• Bulletin of the Korean Chemical Society
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• v.22 no.8
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• pp.857-866
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• 2001

Efficient syntheses of PGI2 analogue 2a and its epimer 3 have been accomplished. Using aryl iodide 6 as the common intermediate, either radical or palladium-assisted tandem alkene insertion strategies have been employed for construction of the benzoprostacyclin framework.

• Korean Journal of Plant Resources
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• v.26 no.3
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• pp.347-354
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• 2013

Apple and pear are popular fruits consumed in Korea and are common fruit in daily diet. In order to compare the antioxidant activity of the apple and pear peels, total polyphenol contents, total flavonoid contents, $ABTS^+$ free radical scavenging activity, and DPPH free radical scavenging activity were measured from hot water, ethanol, and methanol extracts of the two fruit peels. The total polyphenol and flavonoid contents were highest in 95% methanol extracts of the apple peelsand 70% ethanol extract of the pear peels, respectively. Total polyphenol contents of the pear peels were higher than that of apple peels, and total flavonoid contents of the apple peels were higher than that of pear peels. The apple and pear peels had the highest $ABTS^{+{\cdot}}$ and DPPH free radical scavenging activity in 95% methanol extracts and 70% ethanol extracts, respectively. $ABTS^{+{\cdot}}$ and DPPH free radical scavenging activity of pear peels was higher than that of apple peels, and the DPPH free radical scavenging activity of apple and pear peels were detected in hot water, 95% methanol, and 70% ethanol extracts, respectively. Ascorbic acid, a synthetic antioxidant used as positive control, had significantly higher scavenging activity than the apple and pear peels. In conclusion, the apple and pear peelshave great potential as natural antioxidants. Therefore, above results should be considered to provide the possibility for the development of high functional antioxidants.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.1
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• pp.1-10
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• 2001

Since the Industrial Revolution, people have enjoyed an abundant life, owing to the technological innovations of science. However, because of changes in the environment or polution to the environment, it has brought on many chronic diseases. Especially, even though it may be a small amount, if cadmium gets into a human body, because its biological half life is long, it fatally causes a kidney disease and damage to human organisms. It was reported that Metallothioneins(MT), a substance that is closely related with a free radical that comes from environmental pollution and the course of which cadmium, which causes chronic addition in the body, is formed, along with harmful metals, make the toxicity reduce. MT compound led into the body by cadmium indirectly functions as an antioxidation, supplied adequate amount of vitamin E, and suppresses the accumulation of cadmium in heart, liver and blood. Cadmium content found in Korean soil according to the test conducted from 1992 to 1996 was 0.02~0.03mg/kg in cereals, pulses, and potatoes. Free radical scavenger, finding solution for metal substance that comes from environmental pollution from food and natural substances implicates a better future for the study of food science.

• Elastomers and Composites
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• v.39 no.4
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• pp.281-285
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• 2004

In this paper, the simple way to evaluate the value of the activation energy for the overall rate of free radical polymerization by using DSC thermograms was studied using free radical polymerization or butylacrylate as a model. Activation ehergies were determined at heating rates of 1, 2, 5, and $10^{\circ}C/min$ by applying the multiple scanning-rate methods of Kissinger, Osawa, and half-width methods as well as the single rate method of Barrett. The value of the overall activation energy measured was closely matched with the values calculated from individual data. This work also demonstrated that the use of the isoconversional method was a simple and effective way to estimate the activation energy for the overall free radical polymerization.

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.303-306
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• 2003

Indonesia is a tropical country having a temperature range of 25-35$^{\circ}C$ which can affect the skin and causes damages like aging. This aging process is due, at least, to free radical reactions. For this reason, many attempts had been done to find out creams containing natural antioxidant compound which have a potential of free radical scavenger. Kluwek, a fermented form of foot ball fruit or picung (Pangium edule.Reinw), had been proved to contain antioxidant compound in its methanol fraction oil to which antiaging cream was formulated. Stability evaluation was conducted for cream with Kluwek oil compared to base cream, including organoleptic (colour and odour), pH, viscosity, particle size, centrifugation test and flow characteristics either in room temperature (27$^{\circ}C$) or stress condition (4$^{\circ}C$ and 5$0^{\circ}C$) for 8 weeks continuously, and six times cycling test at 4$^{\circ}C$ and 5$0^{\circ}C$ every 24 hours. The results showed that cream with Kluwek oil and base cream were stable at temperature 27 and 4$^{\circ}C$, cycling test and centrifugation test, but not stable at 5$0^{\circ}C$. Free radical evaluation was done by Electron Spin Resonance and the result showed that cream with Kluwek oil had less free radicals compared to base cream.

