• Bulletin of the Korean Chemical Society
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• 제31권10호
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• pp.2873-2876
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• 2010

Excess free iron generates oxidative stress that may contribute to the pathogenesis of various causes of neurodegenerative diseases. Previous studies have shown that one of the primary causes of increased brain iron may be the release of excess iron from intracellular iron storage molecules. In this study, we attempted to characterize the oxidative damage of DNA induced by the reaction of ferritin with $H_2O_2$. When DNA was incubated with ferritin and $H_2O_2$, DNA strand breakage increased in a time-dependent manner. Hydroxyl radical scavengers strongly inhibited the ferritin/$H_2O_2$ system-induced DNA cleavage. We investigated the generation of hydroxyl radical in the reaction of ferritin with $H_2O_2$ using a chromogen, 2,2'-azinobis-(2-ethylbenzthiazoline-6-sulfonate) (ABTS), which reacted with ${\cdot}OH$ to form $ABTS^{+\cdot}$. The initial rate of $ABTS^{+\cdot}$ formation increased as a function of incubation time. These results suggest that DNA strand breakage is mediated in the reaction of ferritin with $H_2O_2$ via the generation of hydroxyl radicals. The iron-specific chelator, deferoxamine, also inhibited DNA cleavage. Spectrophotometric study using a color reagent showed that the release of iron from $H_2O_2$-treated ferritin increased in a time-dependent manner. Ferritin enhanced mutation of the lacZ' gene in the presence of $H_2O_2$ when measured as a loss of $\alpha$-complementation. These results indicate that ferritin/$H_2O_2$ system-mediated DNA cleavage and mutation may be attributable to hydroxyl radical generation via a Fenton-like reaction of free iron ions released from oxidatively damaged ferritin.

• Bulletin of the Korean Chemical Society
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• 제30권4호
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• pp.787-790
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• 2009

The predictions of the radical reaction sites for phenol, 2-, 3- and 4-chlorophenols (CPs) and 4-chloronitrobenzene (CNB) were studied by atomic charge distribution calculations. The atomic charge distributions on each atom of these molecules were obtained using the CHelpG and MK (Merz-Kollman/Singh) methods with the optimized structural parameters determined by DFT calculation at the level of BLYP/6-311++G(d,p). By comparing the experimentally obtained hydroxyl addition site(s) and the calculated atomic charges on carbon atoms of phenol and CPs, we found that hydroxyl substitution by oxidation reaction mainly occurred to the carbon(s) with high atomic charges. With these results, we were easily able to predict the position(s) of the ·OH reaction site(s) of phenol, CPs and CNB through atomic charge distribution calculations.

• 한국식품영양과학회지
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• 제38권12호
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• pp.1656-1663
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• 2009

