• Analytical Science and Technology
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• v.22 no.3
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• pp.254-262
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• 2009

Activated carbon fiber treated with iron compound (Fe-ACF) was employed for preparation of Feactivated carbon fiber/$TiO_2$ (Fe-ACF/$TiO_2$) composite catalysts. Then, the prepared Fe-ACF/$TiO_2$ composite catalysts were characterized by employing BET, SEM, XRD and EDX instruments. It showed that BET surface area was related to adsorption capacity for each composite. The SEM results showed that ferric compound and titanium dioxide were distributed on the surfaces of ACF. The XRD results showed that Fe-ACF/$TiO_2$ composite mostly contained an anatase structure with a Fe mediated compound. EDX results showed the presence of C, O, and Ti with Fe peaks in Fe-ACF/$TiO_2$ composites. From photocataytic degradation effect, it was observed in the organic dye (Methylene blue, MB) degradation by these composites. Different degradation effect can be attributed to the synergetic effects of photo-Fenton reaction of Fe. It was considered that the combined reactions of Fe-ACF/$TiO_2$ produce powerful photo-Fenton process in the MB degradation.

• BMB Reports
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• v.28 no.3
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• pp.249-253
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• 1995

The nonenzymatic glycation of copper, zinc-superoxide dismutase (Cu,Zn-SOD) led to inactivation and fragmentation of the enzyme. The glycated Cu,zn-SOD was isolated by boronate affinity chromatography. The formation of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) in calf thymus DNA and the generation of strand breaks in pBhiescript plasmid DNA by a metal-catalyzed oxidation (MCO) system composed of $Fe^{3+}$, $O_2$, and glutathione (GSH) as an electron donor was enhanced more effectively by the glycated CU,Zn-SOD than by the nonglycated enzyme. The capacity of glycated Cu,Zn-SOD to enhance damage to DNA was inhibited by diethylenetriaminepentaacetic acid (DETAPAC), azide, mannitol, and catalase. These results indicated that incubation of glycated CU,Zn-SOD with GSH-MCO may result in a release of $Cu^{2+}$ from the enzyme. The released $Cu^{2+}$ then likely participated in a Fenton-type reaction to produce hydroxyl radicals, which may cause the enhancement of DNA damage.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.293.3-294
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• 2002

In the brain, glial cells serve in the role to sequester metal from the neural microenvironment and therefore play an important role as a cellular deposition site. The central nervous system is highly vulnerable to oxidative stress, and free iron can stimulate oxidative stress by the Fenton reaction. Aluminum may upregulates the transferrin-independent iron uptake system and stimulate oxidative stress. Nramp2. also known as DMT 1. is a 12-transmembrane(TM) domain protein responsible for dietary iron uptake as well as metal ions such as iron. lead, mangamese. zinc. copper, and cobait. (omitted)

• The Journal of Korean Medicine
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• v.26 no.3 s.63
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• pp.204-214
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• 2005

Objectives : The verity extract of the Gagam-Hyungbang-Gihwang-tang (GHG) was assessed to determine the mechanisms of its antioxidant activity. Methods : The fellowing effects were measured : GHG exhibited a concentration-treatment; scavenging ${\alpha},\;{\alpha}-diphenyl-\beta-picrylhydrazyl$ (DPPH) radical, linoleic acid oxidation in a thiocyanate assay system, and superoxide anion, hydroxyl radical-induced DNA nicking. We investigated mRNA levels such as superoxide-dismutase. Results : The GHG extract showed dose-dependent free radical scavenging activity, including DPPH radicals, hydroxyl radicals, and superoxide anion, using different systems. The GHG was also found to be effective in protecting plasmid DNA against the strand breakage induced by hydroxyl radicals in Fenton's reaction mixture. Furthermore, SOD-1 mRNA expression levels increased in tat hepatoma H4IIE cells Conclusions : We expect that GHG will to helpful to the development of antioxidant activity treatments.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.37-40
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• 2006

The batch tests were performed to determine the ratio of hydrogen peroxide on diesel contaminated soil. The objective of test was to determine and optimize the hydrogen peroxide requirements for the remediation of a soil contaminated with diesel fuel. The batch test were done on 5g diesel contaminated soil containing hydrogen peroxide (34.5%). Initial diesel concentration were 2,000mg/kg, 5,000mg/kg, and 10,000mg/kg. The $Diesel(g):H_2O_2(g)$ ratio varied 1:1, 1:10, 1:50, 1:100, with contact reaction time 120 min. Results the batch test, effective ratio of $Diesel(g):H_2O_2(g)$ is 1:100.

