• Journal of Life Science
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• 제12권2호
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• pp.75-79
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• 2002

Tea catechins, the most important compounds in tea polyphenols, can efficiently scavenge superoxide anion free-radical ($O_2$.), hydroxyl radical. (.OH) The mechanism of scavenging active oxygen free radicals was investigated by ESR spin trapping technique and Chemiluminescence. Results showed that various tea catechins constitute an antioxidant cycle in accordance with the decreasing order of the first reductive potential, and produce the effect of cooperative strength each other. Esterificated catechins could scavenge active oxygen free radicals more effectively than the non-esterificated ones. When.OH and $O_2$.- were scavenged by (-)-epigallocatechin gallate [(-)- EGCG], the stoichiometric factors were 6, and the rate constants of scavenging reaction reached $7.71{\times}10^6$ and $3.52{\times}10^{11}$ L $mmol^{-1}s^{-1}$, respectively. In the mean time, tea catechins could scavenge superoxide anion fiee radical ($O_2$-.) and hydroxyl radical (.OH) in a dose dependent manner. But at higher concentration or pH value, tea catechins can induce the prooxidant.

• Journal of Applied Biological Chemistry
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• 제60권3호
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• pp.219-226
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• 2017

본 연구에서는 탁리산 열수추출물을 용매 분획하여 항산화, 주름억제, 미백효과에 대한 활성을 검증하여 화장품 소재로서 이용가능성을 연구하였다. 용매 분획물로 DPPH radical scavenge, ABTS radical scavenge, elastase, tyrosinase 저해활성을 확인하였고 에틸아세테이트 분획물(TW-EA)이 가장 높은 저해활성을 나타내었다. 세포내에서의 주름억제, 미백효과를 확인하기 위해서 western blot을 실시하였고 비교 검증을 위해 사용한 positive contol보다 TW-EA의 억제효과가 뛰어난 것을 확인하였다. 이러한 결과로 탁리산의 화장품소재로서 적용 가능성을 검증하였다.

• Journal of Applied Biological Chemistry
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• 제61권3호
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• pp.283-290
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• 2018

맥문동탕 열수추출물의 용매분획물을 이용하여 1-1-diphenyl-2-picryl-hydrazyl radical scavenge, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenge, elastase, tyrosinase 억제 효과를 검증하였고 그 결과 에틸아세테이트 분획물(MW-EA)에서 가장 우수한 저해활성을 보여주었다. 세포를 이용한 활성 검증에서는 MW-EA를 처리하였을 때 ROS 저해활성에서 34% ($100{\mu}g/mL$), MMPs 저해 50% ($100{\mu}g/mL$) 이상, 미백 활성에서는 tyrosinase를 25% ($50{\mu}g/mL$) 억제하는 것을 확인 하였다. 따라서 맥문동탕은 피부개선 소재로서 개발 가능성이 높다고 사료된다.

• Natural Product Sciences
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• 제5권2호
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• pp.80-84
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• 1999

Peroxynitrite is a cytotoxic intermediate produced by the reaction between the superoxide anion radical and nitric oxide. Flavonoids (afzelin, quercitrin and quercetin 3-O-sambubioside), and chlorogenic acid and its methyl ester obtained from leaves of loquat (Eriobotrya japonica) have recently been shown to scavenge 1,1-diphenyl-2-picrylhydrazyl radical and to inhibit lipid peroxidation in mouse liver homogenate. The aim of this study is to investigate the inhibitory effects of the above components on peroxynitrite produced stimulated by 3-morpholinosydnonimine (SIN-1) to produce superoxide anion radical and nitric oxide at the same time. In addition, the present study tests whether or not the components directly scavenge peroxynitrite itself. The results showed that the components with the aromatic ortho-dihydroxyl groups (catechol) were more potent inhibitors of peroxynitrite formation by SIN-1. In particular, the methyl ester form of chlorogenic acid showed the most potent inhibition. At $5\;{\mu}M$ concentration, the order of minimizing peroxynitrite formation were : methyl chlorogenic acid > quercitrin > quercetin 3-O-sambubioside > chlorogenic acid > afzelin. Authentic peroxynitrite was directly scavenged by the components in a manner similar to peroxynitrite formation by SIN-1. In particular, when compared with penicillamine as a positive control, methyl chlorogenate was as effective in inhibiting peroxynitrite formation and approximately 2 times more effective in scavenging an authentic peroxynitrite. These results demonstrate therefore, that components extracted from the leaves of Eriobotrya japonica effectively scavenged peroxynitrite.

