• 대한한의학방제학회지
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• 제28권3호
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• pp.255-269
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• 2020

Objectives : Hemistepta lyrata Bunge (Bunge) is a wild herb that has been used for managing fever and wound in Korean Traditional Medicine. The present study explored the effects of H. lyrata extract on liver X receptor (LXR) α-dependent lipogenic genes in hepatocyte-derived cells. Methods : After HepG2 cells or Huh7 cells were pre-treated with 1-10 ㎍/mL of H. lyrata extract or its fractionated extract for 0.5 h, the cells were subsequently exposed to LXR ligand for 6-24 h. Cell viability, LXR response element (LXRE)-driven luciferase activity, sterol regulatory element binding protein-response element (SREBP-RE)-driven luciferase activity, SREBP-1c expression, and mRNA levels of LXRα and its-dependent target genes were determined. In addition, LC-MS/MS analysis was conducted to explore major compounds in H. lyrata-chloroform fractionated extract #4 (HL-CF4). Results : Of various H. lyrata extracts tested, chloroform extract and its fractionated extract #4, HL-CF4, significantly decreased T0901317-mediated SREBP-1c expression. In addition, HL-CF4 significantly reduced LXRE atransactivation and LXRα mRNA expression without any cytotoxicity. Moreover, HL-CF4 prevented the SREBP-RE-driven luciferase activity and mRNA levels of fatty acid synthase and stearoyl-CoA desaturase-1 induced by T0901317. Results from LC-MS/MS analysis at positive/negative mode indicated that HL-CF4 contained several compounds showing m/z 197.1176 (C₁₁H₁₇O₃), 693.2913/227.1069 (C₃₈H₄₅O₁₂/C₁₅H₁₅O₂), 203.1797 (C₁₅H₂₃), 181.1225 (C₁₁H₁₇O₂), 591.2957 (C₃₅H₄₃O₈), 379.1040 (C₁₈H₁₉O₉), 409.1509 (C₂₀H₂₅O₉), 309.1348 (C₁₆H₂₁O₆), 391.1404 (C₂₀H₂₃O₈), and 669.2924/389.1248 (C₃₆H₄₅O₁₂/C₂₀H₂₁O₈). Conclusion : Based on its inhibition of the LXRα-dependent signaling pathway, H. lyrata chloroform extract and HL-CF4 have prophylactic potentials for managing non-alcoholic fatty liver.

• BMB Reports
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• 제44권6호
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• pp.399-404
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• 2011

In this study, powder of Orostachys japonicus A. Berger (O. japonicus) was extracted with 95% ethyl alcohol and fractionated using a series of organic solvents, including n-hexane (hexane), dichloromethane (DCM), ethylacetate (EtOAc), n-butanol (BuOH), and water ($H_2O$). We investigated the anti-inflammatory effects of these O. japonicus extracts on lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Their effects on the expression of inflammatory mediators and transcription factors were analyzed by Western blotting. DCM fraction significantly inhibited formation of reactive oxygen species (ROS) as well as nitric oxide (NO) in LPS-stimulated RAW 264.7 cells. Phosphorylation of the pro-inflammatory transcription factor complex nuclear factor-kappa B (NF-${\kappa}$B) p65 and expression of inducible nitric oxide synthase (iNOS), one of its downstream proteins, were also suppressed by DCM fraction. These effects were regulated by upsteam proteins in the mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase/Akt (PI3K/Akt) signaling pathways. Taken together, our data suggest that O. japonicus could be used as a potential source for anti-inflammatory agents.

