• BMB Reports
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• 제39권4호
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• pp.452-456
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• 2006

To elaborate the peroxidase activity of cytochrome c in the generation of free radicals from $H_2O_2$, the mechanism of DNA cleavage mediated by the cytochrome c/$H_2O_2$ system was investigated. When plasmid DNA was incubated with cytochrome c and $H_2O_2$, the cleavage of DNA was proportional to the cytochrome c and $H_2O_2$ concentrations. Radical scavengers, such as azide, mannitol, and ethanol, significantly inhibited the cytochrome c/$H_2O_2$ system-mediated DNA cleavage. These results indicated that free radicals might participate in the DNA cleavage by the cytochrome c and $H_2O_2$ system. Incubation of cytochrome c with $H_2O_2$ resulted in a time-dependent release of iron ions from the cytochrome c molecule. During the incubation of deoxyribose with cytochrome c and $H_2O_2$, the damage to deoxyribose increased in a time-dependent manner, suggesting that the released iron ions may participate in a Fenton-like reaction to produce $\cdot$OH radicals that may cause the DNA cleavage. Evidence that the iron-specific chelator, desferoxamine (DFX), prevented the DNA cleavage induced by the cytochrome c/$H_2O_2$ system supports this mechanism. Thus we suggest that DNA cleavage is mediated via the generation of $\cdot$OH by a combination of the peroxidase reaction of cytochrome c and the Fenton-like reaction of free iron ions released from oxidatively damaged cytochrome c in the cytochrome c/$H_2O_2$ system.

• BMB Reports
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• 제32권4호
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• pp.350-357
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• 1999

At concentrations of 1 mM, the protective effects of carnosine and related compounds including anserine, homocarnosine, histidine, ${\beta}$-alanine were investigated against copper-catalyzed oxidative damage to deoxyribose, ascorbic acid, human serum albumin, liposome, and erythrocytes. Carnosine and anserine reduced Cu (II) to bathocuproine-reactive Cu (I) in a time- a and a dose-dependent manner while the others did not. Carnosine reduced 86% of $100\;{\mu}M$ Cu (II) in 60 min. Carnosine, homocarnosine, anserine, and histidine inhibited copper-catalyzed deoxyribose degradation by 75, 66, 65, and 45%, respectively. In the presence of $1\;{\mu}M$ Cu (II), carnosine and related compounds inhibited ascorbic acid oxidation by 55-85% after incubation for 20 min. In the presence of 0.15 mM ascorbic acid and 0.8 mM $H_2O_2$, carnosine, anserine, homocarnosine, and histidine inhibited copper-catalyzed oxidation of human serum albumin by 41, 21, 29, and 24%, respectively, as determined by carbonyl formation. These compounds also significantly inhibited copper-catalyzed liposomal lipid peroxidation as measured by malondialehyde and lipid hydroperoxides. Carnosine, anserine, homocarnosine, and histidine inhibited hemolysis of bovine erythrocytes induced by 0.1 mM Cu (II). These results suggest that histidine-containing dipeptides may play an important role in protecting against free radical-mediated tissue damage.

• Journal of Ginseng Research
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• 제34권3호
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• pp.168-174
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• 2010

Ethanol and water extracts of white and fermented ginseng were prepared and their ginsenoside composition and antioxidant effects were assessed. The main ginsenosides in white ginseng were $Rb_1$ > Re > $Rg_1$, and those in fermented ginseng were $Rb_2+Rb_3$ > Rd > $Rg_1$. Ginsenosides Rd and $Rg_3$ in fermented ginseng were enriched 11 and 58 times, respectively, over that in white ginseng through fermentation with five Bacillus spp. The greatest levels of 2-deoxyribose and superoxide anion dismutase-like activities were found in 50% ethanol extracts of fermented ginseng. Thus, these data suggest that white ginseng has the greatest free radical scavenging activity and that fermented ginseng has the highest antioxidant activity.

