• Journal of Food Hygiene and Safety
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• v.15 no.3
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• pp.248-251
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• 2000

Electron spin resonance (ESR) spectroscopy was used to detect irradiated chicken eggs, to investigate the effect of irradiation dose on the ESR signal intensity and to identify the stability of radicals under 77 days of storage. Raw chicken eggs were irradiated with doses of 0, 0.5, 1, 2, 3 and 5 kGy at room temperature using a Co-60 irradiator. The samples were prepared by separating, drying and powdering shells from the raw eggs. The irradiated chicken egg shells presented an asymmetric absorption in shape at g$_1$=2.0023$\pm$0.00004 and g$_2$=1.9979$\pm$0.00005, different from the non-irradiated ones. The strength of the ESR signal increased linearly with the applied doses (to S kGy). The intensity of the ESR signals after irradiation were stable even after 77-day of storage at 5$^{\circ}C$ and/or room temperature.

• Archives of Pharmacal Research
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• v.27 no.9
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• pp.947-953
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• 2004

The antioxidative and hepatoprotective potentials of two anthraquinones, alaternin (2-hydroxy-emodin) and emodin, to scavenge and/or inhibit hydroxyl radicals generated by the Fenton reaction and to protect tacrine-induced cytotoxicity in human liver derived HepG2 cells were evaluated, respectively. The inhibitory activity on hydroxyl radical generated in a cell-free chemical system (FeSO$_4$/$H_2O$$_2$) was investigated by a fluorescence spectrophotometer using a highly fluorescent probe, 2$^1$,7$^1$-dichlorofluorescein. The hydroxyl radical scavenging activity was determined by electron spin resonance spectroscopy using 5,5-dimethy-1-pyrroline-N-oxide as hydroxyl radicals trapping agents. Tacrine-induced HepG2 cell toxicity was determined by a 3-［4,5-dimethylthiazole-2yl］-2,5-diphenyltertrazolium bromide assay. Although the scavenging activity of alaternin on hydroxyl radical was similar to that of emodin in dose-dependent pat-terns, the inhibitory activity exhibited by the former on hydroxyl radical generation was stron-ger than that of the latter, with $IC_{50}$/ values of 3.05$\pm$0.26 $\mu$M and 13.29$\pm$3.20 $\mu$M, respectively. In addition, the two anthraquinones, alaternin and emodin showed their hepatoprotective activ-ities on tacrine-induced cytotoxicity, and the EC$_{50}$ values were 4.02 11M and 2.37 $\mu$M, respec-tively. Silymarin, an antihepatotoxic agent used as a positive control exhibited the EC$_{50}$ value of 2.00 $\mu$M. These results demonstrated that both alaternin and emodin had the simultaneous antioxidant and hepatoprotective activities.ies.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.11
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• pp.1559-1564
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• 2012

Raisins (Thailand), dried mangos (Philippines), and dried figs (Iran) were gamma-irradiated (0~5 kGy), and their quality and detection characteristics were investigated. Microbiological characteristics were at safe levels when samples were irradiated at higher than 3 kGy. In color change after irradiation, dried mangoes were the most sensitive. Photostimulated luminescence (PSL) measurement was not applicable to dried fruits, showing negative or intermediate values for the irradiated samples. Thermoluminescence (TL) measurement was good for dried figs, exhibiting a glow curve in range of $150{\sim}200^{\circ}C$, where the signal intensity was dependent on the irradiation dose. Electron spin resonance (ESR) measurement was suitable for raisins and dried mangos, resulting in dose-dependent radiation-induced sugar radical signals.

• ALGAE
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• v.20 no.1
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• pp.69-75
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• 2005

Hizikia fusiformis is well known edible brown seaweed both in Korea and Japan. It has been intensively studied due to its pronounced health benefits. In this study, the radical scavenging (antioxidative) activities of its hydrophilic phlorotannin constituents were studied. An aqueous extract/original extract (OE) of H. fusiformis was initially prepared with heat, enzymes and pH control treatments. Then the original extract was further fractionated (with methylene chloride and methanol) and crude hydrophilic phlorotannin extract (CHPE) was prepared. The radical scavenging activities of both OE and CHPE were determined by using electron spin resonance (ESR) spectrophotometric assays such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and alkyl radical assays. The CHPE reported significantly (p < 0.05) higher total phenolic (phlorotannins) content (1.23 mg ${\cdot}ml^{-1}$) than that of the OE (0.21 mg ${\cdot}ml^{-1}$). Both OE and CHPE have reported good radical scavenging activities and those activities were dose-dependent. The CHPE have demonstrated significantly higher radical scavenging activities than that of the OE. In comparison, the DPPH radical (6 $\times$ 10$^{-5}$ M) scavenging activities of all the CHPE concentrations (0.25, 0.5 and 1 mg ${\cdot}ml^{-1}$) tested were significantly higher (37.3, 78.2 and 91.6%, respectively) than that of the OE counterparts (11.4, 34.6 and 61.7%, respectively). Alkyl radical scavenging percentages of CHPE at 0.0625, 0.125, 0.25 and 0.5 mg${\cdot}ml^{-1}$ were significantly higher (34.3, 69.2, 80.4 and 88.7%, respectively) than that of the OE (16.6, 41.4, 62.3 and 77.4%, respectively). The percentages of hydroxyl radical scavenging activities of CHPE at the concentrations of 0.25, 0.5 and 1 mg ${\cdot}ml^{-1}$ were 32.5, 59.4 and 84.2 % respectively. Moreover, the hydroxyl radical scavenging activity of OE was quite lower than that of the CHPE. Therefore, these results suggest that the hydrophilic phlorotannins of H. fusiformis are potential radical scavengers thus, a great source of antioxidative nutraceuticles.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.64-64
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• 1999

