• Title/Summary/Keyword: phase II enzyme

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The Effect of Korean Red Ginseng Water-extract on Aging-related Changes in the Xenobiotic Metabolizing Enzyme System in the Liver of Rats (홍삼의 물추출물이 노화에 따른 흰쥐 간의 이물질대사 효소계에 미치는 영향)

  • Lee, Dong-Wook;Lim, Heung-Bin
    • Korean Journal of Medicinal Crop Science
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    • v.14 no.6
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    • pp.329-335
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    • 2006
  • The present study was designed to investigate aging-related effects on the activities of xenobiotic metabolizing enzymes of rat liver by dietary supplementation of Korean red ginseng water-extract. Rat did not show any discernible signs of the rejection symptoms, and blood GOT and GPT levels were not influenced by ginseng water extracts, Cytochrome 450 levels and NADPH cytochrome P45O reductase, p-450 dependent ethoxycoumarin O-deethylase, and benzphetamine N-demethylase activities were decreased with aging, however, these phase I system enzymes activities in the ginseng group of24 months were well maintained compared with normal group. But, Levels of cytochrome bs and NADH-cytochrome b$_5$ reductase activities were also decreased with aging and were not found a clear difference between two groups. Glutathione-s-transferase activity, phase II enzyme system, in liver cytosols was also decreased in old ages, but the degree of decrease was higher in normal group than in giuseng supplemented group. These results indicate that long-term supplementation of red ginseng water extracts from weaning to 24 months do not show any side effects to rats, and retard age-related deteriorations of xenobiotic metabolizing enzymes activities in old ages.

Effect of Cnidii Rhizoma Water Extract on Chemopreventive Enzymes for Hepatocarcinoma (천궁 물추출물이 간암예방효소계에 미치는 영향)

  • Shon, Yun-Hee;Kim, Han-Gyu;Nam, Kyung-Soo
    • Korean Journal of Pharmacognosy
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    • v.34 no.4 s.135
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    • pp.297-302
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    • 2003
  • Cnidii Rhizoma water extract (CRW) was tested for liver cancer chemopreventive potential by measuring the inhibition of phase I enzyme and benzo[a]pyrene-DNA adduct formation and induction of phase II detoxification enzymes. There was 17.0% inhibition in the activity of cytochrome P450 1A1 enzyme with the treatment of 150 mg/ml CRW. At concentration of 30 mg/ml CRW, the binding of $[^3H]B[a]P$ metablites to DNA of NCTC-clone 1469 cell was inhibited by 33.3%. CRW was potent inducer of quinone reductase (QR) and glutathione S-transferase (GST) activities in cultured murine hepatoma Hepalc1c7 cells. However, hepatic glutathione (GSH) level was not influenced by CRW. These findings suggest that CRW has chemopreventive potential of liver cancer by inhibiting cytochrome P450 1A1 activity and benzo[a]pyrene-DNA adduct formation and inducing QR and GST activities.

RTP1, a Rat Homologue of Adenovirus ElA-associated Protein BS69, Interacts with DNA Topoisomerase II

  • Oh, Misook;Rha, Geun-Bae;Yoon, Jeong-Ho;Sunwoo, Yang-Il;Hong, Seung-Hwan;Park, Sang-Dai
    • Animal cells and systems
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    • v.6 no.3
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    • pp.277-282
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    • 2002
  • Topoisomearse II is an essential enzyme in all organisms with several independent roles in DNA metabolism. Recently, it has been demonstrated that the C-terminal region of topoisomerases II is associated with hetero-logous protein-protein interactions in human and yeast. In this study, we identified that RTP1, a rat homologue of EIA binding protein BS69, is another topoisomerae II interacting protein by yeast two-hybrid screening. RTP1 has an E1A-binding domain and a MYND motif, which are known to be required for transcriptional regulation by binding to other proteins and interaction with the leucine zipper motif of topoisomerase II. The physical interaction between RTP1 and topoisomerase ll$\alpha$ was examined by GST pull-down assay in vitro. The expression level of RTP1 peaks in S phase as that of topoisomerase ll$\alpha$. These results suggest that the interaction between topoisomerase ll$\alpha$ and RTP1 might play an important role in regulating the transcription of genes involved in DNA metabolism in higher eukaryotes.

