• 청정기술
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• 제25권1호
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• pp.46-55
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• 2019

CdS 및 CdZnS/ZnO를 침전법으로 제조하여 가시광선하에서의 로다민 B의 광분해 반응에 대한 광촉매로 이용하였다. 제조된 광촉매들은 X선 회절분석기와 UV-vis 확산반사 분광법 등으로 특성을 분석하였으며, 그 결과 원하는 결정구조를 지닌 광촉매들이 생성되었으며 또한 CdS 및 CdZnS/ZnO 두 가지 광촉매 모두 자외선뿐만 아니라 가시광선 영역의 빛도 효율적으로 흡수함을 알 수 있었다. 여러 종류의 활성 화학종에 대한 포집제들을 첨가하면서 각각의 광촉매에 대한 활성을 조사하였으며, 특히 두 가지 촉매상에서의 반응기구 차이점에 중점을 두고 고찰하였다. 이때 $CH_3OH$, KI 및 p-benzoquinone을 각각 ${\cdot}OH$ 라디칼, 광여기 정공 그리고 ${\cdot}O_2{^-}$ 라디칼에 대한 포집제로 이용하였다. 각각의 광촉매상에서는 서로 다른 반응기구에 의해서 반응이 진행되는 것으로 나타났다. CdS 광촉매 반응에서는 ${\cdot}O_2{^-}$ 라디칼이 그리고 CdZnS/ZnO 광촉매 반응에 있어서는 광여기 정공이 중요한 역할을 하는 것으로 판단되며, 따라서 CdS와 CdZnS/ZnO 각각의 광촉매상에서는 발색단 골격의 탈알킬화 반응 및 발색단 콘쥬케이트 구조의 절단 과정을 통하여 반응이 우선적으로 진행된다는 것을 알 수 있었다. 이러한 결과들은 CdS, CdZnS 그리고 ZnO 각각 반도체들의 전도대와 가전자대의 띠끝 전위와 활성 화학종 생성에 대한 산화환원 전위의 차이에 주로 기인한 것으로 생각된다.

• 상하수도학회지
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• 제24권6호
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• pp.775-788
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• 2010

The decomposition of 2,4,6-trinitrotoluene (TNT) and the mass balance of nitrogen (N) species as products were investigated in a UV/H2O2system by varying pH, concentrations of $H_2O_2$, and $O_2$. All experiments were conducted in a semi-batch system employing a 50 mL reaction vessel and a coil-type quartz-tube reactor. In contrast with previous studies employing batch mode, TNT decomposition in the semi-batch mode was proportionally enhanced by increasing $H_2O_2$ concentration to 10 mM (0.034%), indicatingthat an inhibitory effect of excess $H_2O_2$on hydroxyl radical (${\cdot}OH$) can be negligible. N compounds are released as $NO_2^-$ in the early stages of the reaction, but $NO_2^-$ is rapidly oxidized to $NO_3^-$ by means of ${\cdot}OH$. $NH_4^+$ was also detected in this study and showed gradually the increase with increasing reaction time. In this study, $NH_4^+$ production can involve the reduction of nitro group of TNT concurrent with the production of $NO_3^-$. Of the N species originating from TNT decomposition, 12 ~ 72% were inorganic forms (i.e. [$NO_3^-$] + [$NO_2^-$] + [$NH_4^+$]). This result suggests that the large remaining N portions indicate that unidentified N compounds can exist.

• Reproductive and Developmental Biology
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• 제35권4호
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• pp.485-489
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• 2011

The present study was conducted to examine the reactive oxygen species (ROS) generation levels and subsequent DNA damage in the bovine cultured somatic cells. Bovine ear skin cells were classified by serum starvation, confluence and cycling cells. Cells were stained in 10 ${\mu}M$ dichlorohydrofluorescein diacetate ($H_2DCFDA$) or 10 ${\mu}M$ hydroxyphenyl fluorescein (HPF) dye to measure the $H_2O_2$ or $^{\cdot}OH$ radical levels. The samples were examined with a fluorescent microscope, and fluorescence intensity was analyzed in each cell. $H_2O_2$ and $^{\cdot}OH$ radical levels of cultured somatic cells were high in confluence group ($7.1{\pm}0.7$ and $8.4{\pm}0.4$ pixels/cell, respectively) and significantly low in serum starvation group ($4.9{\pm}0.4$ and $7.0{\pm}0.4$ pixels/cell, respectively, p<0.05). Comet tail lengths of serum starvation ($148.3{\pm}5.7$ ${\mu}M$) and confluence ($151.1{\pm}5.0$ ${\mu}M$) groups were found to be significantly (p<0.05) increased in comparison to that of cycling group ($137.1{\pm}7.5$ ${\mu}M$). These results suggest that the culture type of donor cells can affect the ROS generation, which leads the DNA fragmentation of the cells.