다결정 실리콘-게르마늄(poly-SiGe)은 태양전지 및 TFT-LCD와 같은 소자 응용에 있어서 중요하게 연구되고 있는 물질이다. 우리는 수소화된 비정질 실리콘-게르마늄 (a-Si1-xGex:H) 박막을 증착시키고 고상결정화시키며 XRD(x-ray diffraction) 및 ESR (electron spin resonance) 측정을 수행하였다. PECVD 증착가스는 SiH4과 GeH4가스를 사용하였고 Ge의 성분비는 x=0.0, 0.1, 0.5 정도로 조절되었다. 기판은 Corning 1737 glass를 사용하였고, 기판 온도는 20$0^{\circ}C$ 이었다. 증착압력과 r.f. 전력은 각각 0.6Torr와 3W이었다. 증착된 SiGe 박막은 고상결정화를 위해 $600^{\circ}C$ N2 분위기에서 가열되고, 그에 따른 XRD 및 ESR spectrum의 변화를 관찰하였다. ESR 측정은 X-band 그리고 상온에서 행해졌다. 먼저 XRD 측정으로부터 박막의 고상결정화 정도를 알 수 있었고, 고상결정화 과정이 초기 핵형성 단계와 결정화 단계, 그리고 더 이상 결정화가 일어나지 않는 완료 단계로 구분될 수 있음을 보여주었다. X값이 증가함에 따라 결정화 시간은 훨씬 단축되었다. ESR로 측정된 스핀 밀도는 a-Si1-xGex:H 박막이 처음 가열됨에 따라 전체적으로 크게 증가했다가, 결정화가 일어나면서 다시 감소하여 나중에는 거의 변화가 없었다. ESR 신호의 초기 증가는 수소 이탈에 의한 dangling bond의 증가에 기인하며, 다음 단계의 감소 및 안정 상태는 결정화에 따른 결정경계 영역의 감소와 결함들의 안정성에 기인하는 것으로 생각된다. 그러나 흥미로운 것은 Si1-xGex 합금의 경우 가열시간이 증가됨에 따라 Si-db(Si-dangling bond)와 Ge-db에 의한 신호가 서로 분리되어 나타났으며, 이 Si-db 스핀 밀도와 Ge-db 스핀밀도의 변화정도는 x값에 크게 의존함을 보여준 것이다. 즉 순수한 a-Si:H의 경우 Si-db 의 스핀밀도의 증가시간은 4시간 정도였고, 그리고 다시 감소하였으며, x=0.1 인 박막에서 Si-db와 Ge-db의 변화 시간은 순수 S-db 변화의 경우와 거의 유사하였다. 그러나 x=0.5 샘플에서는 Si-db의 변화가 빨라져서 0.1 시간 안에 증가되었고, Ge-db의 변화는 더 빠르게 수 분 동안에 증가 된후 다시 감소하였다. 이것은 수소의 Si에 대한 친화력 뿐 만아니라 Si-H과 Ge-H 결합에너지가 주위 원자들의 구성에 크게 영향받을 수 있는 가능성을 제시해준다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.4
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• pp.717-721
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• 2002

Study was carried out with electron spin resonance (ESR) spectroscopy to identify irradiated Korean medicinal herbs. Pueraria thunbergiana Benth., Angelica gigas Nakai, Agaricus blazei Murill and Astragalus membranaceus Bunge were irradiated with doses of 0, 1, 5 and 10 kGy at room temperature using a Co-60 irradiator. The irradiated Korean medicinal herbs exhibited an asymmetric absorption, which was different from the non-irradiated ones. The strength of ESR signals linearly increased by dose-dependent manner (1~10 kGy) and highly positive correlation coefficients ($R^2$=0.9428~0.9942) were obtained between the irradiation doses and the corresponding ESR signal intensities. Detection of the irradiated Korean medicinal herbs was possible even after 6 weeks of storage although the signal intensities of the irradiated samples decreased until 2 weeks at room temperature.

