• Journal of Dairy Science and Biotechnology
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• 제38권3호
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• pp.134-141
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• 2020

Oxidative stress is a cascade reaction characterized by a significant increase in the amount of oxidized components. Free radicals produced by oxidative stress are one of the common features in several experimental models of disease, and contribute to wide range of neurodegenerative diseases, including Alzheimer's disease. Iron (II) species can participate in the Fenton, and Fenton-like reactions, to react with hydrogen peroxide and generate hydroxyl radical. As iron accumulation and oxidative stress are associated with the pathological progression of neurodegenerative diseases, iron chelation and antioxidant therapies have become strategies to combat these diseases. Due to the complexity of the redox system in vivo, a multifaceted approach may be an attractive therapeutic strategy. Further investigations are highly expected for the prevention and treatment of neurodegenerative diseases in future.

• 한국지하수토양환경학회지:지하수토양환경
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• 제10권4호
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• pp.62-69
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• 2005

본 연구에서는 천연 망간산화물에 의한 4-클로로페놀 화합물의 제거효과를 평가하였으며 자연유기물질과 용액의 pH에 의한 분해율 변화를 살펴보았다. 천연망간산화물은 4-클로로페놀 화합물의 제거에 효과적이었으며 실험결과의 분석을 통하여 반응계수 및 차수에 대한 정량적인 값을 도출하였다. 그 결과, 전체적인 반응은 2차반응으로서 4-클로로페놀 화합물에 대하여 1차, 망간산화물에 대하여 1차에 비례하는 반응이었다. 망간산화물에 의한 4-클로로페놀 화합물의 산화반응은 표면에서 일어나며 pH에 큰 영향을 받았다. 용액의 pH가 망간산화물의 영가전위(PZC) 값보다 클 경우 반응율은 급격히 감소하였으며 PZC 보다 pH가 작은 경우에도 반응율은 감소하였다. 휴믹산을 첨가한 경우 4-클로로페놀 화합물의 산회중합 반응은 다소 증가하는 경향을 보여 휴믹산이 중합반응에 관여하고 있다고 평가할 수 있다. 본 연구 결과, 경제적인 비용으로서 천연망간산화물을 이용하여 페놀계 오염물의 제거에 효과적으로 사용 할 수 있는 방안을 제시하였다.

• 대한화학회지
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• 제37권2호
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• pp.244-248
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• 1993

니트로 알코올은 브로모 알코올의 치환반응으로 얻었다. 두번째 니트로 원자단은 사슬 길이에 따라 다른 방법으로 도입했다. 3,3-dinitro-1-propanol은 분자내 염기성 니트로화 반응으로 형성되면 5,5-dinitro-1-pentanol은 산화촉매 니트로화 반응으로 얻었다. 3,3-dinitro-1,6-hexanediol과 4,4-dinitro-1,8-octanediol은 3,3-dinitro-1-propanol과 5,5-dinitro-1-pentanol에 acrolein을 가해 Michael 반응으로 알데히드를 얻고 환원하여 합성했다. 치환반응시 알코올 보호기는 아세틸기가 좋으며 산화촉매 니트로 반응에서는 THP 원자단이 좋은 보호기이다.

• Bulletin of the Korean Chemical Society
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• 제33권9호
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• pp.3009-3016
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• 2012

This study evaluated the use of iron-impregnated SBA-15 (Fe/SBA-15) as a catalyst for the oxidative degradation of persistent phenol analogues, such as 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2-nitrophenol (2-NP), 4-nitrophenol (4-NP) and 2,4,6-trichlorophenol (2,4,6-TCP) in water. The oxidation reactions were carried out with reaction time, concentration of the phenols, amount of the catalysts, reaction temperature, pH of the reaction mixture as the process variables with or without using hydrogen peroxide as the oxidizing agent. The conversion achieved with Fe/SBA-15 at 353 K for 2-CP, 4-CP, 2-NP, 4-NP, 2,4,6-TCP was 80.2, 71.2, 53.1, 62.8, 77.3% in 5h with a reactant to $H_2O_2$ mole ratio of 1:1, and 85.7, 65.8, 61.9, 63.7, 78.1% in the absence of $H_2O_2$, respectively. The reactions followed pseudo first order kinetics. The leachability study indicated that the catalyst released very little iron into water and therefore, the possibility of secondary pollution is negligible.