• 대한한의학방제학회지
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• 제25권1호
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• pp.51-68
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• 2017

Objectives : Oxidative stress due to excessive accumulation of reactive oxygen species (ROS) is one of the risk factors for the development of several chronic diseases, including neurodegenerative diseases. Methods : In the present study, we investigated the protective effects of cheongnoemyeongsin-hwan (CNMSH) against oxidative stress‑induced cellular damage and elucidated the underlying mechanisms in neuronal-derived SH-SY5Y cells. Results : Our results revealed that treatment with CNMSH prior to hydrogen peroxide (H2O2) exposure significantly increased the SH-SY5Y cell viability, indicating that the exposure of the SH-SY5Y cells to CNMSH conferred a protective effect against oxidative stress. CNMSH also effectively attenuated H2O2‑induced comet tail formation, and decreased the phosphorylation levels of the histone ${\gamma}H2AX$, as well as the number of apoptotic bodies and Annexin V‑positive cells. In addition, CNMSH exhibited scavenging activity against intracellular ROS generation and restored the mitochondria membrane potential (MMP) loss that were induced by H2O2, suggesting that CNMSH prevents H2O2‑induced DNA damage and cell apoptosis. Moreover, H2O2 enhanced the cleavage of caspase-3 and degradation of poly (ADP-ribose)-polymerase, a typical substrate protein of activated caspase-3, as well as DNA fragmentation; however, these events were almost totally reversed by pretreatment with CNMSH. Furthermore, CNMSH increased the levels of heme oxygenase-1 (HO-1), which is a potent antioxidant enzyme, associated with the induction of nuclear factor-erythroid 2-related factor 2 (Nrf2). According to our data, CNMSH is able to protect SH-SY5Y cells from H2O2-induced apoptosis throughout blocking cellular damage related to oxidative stress through a mechanism that would affect ROS elimination and activating Nrf2/HO-1 signaling pathway. Conclusions : Therefore, we believed that CNMSH may potentially serve as an agent for the treatment and prevention of neurodegenerative diseases caused by oxidative stress.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2022년도 추계학술대회
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• pp.31-31
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• 2022

Plant-derived antioxidants are used as a healthy diet and are known to inhibit various human diseases. In this study, we investigated free radical scavenging and antioxidant activity of extracts from three plants (Ammannia multiflora, Ammannia coccinea and Salix gracilistyla) with the most DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity from 196 plant extracts inhabiting along Nakdong River in Republic of Korea. The three extracts also have strong total antioxidant activity. Moreover, the extracts inhibited hydrogen peroxide (H₂O₂)-induced reactive oxygen species production and depolarized mitochondrial membrane potential in RAW264.7 macrophages. In zebrafish larvae, 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) fluorescent intensity, induced by H₂O₂, was markedly reduced by the extracts of A. multiflora, A. coccinea and S. gracilistyla. Meanwhile, the extracts were upregulated Nrf2 and HO-1 expression, and an HO-1 inhibitor reversed the extract-induced oxidative responses both in vivo and in vitro. The data suggest that the extracts of A. multiflora, A. coccinea, and S. gracilistyla exert potential free radical scavenging and antioxidant capacities both in vivo and in vitro by activating the Nrf2/HO-1 signaling pathway.

• Journal of Microbiology and Biotechnology
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• 제18권2호
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• pp.270-282
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• 2008

The yeast Saccharomyces cerevisiae has defense mechanisms identical to higher eukaryotes. It offers the potential for genome-wide experimental approaches owing to its smaller genome size and the availability of the complete sequence. It therefore represents an ideal eukaryotic model for studying cellular redox control and oxidative stress responses. S. cerevisiae Yap1 is a well-known transcription factor that is required for $H_2O_2$-dependent stress responses. Yap1 is involved in various signaling pathways in an oxidative stress response. The Gpx3 (Orp1/PHGpx3) protein is one of the factors related to these signaling pathways. It plays the role of a transducer that transfers the hydroperoxide signal to Yap1. In this study, using extensive proteomic and bioinformatics analyses, the function of the Gpx3 protein in an adaptive response against oxidative stress was investigated in wild-type, gpx3-deletion mutant, and gpx3-deletion mutant overexpressing Gpx3 protein strains. We identified 30 proteins that are related to the Gpx3-dependent oxidative stress responses and 17 proteins that are changed in a Gpx3-dependent manner regardless of oxidative stress. As expected, $H_2O_2$-responsive Gpx3-dependent proteins include a number of antioxidants related with cell rescue and defense. In addition, they contain a variety of proteins related to energy and carbohydrate metabolism, transcription, and protein fate. Based upon the experimental results, it is suggested that Gpx3-dependent stress adaptive response includes the regulation of genes related to the capacity to detoxify oxidants and repair oxidative stress-induced damages affected by Yap1 as well as metabolism and protein fate independent from Yap1.