Purification and Characterization of an Angiotensin Converting Enzyme Inhibitor from Squid Ink

  • Kim, So-youn;Kim, Sun-hye;Song, Kyung-Bin
    • Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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    • 2003.10a
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    • pp.135.2-135
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    • 2003
  • Angiotensin converting enzyme (ACE) converts angiotensin I into angiotensin II by cleaving C-terminal dipeptide of angiotensin I and inactivates bradykinin. ACE inhibitors have been screened from various food sources since the inhibitors decrease blood pressure. Therefore, in this study, an ACE inhibitor was isolated and purified from squid ink using membrane filtration, gel permeation chromatography, normal phase HPLC, and fast protein liquid chromatography. The purified inhibitor was identified to be a molecular mass of 294 by mass spectrometry, and to have IC$\sub$50/ value of 4.9 $\mu\textrm{g}$/mL.

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Effects of Natural Products on the Induction of NAD(P)H: Quinone Reductase in Hepa 1c1c7 Cells for the Development of Cancer Chemopreventive Agents

  • Kim, Young-Mi;Chang, Il-Moo;Mar, Woong-Chon
    • Natural Product Sciences
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    • v.3 no.2
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    • pp.81-88
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    • 1997
  • NAD(P)H:quinone reductase (QR) is one of the protective phase II enzymes against toxicity that accomplishes the capacity of detoxification by modulating the effects of mutagens and carcinogens. The detoxification mechanism is that quinone reductase promotes the 2-electron reduction of quinones to hydroquinones which are less reactive. This study is to search new inducers of quinone reductase from natural products, which can be used as cancer chemopreventive agents. Plant extracts were evaluated by using quinone reductase generating system With Hepa 1c1c7 murine hepatoma cell lines for enzyme inducing properties and crystal violet staining method for the measurement of cytotoxicity provoked. We have tested approximately 106 kinds of natural products after partition into n-hexane, ethyl acetate and aqueous layers from 100% methanol extracts of natural products. The ethyl acetate fractions of Vitex rotundifolia $(fruits,\;2FC:\;12.7\;{\mu}g/ml)$, Cnidium officinale $(aerial\;parts,\;2FC:\;10.5\;{\mu}g/ml)$, Chrysanthemum sinese $(flowers,\;2FC:\;17.4{\mu}g/ml)$ and the hexane fractions of Angelica gigas $(roots,\;2FC:\;13.2\;{\mu}g/ml)$, Smilax china $(roots,\;2FC:\;l1.9\;{\mu}g/ml)$, Sophora flavescens $(roots,\;2FC:\;16.3\;{\mu}g/ml)$ revealed the significant induction of quinone reductase in a murine hepatic Hepa 1c1c7 cell culture system.

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Anti-Inflammatory and Antioxidative Effects of Gracilaria textorii Ethanol Extract in LPS-PG-Stimulated Human Gingival Fibroblast-1 Cells (사람 치은섬유모세포에서 잎꼬시래기 에탄올 추출물의 항염증 및 항산화 효과)