• Archives of Pharmacal Research
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• 제26권6호
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• pp.458-462
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• 2003

The antioxidant activity of the stem bark from Albizzia julibrissin was evaluated for its potential to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, to inhibit the generation of the hydroxyl radical ($\cdot OH$), total reactive oxygen species (ROS) and to scavenge authentic peroxynitrites ($ONOO^{-}$). The methanol extract of A. julibrissin exhibited strong antioxidant activity in the tested model systems. Therefore, it was further fractionated using several solvents. The antioxidant activity of the individual fractions were in the order of ethyl acetate (EtOAc) ＞ n-butanol (n-BuOH) ＞ dichloromethane ($CH_2 CI-2$) ＞ and water ($H_2O$). The ethyl acetate soluble fraction, which exhibited strong antioxidant activity, was further purified by repeated silicagel, Sephadex LH-20 and RP-18 gel column chromatography. Sulfuretin (1) and 3 ,4 ,7-trihydroxyflavone (2) were isolated as the active principles. Compounds 1 and 2 exhibited good activity in all tested model systems. Compound 1 exhibited five times more inhibitory activity on the total ROS than Trolox. Compound 2 showed six times stronger DPPH radical scavenging activity than L-ascorbic acid. These results show the possible antioxidant activity of the A. julibrissin crude extract and its major constituents.

• 한국약용작물학회지
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• 제26권2호
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• pp.134-140
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• 2018

Background: The extract of Abies holophylla is used as an ingredient in cosmetics. This study assessed the antioxidant and antibacterial activities of the material remaining after the extract is used. Methods and Results: The 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azinobis (3-ethyl benzothiazoline)-6-sulfonic acid (ABTS) radical scavenging abilities were assessed to determined the free radical scavenging activity. The total phenol and flavonoid contents were determined to measure the antioxidant activity. The DPPH and ABTS radical scavenging activities of the resudual extract were higher (95.61 - 99.42% and 74.26 - 77.98% in water extract respectively) than those of the positive control. In 50% EtOH extract, the total phenol content was $389.84mg{\cdot}GAE/m{\ell}$, and the total flavonoid was $0.15mg{\cdot}QE/m{\ell}$. The minimum inhibition concentration degree for antibacterial activity against Staphylococcus aureus was < 8 to < $125{\mu}g/m{\ell}$ compared to that of the positive control in all extracts. The clear zone against S. aureus was found to be $12.2{\pm}3.8mm$. Conclusions: The A. holophylla byproducts were found to have antioxidant and antibacterial activities. Therefore, the materials remaining after the A. holophylla extract is used in cosmetics has potential functional uses.

• Advances in Traditional Medicine
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• 제8권3호
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• pp.266-278
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• 2008

Erythrina stricta, a deciduous tree widely used traditionally in indigenous system of medicine for various ailments such as rheumatism, fever, leprosy, epilepsy etc. The leaves of Erythrina stricta was extracted with ethanol (70%) and used for the evaluation of various in vitro antioxidant assays which includes H - donor activity, nitric oxide scavenging, superoxide anion scavenging, reducing ability, hydroxyl radical, hydrogen peroxide scavenging, total phenolic content, total flavonoid content, total antioxidant activity by thiocyanate and phosphomolybdenum method, metal chelating, $\beta$-carotene bleaching, total peroxy radical assays. The pro-oxidant activity was measured using bleomycin-dependent DNA damage. Ex vivo models like lipid peroxidation and erythrocyte haemolysis were also used to study the antioxidant property of the extract. The various antioxidant activities were compared with suitable standard antioxidants such as ascorbic acid, butylated hydroxyl toluene, $\alpha$-tocopherol, curcumin, quercetin and Trolox. The generation of free radicals viz. $O_2^{{\cdot}-}$, $OH^{\cdot}$, $H_2O_2$, $NO^{\cdot}$ and peroxyl radicals were effectively scavenged by the ethanolic extract of Erythrina stricta. In all the methods, the extract offered strong antioxidant activity in a concentration dependent manner. The total phenolic content, flavonoid content and total antioxidant activity in Erythrina stricta were determined as microgram (g) pyrocatechol, quercetin and $\alpha$-tocopherol equivalent/mg respectively. The extract did not exhibit any prooxidant activity when compared with ascorbic acid. The results obtained in the present study clearly indicates that Erythrina stricta scavenges free radicals and reduces lipid peroxidation, ameliorating the damage imposed by oxidative stress in different disease conditions and serve as a potential source of natural antioxidant.