• Korean Journal of Pharmacognosy
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• v.28 no.3
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• pp.156-161
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• 1997

For the search of hepatoprotective compounds from the folk medicines, 14 natural products which have been traditionally used as hepatoprotective drugs in Korea were extracted with methanol. The extracts were screened for the antioxidant activity on lipid peroxidation induced by Fenton reaction in rat homogenate and Ac2F cell toxicity by t-hydroperoxide. Dendrobium moniliforme and Castanea crenata were chosen for the further investigation and its therapeutic effects on the liver damage induced by carbon tetrachloride in rats were evaluated. Oral administration of the extracts reduced the aspartate aminotransferase(AST) and alanine aminotransferase(ALT) activities in the serum of the carbon tetrachloride intoxicated rat. And the treatment of the extracts prevented the decrease of aminopyrine N-demethylation and aniline hydroxylation activities of the carbon tetrachloride-intoxicated rat liver. These results suggest that oral administration of Dendrobium moniliforme and Castanea crenata is effective in recovering the liver function in $CCl_4-treated$ rats.

• Bulletin of the Korean Chemical Society
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• v.31 no.10
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• pp.2873-2876
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• 2010

Excess free iron generates oxidative stress that may contribute to the pathogenesis of various causes of neurodegenerative diseases. Previous studies have shown that one of the primary causes of increased brain iron may be the release of excess iron from intracellular iron storage molecules. In this study, we attempted to characterize the oxidative damage of DNA induced by the reaction of ferritin with $H_2O_2$. When DNA was incubated with ferritin and $H_2O_2$, DNA strand breakage increased in a time-dependent manner. Hydroxyl radical scavengers strongly inhibited the ferritin/$H_2O_2$ system-induced DNA cleavage. We investigated the generation of hydroxyl radical in the reaction of ferritin with $H_2O_2$ using a chromogen, 2,2'-azinobis-(2-ethylbenzthiazoline-6-sulfonate) (ABTS), which reacted with ${\cdot}OH$ to form $ABTS^{+\cdot}$. The initial rate of $ABTS^{+\cdot}$ formation increased as a function of incubation time. These results suggest that DNA strand breakage is mediated in the reaction of ferritin with $H_2O_2$ via the generation of hydroxyl radicals. The iron-specific chelator, deferoxamine, also inhibited DNA cleavage. Spectrophotometric study using a color reagent showed that the release of iron from $H_2O_2$-treated ferritin increased in a time-dependent manner. Ferritin enhanced mutation of the lacZ' gene in the presence of $H_2O_2$ when measured as a loss of $\alpha$-complementation. These results indicate that ferritin/$H_2O_2$ system-mediated DNA cleavage and mutation may be attributable to hydroxyl radical generation via a Fenton-like reaction of free iron ions released from oxidatively damaged ferritin.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.3
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• pp.323-330
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• 2008

The study presents the results of 1,4-dioxane degradation using zero valent (Fe$^0$) or Fe$^{2+}$ ions with and without UV. During the reaction, the change of [Fe$^{2+}$] and [Fe$^{2+}$]/[Fe(t)], the concentration ratio of ferrous ion to total iron ion in solution was measured. Less than 10% degradation of 1,4-dioxane was observed by UV-only, Fe$^0$-only, and Fe$^{2+}$-only conditions, and also the changes of [Fe$^{2+}$] and [Fe$^{2+}$]/[Fe(t)] were minimal in each reaction. However, the oxidation of Fe$^0$ was enhanced with the irradiation of UV by approximately 25% and the improvement of 1,4-dioxane degradation was observed. Fenton reaction ($Fe^{2+}+H_2O_2$) showed higher degradation efficiency of 1,4-dioxane until 90 min, which of the degradation was stopped after that time. In the reaction of Fe$^{2+}$ and UV, the ratio of [Fe$^{2+}$]/[Fe(t)] decreased then slowly increased after a certain time indicating the reduction of Fe3+ to Fe$^{2+}$. In case of Fe$^0$ in the presence of UV, the first-order rate constant was found to be 1.84$\times$10$^{-3}$ min$^{-1}$ until 90 min, and then changed to 9.33$\times$10$^{-3}$ min$^{-1}$ when the oxidation of Fe$^{2+}$ mainly occurred. In this case [Fe$^{2+}$]/[Fe(t)] kept decreasing for the reaction. However, the addition of perchlortae (ClO$_4^-$) in the reaction of Fe$^0$ and UV induced the continuous increase of [Fe$^{2+}$]/[Fe(t)] ratio. The results mean the primary degradation factor of 1,4-dioxane is the oxidation by the radicals generated from the redox reaction between Fe$^{2+}$ and Fe$^{3+}$. Also, both UV and ClO$_4^-$ played the role inducing the reduction of Fe$^{3+}$, which is important to degrade 1,4-dioxane by enhancing the generation of radicals.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.24-29
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• 1999

