• Membrane Journal
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• v.18 no.3
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• pp.219-225
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• 2008

In this research, polydimethylsiloxane-polymethylmethacrylate (PDMS-PMMA) block copolymer was synthesized from polydimethylsiloxane (PDMS) and methylmethacrylate (MMA) monomer using atom transfer radical polymerization (ATRP). The synthesis characterization of the PDMS-b-PMMA copolymer membrane was carried out by a FT-IR, $^1H$-NMR, GPC and DSC. The permeabilities of nitrogen and hydrogen gases were observed being $1.2{\sim}l.5$ barrer and $6.2{\sim}10.5$ barrer, respectively. Simultaneously, selectivities of hydrogen against nitrogen were $5.3{\sim}6.9$. The permeability and selectivity of PDMS-b-PMMA copolymer membrane were showed lower than the PDMS membrane, but higher than the PMMA membrane.

• Preventive Nutrition and Food Science
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• v.13 no.3
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• pp.176-181
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• 2008

This study analyzed the some of the physiological activities of 70% ethanol extracts of specialty rough rice ('Goami2', 'Keunnunbyeo', and 'Heugkwangbyeo' rough rice cultivars) before and after germination. The physiological activities of the extracts were analyzed for their inhibition of linoleic acid peroxidation, hydrogen peroxide radical scavenging activity, superoxide dismutase-like activity, xanthine oxidase inhibitory activity, and nitrite scavenging effects. The most active rough rice cultivar was 'Heugkwangbyeo' and germinated 'Heugkwangbyeo' rough rice was more effective than ungerminated rough rice, having higher inhibition activity of linoleic acid peroxidation (1.2-fold), hydrogen peroxide radical scavenging activity (1.4-fold), superoxide dismutase-like activity (1.2-fold), and xanthine oxidase inhibitory activity (1.1-fold). The nitrite scavenging effect was increased after germination (2.1-fold) and decreased as pH increased. According to the results obtained in this study, 70% ethanol extracts from germinated 'Heugkwangbyeo' rough rice can be used for industrial applications such as the functional food materials.

• International Journal of Oral Biology
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• v.34 no.1
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• pp.15-20
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• 2009

In our present study, total methanol extracts prepared from B. platyphylla var. japonica showed a significant increase in cell proliferation upon the induction of oxidative stress by hydrogen peroxide or $\gamma$-ray irradiation. Total methanol extracts were fractionated into five separate preparations i.e. n-hexane, dichloromethane, ethylacetate, n-butanol and water fractions. Among these, the ethylacetate and butanol fractions of B. platyphylla var. japonica showed the highest protective effects against oxidative stress induced by hydrogen peroxide. These fractions also showed strong protective effects against $\gamma$-ray irradiation. When we evaluated the cytotoxicity of these fractions, the butanol fraction showed no effects in a colony formation assay. In addition, the butanol fraction showed a cell proliferation activation effect evidenced by significant increase in the colony formation of $\gamma$-ray irradiated cells. Both a radical scavenging activity and clonogenic activity assay suggested that the mechanism behind this protective effect against reactive oxygen species may be due to the radical scavenging and cell proliferation activity of B. platyphylla var. japonica extracts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.2
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• pp.172-178
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• 2010

This study was conducted to investigate total polyphenol contents and antioxidative effects of the enzymatic hydrolysates digested by several kinds of carbohydrases from the powder of ripened pumpkin (Cucurbita moschata), sweet pumpkin (C. maxima) and green pumpkin (C. moschata). The total polyphenol contents of all enzymatic hydrolysates from green pumpkin powder were higher than those of ripened and sweet pumpkins. DPPH radical scavenging activities of the enzymatic hydrolysates digested by AMG and Termamyl from green pumpkin were also very strong compared to ripened and sweet pumpkins. However, the most enzymatic hydrolysates of ripened and sweet pumpkin powders, except Viscozyme digestion, were higher superoxide anion scavenging activities than green pumpkin powder. Hydrogen peroxide scavenging activities in the enzymatic digests (not Ultroflo) of green pumpkin were potent compared to other pumpkin powders whereas hydroxyl radical scavenging activities were low at less than 14% in hydrolysates of all pumpkin species. Nitric oxide scavenging activities were very effective in Viscozyme digests of sweet and green pumpkin, and other enzymatic hydrolysates also showed higher activity than $\alpha$-tocopherol control (not BHT).

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.1
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• pp.1-7
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• 2010

This study was carried out to investigate total polyphenol contents, total flavonoid contents and antioxidative activities of the methanol extracts from dried Citrus sunki and C. unshiu peels. The dried C. sunki peels displayed higher total polyphenol and flavonoid contents for older dried peels. In contrast, the dried C. unshiu peels displayed higher total polyphenol contents for more recently dried and displayed high total flavonoid contents by order of 2007, 2008 and 2006. DPPH radical scavenging activities of dried C. sunki peels were high by order of 2007 (0.25 mg/mL exception), 2006 and 2008, but C. unshiu peels could not confirm clear regularity. In particular, the dried C. sunki (2008, exception) and C. unshiu peels displayed very high activities of more than 86% in 1.0 mg/mL. Alkyl radical scavenging activities of dried C. sunki peels were higher for older dried peels (2007, 1.0 mg/mL exception), and that of dried C. unshiu peels were higher for more recently dried in below 0.5 mg/mL but were higher for older peels in 1.0 mg/mL. Hydrogen peroxide scavenging activities of dried C. sunki peels were higher for older peels (2007, 2.5 mg/mL exception), on the other hand, dried C. unshiu were higher for more recently dried. In particular, dried C. unshiu peels displayed high activities of more than 85% in 2.5 mg/mL. Hydroxyl radical scavenging activities of dried C. sunki and C. unshiu peels displayed low activities compared to other reactive oxygen species as the range of $49.9\pm2.2\sim63.5\pm0.9$% in 1.0 mg/mL.