곰취(Ligularia fischeri, GC), 고추잎(Capsicum annuum L., GCY), 취나물(Aster scaber, CNM), 머위대(Petasites japonicus S. et Z. Max, MYD) 및 고구마순(Ipomoea batatas L. (Lam), GGM)과 같은 산채들의 물 추출물의 항산화능력을 평가하고 이들 동결건조 블록 물 추출물들의 항산화력과 비교하였다. 산채 물 추출물들과 그들의 동결건조 블록물 추출물들의 항산화력 측정은 2,2-diphenyl-1-picrylhydrazyl(DPPH) radical 소거작용, hydroxyl radical 소거작용 및 아질산염 소거작용과 같은 방법에 의해 알아보았다. 산채 물 추출물은 그들의 동결건조 물 추출물보다 총 페놀함량이 더 높았다. GC, GCY, CNM, MYD 그리고 GGM 물추출물들의 총 페놀 함량은 각각 $471.66{\pm}3.52\;{\mu}g/mg,\;141.33{\pm}2.51\;{\mu}g/mg,\;177.33{\pm}2.88\;{\mu}g/mg,\;238.66{\pm}9.50\;\mu}g/mg\;그리고\;122.67{\pm}3.51\;{\mu}g/mg$이었다. 1000 ppm GC, GCY, CNM 그리고 GGM 물 추출물의 DPPH radical 소거작용은 그들의 동결건조 블록 물 추출물보다 더 높았고, 1000 ppm CNM, GC, GCY, MYD 그리고 GGM의 물 추출물의 DPPH radical 소거작용은 각각 90.9%, 89.9%, 76.6%, 71.1% 그리고 57.4%였다. 10000 ppm GC, GCY, CNM, MYD 그리고 GGM 물 추출물들은 hydroxyl radical 소거작용을 각각 38.8%, 33.4%, 35.9%, 34.3% 그리고 33.8%까지 증가시켰고, GCY, CNM 그리고 GGM의 물 추출물은 동결건조 블록 물 추출물과 유사한 활성을 나타내었으나 GC와 MYD의 물 추출물이이들 동결건조 블록들의 물 추출물의 hydroxyl radical 소거작용보다 약간 더 영향력이 있었다. 산채 물 추출물들과 이들 동결건조 블록 물 추출물들은 실험된 모든 농도에서 DPPH radical 소거작용 및 hydroxyl radical 소거작용을 나타내었다. GC 물 추출물의 아질산염 소거작용은 현저하게 농도 의존적으로 증가하였고, GC 물 추출물의 아질산염 소거작용이 그것의 동결건조 블록 물 추출물의 아질산염 소거작용보다 높았다. 이상의 결과들로부터 동결건조블록이 산채와 비교하여 산채가 가지고 있는 항산화력을 유지하고 있다는 것을 알수 있었다.

• Bulletin of the Korean Chemical Society
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• 제26권8호
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• pp.1251-1254
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• 2005

It has been proposed that oxidation of L-3,4-dihydroxyphenylalanine (DOPA) may contribute to the pathogenesis of neurodegenerative disease. In this study, L-DOPA-Fe(III)-mediated DNA cleavage and the protection by carnosine and homocarnosine against this reaction were investigated. When plasmid DNA was incubated with L-DOPA in the presence of Fe(III), DNA strand was cleaved. Radical scavengers and catalase significantly inhibited the DNA breakage. These results suggest that $H_2O_2$ may be generated from the oxidation of DOPA and then $Fe^{3+}$ likely participates in a Fenton’s type reaction to produce hydroxyl radicals, which may cause DNA cleavage. Carnosine and homocarnosine have been proposed to act as anti-oxidants in vivo. The protective effects of carnosine and homocarnosine against L-DOPA-Fe(III)-mediated DNA cleavage have been studied. Carnosine and homocarnosine significantly inhibited DNA cleavage. These compounds also inhibited the production of hydroxyl radicals in L-DOPA/$Fe^{3+}$ system. The results suggest that carnosine and homocarnosine act as hydroxyl radical scavenger to protect DNA cleavage. It is proposed that carnosine and homocarnosine might be explored as potential therapeutic agents for pathologies that involve damage of DNA by oxidation of DOPA.

• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1644-1646
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• 2009

• 한국식품영양학회지
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• 제26권1호
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• pp.150-153
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• 2013

본 연구에서는 한국, 중국, 일본 등의 대표적 면요리 육수의 항산화 활성을 검토하였다. 이를 위하여, 한국식, 중국식, 일본식 육수를 각각 제조하여, ESR과 비색법을 이용하여 DPPH, hydroxyl, peroxyl, superoxide, ABTS 등의 radical 소거 활성을 측정함으로써 항산화력을 비교하였다. 한국식 육수, 중국식 육수 및 일본식 육수의 DPPH radical 소거 활성은 2 $mg/m{\ell}$의 농도의 실험에서 2.78%, 25.37% 및 40.74%의 소거 활성을 보였다. 한국식 및 중국식 육수는 hydroxyl radical 소거 활성은 매우 낮았으나, 일본식 육수는 0.5 $mg/m{\ell}$에서 59.06%로 소거 활성이 높았다. 한국식, 중국식 및 일본식 육수의 peroxy radical 소거 활성($IC_{50}$)은 각각 0.121 $mg/m{\ell}$, 0.222 $mg/m{\ell}$ 및 0.013 $mg/m{\ell}$으로 일본식 육수가 peroxy radical 소거 활성이 높았다. 한국식, 중국식 및 일본식 육수의 ABTS radical 소거 활성의 $IC_{50}$ 값은 1.2 $mg/m{\ell}$, 1.8 $mg/m{\ell}$ 및 1.249 $mg/m{\ell}$였다.

