• Preventive Nutrition and Food Science
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• 제7권1호
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• pp.57-61
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• 2002

Electron spin resonance (ESR) spectroscopy was used to investigate the effect of irradiation dose and storage time on the free radical concentrations in gamma-irradiated dried seasoning powder. Seasoning powders of dried squid flavor, shrimp flavors, kimchi flavor, spicy beef soup flavor and soy sauce flavor were irradiated with doses of 0, 1, 3, 5, 7 and 9 kGy at room temperature using a Co-60 irradiator. Characteristic signals of free radicals were observed in all the irradiated samples of this experimental while these signals were not detected in non-irradiated samples. Since the free radical concentrations linearly increased with the applied doses (1~9 kGy), highly positive correlation coefficients ($R^2$ = 0.9285~0.9965) were obtained between irradiation doses and free radical concentrations during all the storage times. Free radical concentrations of the irradiated flavored seasoning powder did not change even at 16 weeks of storage at room temperature, while those of dried squid, shrimp and spicy beef soup flavors decreased until 2 weeks of storage after irradiation with 5 kGy or over, and these of soy cause flavors slowly decreased until 8 weeks of storage after irradiation with 3 kGy or over. Although the free radical concentrations decreased with storage times, the characteristic signals of the irradiated seasoning powders of dried squid, shrimp, spicy beef and soy sauce flavors were observed even after 16 weeks of storage at room temperature.

• 대한의생명과학회지
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• 제9권2호
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• pp.75-84
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• 2003

To evaluate the influence of hepatic oxygen free radical systems on liver injury by topical p-phenylenediamine (PPD) application on rat skin, PPD (25 mg/16.5 $\textrm{cm}^2$) was topically applied to the abdominal region 5 times every other day and sacrificed. By PPD treatment, increasing rate of liver weight/body weight (%), serum activities of alanine aminotransferase and aspartate aminotransferase and decreasing rate of microsomal glucose-6-phosphatase activity were higher in the rats fed tungstate supplemented diet than those fed a standard diet. These findings indicate that group fed tungstate supplemented diet have more severe liver injury compared with group fed standard diet on topical PPD application. However, the activities of oxygen free radical generating enzymes such as xanthine oxidase (XO) and cytochrome P450 dependent aniline hydroxylase and those of oxygen free radical scavenging enzymes were not found to be different between these two animal groups. In the present study, a novel monitoring method to detect the generating of oxygen free radicals in liver extract was devised. Throughout this method, the oxidized PPD produced by oxygen free radicals was determined colorimetrically. The increasing rate of PPD oxidation by liver homogenate was higher in tungstate fed animals than in standard diet fed ones. Among the fractionations of liver extract, the mitochondrial and postmitochondrial fractions in the liver extract of tungstate fed animals led to a higher availability of PPD oxidation by PPD treatment compared with standard diet fed ones. In conclusion, these results suggest that an enhanced liver injury in tungstate fed animals treated with PPD may be due to oxygen free radicals produced in other systems except oxygen free radicals generating from cytosolic XO system. Especially, oxidative availability by PPD can be used for oxygen free radical detection in some tissue.

• 한국식품위생안전성학회지
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• 제14권2호
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• pp.179-185
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• 1999

Previous studies have shown that methanol extract and its butanol fraction of Carthamus tinctorius L. Semen have the hepatoprotective effect on the CCl4-induced hepatotoxicity. The hepatoprotective effect of the subfractions of butanol fraction has been evaluated by analyzing oxygen free radical scavenging enzyme activities and histopathological examinations. In BS-5 subfraction treated group, the activity of superoxide dismutase has been significantly increased as compared with that of CCl4, treated rats. Antioxidant activity has been evaluated by the examination of the scavenging activity against 1,1-diphenyl-2-picrylhydrazyl radical. BS-5 subfraction has shown strong antioxidant activities. The histopathological examination showed that the treatment of BS-5 subfraction has relieved the ballooning degeneration of hepatocytes which had been generated by CCl4. It appears that the protective effect of BS-5 subfraction would be mediated of the attenuation of lipid peroxidation by acting as a free radical scavenger, which were based on the increase of superoxide dismutase activity.