  • Park, Chungmu;Yoon, Hyunseo
    • Journal of The Korean Society of Integrative Medicine
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    • v.7 no.4
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    • pp.61-69
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    • 2019
  • Purpose : Human gingival fibroblast cell is one of the the main cell types in periodontal tissue, which they can show anti-inflammatory activity through the production of numerous lines of inflammatory mediators such as inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2 and interleukins. Porphyromonas gingivalis, one of the oral pathogens, has reported to play a critical role in the development of periodontal diseases. This study aimed to investigate anti-inflammatory and antioxidative activities of Gracilaria textorii ethanol extract (GTEE) in P. gingivalis derived lipopolysaccharide (LPS-PG) stimulated human gingival fibroblast (HGF)-1 cell line. Methods : In order to analyze anti-inflammatory and antioxidative activities of GTEE in HGF-1 cell line, NOS enzyme activity, expression levels of iNOS, COX-2, NAD(P)H quinone dehydrogenase (NQO)1 and their transcription factors were estimated by Griess reaction and western hybridization. Results : LPS-PG induced overexpression of iNOS and COX-2, which was significantly attenuated by GTEE treatment in a dose-dependent manner without any cytotoxicity. In addition, intracellular NOS activity was in accordance with the result of iNOS expression. Due to important role in the regulation of inflammatory responses, phosphorylated status of p65 and c-jun, each subunit of nuclear factor (NF)-κB and activator protein (AP)-1, was also dose-dependently ameliorated by GTEE treatment. One of phase II enzymes, NQO1, and its transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), were analyzed since elevated phase II enzyme expression inhibited inflammatory response, which was significantly elevated by GTEE treatment in HGF-1 cell line. Conclusion : In conclusion, GTEE mitigated LPS-PG-stimulated inflammatory responses by attenuating NF-κB and AP-1 activation as well as accelerating NQO1 and Nrf2 expression in HGF-1 cell line. These results indicate that GTEE might be utilized a promising strategy for potential anti-inflammatory agent in periodontal diseases.

Keap1 represses nuclear activation of antioxidant responsive elements by Nrf2 through binding to the amino-terminal Neh2 domain

  • Itoh, Ken;Wakabayashi, Nobunao;Katoh, Yasutake;Ishii, Tetsuro;Igarashi, Kazuhiko;Engel, James Douglas;Yamamoto, Masayuki
    • Proceedings of the Korea Environmental Mutagen Society Conference
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    • 2002.05a
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    • pp.25-35
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    • 2002
  • Transcription factor Nrf2 is essential for the antioxidant responsive element (ARE)-mediated induction of phase II detoxifying and oxidative stress enzyme genes. Detailed analysis of differential Nrf2 activity displayed in transfected cell lines ultimately led to the identification of a new protein, which we named Keap1, that suppresses Nrf2 transcriptional activity by specific binding to its evolutionarily conserved amino-terminal regulatory domain. The closest homolog of Keap1 is a Drosophila actin-binding protein called Kelch, implying that Keap1 might be a Nrf2 cytoplasmic effector. We then showed that electrophilic agents antagonize Keap1 inhibition of Nrf2 activity in vivo, allowing Nrf2 to traverse from the cytoplasm to the nucleus and potentiate the ARE response. We postulate that Keap1 and Nrf2 constitute a crucial cellular sensor for oxidative stress, and together mediate a key step in the signaling pathway that leads to transcriptional activation by this novel Nrf2 nuclear shuttling mechanism. The activation of Nrf2 leads in turn to the induction of phase II enzyme and antioxidative stress genes in response to electrophiles and reactive oxygen species.

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Standardized ileal digestibility of amino acids of protein sources associated with exogenous enzymes for broilers

  • Fortes, Bruno Duarte Alves;Mello, Heloisa Helena de Carvalho;Cafe, Marcos Barcellos;Arnhold, Emmanuel;Stringhini, Jose Henrique
    • Animal Bioscience
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    • v.35 no.7
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    • pp.1030-1038
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    • 2022
  • Objective: Two experiments were conducted to evaluate the effect of enzyme complex (EC) on the standardized ileal digestibility (SID) of amino acids (AA) in corn gluten meal (60%) (CGM), soy protein concentrate (SPC), dried bovine plasma (DBP), and poultry offal meal (POM). Experiments I and II were conducted with broilers in the pre-starter (1 to 7 days of age) and starter (1 to 21 days of age) phases, respectively. Methods: The treatments consisted of a protein-free diet (PFD) containing feedstuffs either supplemented with EC (xylanase, amylase, and protease) or not. In Experiment I, a total of 360 one-day-old male Cobb-500 broiler chicks were randomly housed in 45 pens, resulting in five replicates with eight birds each, totalizing eight treatments and one PFD group. In Experiment II a total of 270 one-day-old male Cobb-500 broiler chicks were randomly housed in 45 pens, resulting in five replicates with six birds each, totalizing eight treatments and one PFD group. The PFD groups were used to assess the endogenous AA losses. The birds were slaughtered to collect the ileal content. Results: In the pre-starter phase, the SID of arginine, branched chain-aminoacids, glycine, serine, aspartate, and glutamic acid increased with EC addition. The EC improved the SID of arginine and glutamic acid of CGM; the SID of valine and cystine of SPC; the SID of leucine, glycine, and aspartate of POM and the SID of isoleucine of DBP. In the starter phase, the SID of isoleucine, phenylalanine and glycine increased in EC-supplemented diets. The EC improved the SID of isoleucine of DBP; the SID of phenylalanine of CGM and POM. The SID of AA of SPC was not influenced by the EC. Conclusion: The addition of an EC to broiler pre-starter and starter diets is efficient in increasing the SID of AA on SPC, POM, and DBP.