Naturally-occurring iron minerals, goethite, magnetite, and hydrogen peroxide were used to catalyze and initiate Fenton-like oxidation of silica sand contaminated with mixture of diesel and kerosene in batch system. Optimal reaction conditions were investigated by varying pH(3, 7), $H_2O_2$ concentration(0%, 1%, 7%, 15%, 35%), initial contaminant concentration(0.2, 0.5, 1.0 g-mixture of diesel and kerosene/ kg-soil), and iron mineral contents(1, 5, and 10 wt % magnetite or goethite). Contaminant degradations in silica sand-iron mineral-$H_2O_2$ systems were identified by determining total petroleum hydrocarbon(TPH) concentration. The optimal pH of the system was 3. The system which iron minerals were the only iron source was more efficient than the system with $FeSO_4$ solution due to lower $H_2O_2$ consumption. In case of initial contaminant concentration of 1g-contaminant/kg-soil with 5 wt % magnetite, addition of 0%, 1%, 7%, 15%, and 35% of $H_2O_2$ showed 0%, 24.5%, 44%, 52%, and 70% of TPH reduction in 8 days, respectively. When the mineral contents were varied 0, 1, 5, and 10wt%, removal of contaminants were 0%, 33.5%, 50%, and 60% for magnetite and 0%, 29%, 41%, and 53% for goethite, respectively. Reaction of magnetite system showed higher degradation than that of goethite system due to dissolution of iron and mixed presence of iron(II) and iron(III); however, dissolved iron precipitated on the surface of iron mineral and seemed to cause reducing electron transfer activity on the surface and quenching $H_2O_2$. The system using goethite has better treatment efficiency due to less $H_2O_2$ consumption. When cach system was mixed by shaker, removal of contaminants increased by 41% for magnetite and 30% for goethite. Results of this study showed catalyzed $H_2O_2$ system made in-situ treatment of soil contaminated with petroleum possible without addition of iron source since natural soils generally contain iron minerals such as magnetite and goethite.

• Journal of Life Science
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• v.25 no.9
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• pp.1000-1006
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• 2015

α-Asarone is the main component of Acorus gramineus, which is a widely used oriental traditional medicine. A. gramineus is known to have a variety of medicinal effects, such as anti-gastric ulcer, antiallergy and antioxidant activity. It is also known to inhibit the release of histamine. However, the mechanism of its action remains unclear in humans. In this study, the effects of α-asarone on matrix metalloproteinase (MMP) and its antioxidant effect in a cell-free system were examined in HT1080 cells. In an MTT assay, the effect of α-asarone on cell viability showed no cytotoxicity below 16 μM. In an antioxidant assay, α-asarone increased reducing power in a dose-dependent manner but not the scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. In addition, α-asarone exhibited the protective effect against DNA oxidation induced by hydroxyl radicals produced by the Fenton reaction. Furthermore, in a gelatin disk assay, α-asarone enhanced collagenase activity. It also increased the activities of MMP-2 and MMP-9 stimulated by phorbol 12-myristate 13-acetate (PMA) in a gelatin zymography. On the other hand, the activity of MMP-9 stimulated by phenazine methosulfate (PMS) but not that of MMP-2 was increased in the presence of α-asarone. These findings suggest that α-asarone could be a candidate for the prevention and treatment of pathological diseases related to oxidative stress and MMPs.