• BMB Reports
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• 제40권5호
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• pp.684-689
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• 2007

The endogenous neurotoxin, 1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (salsolinol), has been considered a potential causative factor for the pathogenesis of Parkinson's disease (PD). In the present study, we examined the pattern of human Cu,Zn-superoxide dismutase (SOD) modification elicited by salsolinol. When Cu,Zn-SOD was incubated with salsolinol, some protein fragmentation and some higher molecular weight aggregates were occurred. Salsolinol led to inactivation of Cu,Zn-SOD in a concentration-dependent manner. Free radical scavengers and catalase inhibited the salsolinol-mediated Cu,Zn-SOD modificaiton. Exposure of Cu,Zn-SOD to salsolinol led also to the generation of protein carbonyl compounds. The deoxyribose assay showed that hydroxyl radicals were generated during the oxidation of salsolinol in the presence of Cu,Zn-SOD. Therefore, the results indicate that free radical may play a role in the modification and inactivation of Cu,Zn-SOD by salsolinol.

• 한국환경성돌연변이발암원학회지
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• 제25권2호
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• pp.71-75
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• 2005

Green tea and their major constituents such as catechins are famous materials for their anti-oxidative and anti-carcinogenic activity, but many compounds with reducing power can promote the oxidation in their oxidized form or in the presence of metal ion. We investigated the pro-oxidative effect of the ethanol extract equivalent up to 30mg of dried weight of green tea leaves in four in vitro systems which could be used for detecting DNA damage. Although ethanol extract of green tea did not show significant mutagenicity in Salmonella typhimurium TA102, which is sensitive strain to oxidative stress, it degraded deoxyribose extensively in the presence of $FeCl_3-EDTA$ complex, promoted 8-oxoguanine formation in the live bacteria cell, Salmonella typhimurium TAI04, and cleaved super coiled DNA strand with the help of copper ion. It suggested that green tea, famous anti-oxidative material, can be pro-oxidant according to the condition of extraction or metal existence.

• 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.

• 한국축산식품학회지
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• 제22권1호
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• pp.13-19
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• 2002

솔잎과 녹차의 열수와 에탄올 추출물을 이용하여 free radical 반응 및 지방산화에 미치는 영향과 아질산염 소거작용을 검토하였다. 각종 항산화제와 항산화력 비교에서 추출물 농도별 지방산화 억제능력은 0.1%보다는 0.3%가 낮은 TBARS값을 나타내었고, iron sources에 대한 binding 능력은 열수추출물이 우수하였다. Deoxyribose상에서의 hydroxyl radical 포집능력은 솔잎과 녹차 에탄올추출물이 대조구 보다 낮은 TBARS값을 나타내었다. 추출물의 iron 함량은 솔잎 에탄올 추출물이 가장 높은 함량을 나타내었으며, ascorbic acid 함량은 녹차의 열수와 에탄올 추출물에서 높은 값을 나타내었다. 전자공여능은 열수추출보다는 에탄올 추출물이 높은 활성을 나타내었다. 또한 솔잎과 녹차추출물은 각종 항산화제에 비하여 높은 전자공여능을 나타내었다. 아질산염 소거작용은 pH의 감소에 따라 높게 나타났으며, 0.3%의 솔잎과 녹차 추출물은 pH 1.2와 pH 3.0에서 95% 이상의 소거능을 나타내었으며, ascorbic acid 자체보다도 높은 소거능을 나타내었다. 이상의 결과로 보아 솔잎과 녹차추출물은 각종 육제품 제조시 첨가물로서 산화방지 효과 및 아질산염 소거제로서의 사용을 시사하는 것이다.