• 한국수산과학회지
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• 제33권2호
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• pp.87-92
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• 2000

간장중의 활성산소 및 제거효소의 활성에 미치는 영향을 평가하기 위하여 미역의 건조분말을 $10{\%},\;20{\%},\;40{\%}$-첨가 조제한 미역국수 ($10{\%},\;20{\%},\;40{\%}\;FBA-noodle$)를 4주동안 SD계 흰쥐에 투여하여 미역국수의 생리작용을 평가하였다. $10{\%},\;20{\%},\;40{\%}$ FBA-noodle의 투여그룹의 mitochondria의 ${\cdot}OH$ 생성은 대조그룹 대비 각각 $20{\%},\;25{\%},\;35{\%}$의 현저한 OH 생성 억제효과가 인정되었다. 또한 $10{\%},\;20{\%},\;40{\%}$ FBA-noodle의 투여그룹의 microsome의 ${\cdot}OH$ 생성도 대조그룹 대비 $12{\~}20{\%}$의 유의적인 ${\cdot}OH$ 생성 억제효과가 인정되었다. $10{\%},\;20{\%},\;40{\%}$ FBA-noodle의 microsome의 $H_2O_2$의 생성은 유의적인 억제효과를 인정할 수 없었지만, cytosol중의 $O_2^({\cdot}-)$ 생성은 $20{\%},\;40{\%}$ FBA-noodle에서 $10{\%}$의 $O_2^({\cdot}-)$의 생성 억제효과가 인정되었다. $10{\%},\;20{\%},\;40{\%}$ FBA-noodle 투여그룹의 간장 mitochondria의 Mn-SOD 활성은 대조그룹 대비 $10{\~}15{\%}$의 Mn-SOD 활성의 증가효과가 인정되었다. 간장 microsome의 Mn-SOD 활성은 $10{\%} 및 20{\%}$ FBA-noodle 투여그룹은 Mn-SOD 활성의 유의적인 증가 효과를 인정할 수 없었지만, $40{\%}$ FBA-noodle 투여그룹은 $12{\%}$의 유의적인 Mn-SOD 활성 증가효과가 인정되었다. 또한 $10{\%},\;20{\%},\;40{\%}$ FBA-noodle의 투여그룹의 간장 cytosol의 Cu, Zn-SOD 활성은 대조그룹 대비 $10{\~}20{\%}$의 Cu, Zn-SOD 활성의 유의적인 증가효과가 인정되었다. 한편 간장 cytosol의 글루타치온 퍼옥시다아제 (GSHPx) 활성을 평가하여 보면 $10{\%}, 20{\%}, 40{\%}$ FBA-noodle 투여그룹의 cytosol의 GSHPx 활성은 대조그룹 대비 $20{\~}40{\%}$의 매우 효과적인 GSHPx활성의 증가효과가 인정되었다. $10{\%}, 20{\%}, 40{\%}$ FBA-noodle 투여그룹의 mitochondria의 LPO의 함량을 비교하여 보면 $10{\%}$ FBA-noodle은 유의적인 LPO의 생성 억제효과를 인정할 수 없었지만, $20{\%},\;40{\%}$ FBA-noodle은 $10{\%}$의 유의적인 LPO 생성 억제효과가 인정되었다. $10{\%},\;20{\%},\;40{\%}$ FBA-noodle 투여그룹의 microsome의 LPO의 함량은 $10{\%}$ FBA-noodle은 유의적인 LPO의 생성 억제효과를 인정할 수 없었지만, $20{\%} 및 40{\%}$ FBA-noodle은 약 $10{\~}12{\%}$의 유의적인 LPO 생성 억제효과가 인정되었다.