• Korean Journal of Exercise Nutrition
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• v.13 no.1
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• pp.29-35
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• 2009

The purpose of this study was to investigate the effects of oral supplementation of coenzyme Q10 (CoQ10) for 4 weeks on the plasma free oxygen radical and total antioxidant capacity at resting and after one bout exercise in healthy old men. Thirty volunteers with an average (+/-SD) age of 62.59+/-5.3 years participated in this study and were divided with three groups; CoQ10 (200 mg daily) group, vitamin C & E (800mg, 400 IU daily) group, and placebo group. A cycle exercise (60% HRR) test was performed at the end of study. Blood samples were taken for the analyses at rest and pre-, post-, 30min after cycle exercise, before and after the 4 weeks of supplementation. After supplementation, there were no significant differences in the plasma free oxygen radical levels and total antioxidant capacity at resting. Plasma free oxygen radical level and total antioxidant capacity in three groups were significantly elevated after exercise, however, it did not vary significantly between groups. CoQ10 supplementation showed significant difference in total antioxidant capacity during recovery phase compared with placebo group. Our results demonstrated that supplementation of CoQ10 in healthy old men improve blood total antioxidant capacity after one bout exercise, despite no alteration of plasma free oxygen radical levels.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.39 no.3
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• pp.195-203
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• 2013

In this study, antioxidative effects of the extracts of different species and flowering periods of Inula britannica were investigated. According to the free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity of the extracts, The I. britannica var. chinensis flower extract (500 ${\mu}g/mL$) was measured in a 79.89% free radical scavenging activity, but the flower extracts of similar species (I. britannica var. linariaefolia Regel, I. britannica var. ramosa, I. salicina var. asiatica) did not show any effect on the free radical scavenging activity. The effects of the free radical scavenging activity of I. britannica var. chinensis flower extracts were exhibited in the order of full bloom (93.68%), bud (43.28%), and fallen blossom (14.11%). Next, we established optimum condition of extract solvent, temperature, extraction time. The extract from ethanol at $60^{\circ}C$ showed the most free radical scavenging activity among other conditions and extraction time not relevant in free radical scavenging activity. The protective effects of the extract of I. britannica var. chinensis flower on the photohemolysis of human erythrocytes by using rose bengal were increased in a concentration-dependent manner (5 ~ 50 ${\mu}g/mL$). In particular, the extract in 50 ${\mu}g/mL$ concentration exhibited better protective activity (${\tau}_{50}$ = 116.1 min) than (+)-${\alpha}$-tocopherol (${\tau}_{50}$ = 73.44 min), which is a known lipophilic antioxidant. Principle component of I. britannica var. chinensis flower was identified as quercetin of flavonoids by high-performance liquid chromatography (HPLC). These results indicate that the extract of I. britannica var. chinensis flower can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging free radical and $^1O_2$, and protect cellular membranes against ROS. It is concluded that the antioxidative effects of the extract of I. britannica var. chinensis flower could be applicable to functional cosmetics.

• Journal of Life Science
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• v.12 no.2
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• pp.75-79
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• 2002

Tea catechins, the most important compounds in tea polyphenols, can efficiently scavenge superoxide anion free-radical ($O_2$.), hydroxyl radical. (.OH) The mechanism of scavenging active oxygen free radicals was investigated by ESR spin trapping technique and Chemiluminescence. Results showed that various tea catechins constitute an antioxidant cycle in accordance with the decreasing order of the first reductive potential, and produce the effect of cooperative strength each other. Esterificated catechins could scavenge active oxygen free radicals more effectively than the non-esterificated ones. When.OH and $O_2$.- were scavenged by (-)-epigallocatechin gallate [(-)- EGCG], the stoichiometric factors were 6, and the rate constants of scavenging reaction reached $7.71{\times}10^6$ and $3.52{\times}10^{11}$ L $mmol^{-1}s^{-1}$, respectively. In the mean time, tea catechins could scavenge superoxide anion fiee radical ($O_2$-.) and hydroxyl radical (.OH) in a dose dependent manner. But at higher concentration or pH value, tea catechins can induce the prooxidant.

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.58-58
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• 2003

포유동물 체외 수정란의 체외 발육율을 향상시키기 위해서는 배양액내에 생성되는 free radical을 제거하는 것이 한가지 요인으로 지적되고 있다. 체외 배양액내에 생성되는 free radical을 제거하기 위하여 여러 종류의 항산화제 첨가 배양이 많이 이용되어 체외발육성적을 향상시키고 있다. 포유동물의 번식에 있어서 Melatonin은 광주기 조절 작용에 기여하는 호르몬으로서 혈중 Melatonin의 농도는 번식 작용에 중요한 역할을 하며, 또한 수정란의 세포분열과 세포주기에 영향을 미치며 배양액내의 free radical을 제거하여 수정과 초기 수정란 발달에 영향을 미쳐 항산화 기능이 있는 것으로 보고되고 있다.

• Journal of Life Science
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• v.4 no.1
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• pp.11-18
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• 1994

Plant phenolics은 식물 생체에 널리 분포되어 있으므로 매일 일정량이 식품으로 섭취되어지고 있으며, 이 물질들은 식품 외에도 일부 향신료 및 의약용으로 이용되어지고 있다. 본 논문에서는 plant phenolics이 free radical scavenger로서의 주요 작용을 포함한 항산화 메카니즘과 기타 항산화 특성, 그리고 plant phenolic계 free radical scavenger 물질인 flavonoids와 hydroxycinnamic acids 및 hydroxycinnamic acid derivatives의 항산화 활성과 구조 간의 관계에 초점을 두어 고찰하였다. 또한 주요 식물별 plant phenolics 물질의 특성과 항산화 활성에 대하여서도 검토하였다.