Repression of γ-Glutamylcysteine Synthetase and Glutathione S-Transferases by Metformin, an Anti-diabetic Agent, in H4IIE Rat Hepatocytes

  • Bae, Eun-Ju;Cho, Min-Joo;Kim, Sang-Geon
    • Toxicological Research
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    • v.23 no.2
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    • pp.127-133
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    • 2007
  • Metformin is a drug used to lower blood sugar levels in patients with type 2 diabetes via activation of adenosine monophosphate (AMP)-activated protein kinase (AMPK). The primary objective of this study was to investigate whether metformin at the pharmacologically effective concentrations affects the expressions of ${\gamma}$-glutamylcysteine synthetase and phase II antioxidant genes in the H4IIE cell. Treatment of the cells with either metformin or 5-aminoimidazole-4-carboxamide riboside (AICAR) abrogated tert-butylhydroxyquinone (t-BHQ) induction of ${\gamma}$-glutamylcysteine synthetase, a rate limiting enzyme of GSH synthesis. The ability of t-BHQ to induce glutathione S-transferases (GSTs), a major class of phase II detoxifying enzymes that playa critical role in protecting cells from oxidative stress or electrophiles, was also inhibited by the agents. Transcriptional gene repression by metformin was verified by the GSTA2 promoter luciferase assay. Moreover, either metformin or AICAR treatment significantly decreased t-BHQ-dependent induction of other GSTs (i.e., $GST{\mu}$ and $GST{\pi}$ forms). Taken together, our data indicate that metformin treatment may result in the repression of ${\gamma}$-glutamylcysteine synthetase and glutathione S-transferase genes possibly via AMPK activation.

Induction of Phase II Enzyme Activity by Artemisia asiatica Nakai Aqua-acupuncture Solution (애엽(艾葉) 약침액(藥鍼液)에 의한 Phase II 효소 활성 유도)

  • Yoon Sung-Mook;Cho Kyoung-Hee;Shon Yun-Hee;Nam Kyung-Soo;Lim Jong-Kook
    • Korean Journal of Acupuncture
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    • v.18 no.1
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    • pp.1-9
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    • 2001
  • Artemisia asiatica Nakai aqua-acupuncture solution (ANAS) was administered once daily for 10 days before the tumor implantation ($1{\times}10^6\;cells$). Body weight, spleen weight and the number of ascitic tumor cells were measured at 6 days after tumor implantation. The change of body weight and the survival rate of mice were observed for 21 days. It was used three biomarkers (quinone reductase, glutathione, glutathione S-transferase) to test chemopreventive potentials of ANAS. ANAS exerted antitumor activity by inhibiting the growth of Ehrlich ascites tumor cells in vivo. Mice given Ehrlich cells and ANAS at $CV_{12}$ and $BL_{18}$ had 57.1% to 49.2% survival after 21 days. Quinone reductase activity and glutathione levels were increased with ANAS. However, glutathione S-transferase level was 1.1-fold with ANAS. These results suggest that ANAS has chemopreventive potential by inducing QR activity and increasing GSH level.

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