cell apoptosis and inflammatory pathways. Rutin and chlorogenic acid were identified as the main physiological compounds. Moreover, it was expected that EFEL, including rutin and chlorogenic acid, could be functional food substances with neuroprotective effects against PM_2.5-induced oxidative stress.