• Journal of Naturopathy
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• v.7 no.2
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• pp.70-74
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• 2018

Purpose: This study was conducted to investigate the antioxidative, collagenase and elastase activities of defatted perilla ethanol extracts. In addition, the possibility of its use as a functional cosmetic material has been studied. Methods: In order to investigate the antioxidant function of the perilla extract, electron spin resonance (ESR) was measured with a spectrometer by analyzing the scavenging ability of diphenyl-β-picrylhydrazyl (DPPH) free radicals. Results: The antioxidant activity of DPPH free radical scavenging activity of the perilla extract was about 68% at 85 ㎍/ml, 85% at 20 ㎍/ml, 90% at 40-100 ㎍/ml, and showed antioxidant ability. The inhibitory activity of collagenase was increased to 4.1% at 20 mg/ml, 12% at 40 mg/ml and 26.7% at 100 mg/ml. The inhibitory activity increased in proportion to the concentration. The inhibitory activity of elastase was increased to 3.8% at 20 mg/ml, 15% at 40 mg/ml, 28% at 80 mg/ml and 35.7% at 100 mg/ml. Conclusions: These results suggest that the ethanol extract of perilla may inhibit the antioxidant activity and the activity of collagenase and elastase to improve the skin aging and wrinkles.

• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2379-2386
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• 2020

This paper presents the results of the first intercomparison exercise performed by the Korea retrospective dosimetry (KREDOS) working group using electron paramagnetic resonance (EPR) spectroscopy. The intercomparison employed the alanine dosimeter, which is commonly used as the standard dosimeter in EPR methods. Four laboratories participated in the dose assessment of blind samples, and one laboratory carried out irradiation of blind samples. Two types of alanine dosimeters (Bruker and Magnettech) with different geometries were used. Both dosimeters were blindly irradiated at three dose levels (0.60, 2.70, and 8.00 Gy) and four samples per dose were distributed to the participating laboratories. Assessments of blind doses by the laboratories were performed using their own measurement protocols. One laboratory did not participate in the measurements of Magnettech alanine dosimeter samples. Intercomparison results were analyzed by calculating the relative bias, E_n value, and z-score. The results reported by participating laboratories were overall satisfactory for doses of 2.70 and 8.00 Gy but were considerably overestimated with a relative bias range of 10-95% for 0.60 Gy, which is lower than the minimum detectable dose (MDD) of the alanine dosimeter. After the first intercomparison, participating laboratories are working to improve their alanine-EPR dosimetry systems through continuous meetings and are preparing a second intercomparison exercise for other materials.

• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.194-201
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• 2015

We have investigated the EPR signal properties in 12 components of two mobile phones (LCD, OLED) using electron paramagnetic resonance (EPR) spectrometer in this study.EPR measurements were performed at normal atmospheric conditions using Bruker EXEXSYS-II E500 spectrometer with X-band bridge, and samples were irradiated by $^{137}Cs$ gamma-ray source. To identify the presence of radiation-induced signal (RIS), the EPR spectra of each sample were measured unirradiated and irradiated at 50 Gy. Then, dose-response curve and signal intensity variating by time after irradiation were measured. As a result, the signal intensity increased after irradiation in all samples except the USIM plastic and IC chip. Among the samples, cover glass(CG), lens, light guide plate(LGP) and diffusion sheet have shown fine linearity ($R^2$ > 0.99). Especially, the LGP had ideal characteristics for dosimetry because there were no signal in 0 Gy and high rate of increase in RIS. However, this sample showed weakness in fading. Signal intensity of LGP and Diffusion Sheet decreased by 50% within 72 hours after irradiation, while signals of Cover Glass and Lens were stably preserved during the short period of time. In order to apply rapidly EPR dosimetry using mobile phone components in large-scale radiation accidents, further studies on signal differences for same components of the different mobile phone, fading, pretreatment of samples and processing of background signal are needed. However, it will be possible to do dosimetry by dose-additive method or comparative method using unirradiated same product in small-scale accident.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.1
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• pp.91-100
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• 2003