• 대한의생명과학회지
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• 제5권1호
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• pp.51-58
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• 1999

실험동물에 있어서 $CCl_4$에 의한 급성 간손상시 피부조직의 oxygen free radical 대사효소 활성 변동을 검토하기 위해 흰쥐에 $CCl_4$와 olive oil의 동량 혼합액을 체중 100g당 0.1 ml씩 복강으로 투여하여 처치하였다. $CCl_4$ 투여로 인한 혈청 alanine aminotransferase 및 xanthine oxidase (XO) 활성은 현저히 증가되었으며 체중당 간무게 (%)및 간조직의 malondialdehyde함량 역시 유의하게 증가되었다. 그리고 병리조직 검사에서도 $CCl_4$투여군에서 간조직의 괴사성 병변이 관찰되었다. 따라서 $CCl_4$를 투여한 실험동물이 급성 간손상 모델로 확인되었다. 이와 같은 간손상 실험동물의 피부조직중 oxygen free radical의 생성 효소인 XO 활성은 대조군과 별다른 차이를 볼 수 없었으나 oxygen free radical의 scavenging 효소인 superoxide dismutase, glutathione peroxidase 및 catalase 활성은 대조군에 비하여 유의하게 감소되었다. 또한 세포화학적 검사에서 cerrous perhydroxide과립이 간손상 실험동물의 피부조직에서 많이 나타났다. 이상 실험결과는 $CCl_4$에 의한 급성 간손상 유도 실험동물의 피부조직에 $H_2O$$_2$의 축적이 나타나는 현상을 시사해주고 있다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2000년도 춘계학술대회
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• pp.6-7
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• 2000

Recently, free radicals such as active oxygen species, nitric oxide, etc are believed to be one of the key substances in physiological and pathological, toxicological phenomena, and oxidative damages, and all organism have defencing system against such as free radicals. Formation and extinction of free radicals may be regulated through bio-redox system, in which various enzymes and compounds should be involved in very complicated manner. Thus, direct and non-invasive measurement of in vivo free radical reactions with living animals must be essential to understand the role of free radicals in pathophysiological phenomena. Electron spin resonance spectroscopy (ESR) is very selective and sensitive technique to detect free radicals, but a conventional ESR spectrometer has large detect in application to living animals, since high frequent microwave is absorbed with water, resulting in generation of high fever in living body. In order to estimate in vivo free radical reactions in living whole animals, we develop in vivo ESR-CT technique using nitroxide radicals as spin probes. Nitroxide radicals and their reduced forms, hydroxylamines, are known to interact with various redox systems. We found that! ! the signal decay due to reduction of nitroxyl radicals is influenced by aging, inspired oxygen concentration, ischemia-referfusion injury, radiation, etc. In the present paper, I will introduce in vivo ESR technique and my laboratory recent results concerning non-invasive evaluation of free radical reactions in living mice.

• Preventive Nutrition and Food Science
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• 제12권3호
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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.

• Advances in Traditional Medicine
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• 제8권3호
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• pp.260-265
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• 2008

Annona reticulata belonging to the family Annonaceae is traditionally used as anthelmintic and it is reported to have anticancer activity. Free radicals are known to be involved in various types of diseases like cancer, diabetes, neurological disorders etc. The present study was aimed to evaluate free radical scavenging property of methanol extract of the leaves of Annona reticulata in some in vitro models e.g. DPPH, nitric oxide, superoxide and lipid peroxide radical model. The extract showed good dose-dependent free radical scavenging property in all the models. $IC_{50}$ values were found to be 3.22, 170.01, 25.12 and $140.12\;{\mu}g/ml$ respectively in DPPH, nitric oxide, superoxide and lipid peroxidation inhibition assays. Reductive ability of the extract was also tested based on potassium ferricyanide reduction where dose dependant reducing capability was observed. Measurement of total phenolic compounds by Folin-Ciocalteu's phenol reagent indicated that 1mg of the extract contained $146.20\;{\mu}g$ equivalent of pyrocatechol. The findings ascertain promising free radical scavenging property of the extract and the antioxidant property of the extract may be due to the high content of phenolic compounds.

