• Title/Summary/Keyword: Radical mechanism

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The Formation of Reactive Species on the Nitrogen Oxide in the Ultraviolet Photolysis of N-Nitrosodimethylamine (N -Nitrosodimethylamine의 자외선 광분해 시 질소산화물 생성에 미치는 반응성 화학종의 형성)

  • Kwon, Joongkuen;Kim, Jongoh;Kwon, Bumgun
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.2
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    • pp.75-81
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    • 2012
  • Because N-Nitrosodimethylamine(NDMA) is well-known as a potential carcinogen, extensive research has addressed its treatment by ultraviolet(UV) and its degradation pathway. However, the detailed mechanism by which NDMA is photolyzed to form oxidized products, i.e., ${NO_2}^-$ and ${NO_3}^-$, is still not understood. This study reveals a key reactive species during the photolysis of NDMA. The study on a key reactive species was indirectly performed with the formation of nitrogen oxidized products and reactions between methanol and an unknown reactive species formed during the photolysis of NDMA. The peroxynitrite($ONOO^-$) generated by the direct UV photolysis of NDMA would be identified as a key reactive species in oxidizing nitrogen intermediates to ${NO_2}^-$and ${NO_3}^-$.

Thermal Stability Improvement of Liquid Fuel by Using Some Additives (첨가제를 이용한 액체연료의 열안정성 향상)

  • Park, Sun-Hee;Kim, Joong-Yeon;Chun, Byung-Hee;Han, Jeong-Sik;Jeong, Byung-Hun;Kim, Sung-Hyun
    • Journal of the Korean Society of Propulsion Engineers
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    • v.15 no.5
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    • pp.48-53
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    • 2011
  • We investigated thermal stability improvement of exo-tetrahydrodicyclopentadiene (exo-THDCP) with thermal stabilizers (additives). The reaction products were sample during the reactions. The compositions of products were determined by gas chromatography-mass spectrometry (GC-MS) to measure thermal decomposition products of exo-THDCP and to specify mechanism for thermal stabilizers. Hydrogen donors (thermal stabilizers) such as 1,2,3,4-tetrahydroquinoline (THQ), benzyl alcohol (BnOH) increased thermal stability of exo-THDCP. These materials donated hydrogen to radical of exo-THDCP produced after initiation of exo-THDCP. We found that stabilization of exo-THDCP radicals decreased activity of primary products of exo-THDCP and lowered formation of secondary products (above-$C_{11}$ products).

The protective effects of Moxi-tar on injury induced by H2O2 in C6-glioma (H2O2로 유발된 뇌신경세포 상해에 대한 구진의 보호효과)

  • Ahn, Sung-hun;Koo, Sung-tae;Kim, Sun-young;Kim, Kyung-sik;Sohn, In-cheul
    • Journal of Acupuncture Research
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    • v.21 no.3
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    • pp.29-41
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    • 2004
  • Objective : This study was produced to examine the effects of moxibustion that had been played important role to traditional oriental medical treatment on disease. Recently, it was reported that moxi-tar which is generated in the process of moxibustion as burning combustibles decreased NO and iNOS generation in C6-glioma and RAW 264.7 cells in our lab. Methods : C6-glioma cells were cultured in RPMI 1640 with FBS 10% in CO2 incubator. To study the protective effects of moxi-tar, we observed cell viability, DPPH activity, SOD activity, catalase activity and cell morphology after injury with $H_2O_2$. Results and Conclusions : Moxi-tar increased cell viability about twice as much as that of being injury by $H_2O_2$(moxi-tar $40{\mu}g/m{\ell}$, $H_2O_2$ $500{\mu}M$). And the results of free radical scavenger activity($80{\mu}g/m{\ell}$ : $78.91{\pm}4.4%$), SOD activity and catalase activity($80{\mu}g/m{\ell}$ : 21.6unit/mg protein) were increased by moxi-tar as dose-dependent manner. So we concluded that the effects of moxibustion which is played important role in Oriental medicine, might be free radical scavenger effects induced by moxi-tar. Conclusion : These results indicate that tBHP induces apoptosis through a lipid peroxidation-dependent mechanism and JS exerts the protective effect against the apoptosis by preventing peroxidation of membrane lipids.