• Natural Product Sciences
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• 제16권3호
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• pp.169-174
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• 2010

The seed of Phaseolus calcaratus Roxburgh (PHCR) is traditionally used for anti-pyretic and antiinflammatory effects. Although these effects are believed to be related to its antioxidant potential, little information is available for the mechanisms by which PHCR seed might scavenge free radicals or otherwise act as an antioxidant. In the present study, we purified some fractions from the ethanol extract of PHCR seed and evaluated each fraction's ability to scavenge free radicals generated by cell-free systems. We also identified active compound that is putatively responsible for free radical scavenging by analyzing NMR spectra. PHCR samples exhibited a concentration-dependent radical scavenging activity against hydroxyl radicals, superoxide anions, and DPPH radicals. Of the samples tested, a methanol-eluted sub-fraction from the PHCR extract, named $FF_4$, scavenged these radicals more effectively than the other fractions. We identified catechin-7-O-$\beta$-Dglucopyranoside as the active compound responsible for free radical scavenging potential of $FF_4$.

• 한국자원식물학회지
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• 제22권3호
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• pp.195-202
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• 2009

Schisandra chinensis have been traditionally used in Asia for the treatment of dyspnea, cough, mouth dryness, spontaneous diaphoresis, nocturnal diaphoresis, nocturnal emission, dysentery, insomnia and amnesia. The purpose of this study is to evaluate the protective effects of Schisandra chinensis on oxidative DNA damage and lipid peroxidation induced by ROS in non cellular and cellular system. DPPH radical, hydroxyl radical and hydrogen peroxide scavenging assay were used to measure the antioxidant activities. Phi X-174RF I plasmid DNA cleavage assay and intracellular DNA migration assay were used to evaluate the protective effect on oxidative DNA damage. MTT assay and lipid peroxidation assay were used for evaluating the protective effect on oxidative cell damage. It was found to scavenge DPPH radical, hydrogen peroxide and hydroxyl radical and it inhibited oxidative DNA damage, lipid peroxidation and cell death induced by hydroxyl radical. These data indicate that Schisandra chinensis possesses a spectrum of antioxidant and DNA-protective properties

• 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.

• 생약학회지
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• 제36권3호통권142호
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• pp.159-163
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• 2005

We screened the anti-oxidative effect on V79-4 hamster lung fibroblast cells induced by hydrogen peroxide with fifteen herbal extracts. Uncariae rhynchophylla JACKS and Rheum coreanum NAKAI were found to show DPPH radical scavenge activity (25 and 29% compared to control). Rheum coreanum NAKAI and Siegesbeckia orientalis L. were shown to scavenge intracellular reactive oxygen species (57 and 55% compared to control) which is measured by dichlorodihydrofluorescin diacetate method (DCHF-DA). Rheum coreanum NAKAI which showed the most strong intracellular reactive oxygen species scavenging activity had low DPPH radical scavenging activity compared to Uncariae rhynchophylla JACKS.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.381.3-382
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• 2002

Free radical-mediated cell damage and free radical attack on polyunsaturated fatty acids result in the formation of lipid radicals. These lipid radicals react readily with molecular oxygen to produce peroxy radicals responsible for initiating lipid peroxidation. The peroxidation of cellular membrane lipid can lead to cell necrosis and considered to be implicated in a number of pathophysiological conditions as well as in the toxicity of many xenobiotics. DPPH is known to abstract labile hydrogen and the ability to scavenge the DPPH radical is related to the inhibition of lipid peroxidation. (omitted)

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권1호
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• pp.13-18
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• 2006

The antioxidant activity of the extract of Erigeron annuus was assessed by means of two different in vitro tests: bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radical (DPPH test) and the scavenging of authentic peroxynitrite in company with peroxynitrite generation from 3-morpholinosydnonimine (SIN-1). In both tests, the 85% aq. MeOH and n-BuOH soluble fractions of the crude extract showed a significant scavenging effect on peroxynitrite and DPPH radical in comparison to L-ascorbic acid. And bioassay-guided fractionation of the n-BuOH soluble fraction led to the isolation of three compounds: Apigenin (1), quercetin-3-O-glucoside (2), and caffeic acid (3). The structures of the isolated compounds were elucidated on the basis of their spectroscopic data and their antioxidant activities were measured by determining their capacity to scavenge peroxynitrite and the DPPH radical.