• Journal of Microbiology and Biotechnology
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• 제33권5호
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• pp.591-599
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• 2023

Fisetin is a bioactive flavonol molecule and has been shown to have antioxidant potential, but its efficacy has not been fully validated. The aim of the present study was to investigate the protective efficacy of fisetin on C2C12 murine myoblastjdusts under hydrogen peroxide (H₂O₂)-induced oxidative damage. The results revealed that fisetin significantly weakened H₂O₂-induced cell viability inhibition and DNA damage while blocking reactive oxygen species (ROS) generation. Fisetin also significantly alleviated cell cycle arrest by H₂O₂ treatment through by reversing the upregulation of p21WAF1/CIP1 expression and the downregulation of cyclin A and B levels. In addition, fisetin significantly blocked apoptosis induced by H₂O₂ through increasing the Bcl-2/Bax ratio and attenuating mitochondrial damage, which was accompanied by inactivation of caspase-3 and suppression of poly(ADP-ribose) polymerase cleavage. Furthermore, fisetin-induced nuclear translocation and phosphorylation of Nrf2 were related to the increased expression and activation of heme oxygenase-1 (HO-1) in H₂O₂-stimulated C2C12 myoblasts. However, the protective efficacy of fisetin on H₂O₂-mediated cytotoxicity, including cell cycle arrest, apoptosis and mitochondrial dysfunction, were greatly offset when HO-1 activity was artificially inhibited. Therefore, our results indicate that fisetin as an Nrf2 activator effectively abrogated oxidative stress-mediated damage in C2C12 myoblasts.

• 대한본초학회지
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• 제35권4호
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• pp.9-16
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• 2020

Objective : To identify the effects of the water extract of Liriope platyphylla tuber (Liriopis tuber, LT) on the activation of astocytes, we investigated the regulatory effects of LT extract on H₂O₂-induced oxidative damage in C6 rat astrocytes. Methods : LT extract was extracted with boiling water. C6 cell line were treated with LT extract at 1, 2, and 3 mg/㎖ or without for 30 min and then stimulated with H₂O₂ at 5 ㎛ for 24 hr. The cell viability was measured by MTT assay. The expression of glial fibrillary acidic protein (GFAP), signal transducer and activator of transcription 3 (STAT3), phospho-STAT3 (pSTAT3), cyclooxygenase (COX-2), Nuclear factor-κB (NF-κB), superoxide dismutase 2 (SOD2), heme oxygenase-1 (HO-1), catalase, Akt, phospho-Akt (p-Akt) phosphoinositide 3-kinases (PI3K), and protein kinase C alpha (PKCα) proteins were determined by Western blot, respectively. GFAP expression was also observed with immunocytochemistry under a fluorescence microscope. Results : LT extract induced cell proliferation in H₂O₂-stimulated C6 cells. LT extract significantly inhibited the expression of GFAP, NF-κB and COX-2 and increased the expression of HO-1 and the phosphorylation of STAT3 in H₂O₂-stimulated C6 cells. LT extract also significantly increased the phosphorylation of Akt and decreased the expression of PKCα in a dose-dependent manner in H₂O₂-stimulated C6 cells. Conclusions : LT extract can regulate H₂O₂-induced activation of astrocytes through inhibiting the expression of NF-κB, COX-2 and regulating Akt / HO-1, STAT3 or PKCα signaling pathway.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2005년도 국제학술심포지움 The 44th Annual Meeting of Korean Society for Life Science
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• pp.23-36
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• 2005