• Bulletin of the Korean Chemical Society
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• 제17권11호
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• pp.1009-1018
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• 1996

A study on the application of vinyl radical cyclization via free radical allylation reaction in the synthesis of various carbocyclic compounds is described. In connection with this study, a new allyl transfer reagent, 2-bromo-3-(phenylthio)propene 1 is developed and it was shown that vinyl radical cyclization through free radical allylation reaction using reagent 1 provides a valuable approach to carbocyclic systems with a reactive exo-alkylidene moiety, which is advantageous for further transformations.

• 한국식품영양과학회지
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• 제31권1호
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• pp.117-123
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• 2002

본 연구는 김치가 노화와 직접적인 관련이 있는 유리기 생성 및 항산화 효소활성에 미치는 영향을 살펴보기 위하여 배추김치, 배추갓김치 그리고 갓김치를 식이중량의 5% 첨가하여 실험식이를 제조하고 이를 녹화촉진주인 SAMP8에게 1년간 섭취시켰다. 총유리기, OH radical, $H_2O_2$ 농도 그리고 TBARS 오 모두 가령에 따라 증가하였으며, 김치섭취시 유의적으로 감소되었다(p<0.05). 김치군에 있어서 생성된 유리기를 제거하기 위해 항산화계 효소인 SOD, catalase, GSH-px 그리고 GSH/GSSG는 모든 김치군에서 유의적으로 증가 하였다(p<0.05). 따라서 김치섭취는 먼저 가령에 의해 생성되는 유리기의 생성은 억제시키면서, 둘째 이를 제거하기 위한 항산화계 효소 활성은 더욱 활성화시키므로써 항노화 기능을 발휘한다고 생각된다. 김치종류 중에서는 배추갓김치와 갓김치가 배추김치보다 유리기 생성을 억제하고, 항산화계 활성을 증진시킨 것으로 보아 이들의 항노화 효과가 클 것으로 생각된다.로 생각된다.

• 한국식품과학회지
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• 제35권1호
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• pp.121-124
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• 2003

본 연구는 거봉종 포도의 종자와 과피로부터 에탄올용매의 농도와 추출 온도변화에 의한 추출물의 수율의 차이와 그에 따른 free radical 소거 활성을 비교하였다. 각 분획물은 에탄올 추출물로부터 hexane 분획물, chloroform 분획물, ethyl acetate 분획물, butanol 분획물 및 물 분획물로 나누어 free radical 소거 활성을 $RC_{50}$으로 타나내었다. 추출 수율은 종자 및 과피 모두에서 추출 온도 $78^{\circ}C$, 에탄올 농도 100%에서 36.0%와 49.5%로 다른 온도와 농도 조건에 비하여 높은 수율을 나타내었다. 각 분획물 중에서는 물 분획물이 종자에서는 72.1%인데 비하여 과피에서는 92.7%로 다른 분획층에 비하여 많이 차지하였다. DPPH법에 의한 free radical 소거 활성에서는 종자의 경우, $78^{\circ}C$ 에탄올 추출물이 $RC_{50}\;=\;409.7\;{\mu}g/mL$이며, 분획물에서는 ethyl acetate층이 $RC_{50}\;=\;136.7{\mu}g/mL$로 가장 높은 활성을 나타내었다. 과피의 경우, $78^{\circ}C$ 에탄올 추출물이 $RC_{50}\;=\;6528.8\;{\mu}g/mL$로, 분획물에서는 ethyl acetate층이 $RC_{50}\;=\;694.7\;{\mu}g/mL$로 가장 높은 활성을 나타내었으나, 물 분획물은 free radical 소거 활성을 보이지 않았다. 이상의 결과를 통하여 추출온도와 용매 온도에 따른 수율의 차이가 나타났으며 추출온도와 free radical 소거 활성의 효능은 별다른 차이가 없는 것으로 나타났다. 전반적으로, 본 연구 결과 종자 에탄올 추출물과 분획물 모두 과피 추출물보다 현저히 높은 활성을 나타내었다.