In the present study, we investigated the protective effect of the Lycii Fructus water extracts (LFE) against CCl4-induced hepatotoxicity and the mechanism underlying these protective effects in the rats. The pretreatment of LFE has shown to possess a significant protective effect by lowering the serum alanine and aspartate aminoteansferase (AST and ALT) and alkaline phosphatase (ALP). This hepatoprotective action was confirmed by histological observation, In addition, the pretreatment of LFE prevented the elevation of hepatic malondialdehyde (MDA) formation and the depletion of reduced glutathione (GSH) content and catalase activity in the liver of CC1₄-injected rats. The LFE also displayed hydroxide radical scavenging activity in a dose-dependent manner (IC50 = 83.6 μg/ml), as assayed by electron spin resonance (ESR) spin-trapping technique. Moreover, the expression of cytochrome P450 2E1 (CYP2E1) mRNA, as measured by reverse transcriptase-polymerase chain reaction (RT-PCR), was significantly decreased in the liver of LFE-pretreated rats when compared with that in the liver of control group. Based on these results, it was suggested that the hepatoprotective effects of the LFE may be related to antioxidant effects and regulation of CYP2E1 gene expression.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.2
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• pp.297-307
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• 2003

In the present study, we investigated the protective effect of the Puerarie Radix water extract (PRE) against CCl₄-induced hepatotoxicity and the mechanism underlying these protective effects in the rats. The pretreatment of PRE has shown to possess a significant protective effect by lowering the serum alanine and aspartate aminoteansferase (AST and ALT) and alkaline phosphatase (ALP). This hepatoprotective action was confirmed by histological observation. In addition, the pretreatment of PRE prevented the elevation of hepatic malondialdehyde (MDA) formation and the depletion of reduced glutathione (GSH) content and catalase activity in the liver of CC1₄-injected rats. The PRE also displayed hydroxide radical scavenging activity in a dose-dependent manner (IC50 = 83.6 μg/ml), as assayed by electron spin resonance (ESR) spin-trapping technique. Moreover, the expression of cytochrome P450 2E1 (CYP2E1) mRNA, as measured by reverse transcriptase-polymerase chain reaction (RT-PCR), was significantly decreased in the liver of PRE-pretreated rats when compared with that in the liver of control group. Based on these results, it was suggested that the hepatoprotective effects of the PRE may be related to antioxidant effects and regulation of CYP2E1 gene expression.

• Journal of Marine Bioscience and Biotechnology
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• v.7 no.1
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• pp.19-27
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• 2015

The objective of the current study was to evaluate the inhibitory and antioxidant activities of powdered katsuobushi (dried bonito) protein hydrolysates and their corresponding fractions. The powdered katsuobushi (dried bonito) hydrolysates were obtained by enzymatic hydrolysis using Alcalase, ${\alpha}$-chymotrypsin, Neutrase, pepsin, papain, and trypsin. The antioxidant efficacy of the respective hydrolysates were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, superoxide, and alkyl radical-scavenging activities. Among the hydrolysates, the peptic-derived hydrolysate exhibited the highest antioxidant activity compared to other enzymatic hydrolysates. Therefore, the peptic-derived hydrolysate was further analyzed, and was found to contain an active peptide with an amino acid sequence identified as Pro-Met-Pro-Leu-Asn-Ser-Cys (756 Da). The purified peptides from powdered katsuobushi (dried bonito) had an $EC_{50}$ value of $105.82{\mu}M$, and exhibited an inhibitory effect against DNA oxidation induced by hydroxyl radicals. Taken together, these results suggests that powdered katsuobushi (dried bonito) could be used as a natural antioxidant in functional foods and prevent oxidation reactions in food processing.