Bax, a mammalian pro-apoptotic member of the Bcl-2 family, induces cell death when expressed In yeast. To investigate whether .Bax expression can induce cell death in plant, we produced transgenic Arabidopsis plants that contained murine Bax cDNA under control of a glucocorticoid-inducible promoter. Transgenic plants treated with dexamethasone, a strong synthetic glucocorticoid, induced Bax accumulation and cell death, suggesting that some elements of cell death mechanism by Bax may be conserved among various orgarusms. Therefore, we developed novel yeast genetic system, and cloned several Plant Bax Inhibitors (PBIs). Here, we report the function of two PBIs In detail. PBIl is ascorbate peroxidase (sAPX). Fluorescence method of dihydrorhodamine123 oxidation revealed that expression of Bax in yeast cells generated reactive oxygen species (ROS), and which was greatly reduced by co-expression with sAPX. These results suggest that sAPX inhibits the generation of ROS by Bax, which in turn suppresses Bax-induced cell death in yeast. PBI2 encodes nucleoside diphosphate kinase (NDPK). ROS stress strongly induces the expression of the NDPK2 gene in Arabidopsis thaliana (AtNDPK2). Transgenic plants overexpressing AtNDPK2 have lower lovels of ROS than wildtype plants. Mutants lacking AtNDPK2 had higher levels of ROS than wildtype. H$_{2O2}$ treatment induced the phosphorylation of two endogenous proteins whose molecular weights suggested they are AtMPK3 and AtMPK6. In the absence of H2O2 treatment, phosphorylation of these proteins was slightly elevated in plants overexpressing AtNDPK2 but markedly decreased In the AtNDPK2 deletion mutant. Yeast two-hybrid and in vitro protein pull-down assays revealed that AtNDPK2 specifically interacts with AtMPK3 and AtMPK6. Furthermore, AtNDPK2 also enhances the MBP phosphorylation activity of AtMPK3 i'n vitro. Finally, constitutive overexpression of AtNDPK2 in Arabidopsis plants conferred an enhanced tolerance to multiple environmental stresses that elicit ROS accumulation In situ. Thus, AtNDPK2 appears to play a novel regulatory role in H2O2-mediated MAPK signaling in plants.

• The Korean Journal of Physiology and Pharmacology
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• 제24권6호
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• pp.473-479
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• 2020

Endothelial cell injury is a major contributor to cardiovascular diseases. The 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-Glucoside (TSG) contributes to alleviate human umbilical vein endothelial cells (HUVECs) injury through mechanisms still know a little. This study aims to clarify the TSG effects on gene expression (mRNA and microRNA) related to oxidative stress and endoplasmic reticulum stress induced by H₂O₂ in HUVECs. We found that TSG significantly reduced the death rate of cells and increased intracellular superoxide dismutase activity. At qRT-PCR, experimental data showed that TSG significantly counteracted the expressions of miR-9-5p, miR-16, miR-21, miR-29b, miR-145-5p, and miR-204-5p. Besides, TSG prevented the expression of ATF6 and CHOP increasing. In contrast, TSG promoted the expression of E2F1. In conclusion, our results point to the obvious protective effect of TSG on HUVECs injury induced by H₂O₂, and the mechanism may through miR16/ATF6/ E2F1 signaling pathway.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2011년도 임시총회 및 추계학술발표회
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• pp.14-14
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• 2011

Polyamines (putrescine, spermidine and spermine) play pivotal roles in plant defense to different abiotic and biotic stresses. In order to understand the function of ginseng spermidine synthase gene, a key gene involved in biosynthesis of polyamines, transgenic plant was generated in Arabidopsis. The transgenic plants exhibited high levels of polyamines compared to the untransformed control plants. We investigated the tolerance capacity of transgenic plants to abiotic stresses such as salinity and copper stress. In addition, transgenic plants also showed increased resistance against one of the important fungal pathogens of ginseng, the wilt causing Fusarium oxysporum and one of important bacteria, bacterial blight causing Pseudomonas syringae. However, an activity of the polyamine catabolic enzyme, diamine oxidase (DAO) was increased significantly in F. oxysporum and P. syringae infected transgenic plant. Polyamine catabolic enzymes which may trigger the hypersensitive response (HR) by producing hydrogen peroxide ($H_2O_2$) seem act as an inducer of PR proteins, peroxidase and phenyl ammonium lyase activity. The transgenic plants also contained higher antioxidant enzyme activities, less MDA and $H_2O_2$ under salt and copper stress than the wild type, implying it suffered from less injury. These results strongly suggest an important role of spermidine as a signaling regulator in stress signaling pathways, leading to build-up of stress tolerance mechanisms.