• Bulletin of the Korean Chemical Society
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• 제35권6호
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• pp.1633-1638
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• 2014

[6]-Gingerol is known as the major bioactive constituent of ginger. In the study, it was observed to effectively protect against ${\bullet}OH$-induced DNA damage ($IC_{50}$ $328.60{\pm}24.41{\mu}M$). Antioxidant assays indicated that [6]-gingerol could efficiently scavenge various free radicals, including ${\bullet}OH$ radical ($IC_{50}$ $70.39{\pm}1.23{\mu}M$), ${\bullet}O_2{^-}$ radical ($IC_{50}$ $228.40{\pm}9.20{\mu}M$), $DPPH{\bullet}$radical ($IC_{50}$ $27.35{\pm}1.44{\mu}M$), and $ABTS{^+}{\bullet}$radical ($IC_{50}$ $2.53{\pm}0.070{\mu}M$), and reduce $Cu^{2+}$ ion ($IC_{50}$ $11.97{\pm}0.68{\mu}M$). In order to investigate the possible mechanism, the reaction product of [6]-gingerol and $DPPH{\bullet}$ radical was further measured using HPLC combined mass spectrometry. The product showed a molecular ion peak at m/z 316 $[M+Na]^+$, and diagnostic fragment loss (m/z 28) for quinone. On this basis, it can be concluded that: (i) [6]-gingerol can effectively protect against ${\bullet}OH$-induced DNA damage; (ii) a possible mechanism for [6]-gingerol to protect against oxidative damage is ${\bullet}OH$ radical scavenging; (iii) [6]-gingerol scavenges ${\bullet}OH$ radical through hydrogen atom ($H{\bullet}$) transfer (HAT) and sequential electron (e) proton transfer (SEPT) mechanisms; and (iv) both mechanisms make [6]-gingerol be oxidized to semi-quinone or quinone forms.

• 한국자원식물학회지
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• 제21권1호
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• pp.91-95
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• 2008

본 연구에서는 ${O_2}^-,{\cdot}OH$ radical, NO, $ONOO^-$ 자유라디칼을 유발시키는 in vitro assay system과 free radical-induced oxidative stress에 의한 단백질 손상에 대한 진흙버섯속에 속하는 상황버섯 물 추출물의 항산화 효과를 측정하였다. 상황버섯 물 추출물의 ${O_2}^-,{\cdot}OH$ radical, NO, $ONOO^-$ 자유라디칼 억제효과에서는 실험에 사용된 양성 대조물 보다는 낮게 나타났으나 모든 실험계에서 대조군에 비해 뚜렷하게 자유라디칼 소거효과를 나타냈다. 또한 상황버섯 물 추출물은 산화적 스트레스에 의한 단백질 손상 억제효과에서도 대조군에 비해 명확한 저해효과를 나타냈다. 그러므로 상황버섯의 항산화 효과는 상황버섯의 약리학적 효능을 설명하는데 중요한 기초 자료라고 사료된다.

• KSBB Journal
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• 제19권1호
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• pp.67-71
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• 2004

본 연구에서는 염생식물의 하나인 해당화의 항산화효과를 탐색하기 위해 해당화의 dichloromethane과 methanol의 조추출물을 합하여 n-hexane, 15% aq. MeOH, n-BuOH, $H_2O$로써 순차적으로 용매 분획하여 DPPH 라디칼, peroxynitrite의 소거 활성과 지질 과산화 저해 활성을 측정하였다. 그 결과 각각의 실험에서 해당화의 유의적인 항산화 효과가 확인되었으며, 특히, 4개의 분획물들 중 n-BuOH 획분이 가장 뛰어난 항산화 효과가 있는 것으로 나타났다. 따라서 해당화의 항산화 효과는 비교적 극성이 큰 2차 대사산물에 의한 것임을 추측할 수 있으며, 해당화의 많은 생물학적인 활성들 중 peroxynitrite 소거 효과와 마우스 간 균질물을 이용한 지질 과산화물 생성 억제 활성에 관한 보고는 이것이 처음이다.