• Nutrition Research and Practice
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• v.5 no.6
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• pp.495-502
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• 2011

In this study, antioxidant and free radical scavenging activities of the natural antioxidative compound, pyrogallol-phloroglucinol-6,6'-bieckol (PPB) isolated from brown algae, Ecklonia cava was assessed in vitro by measuring the radical scavenging activities (DPPH, alkyl, hydroxyl, and superoxide) using electron spin resonance (ESR) spectrometry, intracellular reactive oxygen species (ROS) scavenging activity, and DNA damage assay. According to the results of these experiments, the scavenging activity PPB against difference radicals was in the following order: DPPH, alkyl, hydroxyl, and superoxide radicals ($IC_{50}$; 0.90, 2.54, 62.93 and $109.05{\mu}M$). The antioxidant activities of PPB were higher than that of the commercial antioxidant, ascorbic acid. Furthermore, PPB effectively inhibited DNA damage induced by $H_2O_2$. These results suggest that the natural antioxidative compound, PPB, can be used by the natural food industry.

• Macromolecular Research
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• v.15 no.4
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• pp.324-329
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• 2007

An octa-functional alkoxyamine initiator, with the 2,2,6,6-tetramethyl-l-piperidinyloxy (TEMPO) free radical, was synthesized based on resorcinarene, with its efficiency to initiate the nitroxide-mediated free radical copolymerization of styrene and methyl methacrylate (MMA) described. A difunctional analogue of this initiator was also synthesized, using resorcinol as the core molecule. The structures of the resulting initiators were confirmed by homolysis studies based on electron spin resonance spectroscopy and molecular modeling. The polymerization behavior and characteristics of the polymers obtained using these two initiators were also compared. Well-defined star-shaped and linear random copolymers, with low polydispersities and controlled molecular weights, were prepared. The efficiencies of these initiators towards copolymerization, as well as the parameters permitting the formation of well-defined polymers, were also investigated. The reactivity ratios were $r_a=0.42(a=styrene)\;and\;r_b=0.33(b=MMA)$ for the octa-functional initiator system and $r_a=0.45\;and\;r_b=0.39$ for the difunctional initiator system.

• Journal of Environmental Science International
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• v.25 no.3
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• pp.373-383
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• 2016

The aim of this study is to determine the exposure concentration of tetrabromobisphenol A(TBBPA) in southwestern coast and their photodecomposition rate. Also, it is to identify the radical species of the photodecomposition of TBBPA and their reactive byproducts using the electron spin resonance(ESR) method. TBBPA was not detected in any of the sea water samples from Mokpo, Gunsan, or Goheung. The sediment samples from Mokpo contained not detection(N.D)~50.0 ng/g dry wt., while those from Gunsan contained N.D~28.5 ng/g dry wt. and those from Goheung contained N.D~7.3 ng/g dry wt. The photodecomposition rates were $2.56{\times}10^{-6}/hr$ by visible light(400 nm), $7.98{\times}10^{-6}/hr$ by ultraviolet light(300 nm <), and $6.78{\times}10^{-6}/hr$ by sunlight. Also, we confirmed that singlet oxygen and hydroxyl radicals are the key reactive oxygen species at wavelengths greater than 400 and 300 nm, respectively. This study shows that the main byproducts formed during irradiation at wavelengths above 300 nm are 2,6-dibromobenzosemiquinone radical(2,6-$DBSQ{\cdot}^-$) and g-value 2.0048 doublet spectrum.

• Journal of the Korean Ceramic Society
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• v.51 no.3
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• pp.150-155
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• 2014

In aprevious study, the mutual interaction between $Fe_2O_3$ and $TiO_2$ was found to influence the color of celadon glaze. Celadon samples were prepared with varying concentrations of $TiO_2$ at a fixed level of $Fe_2O_3$. The electronic states of Fe and Ti were analyzed by M$\ddot{o}$ssbauer spectroscopy and electron spin-resonance spectroscopy, respectively. These results were examined with the celadon colors measured according to CIELAB values. This study revealed that an increase of $Ti^{3+}$ in the glassy phase decreased the $Fe^{2+}/Fe^{3+}$ ratio, resulting in a color change of the celadon samples in the GY and Y groups. The maximum reflectance wavelength was shifted from 505 nm to 610 nm with an increase in the $TiO_2$ concentration.