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Cytotoxic Effect of Free Radical on Rat Primary Astrocytes (자유라디칼이 백서의 뇌별아교세포에 미치는 독성작용)

  • Jang, Hyuk;Kim, Myung-Sunny;Park, Hyun-Young;Kim, Yo-Sik;Cho, Kwang-Ho;Chung, Hun-Taeg;Park, Rae-Kil
    • Toxicological Research
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    • v.16 no.1
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    • pp.1-8
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    • 2000
  • Astrocytes generate free radicals including nitric oxide (NO) and reactive oxygen intermediates(ROI) which in turn play roles in the pathogenesis of degenerative diseases and sclerotic changes of the brain. This study was designed to evaluate the mechanism that free radicals contribute to the cytotoxicty of rat neonatal primary astrocytes. Treatment with NO donors alone including soldium nitroprusside(SNP), S-nitrosoglucathinoe (GSNO), and S-nitroso-n-acetylpenicillamine (SNAP) showed a little effect on the death of rat neonatal primary astrocytes, whereas SNP markedly induced the death of RAW 264.7 cells. ROI inculding H2O2 and O2 donor also slightly induced the death of rat primary astrocytes. However, 3-morpholinosydnonimine(SIN-1), a donor of peroxynitrite (ONOO), which is a reactive compound of NO with superoxide, significantly decreased the viability of rat primary astrocytes in a dose-dependent manner. Cells were retarded in outgrowth of viability of cellular processes with cell shrinkage and detachment from culture dishes. Hoechst staining demonstrated that SIN-1-induced cell death might be due to an apoptosis which was characterized by nuclear condensation and fragmentation. SIN-1-induced apoptosis was prevented by the pretreatment with superoxide dismutase (SOD) and catalase in rat primary astorocytes. Furthermore, prevention of the generation of reduced glutathione (GSH) by DL-buthionine-[S, R]-sulfoximine (BSO) aggravated the cytotoxic effects of SNP, benzene triol, and SIN-1 in rat primary astrocytes. Taken together, it is suggested that peroxynitrite may be a major effector of apoptosis and cellular antioxidant system is important for cell survival in rat prima교 astrocytes.

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Cytoprotective Effect of Lespedeza Cuneata Extract on Glucose Toxicity (야관문(夜關門)의 포도당 독성에 대한 세포 보호 효과)

  • Choi, Jeong-Sik;Cho, Chung-Sik;Kim, Cheol-Jung
    • The Journal of Korean Medicine
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    • v.31 no.4
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    • pp.79-100
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    • 2010
  • Objective: Production of ROS from glucose toxicity results in injury of pancreatic $\beta$-cells in diabetes models. This study was undertaken to examine the influence of Lespedeza Cuneata extract (LCE) on cytoprotective effects on glucose toxicity, insulin secretion and gene expression in RIN-m5F cells. Methods: First, we measured LCE's antioxidant activity by DPPH free radical-scavenging activity and SOD activity. After the various concentrations of LCE were added to the RIN-m5F cells, we measured cell viability with glucose stimulation by MTT assay and glucose-stimulated insulin secretion. We analyzed gene expression with Agilent whole mouse genome 44K oligo DNA microarray and searched for related pathways in KEGG (Kyoto Encyclopedia of Genes and Genomes). Lastly we measured INS-1, INS-2, INS-R, IRS-1, IRS-2, IRS-3, GLP-1R, and GLP-2R mRNA expression by real time RT-PCR. Results: Free radical-scavenging activity, SOD activity and insulin secretion increased dependent on LCE concentration, but LCE did not show considerable cytoprotective effect on RIN-m5F cells. More than twice expressed gene was 6362 in Oligo DNA chip. In KEGG, the most related pathway was the metabolic pathway. In the insulin signaling pathway, up expressed genes were Irs1, Mapk8, Akt1, and Lipe and down expressed genes were Rhoq, Fbp2, Prkar2b, Gck, and Prkag1. In real time RT-PCR, IRS-2, and IRS-3 expression increased significantly compared to the control group on LCE $12{\mu}g/m{\ell}$ concentration and GCK expression decreased significantly compared to the control group. Conclusions: These results show that LCE encourages insulin secretion and insulin metabolism by complicated gene mechanisms. Further mechanism study and clinical study seem to be necessary about Lespedeza Cuneata.