• 상하수도학회지
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• 제20권6호
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• pp.905-910
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• 2006

In order to evaluate the optimum operation condition of ozonation to minimize bromate formation, based on the NOM characteristics of raw waters, the pathway of bromate formation by ozonation in domestic raw waters was investigated. Considering the bromate formation reactions, the fractions of bromate formation from bromide by OH radical and molecular ozone were calculated with measured values of ozone decay rate ($k_c$) and Rct. The results showed that molecular ozone is more important role in the formation of bromate in domestic raw waters than OH radical. The ratio of bromide oxidation reaction by molecular ozone ranged 73~88%. Fractions of $HOBr/OBr^-$ reaction with both molecular ozone and OH radical were also determined. OH radical reaction with $HOBr/OBr^-$ was dominant. The differential equations based on the stoichiometry of bromate formation were established to predict the formation rate of bromate by ozonation. The results shows good correlation with experimental results.

• 한국식품영양과학회지
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• 제37권10호
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• pp.1318-1322
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• 2008

본 연구는 구기엽(Lycium chinesis Miller Lycii folium)의 항산화 활성이 높은 최적추출 용매를 설정하고자 100% MeOH, 80% MeOH, 80% EtOH 및 water로 혼합 용매를 제조하여 구기엽 추출물을 제조하였다. 각 추출물의 총 페놀 화합물은 80% MeOH 1.420 mg/mL> 80% EtOH 1.382 mg/mL> 100% MeOH 1.085 mg/mL> water 1.084 mg/mL 순으로 나타났고, 전자공여능 및 SOD 유사활성에서도 80% MeOH 추출물에서 83.85%, 88.46%로 가장 높은 활성을 나타내었으며, water 추출물에서 54.65%, 67.47%로 가장 낮은 활성을 나타내었다. Hydroxyl radical 소거능에서는 80% MeOH 추출물에서 73.58%로 가장 높았고, 100% MeOH 추출물에서 66.65%로 가장 낮은 활성이었다. Hydrogen radical 소거능 또한 80% MeOH에서 35.40%로 가장 높은 활성을 보였고, 100% MeOH 추출물에서 11.70%로 가장 낮은 활성을 나타내었다. 본 실험 결과 아직 초기 단계에 불과하지만 구기엽의 항산화 활성 검토에서 80% MeOH 추출물에서 가장 높은 활성을 보여 구기엽 추출물의 기능성 소재로 개발 가능성이 시사되었다.

• 한국물환경학회지
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• 제22권4호
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• pp.672-677
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• 2006

Ozone/UV combined process is an effective technique to enhance generation of OH radical which is non-selective and powerful oxidant. The objective of this study is to evaluate the inactivation rates of B. subtilis spores by three candidate processes (ozone alone, UV alone, ozone/UV combined processes) at 4 and $20^{\circ}$ and to investigate the effects of OH radical on inactivation of B. subtilis spores. On the UV alone process, required UV dosages for lag phase and 3-log inactivation of B. subtilis spores were determined as $8.9mJ/cm^2$ and $47mJ/cm^2$. However, the inactivation of B. subtilis spores didn't occured beyond 4.5-log inactivation despite increasing UV dose. The inactivation of B. subtilis spores by ozone alone and ozone/UV combined process was investigated with ozone CT (Concentration of disinfectant ${\times}$ Contact time) concept. As a result, inactivation of B. subtilis spores by ozone/UV combined process was faster than by ozone alone, and especially $CT_{lag}$ value B. subtilis spores in the presence and absence of t-BuOH, OH radical scavenger, was investigated to evaluate effects of OH radical formed during ozone/UV combined process. We found that OH radical plays important roles on inactivation of B. subtilis spores.

• Ocean and Polar Research
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• 제34권4호
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• pp.445-451
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• 2012

The EtOH extracts of red seaweeds (Symphyocladia latiuscula, Chondrus ocellatus and Carpopeltis affinis) and solvent partitioned fractions were investigated for their 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 1,1-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging effects and the total phenolic contents were correlated with ABTS and DPPH radical scavenging activities. The EtOH extracts and their solvent partitioned fractions exhibited strong ABTS and DPPH radical scavenging activities. Among the solvent partitioned fractions obtained from n-Hexane (HX), methylenchloride (MC), ethylacetate (EA), and buthanol (BuOH), the HX fraction from C. affinis showed higher radical scavenging activities than other fractions. Total phenolic contents showed significant correlation ($r^2$ = 0.709) with ABTS radical scavenging activity. The results of this study suggest that the strong radical scavenging activity of HX fraction from C. affinis is a promising natural antioxidant for healthcare products.