• 상하수도학회지
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• 제27권1호
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• pp.39-47
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• 2013

This study demonstrates the oxidative degradation of pharmaceutical compounds during ozonation of surface waters in Ulsan. Diclofenac, carbamazepine, bezafibrate, and ibuprofen were selected as surrogate pharmaceutical compounds, and ozonation experiments were performed using raw waters collected from the Sayeon Dam and the Hoeya Dam in Ulsan. Diclofenac and carbamazepine which have high reactivity with molecular ozone showed higher removal efficiencies than bezafibrate and ibuprofen during ozonation. The addition of tert-butanol, a hydroxyl radical scavenger, increased the removal efficiencies of diclofenac and carbamazepine by increasing the ozone exposure. However, the oxidation of bezafibrate and ibuprofen was inhibited by the presence of tert-butanol due to the suppression of the exposure to hydroxyl radical. The elimination of the selected pharmaceuticals could be successfully predicted by the kinetic model base on the $R_{ct}$ concept. Depending on the experimental condition, $R_{ct}$ values were determined to be $(1.54{\sim}3.32){\times}10^{-7}$ and $(1.19{\sim}3.04){\times}10^{-7}$ for the Sayeon Dam and the Hoeya Dam waters, respectively. Relatively high $R_{ct}$ values indicate that the conversion of $O_3$ into $^{\cdot}OH$ is more pronounced for surface waters in Ulsan compared to other water sources.

• Food Science and Biotechnology
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• 제18권1호
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• pp.167-171
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• 2009

This study examined the antioxidative activity of delphinidin, a kind of anthocyanidin from eggplant. Cellular protective potential from oxidative damage by nitric oxide (NO), superoxide anion ($O_2^-$), and peroxynitrite ($ONOO^-$) using epithelial cell line LLC-PK1 cell as well as in vitro radical scavenging effects were investigated. Delphinidin showed strong in vitro radical scavenging effects against NO, $O_2^-$, and hydroxyl radical (${\cdot}OH$) in dose-dependent manners. In addition, delphinidin increased cell viability in LLC-PK1 cells in a concentration-dependent manner when viability was reduced by $ONOO^-$-induced oxidative damage. To elucidate the protective mechanisms of delphinidin from $ONOO^-$, sodium nitroprusside (SNP), and pyrogallol were also employed to generate NO and $O_2^-$, respectively. The treatment of delphinidin recovered reductions in cell viability caused by SNP and pyrogallol, indicating that delphinidin can attenuate oxidative stress induced by NO and $O_2^-$. The present study suggests that delphinidin is a promising anti oxidative agent.

• Korean Journal of Acupuncture
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• 제22권4호
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• pp.57-65
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• 2005

대계는 전통 한의학에서 약용 물질로 널리 쓰이고 있으므로, 대계의 약침을 조제하여 항산화적 활성을 검증해 보았다. 실험의 재료로 쓰인 대계는 동국대학교 한의과대학 부속 한방 병원에서 구입하여 사용하였고 (경상북도 경주), 이를 약침액으로 조제한 후 동결 건조 방법으로 5.1 %의 분말을 회수 하였다. 대계 약침액의 항산화 능력을 측정하기 위하여 DPPH자유기의 소거능은 Gyamfi et al. 의 방법을 따랐고, superoxide radicals $(O_2^-{\cdot})$ 소거능은 Gotoh et al.의 방법을 일부 수정하여 사용하였다. Hydroxyl radicals의 직접적인 소거능과 iron ions 사이의 관계는 deoxyribose assay를 통하여 검증하였다. 이상의 실험 결과에서 1) Non-site-specific scavenging assay (hydroxyl radicals, OH) 및 2) Site-specific scavenging assay (chelate iron ions) 그리고 3) 전산화 효과에서 모두 대계 약침액은 농도 의존적인 저해 효과를 보였으며, 특히 pro-oxidant 실험에서는 산화를 촉진하지 않는 것으로 나타났다. 끝으로 hydorxyl radical에 의하여 매개되는 DNA의 분절 효과를 적절하게 방어하는 것을 관찰할 수 있었다. 따라서 대계 약침액은 산화적 스트레스를 직접적으로 방어 하고, 다양한 산화적 손상에 의한 병증을 예방할 것으로 사료된다.