• 한국식품영양과학회지
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• 제23권5호
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• pp.867-878
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• 1994

A general overview of the lipid peroxidation and its nutritional significance are presented ,with emphasis on the reaction mechaisms, peroxidized products, further interaction and nutritional/biological deterioration in a series of oxidative process. Overall mechanism with various factors and elements for initiation , propagation and termination of free radical reaction is reviewed and the primary /secondary products of peroxidized lipids are defined. Since these products are potentially reactive substances that can cause deterioration of proteins /amino acids and vitamins (carotene, tocopherols and ascorbic acid etc), mechanism and actual damages of their deterioration in some foods and biological models are outlined. Especially , chemical changes caused by interaction of peroxidized products (related hydroperoxides, radicals and malonaldehye etc) and protein are emphasized here. And also, the detailed mechanisms on radical scavenging of the these vitamins which are the most prominent natural antioxidants are presented . Additionally , the possible roles of peroxidicaed lipids and their secondary products in the process of aging an carcinogenesis are briefly discussed . However, it is important to not that more detailed and integrated studies on the reaction kinetics, energetics of peroxidation, their decomposed products , biochemical interaction potential damaging/aging / carcinogenic effects, protection from their oxidative spoilage and novel antioxidants in food and heterogeneous biological systems will be essential in order to assessing the implication of lipid peroxidation to human nutrition and health.

• 생명과학회지
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• 제14권3호
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• pp.406-410
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• 2004

Glycation 반응은 glucose와 amino group 간에 일어나는 비효소적 축합 반응인 maillard 반응의 초기 반응으로 non enzymatic glycation 이라고도 한다. 생체내 glycation 반응을 통해 다수의 dicarbonyl화합물이 생성되고, 이들 dicarbonyl들 중에서 매우 반응성이 큰 것으로 확인된 glyoxal과 methylglyoxal과 catalase를 반응 시켜 glycation catalase의 활성 변화를 확인하였다. Non-glycated catalase에 비해 glycation catalase에서 구조적 인 modification과 degradation이 일어났으며, glycation반응 시간에 따라 활성이 크게 저하되는 것으로 확인 할 수 있었다. 특히 glycation 반응 시간 20일 경과 이후 glycation catalase 경우 활성이 거의 상실한 것으로 나타났다 Glyoxal과 methylglyoxal의 농도를 달리 해서 DNA와 반응 시켜 glycation propagator에 의한 직접적인 DNA damage를 확인 한 결과 Glyoxal과 methylglyoxal의 농도와 반응 시간에 따라 DNA mobility sit의 차이를 나타냈다. Fenton reaction 조건에 glyoxal과 methylglyoxal에 의해 활성이 저하된 catalase를 첨가 시켜 8-OH-dG의 생성을 확인한 결과 두 glycation propagator와의 반응 시간 의존적으로 8-OH-dG의 생성이 증가함을 보였다. 이상의 결과를 통해 glyoxal과 methylglyoxal의 antioxidant의 glycation은 oxidative stress의 증사를 유발해 생체내 활성 산소로부터 방어 기작에 심각한 문제를 야기하는 것으로 사료된다.

• Bulletin of the Korean Chemical Society
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• 제23권9호
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• pp.1257-1262
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• 2002

$[(C_2B_9H_{11})Mo(CO)_3]_2PPN_2$ $(2{\cdot}PPN_2)$, a new precursor for the oxidative decarbonylation reaction, was synthesized in high yield by the one-electron oxidation reaction of $[(C_2B_9H_{11})Mo(CO)_3]PPN_2$. $2{\cdot}PPN_2$ was structurally characterized, showing a dimeric nature with long (3.321 ${\AA}$) Mo-Mo bonding. Reaction of $2{\cdot}PPN_2$ with sulfur gave the completely decarbonylated product $[(C_2B_9H_{11})Mo({\mu}-S)(S)]_2PPN_2$ ($3{\cdot}PPN_2$). The ligand substitution of the terminal sulfur ligands in $3{\cdot}PPN_2$ to oxygen ligands was carried out with the use of PhIO to give $[(C_2B_9H_{11})Mo({\mu}-S)(O)]_2PPN_2$ ($4{\cdot}PPN_2$). The structures of $3{\cdot}PPN_2$ and $4{\cdot}PPN_2$ were also studied.

