• Preventive Nutrition and Food Science
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• 제14권1호
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• pp.86-89
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• 2009

In this study, we investigated the free radical [1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (${\cdot}OH$) and superoxide anion (${O_2}^-$)] scavenging activity of MeOH extract and 3 fractions of Citrus junos. Of the tested fractions, the BuOH fraction showed the strongest DPPH scavenging activity, showing the $IC_{50}$ values of 63.4 mg/mL. Therefore, we continuously carried out DPPH, ${\cdot}OH$ and ${O_2}^-$ scavenging activity tests of BuOH fraction of Citrus junos. The BuOH fraction of Citrus junos inhibited DPPH radical to 97.5% at a concentration of 1000 mg/mL and the scavenging activities were increased concentration-dependently. In addition, BuOH fraction from Citrus junos also scavenged ${\cdot}OH$ in a concentration dependent manner from 5 to 1000 mg/mL. Furthermore, BuOH fraction showed about 56% ${O_2}^-$-scavengimg activity at 25 mg/mL concentration but, the scavenging activities were not enhanced in a dose dependent manner. The present results suggest that BuOH fraction of Citrus junos would have the protective potential from oxidative stress induced by free radicals.

• 대한한의학방제학회지
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• 제10권2호
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• pp.159-188
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• 2002

The purpose of this study was to reseach the effect of Daehwanggamchoeumja(大黃甘草飮子) and its component groups on diabetes, free radicals, and antioxidants system in Alloxan-induced diabetic rats. The experimental group was divided into three groups: Daehwanggamchoeumja(DG), and its components groups, Gamdutang (Gamcho&Daedu; DG-I) and Daehwanggamchotang(DG-2). The results were obtained as follows: 1. In the study of effect on diabetic metabolic dysfunction(Glucose, Triglyceride, Total Cholesterol, HDL Cholesterol, Total Protein, Albumin, Creatine, BUN), only DG has a significant effect. 2. In the study on free radical scavenging effect in vitro(the suppressing effect on peroxidation of linoleic acid on concentration, the scavenging effect of DPPH radical, inhibitory effect of superoxide in xanthine-xanthine oxidase system, inhibitory effect on lipid peroxidation reaction by hydroxy radical in $H_2O_2Fe^{2-}$system, and the effect on Nitrate reductase activity), DG and DG-2 have more effect than DG-l relatively. 3. In the study on antioxidants system in vivo(The level of serum LPO, The level of hepatic LPO, Catalase, GSH, GST), only DG has a significant effect. These results suggest that Daehwanggamchoeumja(大黃甘草飮子) has an effect on diabetes, peroxidative damage by free radical, so it seems to be useful to prevent and treat diabetes. The mechanisms of these are supposed to be involved in antioxidant and three drugs' cooperative synergy effect.

• Journal of Applied Biological Chemistry
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• 제51권3호
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• pp.111-116
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• 2008

Aralia elata seeds were successively extracted with water, methanol, ethanol, acetone and chloroform. The crude extracts were investigated for antioxidant and antidiabetic activities. The antioxidant properties of various extracts were evaluated by antioxidant tests, such as DPPH free radical-scavenging activity, hydroxyl radical-scavenging assay, metal-chelating activity, lipid peroxidation inhibition activity and reducing power assay. The 70% methanol extract exhibited the highest activity in the in vitro models of DPPH free radical-scavenging activity, metal-chelating activity, and reducing power assay. Acetone extract showed good effects on lipid peroxidation inhibition and hydroxyl radical-scavenging assay at a low concentration. In addition, the $\alpha$-glucosidase inhibition assay showed that 70% methanol extract had the highest activity. These results indicate the high possibility of using A. elata seeds for medical application due to their efficient antioxidant properties.

• Journal of Applied Biological Chemistry
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• 제53권1호
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• pp.8-12
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• 2010

The antioxidant activity of hawthorn fruit (Crataegus pinnatifida Bunge var. typica Schneider) extracts was investigated by several in vitro antioxidants properties, including DPPH free radical scavenging activity, total phenolic and flavonoid contents, hydroxyl radical scavenging activity, reducing power activity, iron-chelating capacity and nitrite scavenging activity. Among the extracts in this study, the 70% EtOH extract showed higher antioxidant activity than the others. The $IC_{50}$ value of DPPH free radical scavenging activity was $99.26\;{\mu}g/mL$. Furthermore, the 70% EtOH extract also showed significantly high total phenolic and flavonoids contents and reducing power activity. However, the MeOH extract exhibited stronger effects on hydroxyl radical scavenging activity, iron-chelating capacity and nitrite scavenging activity. All the results implicated that, the hawthorn fruit may has the available potential to be utilize as a potential source of natural antioxidant.