• Bulletin of the Korean Chemical Society
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• v.27 no.6
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• pp.830-834
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• 2006

Lipid peroxidation induced by the reaction of cytochrome c with $H_2O_2$ was investigated. When linoleic acid micelles or phosphatidyl choline liposomes were incubated with cytochrome c and $H_2O_2$, lipid peroxidation was increased in cytochrome c and $H_2O_2$ concentrations-dependent manner. Radical scavengers, azide, formate and ethanol prevented lipid peroxidation induced by the cytochrome c/$H_2O_2$ system. Iron specific chelator, desferoxamine also prevented the cytochrome c/$H_2O_2$ system-mediated lipid peroxidation. These results suggest that lipid peroxidation may be induced by the cytochrome c/$H_2O_2$ system via the generation of free radicals. Carnosine, homocarnosine and anserine are present in the muscle and brain of many animals and human. Previous studies show that these compounds have an antioxidant function. In the present study, carnosine, homocarnosine and anserine significantly prevented the cytochrome c/$H_2O_2$ system-mediated lipid peroxidation. Carnosine and related compounds also inhibited the free radical-generating activity of cytochrome c. The results suggest that carnosine, homocarnosine and anserine may prevent lipid peroxidation induced by the cytochrome c/$H_2O_2$ system through a free radical scavenging.

• 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.

• Environmental Analysis Health and Toxicology
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• v.15 no.4
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• pp.147-155
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• 2000

In order to evaluate anti -oxidant activities and protective effect against oxidatve damage, DPPH radical scavenging activity and lipid peroxidation inhibitory activity were measured among methanol extracts prepared from natural medicinal plants. Fourteen natural medicinal plants which were reported to have anti -oxidative or anti-inflammatory effects were selected based on our previous report. In addition to the total methanol extracts, n-hexane, dichloromethane, ethylacetate, n-butanol and water fractions were prepared from each total extract. DPPH radical scavenging assay was performed against 14 total extracts and all samples showed dose-dependent activities in various extent. Among those, 6 samples, methanol extracts of Euryale ferox, paeonia suffruticosa, Areca catechu var. dulcissima, Cinnamomun cassia, Alpinia katsumadai and Betula platyphlla var. japonica showed IC$\sub$50/ value lower than 6.0 $\mu\textrm{g}$/ml. The highest DPPH radical scavenging activity was found in ethylacetate fraction of paeonia suffruticosa with IC$\sub$50/ value of 1.1 $\mu\textrm{g}$/ml. Analysis of lipid peroxidation inhibitory activity on hydrogen peroxide-induced oxidative damage in Chinese hamster lung fibroblast (V79-4) cells revealed that the highest inhibitory effect was observed in methanol extract of Betula platyhpylla var. japonica. Lipid peroxidation inhibitory activity was observed as a dose-dependent manner in all samples used in this study. Among fraction samples, ethylacetate fraction of Alpinia katsumadai had the strongest inhibitory activity with IC$\sub$50/ value of 0.9 $\mu\textrm{g}$/ml.

• Biomedical Science Letters
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• v.14 no.3
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• pp.193-198
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• 2008

In order to evaluate on the effect of kaempferol on the cytotoxicity of oxygen tree radicals, XTT assay was performed to determine the cell viability after skin fibroblasts derived from human (Detroit 51) that were treated with various concentrations of hydrogen peroxide $(H_2O_2)$. And also, the effect of kaempferol on the cytotoxicity induced by H202 that was examined by cell viability, lactate dehydrogenase (LDH) activity and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity in these cultures. $H_2O_2$ decreased cell viability in dose-dependent manner in these cultures and the $XTT_{90}\;and\;XTT_{50}$ values were determined at concentration of $35{\mu}M\;and\;90{\mu}M$ of $H_2O_2$ after skin fibroblasts derived from human were treated with $15{\sim}90{\mu}M$ of $H_2O_2$ for 6 hours, respectively. $H_2O_2$ was highly toxic on cultured skin fibroblasts derived from human by toxic criteria of Brenfreund and Puerner (1984). In the protective effect of kaempferol on $H_2O_2$-induced cytotoxicity, kaempferol increased DPPH radical scavenging activity and significantly decreased LDH activity. From these results, it is suggested that oxygen tree radical, $H_2O_2$, was highly toxic on cultured skin fibroblasts derived from human, and also kaempferol of flavonoid showed the protection on $H_2O_2$-induced cytotoxicity.

• ALGAE
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• v.21 no.1
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• pp.149-156
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• 2006

The aim of the present study was to evaluate the antioxidant activity of red algae in Jeju Island. The algal extracts were obtained with MeOH and fresh water at 20 and 70°C, and screened for antioxidant activities using hydroxyl radical (HO·), superoxide anion (O2–), hydrogen peroxide (H2O2) and DPPH free radical scavenging assays. Among them, Gracilaria verrucosa methanolic extract at 20°C (20ME, 96.85%), G. textorii aqueous extract at 20°C (20AE, 88.01%), Grateloupia filicina 20AE (85.35%), and Polysiphonia japonica 20ME (94.92%) exhibited the highest scavenging activities against HO·, O2–, H2O2, and DPPH free radicals, respectively. Moreover, P. japonica (20ME and 70ME) is correlated between DPPH free radical scavenging activity and polyphenolic contents. These results indicate that some red algae in Jeju Island could be potential candidates for development of antioxidants.