• Natural Product Sciences
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• 제11권3호
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• pp.150-154
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• 2005

The radical scavenging effect of the MeOH extract of Fraxini Cortex on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical was examined. The $CH_2Cl_2$-and n-BuOH-soluble fractions of MeOH extract showed the promising DPPH radical scavenging effects, and further purified by silica gel, Sephadex LH-20 column chromatography, and reversed-phase C-18 MPLC to yield five coumarins, esculetin (1), fraxidin (2), fraxetin (3), fraxidin $8-O-{\beta}-D-glucopyranoside$ (fraxin methyl ether) (5), esculin (6), and a secoiridoid oleuropein (4), and a coumarin-secoiridoid escuside (7). Compounds 1, 3, and 4 showed potent DPPH radical scavenging effects, exhibiting $IC_{50}$ values of 14.68, 9.64, and $22.03\;{\mu}M$, respectively. Compounds 6 and 7 also showed moderate effects with $IC_{50}$ values of 147.79 and $72.73\;{\mu}M$, respectively. L-Ascorbic acid was used as a positive control and exhibited the $IC_{50}$ value of $50.31\;{\mu}M$.

• 한국환경과학회지
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• 제20권7호
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• pp.891-898
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• 2011

The aim of this research was to evaluate the effect of combination of disinfection process (electrolysis, UV process) on Escherichia coli (E. coli) disinfection and oxidants (OH radical, $ClO_2$, HOCl, $H_2O_2$ and $O_3$) generation. The effect of electrolyte type (NaCl, KCl and $Na_2SO_4$) on the E. coli disinfection and oxidants generation were evaluated. The experimental results showed that performance of E. coli disinfection of electrolysis and UV single process was similar. Combination of electrolysis and UV process enhanced the E. coli disinfection and 4-carboxybenzaldehyde (4-CBA, indicator of the generation of OH radical) degradation. It is clearly showed synergy effect on disinfection and OH radical formation. However chlorine ($ClO_2$, HOCl) and oxygen type ($H_2O_2$, $O_3$) oxidants were decreased with the combination of two process. In electrolysis + UV complex process, electro-generated $H_2O_2$ and $O_3$ were reacted with UV light of UV-C lamp and increased 4-CBA degradation(increase OH radical). Disinfection of electrolyte of chlorine type was higher than that of the sulfate type electrolyte due to the higher generation of OH radical and oxidants.

• 대한환경공학회지
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• 제22권5호
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• pp.869-877
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• 2000

Phenanthrene과 benzo[a]pyrene으로 오염된 토양을 슬러리상에서 오존처리시 반응메커니즘을 조사하였다. 토양내 오존주입시 OH-radical의 생성과 반응에 있어서 유 무기물의 영향을 알아보기 위하여 단순화된 토양매질로써 baked sand(BS), sand(S), glass beads(GB)를 택하여 실험한 결과 제거속도가 BS>S>GB 순으로 나타났다. Radical scavenger 실험을 통하여 OH-radical의 발생경향을 살펴보았는데, BS의 경우 OH-radical의 생성으로 오존과의 직접반응과 더불어 제거효율이 22% 상승됨을 알 수 있었다. Humic acid의 초기농도를 0~5 ppm으로 증가시킴에 따라 반응속도상수(psuedo first-order rate constant: $k_o$)가 $1.37{\times}10^{-2}s^{-1}$에서 $0.53{\times}10^{-2}s^{-1}$으로 감소하였으며, S매질상에서 PAHs의 초기농도 10mg-PAHs/kg-soil의 80%를 제거하는데 소모되는 오존 주입량은 phenanthrene의 경우 $67.2mg-O_3/kg-soil$였고, benzo[a]pyrene의 경우 $48.0mg-O_3/kg-soil$로 산정되었다.