• 한국자원식물학회지
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• 제10권3호
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• pp.227-230
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• 1997

The authors isolated four olefinic catechols, commonly referred to as urushiol, from the sap of Korean lacquer tree(Rhus vernicifera STOKES) with stronger antioxidative activities than $\alpha-tocopherol$. The hexane extract with a free radical scavenging activity was purified by silica and ODS gel column chromatography. The active compounds were identified by MS and $^1H-NMR$ as 3-[8'(Z),11'(Z),14'-pentadecatrienyl]catechol, 3-[8'(Z),11'(Z)-pentadecadienyl]catechol, 3-[8'(Z)-pentadecenyl] catechol, and 3-pentadecylcatechol. All of these compounds showed strong free radical scavenging activities on 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical, in which 3-pentadecylacatechol exhibited the highest activity ($IC_{50}$: $1.2{\mu}g/ml$). They also showed a significant inhibitory activity on lipid peroxidation ($IC_{50}$: 2.1 - 3.5 ${\mu}g/ml$). The antioxidative activity of 3-pentadecylcatechol on DPPH radical and lipid peroxidation is approximately two times greater than that of $\alpha$-tocopherol. The results suggest that the urushiol derivatices may contribute to the preservative characteristics effective against oxidative stress and could be a good source for industrial applications including a coating material.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2001년도 추계학술대회 논문집
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• pp.325-326
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• 2001

오존은 태양광선의 존재 하에 질소산화물과 VOCs가 관련하여 발생하는 생성물이다. 대기중의 VOCs 는 히드록실 라디칼(hydroxyl radical, OHㆍ)과 같은 자유 라디칼(free radical)과 반응하여 하이드로퍼옥시 라디칼(hydroperoxy radical, HO$_2$ㆍ)과 알킬 퍼옥시 라디칼(alkyl peroxy radical, RO$_2$ㆍ)을 생성해 낸다. 이 퍼옥시 라디칼들은 NO를 NO$_2$ㆍ로 산화시키며 또한 히드록실 라디칼을 재생하며 이 히드록실 라디칼은 다시 VOCs와 반응한다. 그리고, 이때 산화된 NO$_2$는 햇빛에 의해 NO와 자유산소원자(free oxygen atom)로 광분해 되는데, 여기서 생성된 자유산소인자는 산소분자와 반응하여 오존을 생성한다. (중략)

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.473-476
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• 2004

This study has investigated radiation degradation of low density polyethylene(LDPE). Samples were irradiated using a $Co^{60}\;\gamma-ray$ and ray up to 800 kGy at a dose rate of 5 kGy/hr in the presence of air atmosphere at room temperature. After irradiation, free radical measurement of LDPE has established by electron spin resonance(ESR). Then, each sample was stored for 2 weeks. ESR measurement showed that free radical concentration(FRC) was increased with radiation dose and changed from alkyl, allyl radical to peroxy radical with time.

• 한국식품과학회지
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• 제51권2호
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• pp.133-140
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• 2019

Antioxidant activities of Ulmus davidiana root and bark extracts were evaluated by various antioxidant tests, including DPPH radical-scavenging, nitric oxide-scavenging, superoxide anion radical-scavenging, and ABTS radical-scavenging assays, and superoxide dismutase (SOD)-like activity and reducing power analysis, along with the determination of total phenolic and flavonoid contents. Both the extracts showed strong antioxidant activities by these testing methods. Ulmus davidiana root extract possessed strong reducing power and nitric oxide-scavenging activity, and high scavenging activities against free radicals including the superoxide anion, and the ABTS and DPPH radicals, but a weaker scavenging activity of SOD. In contrast, the Ulmus davidiana bark extract exhibited a strong SOD-like activity, but all the other activities were weak. It was observed that the total phenolic and flavonoid contents of the Ulmus davidiana root extract were higher than those of the Ulmus davidiana bark extract.

• Kyungpook Mathematical Journal
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• 제19권1호
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• pp.3-7
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• 1979

• 한국응용과학기술학회지
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• 제34권4호
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• pp.1025-1035
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• 2017

본 연구에서는 뽕잎(Morus alba)을 노루궁뎅이 버섯균사체(Hericium erinaceum)로 발효시킨 열수 추출물(MA-HE)의 항산화 활성을 확인하고자 하였다. MA-HE의 항산화 활성을 DPPH radical, ABTS radical 소거활성 측정을 통해 알아보았다. 그 결과 DPPH radical 소거활성은 $500{\mu}g/mL$ 농도에서 61.73%, ABTS radical 소거활성은 $250{\mu}g/mL$ 농도에서 97.39%로 나타났다. MA-HE은 DNA의 산화적 손상을 효과적으로 억제하였다. 또한 생체고분자물질인 사람의 혈청단백질의 산화적 손상을 억제하였다. 세포에 $H_2O_2$를 처리하였을 때 세포생존율에 비하여 발효물을 $100{\mu}g/mL$ 농도로 전 처리한 세포생존율은 8% 증가했으며, 발효물을 $50{\mu}g/mL$ 농도로 처리했을 경우 세포 내 활성산소의 축적이 유의적으로 감소되었다. 본 연구 결과는 MA-HE이 항산화 활성을 가지고 있으며 산화적 스트레스에 의해 야기되는 세포 독성에 대한 보호 작용도 뛰어난 것으로 사료되었다.