• 한국자원식물학회지
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• 제21권4호
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• pp.254-259
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• 2008

약용식물 9종의 물 추출물에 대한 항산화 효과를 탐색하기 위해 in vitro 조건에서 강력한 산화력과 독성을 갖는 $ONOO^-$와 ${\cdot}$OH radical의 소거효과를 측정하였다. 그 결과, 감잎, 구기자, 꾸지뽕나무, 담쟁이덩굴, 마디풀, 비파나무, 으름덩굴, 참취 추출물은 10${\mu}g/ml$ 농도에서 50% 이상의$ONOO^$ 소거효과를 나타냈다. 이러한 $ONOO^-$ 소거효과는 양성 대조물인 penicillamine(94.08${\pm}$3.04)에 비해 낮았지만 비파나무 물 추출물(89.87${\pm}$4.57)이 다른 시료에 비해 가장 강력한 $ONOO^-$ 소거효과를 나타냈다. 또한, 가는잎쐐기풀과 감잎 물 추출물은 1mg/ml 농도에서 양성대조물인 thiourea 보다 효과적인${\cdot}$OH radical 억제효 과를 나타냈다. 결론적으로 9종의 약용식물은 $ONOO^-$와${\cdot}$OH radical과 연관된 산화적 스트레스에 의한 세포와 조직의 손상을 억제시킬 수 있는 천연 항산화제로 밝혀졌다.

• Food Science and Biotechnology
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• 제16권6호
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• pp.1041-1045
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• 2007

Heated onion juice was partitioned using the solvents hexane, chloroform, ethyl acetate, and butanol. The ethyl acetate fraction showed the strongest scavenging effect on the ABTS radical. The antioxidant activities of the ethyl acetate fraction from raw and heated onion (120, 130, and $140^{\circ}C$) were evaluated using radical scavenging assays. Radical and nitrite scavenging activities were higher in heated onion than raw onion, and the higher the temperature of heat treatment, the greater the radical and nitrite scavenging activities. Heated onion ($140^{\circ}C$, 2 hr) was more effective than raw onion, having higher DPPH radical scavenging (5.7-fold), hydroxyl radical scavenging (6.4-fold), superoxide radical scavenging (2.3-fold), hydrogen peroxide scavenging (11.8-fold), and nitrite scavenging (4.3-fold) activities. Onion increased its physiologically active materials after heating, and in this regard, heated onion can be used as biological material for the manufacture of health foods and supplements.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2008년도 제49회 학술심포지움 및 국제학술대회
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• pp.57.2-57.2
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• 2008

• 산업식품공학
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• 제15권1호
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• pp.6-14
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• 2011

The polysaccharides from fruit body of Auricularia auricula and Tremella fuciformis were extracted using hot water, and partially purified through ethanol precipitation and dialysis. Free radical scavenging activities of the crude and purified polysaccharides were examined and compared each other. Free radical scavenging activities of the partially purified polysaccharides were higher than those of crude polysaccharides. DPPH free radical, ABTS radical and SOD-like activities of partially purified polysaccharide at 1 mg/mL of concentration from A. auricula were 61.7, 9.6 and 38.9%, respectively, while those of T. fuciformis were 9.6, 5.7 and 15.3%, respectively. Results of site and non-site specific hydroxyl radical scavenging activities indicated that the partially purified polysaccharide fractions from A. auricula and T. fuciformis exhibited the hydroxyl radical scavenging effect by hydrogen donating ability and iron ion chelating ability. Also, reducing powers of A. auricula and T. fuciformis were 77.1 and 14.7% of BHT (0.1%) as standard, respectively. It was suggested that antioxidant activities of A. auricula were about 1.4~6.4 times higher than those of T. fuciformis due to different levels of polyphenol content.