• Journal of the Korean Chemical Society
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• v.35 no.5
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• pp.569-574
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• 1991

Six free base porphyrins were synthesized by reacting pyrrole with benzaldehyde or its derivatives and then reacted with metal chlorides to prepare corresponding metal complexes. In addition, polymer-bonded porphyrins were synthesized by treating chloromethylated styrene-divinyl benzene (1%) copolymer beads with meso-tetra (p-aminophenyl)porphyrin (TNPP) solution and then treated with cupric chloride to obtain Cu(Res-NH-TPP-$NH_2$). The porphyrin compounds were characterized by visible, inffrared and electron spin resonance spectral analyses. The metal contents of metalloporphyrins were determined by atomic adsorption spectrophotometry. The synthesized porphyrin compounds were subsequently examined for their catalytic strength and found the activity to increase in the following order: free base porphyrins; metalloporphyrins; polymer-bonded metalloporphyrin. Among metalloporphyrins, Cu-TNPP showed the greatest catalytic power.

• Biomolecules & Therapeutics
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• v.21 no.4
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• pp.270-276
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• 2013

Fucoxanthin is an important carotenoid derived from edible brown seaweeds and is used in indigenous herbal medicines. The aim of the present study was to examine the cytoprotective effects of fucoxanthin against hydrogen peroxide-induced cell damage. Fucoxanthin decreased the level of intracellular reactive oxygen species, as assessed by fluorescence spectrometry performed after staining cultured human HaCaT keratinocytes with 2',7'-dichlorodihydrofluorescein diacetate. In addition, electron spin resonance spectrometry showed that fucoxanthin scavenged hydroxyl radical generated by the Fenton reaction in a cell-free system. Fucoxanthin also inhibited comet tail formation and phospho-histone H2A.X expression, suggesting that it prevents hydrogen peroxide-induced cellular DNA damage. Furthermore, the compound reduced the number of apoptotic bodies stained with Hoechst 33342, indicating that it protected keratinocytes against hydrogen peroxide-induced apoptotic cell death. Finally, fucoxanthin prevented the loss of mitochondrial membrane potential. These protective actions were accompanied by the down-regulation of apoptosis-promoting mediators (i.e., B-cell lymphoma-2-associated ${\times}$ protein, caspase-9, and caspase-3) and the up-regulation of an apoptosis inhibitor (B-cell lymphoma-2). Taken together, the results of this study suggest that fucoxanthin defends keratinocytes against oxidative damage by scavenging ROS and inhibiting apoptosis.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1060-1063
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• 2003

Electron spin resonance (ESR) spectroscopy was used to investigate the effects of irradiation doses and storage times on three spices. Three imported spices (Brassica juncea, Origanum vulgare, Laurus nobilis) were irradiated with doss of 0, 1, 5 and 10 kGy using a Co-60 irradiator at room temperature. ESR signals were measured from each sample by a Bruker-EPR spectrometer. The gamma-irradiated Brassica and Laurus nobilis exhibited characteristic signals, which were different from those of the non-irradiated ones. Non-irradiated and irradiated Origanum vulgare exhibited single lines, with higher ESR signals in irradiated sample than in non-irradiated sample. The ESR signals increased linearly with increasing irradiation doses $(1{\sim}10kGy)$. A strong positive correlation coefficient $(R^2=0.9939{\sim}0.9993)$ was obtained between the irradiation doses and the corresponding ESR signal intensities. Although the ESR signal intensities decreased with storage time, signals from the three irradiated spices were observed even after 12 weeks of storage at room temperature.

• Journal of Food Hygiene and Safety
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• v.15 no.1
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• pp.1-4
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• 2000

Electron spin resonance (ESR) spectroscopy was used to investigate the effect of irradiation dose on the ESR signal intensity of irradiated crabs and the stability of these radicals under 9 weeks of storage. Swimming and small crabs were irradiated with doses of 0, 1, 3, 5 and 7 kGy using a Co-60 irradiator at ambient temperature. A claw, a walking leg and a cars- pace of the crab pieced and dried were placed in a resonant quart tube within an EPR X-band spectrometer. The irradiated crabs presented an asymmetric absorption in shape at g$_1$=2.002 $\pm$ 0.003 and g$_2$=1.998$\pm$0.005, and were different from the non-irradiated ones. The intensity of the ESR signals was greatest in the claw, intermediate in the carapace and lowest in the walking leg. Samples given low and high doses of irradiation could also be distinguished. The ESR signal after irradiation was stable, even after a 9-week storage.