A study on effects of Ligustri Lucidi Fructus, Ecliptae Herba and Yijihwan on antioxidant activity and blood pressure (여정자(女貞子), 한연초(旱蓮草) 및 이지환(二至丸)의 항산화활성 및 혈압에 미치는 영향에 관한 연구)

  • Kang, Seung-Ho;Kim, Eun-Young;Rhyu, Mee-Ra;Kim, Dong-Il
    • The Journal of Korean Obstetrics and Gynecology
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    • v.20 no.2
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    • pp.83-96
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    • 2007
  • Purpose: Ligustri Lucidi Fructus and Ecliptae Herba has long been used for clinical therapy associated especially with menopausal symptoms in Korea. To provide a scientific rationale for such use, we have investigated the antioxidant and vasorelaxant effects of Ligustri Lucidi Fructus, Ecliptae Herba and its mixture. Methods: The antioxidant activity of the extracts from Ligustri Lucidi Fructus, Ecliptae Herba and its mixture were evaluated and compared with that of BHA (butylated hydroxyanisole), BHT (butylated hydroxytoluene), vitamin C and vitamin E, using the ${\alpha}$,${\alpha}-diphenyl-{\beta}-picrylhydrazyl$ (DPPH) radical scavenging method. Results: Antioxidant activity of all extracts using the DPPH radical scavenging method decreased in the order vitamin C>BHA>vitamin E>Ligustri Lucidi Fructus>Ligustri Lucidi Fructus:Ecliptae Herba(1:1)>Ecliptae Herba>BHT. The vasorelaxant effects of extracts were investigated on the vasomotor tone of the rat thoracic aorta in an organ bath. All of the extracts elicited along-term relaxing response in the endothelium-intact as well as endothelium-denuded rat aorta contracted with norepinephrine. This relaxant effect was abolished by Precontraction with 72 mM KCI. Thus, it is suggested that the mechanism of vasorelaxant effect of extracts not involve voltage-operated $Ca^{2+}$ channel blocking but receptor-mediated route. Conclusion: These antioxidant and vasorelaxant effecs of the extracts may contribute to the beneficial effects in postmenopausal women.

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Antioxidant and Anti-inflammatory Effect of Nardostachys Chinensis in IFN-$\gamma$/LPS-stimulated Peritoneal Macrophage (감송향의 in vitro 항산화 및 항염증 효과)

  • Baek, Seol;Choi, Jae-Hyuk;Ko, Sung-Hoon;Lee, Yong-Jae;Cha, Dong-Seok;Park, Eun-Young;Kang, Yang-Gyu;Jeon, Hoon
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.23 no.4
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    • pp.853-859
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    • 2009
  • Nardostachys chinensis has been used widely as a traditional medicine for the treatment of diverse diseases. The dried plant was extracted with 85% methanol extract (NC). We investigated the antioxidant properties of NC on the 1,1-diphenyl-2-picryhydrazyl (DPPH) radical, superoxide anion and nitric oxide radical scavenging capacity under in vitro assays. NC showed potent antioxidant activity, compared to ascorbic acid. In macrophages, nitric oxide is released as an inflammatory mediator and has been proposed to be an important modulator of many pathophysiological conditions in inflammation. In the present study, it was also investigated that the inhibition effects on NO and the mechanism of down-regulation of immune response by NC in IFN-IFN-$\gamma$/LPS-stimulated mouse (C57BL/6) peritoneal macrophages. Extracts of NC suppressed NO production and the expression of iNOS and COX-2. The present results indicate that NC has an antioxidant and anti-inflammatory properties and therefore may be beneficial in diseases which related to oxidative stress-mediated chronic inflammatory disorders.

Antioxidant Effects and Anti-inflammation Effects of Lophatheri Herba Water Extracts Via Reducing iNOS Synthesis Induced by LPS in RAW 264.7 Cell (담죽엽의 항산화 효과와 RAW 264.7 세포에서 LPS로 유도된 iNOS 발현에 미치는 영향)

  • Hwang, Sung-Yeoun;Lee, Sung-Won;Kwon, Kang-Beom;Choi, Won-Jong;Kim, Jae-Hyo;Ahn, Seong-Hun
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.24 no.6
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    • pp.976-982
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    • 2010
  • We studied to know the anti-inflammation effect on water extracts of Lophatheri Herba which was growing in every places in our country. We objected free radical scanvenger effect and nitrite eliminate effect of the Lophatheri Herba water extracts, and the cell viabillity, the effects of Lophatheri Herba water extracts on NO production, iNOS synthesis induced by LPS. Free radical scavenger effects were $27.91{\pm}0.12%$, $38.96{\pm}0.10%$, $46.22{\pm}0.15%$ depend on 0.5, 1.0, 2.0 mg/ml each dose of Lophatheri Herba water extracts. Nitrite eliminate effects were $9.86{\pm}0.3%$, $80.61{\pm}0.23%$, $97.62{\pm}0.56%$ in 0.1, 1.0, 2.0 mg/ml Lophatheri Herba water extracts on pH 1.2. NO production and iNOS synthesis induced by LPS were reduced in RAW 264.7 cell by Lophatheri Herba water extracts. As the above results, Lophatheri Herba water extracts have anti-inflammation effects via NO production decrease, iNOS synthesis decrease mechanism. So Lophatheri Herba water extracts will be used as the protection or treatment in chronic inflammation desease like a asthma, stomatitis etc.

