• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.964-972
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• 2011

This work investigated the difference between $Fe^{2+}$ autoxidation-induced and Fenton-type cleavage of pBR322 plasmid DNA. $^{\cdot}OH$ generation reactions in the absence and presence of $H_2O_2$ under various conditions were also investigated. Although both the $Fe^{2+}$ autoxidation and Fenton-type reactions showed DNA cleavage and $^{\cdot}OH$ generation, there were significant differences in their efficiencies and reaction rates. The rate and efficiency of the cleavage reaction were higher in the absence of 1.0 mM of $H_2O_2$ than in its presence in 20 mM phosphate buffer. In contrast, the $^{\cdot}OH$ generation reaction was more prominent in the presence of $H_2O_2$ and showed a pH-independent, fast initial reaction rate, but the rate was decreased in the absence of $H_2O_2$ at across the entire tested pH range. Studies using radical scavengers on DNA cleavage and $^{\cdot}OH$ generation reactions in both the absence and presence of $H_2O_2$ confirmed that both reactions spontaneously involved the active oxygen species $^{\cdot}OH$, ${O_2}^{\cdot-}$, $^1O_2$ and $H_2O_2$, indicating that a similar process may participate in both reactions. Based on the above observations, a new mechanism for the $Fe^{2+}$ autoxidation-induced DNA cleavage reaction is proposed.

• Journal of the Korean Chemical Society
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• v.53 no.3
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• pp.340-344
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• 2009

HEMA/vinyl-substituted polyphosphazene was prepared by the ring-opening polymerization of phosphonitrillic chroride trimer at $200{\sim}300\;{^{\circ}C}$, followed by Grignard reaction with vinyl magnesium bromide and then by the reaction with HEMA(2-hydroxyethyl methacrylate). HEMA/vinyl-substituted polyphosphazene was copolymerized with EGDMA(ethylene glycol dimethacrylate; used as a cross-linker for the free-radical copolymerization), NVP (N-vinyl-pyrrolidone) in the presence of AIBN (azobisisobutyronitrile) as a radical initiator. The oxygen transmissibility, water content and visible-ray transmissibility of the resulting copolymer were measured to be Dk/t 88, 30.89% and 87%, respectively, indicating that the copolymer can be used as a good contact lens material.

• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.22-29
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• 2001

To evaluate the cutaneous injury in liver damaged rats by toluene application to the skin, toluene(35mg/㎤) was sequentially applied for 5 days to the dorsal skin of liver damaged rats with $CCl_4$ (6 times ever other day:0.1$m\ell$/100 g body weight-50% $CCl_4$in olive oil). The cutaneous ultrastructural changes were unexoectably not observed in liver from $CCl_4$-treated rats although necrotic liver damage appeared under light microscope. In these animals by the application of toluene to rat skin the cutaneous xanthine oxidase activity was significantly increased(p<0.05), but cytochrome P450 content was not different from that of the control or only $CCl_4$-treated rats. On the other hand, the cutaneous superoxide dismutase and catalase activities in liver damaged animals were significantly respectively(p<0.05, p<0.001), decreased by toluene application to the skin compared with control and especially the former enzyme activity was significantty decreased(p<0.01), compared with that of liver damaged rate rat but glutathione peroxidase, glutathione-S-transferase activities were not significantly different from those of the control or liver damaged rats. Futhermore, the reduced gluathione content of skin was also significantly decreased by toluene application to the liver damaged animals. In conclusion, the great deposits of cerrous peroxide and ultramorphological changes in skin tissue of liver damaged animals by toluene application may be responsible for the oxygen free radical.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.41-41
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• 2011

The aims of this study were to examine the efficacy of phytochemicals of Rumex crispus as anti-oxidant and anti-browning agent. The bioactive properties of Rumex crispus as natural colorants were studied by total phenolic contents, DPPH radical scavenging, ABTS radical scavenging,lipid peroxidation, cell viability, singlet oxygen quenching and photoprotection effect. Among all of the results ($IC_{50}$: the concentration of various extracts required to exert 50% reducing effect), the higher activity of the extract was found in the ethyl acetate and butanol extracts. Anti-browning activity was evaluated by monitoring the change $L^*$, $a^*$, $b^*$ values and total color differences(${\Delta}E$). It was found that ethyl acetate and butanol extracts effectively inhibited browning in apple juice at a concentration below 0.3 mg/ml. Rumex crispus extracts used natural colorants could be of good resources as anti-oxidant and anti-browning agents. The results suggest that our study may contribute to the development of natural and functional materials with potential application to reduce oxidative damage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.7
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• pp.997-1002
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• 2013

This study investigated the physicochemical properties (pH, Brix), total phenol content, antioxidant activities (DPPH radical scavenging activity and oxygen radical absorbance capacity (ORAC)), and nitrite scavenging activity of beverage concentrates and purees. All concentrates and purees were produced from natural materials and have been used as the main ingredients in health-related beverages. Our results show that the pH values and Brix of all concentrates and purees ranged from 2.81 to 5.12 and 1.70 to 70.30 Brix, respectively. The highest total phenol content (182.71 mg GAE/mL), DPPH radical scavenging activity (69.88%) and nitrite scavenging activity (28.19%) were obtained from acai berry puree. The concentrate from wild blueberry had the highest ORAC value ($27,514{\mu}M$ TE/mL). Among the correlation coefficient data, the total phenol content exhibited a high correlation coefficient (r=0.9099) and DPPH radical scavenging activity. These results suggest that concentrates and purees from natural materials contribute to antioxidant activities in healthy beverages.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.1 s.49
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• pp.73-78
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• 2005

