• Natural Product Sciences
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• v.7 no.2
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• pp.45-48
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• 2001

The antioxidative effect of the extracts from the leaves and fruits of Acer ginnala against free radicals was studied by two different methods using DPPH radical-generating system, and hydroxyl radical-generating system $(Cu^{++}/H_2O_2\;system)$ which induces DNA strand breaking. Compared with well known antioxidative plants, green tea, Scutellaria baicalensis, the Acer ginnala extracts showed excellent radical-scavenging activity in DPPH radical-generating system and inhibited effectively hydroxyl radical induced-DNA strand breaking in a concentration-dependent manner in $Cu^{++}/H_2O_2$ system whereas the green tea extract stimulated the strand breaking at a low concentration. These results suggest that he extracts from the leaves and fruits of Acer ginnula could be good antioxidative agents.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.312-316
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• 2009

Antioxidant-rich oils were extracted from different parts of sea buckthorn berry with supercritical $CO_2$ (SC-$CO_2$) and n-hexane. The functional components were analyzed and the extracts were screened for their potential as radical scavengers in 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), 2,2'-azinobis-3-ethylbenzotiazoline-6-sulphonic acid (ABTS), galvinoxyl systems. Minor differences were found in fatty acid composition of oils extracted by the two methods. Seed oil contains the highest content of tocopherols while pulp oil and whole berry oil possessed higher concentration of carotenoids. Whole berry oil, pulp oil, and seed oil extracted by SC-$CO_2$ showed 91.7, 90.9, and 93.5% radical scavenging activity (RSA) at 6 mg/mL towards DPPH and 74.3, 54.3, and 74.8% towards galvanoxyl radical at 10 mg/mL. The hexane-extracted oils showed similar scavenging ability. However, the oils obtained by hexane showed significantly higher RSA (p<0.05) than those obtained by SC-$CO_2$ while whole berry oil has the highest RSA towards ABTS among 3 oil samples.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.4
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• pp.165-169
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• 2012

It is very difficult to detect irradiated South Sea cultured pearls (SSCPs) at a low dose by gemological methods (e.g. optical transmission method, microscopic examination, UV fluorescence reaction, and so on). In this study, however, it was possible to distinguish between irradiated SSCPs from un-irradiated SSCPs by ESR analysis. We have analyzed the pearl nacre and nucleus by separating them for the purposed of providing information about the change of $CO^-_2$ radical as growing absorbed doses. And it was found out that the signal of $CO^-_2$ radical of the nacre is more distinct than the nucleus.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.22 no.2
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• pp.115-123
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• 1996

Methanolic aqueous extracts of 100 plants were screened for antioxidative activity using Fenton's reagen/ethyl linoeate system and free radical scavenging activity using DPPH free radical generating system. The results suggest that at least six plants including Eugenia caryophyllata, Alpinia offiicinarum, Rhus verniciflua, Curcuma longa, Rheum palmatvm and Evodia officinalis may be the potential sources of antioxidant, But only one plant, Cornus officinalis, may be the potential source of free radical scavenger from natural plants.

• Journal of Life Science
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• v.2 no.2
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• pp.91-96
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• 1992

효소에 의한 carotenoid의 co-oxidationgus상은 lipoxygenasechrao하에서 지방산인 linoleic acid가 산화되어 이때 만들어진 free radical에 의해 carotenoid가 쉽게 산화되기 때문에 일어나는 현상이다. 이화같이 carotenoid의 co-oxidation에서 lipoxygenase는 free radical을 만들면서 반응속도를 빠르게 하는 촉매제의 역할을 다음과 같이 담당하고 있다고 할 수 있다. Lipoxygenase에 의한 carotenoid의 co-oxidation 현상을 처음 발견한 것은 대두가루를 밀가루와 혼합하여 사용할 때였다. 대두가루 속에 다량 함유된 lipoxygenase에 의해 밀가루의 carotenoid 색소가 표백되는 것을 보고 이 현상은 lipoxygenase에 의해 기질은 지방산이 산화되는 동안 caroenoid가 쉽게 co-oxidation되기 때문이라는 것을 알아내었다. 즉, carotenoid는 지질이 존재하는 반응시스템에서 항산화제로서 혹은 secondary substrate로서 작용한다고 할 수 있다.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.110.2-110.2
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• 2003