• Environmental Engineering Research
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• 제20권3호
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• pp.205-211
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• 2015

Reduced forms of iron, such as zero-valent ion (ZVI) and ferrous ion (Fe[II]), can activate dissolved oxygen in water into reactive oxidants capable of oxidative water treatment. The corrosion of ZVI (or the oxidation of (Fe[II]) forms a hydrogen peroxide ($H_2O_2$) intermediate and the subsequent Fenton reaction generates reactive oxidants such as hydroxyl radical ($^{\bullet}OH$) and ferryl ion (Fe[IV]). However, the production of reactive oxidants is limited by multiple factors that restrict the electron transfer from iron to oxygen or that lead the reaction of $H_2O_2$ to undesired pathways. Several efforts have been made to enhance the production of reactive oxidants by iron-induced oxygen activation, such as the use of iron-chelating agents, electron-shuttles, and surface modification on ZVI. This article reviews the chemistry of oxygen activation by ZVI and Fe(II) and its application in oxidative degradation of organic contaminants. Also discussed are the issues which require further investigation to better understand the chemistry and develop practical environmental technologies.

• Animal Bioscience
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• 제34권2호
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• pp.312-319
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• 2021

Objective: Stress-induced cytotoxicity caused by xenobiotics and endogenous metabolites induces the production of reactive oxygen species and often results in damage to cellular components such as DNA, proteins, and lipids. The cytochrome P450 (CYP) family of enzymes are most abundant in hepatocytes, where they play key roles in regulating cellular stress responses. We aimed to determine the effects of the antioxidant compound, methylsulfonylmethane (MSM), on oxidative stress response, and study the cytochrome P450 family 3 subfamily A (CYP3A) gene expression in fetal horse hepatocytes. Methods: The expression of hepatocyte markers and CYP3A family genes (CYP3A89, CYP3A93, CYP3A94, CYP3A95, CYP3A96, and CYP3A97) were assessed in different organ tissues of the horse and fetal horse liver-derived cells (FHLCs) using quantitative reverse transcription polymerase chain reaction. To elucidate the antioxidant effects of MSM on FHLCs, cell viability, levels of oxidative markers, and gene expression of CYP3A were investigated in H2O2-induced oxidative stress in the presence and absence of MSM. Results: FHLCs exhibited features of liver cells and simultaneously maintained the typical genetic characteristics of normal liver tissue; however, the expression profiles of some liver markers and CYP3A genes, except that of CYP3A93, were different. The expression of CYP3A93 specifically increased after the addition of H2O2 to the culture medium. MSM treatment reduced oxidative stress as well as the expression of CYP3A93 and heme oxygenase 1, an oxidative marker in FHLCs. Conclusion: MSM could reduce oxidative stress and hepatotoxicity in FHLCs by altering CYP3A93 expression and related signaling pathways.

• 대한화학회지
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• 제36권1호
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• pp.147-156
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• 1992

${\alpha}-{\beta}-,{\gamma}$-알루미나 및 MgO를 담체로 사용하여 담지된 납산화물 촉매를 제조하였다. 담지된 납산화물 촉매상에서 메탄의 $C^{2+}$ 탄화수소로의 전환반응은 MgO 담지촉매에서 $C^{2+}$ 선택도가 최대로 얻어졌으며, ${\gamma}$-알루미나 담지 PbO 촉매에서는 $CO_2$ 선택도가 높았다. 그리고 ${\alpha}$-알루미나 담지촉매에서는 중간정도의 활성이 얻어졌으며, ${\beta}$-알루미나 담지촉매에서는 활성이 거의 나타나지 않았다. 이러한 반응특성은 촉매의 격자산소의 활성에 크게 의존하였으며, 또한 격자 산소의 활성은 담체와 산화물간의 상호작용과 담체의 성질에 영향받았다. 특히 MgO 담지 촉매에서는 X-선 회절분석에서 여타의 담체에서보다 PbO 산화물의 (002)면의 피크 세기가 (111)면의 세기에 비해 훨씬 크게 나타난 것으로 볼 때 메탄의 Oxidative Coupling 반응에서의 표면산화물-담체 상호작용(SOSI)의 한 예로 여겨졌다.