This work was carried out to investigate the antioxidative effects of Acanthopnax sessiliflorus from Jeongseon County for the purpose of development of a novel antioxidant from natural products. The antioxidant activity was determined by using electron paramagnetic resonance (EPR), not measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) which have bun used for antioxidant activity of natural sources. Although DPPH radical scavenging activity assay have been generally used for antioxidant activity, this assay is nut appropriated for determinating which radical is scavenged by extracts from natural products. Using EPR, we determinated whether A. sessiliflorus extracts from Jeongseon County scavenge specific radicals or not. On experiment of scavenging superoxide anion radical, hydroxyl radical, nitrogen dioxide and peroxinitrite. Extracts from A. sessiliflorus showed high antioxidant activities to reactive oxygen and nitrogen species. These result suggest that extracts from A. sessiliflorus act as an antioxidant by scavenging reactive oxygen and nitrogen species and used as new cosmetic ingredients for anti-oxidative stress in skin.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.184-189
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• 1996

A scavenger of superoxide anion radical which causes oxygen toxicity was isolated from Capsella bursa-pastoris, and its physicochemical properties were investigated. The scavenger was isolated and purified by solvent fractionation and liquid column chromatographies (Amberlite XAD-2, Sephadex LH-20, Bio gel P-2, ODS (silica gel with 100% octadecyl silanization)). An active compound of 0.25 g was finally isolated by Fast Protein Liquid chromatography (FPLC) from 100 g ethanol extract of Capsella bursa-pastoris. A 50% decrease of superoxide anion radical was obtained with the scavenger compound of 0.58 g. The compound was assumed to be a phenolic glycoside from its physicochemical properties.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.794-798
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• 2003

The reactive oxygen species (or free radicals) generated by ultraviolet radiation cause damage on cellular components and pigment of skin. The aim of this study was to investigate the skin-whitenig effect of Okyong-san. Inhibitory effects of okyong-san extracts on melanin synthesis were studied. Namely, UV-absorbing ability, free radical scavenging activity and tyrosinase inhibitory activity of okyong-san extracts were investigated. As a result, the extracts of okyong-san were found to inhibit the activity of tyrosinase and they showed an absorbance in the UV-B region and UV-C region. We also observed that extracts of okyong-san had free radical scavenging activity.

• Toxicological Research
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• v.11 no.1
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• pp.57-62
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• 1995

To investigate the ultrastructural changes of kidney and clarify to a cause of its changes in lead intoxicated rats, the 0.5% lead acetate administed orally to the rats and those were sacrifled at 2 day, 1, 2, 4, 6 and 8 week after the treatment of lead acetate. Each extirpated kidney was histopathologically examined under the electron microscopy and histochemical examination was also carried out. Concomitantly, the activity of free radical metabolizing enzyme was determined. The blood levels of lead concentration showed a gradual increase from the first group reaching the plateau at the one or two week group with the slightly decreasing value throughout the whole course of the experiment. And the urinary ALA concentration showed a gradual increase from the first group to the 8 week group. In the kidney tissue of rat sacrified at 6 week, the proximal tubular cells showed dilatation of endoplasmic reticulum, mitochondrial swelling, increased numbers of secondary lysosomes and myelin figure-like residual bodies on electron microscope and oxygen free radicals are identified by histochemistry on light microscope whereas there were no differences in the activity of catalase and glutathione peroxidase between the lead acetate treated group and control group. But the activity of xanthine oxidase was more increased in lead acetate treated rats than control group. Furthermore, the superoxide dismutase activity was significantly increased in the experimental group than the control group. In conclusion, it is assumed the kidney damage in lead intoxicated rat may be induced by free radicals.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2005.04a
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• pp.131-148
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• 2005

This study is peformed to investigate the effect of water extract from Vaccinium uliginosum L., on melanin production in B 16 melanoma cells, procollagen production and matrix metalloproteinase-1(MMP-1) inhibition in human fibroblast cells. One hundred grams of the Vaccinium uliginosum L. was extracted with 2000 mL of water($90^{\circ}C$, 16h, 2times). The water extracts were lyophilized and stored at $4^{\circ}C$ until used. Dry weight yields of extracts of Vaccinium uliginosum L. were $3\%$(w/w). Extracts from Vaccinium uliginosum L. showed scavenger activities on DPPH radical, superoxide anion radical, hydroxyl radical, hydrogen peroxide and singlet oxygen radical. And these substances inhibited release of cyiokines from human keratinocyte after UV B exposure. Therefore we confirmed that extracts from Vaccinium uliginosum L. had antioxidative effect. These substances inhibited purified tyrosinase activity and melanogenesis in B 16 melanoma cells treated/untreated IL-$1{\alpha}$. Moreover this extract stimulated procollagen production and inhibited MMP-1 production in human fibroblast cells treated/untreated IL-$1{\beta}$. Therefore we confirmed that extracts from Vaccinium uliginosum L. had whitening effect. And these substances decreased degree of wrinkle in hairless mouse skin that induced by UV B irradiation. Therefore we confirmed that extracts from Vaccinium uliginosum L. had anti-wrinkle effect. From the above results, it is possible that Vaccinium uliginosum L. may be developed to be an anti-melanogenesis agent and anti-wrinkle agent.