The ethanol extracts of mixed vegetables (Bioactive V, BV), mixed fruits (Bioactive F, BF) and its liquid formulation (Chungpae Plus$\circledR$) were evaluated for their antioxidative and antigenotoxic activity. They were shown to possess the significant free radical scavenging effect against l,l-diphenyl-2-picryl hydrazine (DPPH) radical generation and were revealed to show the inhibitory effect of lipid peroxidation as measured by malondialdehyde (MDA) formation. (omitted)

• Bulletin of the Korean Chemical Society
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• v.7 no.2
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• pp.150-153
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• 1986

Co-sensitized photooxygenation of 1,1-diphenyl-2-vinylcyclopropane (VCP-DPh) with 9,10-dicyanoanthracene and biphenyl in oxygen-saturated acetonitrile solution produced 3,3-diphenyl-5-vinyl-1,2-dioxolane as the major product. The same photoproduct was obtained by acetone sensitized photooxygenation in oxygen-saturated acetone solution. However, VCP-DPh remained intact when directly irradiated with DCA or irradiated with Rose Bengal to generate singlet oxygen. A mechanism involving a cosensitizer radical cation and sensitizer radical anion is proposed.

• Preventive Nutrition and Food Science
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• v.12 no.3
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• pp.177-180
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• 2007

Tocotrienols (T3) are minor plant constituents found abundantly in rice bran, which provide a significant source of vitamin E in animal feeds. T3 was reported to have an intrinsic hypocholesterolemic effect by inhibiting HMG-Co A reductase. It has similar antioxidative properties as tocopherols in food and biological system due to their similar chemical structures. However, the antioxidant activity and mechanism of T3 to scavenge free radicals and to inhibit the peroxidation of linoleic acid are less understood. The purpose of this study was to investigate the scavenging effect of T3 on free radicals and its inhibition of peroxide formation. Free radical scavenging activity was monitored by the DPPH (1,1-diphenyl-2-picrylhydrazyl) method whereas inhibition of linoleic acid peroxidation was evaluated using the thiocyanate method. Thiobarbituric acid (TBA) test was used to determine malonaldehyde formation from linoleic acid peroxidation. Free radical scavenging activity increased with increasing concentration levels of T3. T3 exhibited 38.2, 78.6, 92.7 and 96.2% radical scavenging activity at concentrations of 2, 8, 32 and 128 ppm, respectively. At 128 ppm, it was highly effective in inhibiting linoleic acid peroxidation. The activity of T3 evaluated by the thiocyanate method showed low absorbance values indicating a high level of antioxidant activity. All treatments showed similar trends in antioxidant activity when evaluated by both the thiocyanate method and TBA test.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.170-173
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• 2002

Electron spin resonance (ESR) spectroscopy was used to detect free radicals in irradiated wheat flour and glutinous rice flour. They were irradiated with doses of 0, 0.1, 0.5, 1 and 2 kGy at room temperature using a Co-60 irradiator. Free radicals detected for irradiated wheat flour and glutinous rice flour were higher than those of unirradiated ones. Since concentration of free radicals linearly increased with applied doses $(0.1{\sim}2\;kGy)$, highly positive correlation coefficients $(R^2=0.9995{\sim}0.9998)$ were obtained between irradiation doses and free radical concentrations right after irradiation. Although concentration of free radicals slowly decreased with storage time, the characteristic ESR signals of free radical in irradiated samples were observed even after 4 weeks of storage at room temperature.

• Polymer(Korea)
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• v.34 no.6
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• pp.553-559
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• 2010

The paper describes the preparation and characterization of conductive polyaniline-modified polymers by growing of aniline onto functionalized poly(styrene-co-p-methylstyrene) [P(St-co-MSt)]. For this purpose, P(St-co-MSt) was synthesized via nitroxide mediated radical polymerization (NMRP) and then N-boromosuccinimide was used for introduction of bromine to the benzylic positions of copolymer. Afterwards, 1,4-phenylenediamine was linked to the brominated P(St-co-MSt) and functionalized copolymer $[P(St-co-MSt)-NH_2]$ was prepared. The graft copolymerization of aniline monomers onto functionalized P(St-co-MSt) was initiated by oxidized phenylamine groups after addition of ammonium peroxydisulfate (APS), and p-toluenesulfonic acid-doped PANI was chemically grafted onto P(St-co-MSt) via oxidation polymerization. The obtained terpolymer was studied by FTIR and UV-Vis spectroscopy and its thermal behaviour were examined by DSC and TGA analyses. The conductivity of terpolymer was measured by four-point probe method and electroactivity was measured by cyclic voltammetry (CV). The solubility of P(St-co-MSt)-g-PANI was examined in common organic solvents.