• 셀메드
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• 제5권2호
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• pp.14.1-14.6
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• 2015

Antioxidative and free radical scavenging properties of different stem extracts of Euphorbia trigona were evaluated and correlated with its total phenolic content. Aqueous, acetone and methanolic extracts of shade dried stem were obtained and were concentrated in vacuo. The antioxidant and free radical scavenging activities of stem extracts was determined by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging assay, reducing power assay, deoxyribose degradation assay and $Fe^{2+}$ chelating assay. Total phenolic contents (TPC) were evaluated using Folin-Ciocalteu reagent. The results confirmed that the plant is a rich source of polyphenolic compounds which are invariably higher compared to other herbs. All extracts showed TPC in the range of 146.6 - 168.6 mg/g gallic acid equivalents at $300{\mu}g/ml$ of extract. Among the three extracts ME showed highest scavenging activity as evidenced by maximum scavenging of DPPH (83.2%), $OH{\bullet}$ radicals (94.81%), $Fe^{2+}$ chelating activity (88.59%) and a high reducing power 0.623 at $300{\mu}g/ml$. Our results demonstrate that Euphorbia trigona, an unexplored xerophytic plant could be potential source of natural antioxidants and phytotherapeutic agents. The plant possess invariably high amount of polyphenolic compounds with a broad spectrum of antioxidant properties and could be further used for food, feed and pharmaceutical applications.

• Preventive Nutrition and Food Science
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• 제11권2호
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• pp.100-104
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• 2006

The in vitro antimicrobial and antioxidant activities of the essential oil and methanol extracts of Ledum palustre L. were investigated. Using GC-MS analysis, we identified 37 compounds in the essential oil, constituting 87.58% of the total oil. There are several monoterpenes, of which sabinene is the major compound ($16{\sim}17%$). There are several oxygenated monoterpenes of which terpinen-4-ol(7.6%) and myrtenal (3.5%) are the main constituents. $\beta$-Selinene, a-selinene, $\gamma$-elemene, a-caryophyllene are the main sesquiterpenes ($2{\sim}6%$ range). The oil strongly reduced the diphenylpicrylhydrazyl radical ($IC_{50}=1.56{\mu}g/mL$) formation and exhibited a hydroxyl radical scavenging effect in the $Fe^{3+}-EDTA-H_2O_2$ deoxyribose system ($IC_{50}=2.7{\mu}g/mL$), and also inhibited the nonenzymatic lipid peroxidation of rat liver homogenate ($IC_{50}=13.5{\mu}g/mL$). The polar phase of the extract showed antioxidant activity. The oil showed antimicrobial activity against Streptococcus pneumoniae, Clostridium perfringens, Candida albicans, Mycobacterium smegmatis, Acinetobacter lwoffii and Candida krusei while the water-insoluble parts of the methanolic extracts exhibited slight or no activity. This study confirms that the essential oil of Ledum palustre L. possesses antioxidant and low antimicrobial properties in vitro.

• KSBB Journal
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• 제18권4호
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• pp.282-288
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• 2003

본 연구에서는 항염증 및 항산화 활성을 갖는 유용한 물질 을 검색하기 위해 40여 가지 생약재를 에탄올 추출하여 H HAase 억제 및 라디칼 소거 활성을 측정하였다 .. HAase 억제 활성을 측정한 결과, I mg/mL의 농도에서 황기, 두충, 오미 자, 황금, 오가피, 목과, 목단피, 산사가 50% 이상의 저해활 성을 나타내었고, 이들에 대하여 n-hexane, chloroform, ethyl a acetate, water로 순차적으로 용매분획하여 활성을 측정한 결 과, 모든 시료의 ethyl acetate와 water 분획에서 높은 활성을 보였다 항산화 활성은 DPPH 라디칼에 대한 전자공여능과 F Fenton 반응에 의해 발생한 hydroxyl radical에 대한 소거능으 로 평가하였다 .. DPPH 라디칼에 대한 전자공여능은 복분자, 목단피, 백작약, 차전자, 마가목 에탄올 추출물이 I mg{mL 놓도에서 90% 이상으로 대조군으로 이용한 BHA와 Q - -tocopherol과 유사한 활성을 나타내었다 .. 2-deoxyribose 산화 법에 따른 hydroxyl 라디칼 소거활성에서 대부분의 에탄올 추출물 시료에서 모두 높은 활성을 나타내었다. 활성올 갖는 시료에 대하여 지질과산화 억제 활성을 측정한 결과 linoleic a acid와 phosphatidylcholine liposome 기질 모두에 대하여 오미 자 추출물은 가장 높은 억제 활성을 나타내었다.