Inhibitory Effects of Gamidaeganghwal-tang(Jiaweidaqianghuo-tang) on Rheumatoid Arthritis Induced by Type II Collagen (가미대강활탕(加味大羌活湯)이 Collagen II로 유발된 관절염에 미치는 영향)

  • Kim, Min-Ki;Oh, Min-Suck
    • Journal of Korean Medicine Rehabilitation
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    • v.19 no.2
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    • pp.89-102
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    • 2009
  • Objectives : This study was carried out to understand the immunity responses and anti-oxidation effect of the Gamidaeganghwal-tang(GDT) on rheumatoid arthritis by using the THP-1 cells and the serum of CIA mice. Methods : For this purpose, GDT was orally administerd to mice with rheumatoid arthritis induced by collagen II. To investigate the immunity responses, value of cytokine and gene expression in the THP-1 cell, levels of cytokines in the serum of CIA(collagen type II induced arthritis) mice, number of immunocyte in PBMC of CIA mice were measured. Then, anti-oxidant activity, scavenging activity on DHHP(2,2-diphenyl-1-picrylhydrazyl) free radical and SOD(Superoxide dismutae)-like activity of GDT was observed. Results : 1. The levels of IL-$1{\beta}$, IL-6, IL-8, MCP-1 at 100, $50{\mu}g/m{\ell}$ of GDT were significantly reduced in the THP-1 cell. 2. The levels of TNF-${\alpha}$, COX-2 mRNA expression at 100, $50{\mu}g/m{\ell}$ of GDT and IL-$1{\beta}$, IL-6 at $100{\mu}g/m{\ell}$ of GDT were significantly reduced in the THP-1 cell line. 3. The levels of IL-6, TNF-${\alpha}$ and IL-$1{\beta}$ were significantly reduced in the serum of CIA mice. 4. The absolute number of CD3+, CD4+ and CD8+ cells were significantly induced, CD3+/CD69+, CD3+/CD49+, CD19+, B220+/CD23+ cells were significantly reduced in PBMC. 5. Scavenging activity on DPPH free radical and SOD-like activity were significantly induced in a concentration dependent manner. Conclusions : Taking all these observations, GDT considered to be effective in treating rheumatoid arthritis. Therefore we have to survey continuously in looking for the effective substance and mechanism in the future.

A Study on the Protective Mechanism of Moxi-tar on Cytotoxicity Induced by $H_2O_2$ in $C_6-glioma$ (구진의 $H_2O_2$로 유발된 뇌신경세포 상해에 대한 보호 기전 연구)

  • Ahn, Seoung-Hoon;Ahn, Young-Nam;Baek, Dae-Bong;Song, Moon-Young;Kim, Kyoung-Sik;Sohn, In-Cheul
    • Korean Journal of Acupuncture
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    • v.22 no.2
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    • pp.43-56
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    • 2005
  • Objective : This study was produced to examine the effects of moxibustion that had been played important role to traditional oriental medical treatment on disease. Recently, it was reported that moxi-tar which is generated in the process of moxibustion as burning combustibles decreased NO and iNOS generation in $C_6-glioma$ and RAW 264.7 cells in our lab. The purpose of this research was to investigate the protect reaction on cell injury induced by the $H_2O_2$ in $C_6-glioma$ cells. Methods : $C_6-glioma$ cells were cultured in RPMI 1640 with FBS 10% in $CO_2$ incubator. To study the protective effects of moxi-tar, we observed cell viability, DPPH activity, SOD activity, catalase activity and cell morphology after injury with $H_2O_2$. Results : Moxi-tar increased cell viability about twice as much as that of being injury by $H_2O_2$(moxi-tar $40\;{\mu}g/m{\ell}$, $H_2O_2\;500\;{\mu}\;M$). And the results of free radical scavenger activity ($80\;{\mu}g/\;m{\ell}\;:\;78.91\;{\pm}\; 4.4%$), SOD activity and catalase activity ($80\;{\mu}g/\;m{\ell}$: 21.6 unit/ mg protein) were increased by moxi- tar as dose-dependent manner. Conclusion: we concluded that the effects of moxibustion which is played important role in Oriental medicine, might be free radical scavenger effects induced by moxi-tar.

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