• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2557-2560
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• 2010

To assay for antioxidant capacity of natural products considered important in producing human health benefits, a practical and economical method using pellet techniques was developed. A standard visualizing reagent, 1,1diphenyl-2-picryl-hydrazyl (DPPH), was mixed with a water-miscible polyvinyl alcohol (PVA), serving as a solid phase support for the DPPH reagent. A DPPH pellet was prepared by dropping a small volume of the DPPH solution onto PET film, and drying in an oven. The PVA-based DPPH pellet was dissolved into water, in which the water-miscible PVA plays as a non-ionic surfactant to help the DPPH reagent to be dissolved into the solvent. Using the DPPH assay, the antioxidant capacity of water-soluble extracts of black soybean, barley, green tea, and green gram was examined. Among the natural products tested, green tea showed the highest antioxidant capacity. This PVA-based DPPH antioxidant assay can be further applied in the natural food, raw plant material, and health product inspection field.

• Natural Product Sciences
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• 제22권1호
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• pp.64-69
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• 2016

A method for simultaneously identifying antioxidative compounds was developed using time-based LC-MS coupled with DPPH assay regardless of the time consuming process. The methanolic extract of Polygonum aviculare (Polygonaceae) showed significant DPPH radical scavenging activity. Time-based DPPH assay for simultaneous identification of active compounds from the extracts of P. aviculare was used. Major peaks of ethyl acetate fraction of P. aviculare showed high DPPH radical scavenging activity. A simple phenolic compound (1) and six flavonoids (2-7) were isolated from the ethyl acetate fraction of P. aviculare by silica gel and sephadex LH-20 column chromatography. The structures of seven compounds were determined to be protocatechuic acid (1), catechin (2), myricitrin (3), epicatechin-3-O-gallate (4), avicularin (5), quercitrin (6), and juglanin (7) based on the analysis of the $^1H$-NMR, $^{13}C$-NMR and ESI-MS data. All compounds exhibited significant antioxidant activity on DPPH assay and active compounds were well correlated with predicted one.

• BMB Reports
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• 제37권5호
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• pp.629-633
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• 2004

NADPH-cytochrome P450 reductase (CPR) transfers electrons from NADPH to cytochrome P450, and catalyzes the one-electron reduction of many drugs and foreign compounds. Various forms of spectrophotometric titration have been performed to investigate the electron-accepting properties of CPR, particularly, to examine its ability to reduce cytochrome c and ferricyanide. In this study, the reduction of 1,1-diphenyl-2-picrylhydrazyl (DPPH) by CPR was assessed as a means of monitoring CPR activity. The principle advantage of DPPH is that its reduction can be assayed directly in the reaction medium by a continuous spectrophotometry. Thus, electrons released from NADPH by CPR were transferred to DPPH, and DPPH reduction was then followed spectrophotometrically by measuring $A_{520}$ reduction. Optimal assay concentrations of DPPH, CPR, potassium phosphate buffer, and NADPH were first established. DPPH reduction activity was found to depend upon the strength of the buffer used, which was optimal at 100 mM potassium phosphate and pH 7.6. The extinction coefficient of DPPH was $4.09\;mM^{-1}\;cm^{-1}$. DPPH reduction followed classical Michaelis-Menten kinetics ($K_m\;=\;28\;{\mu}M$, $K_{cat}\;=\;1690\;min^{-1}$). This method uses readily available materials, and has the additional advantages of being rapid and inexpensive.

• 생약학회지
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• 제46권4호
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• pp.303-308
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• 2015

Ten phenolic compounds were isolated from the twigs of Stewartia pseudocamellia. The isolated compounds were identified as 5,7,3',5'-tetrahydroxyflavanone (1), 3,5,7,3',5'-pentahydroxyflavanone (2), quercetin (3), (+)-aromadendrin (4), (+)-ampelopsin (5), myricetin (6), (+)-catechin (7), (-)-epicatechin (8), kaempferol (9), and fraxin (10) by spectroscopic analysis. Compounds 1, 2, 4, 6, 8, and 9 were isolated from this plant for the first time. The antioxidant activities of compounds 1-10 were evaluated by the DPPH and/or ORAC (oxygen radical absorbance capacity) assay. Compounds 3, 5-9 showed significant antioxidative effects on DPPH assay. Among the active compounds, 6 exhibited higher activity compared to trolox on ORAC assay.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 추계학술대회
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• pp.78-78
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• 2019

The aim of the study was to determine the antioxidant activities of the plants with origin of Vietnam. The Embelia scandens (Lour.) Mez which is a species of plant in the family Myrsinaceae and Cornus hongkongensis Hemsl., which is a species of plant in the family Cornaceae were tested for antioxidant activities. Samples were prepared using 95% ethanol using DPPH assay for assessing the antioxidant activity. Ascorbic acid was used for positive control for DPPH assay. DPPH assay experiment showed that extracts of the Embelia scandens (Lour.) Mez and Cornus hongkongensis Hemsl. might have anti-oxidant activity 4.77 times and 5.65 times higher, respectively, compared to control. To determine the cell toxicity, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used. MTT assay experiment showed that Embelia scandens (Lour.) Mez might have 13.1% more toxicity whereas Cornus hongkongensis Hemsl. might have 47.3% less toxicity compared to control. Taken together, these experiments showed that Cornus hongkongensis Hemsl. extracts might have significantly higher antioxidant activities and relatively lower toxicity, compared to control.

• 한국융합학회논문지
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• 제8권12호
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• pp.215-220
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• 2017

도꼬마리 (X. strumarium )는 국화과에 속하며, '창이자'라는 한약명으로 사용되는 다년생 식물이다. 열매부위와 지상부위의 추출물을 이용하여 융합 식물활성작용을 관찰하였다. 산화적 스트레스에 대항하는 실험법으로는 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH), ABTS assay를 사용하였다. 도꼬마리의 추출물은 단일분리가 아닌 ethanol, petroleum ether, 그리고 ethyl acetate로 추출하였다. 산화적 스트레스연구에 사용되는 radical scavenging 능력을 확인하기 위하여 DPPH radical and ABTS를 투여하였다. 본 연구에서 도꼬마리는 천연유래 항산화 효과를 보였다.

• 한국미생물·생명공학회지
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• 제41권3호
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• pp.367-371
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• 2013

2,2'-diphenylpicrylhydrazyl ($DPPH^{\cdot}$) assay와 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid ($ABTS^+$) decolorization assay는 자연상태의 플라보노이드와 이소플라보노이드의 항산화 활성을 확인하는데 사용된다. 억제중간값(half maximal inhibitory concentration ($IC_{50}$) values)과 트롤록스당량 항산화능값(trolox equivalent antioxidant capacity (TEAC) values)은 $DPPH^{\cdot}$ assay와 $ABTS^+$ assay로 계산되었다. DPPH assay 결과, 쿼세틴(quercetin)은 가장 강한 항산화 능력을 가졌고 뒤이어 피세틴(fisetin), 7,8-디하이드록시플라본(7,8-dihydroxyflavone), 모린(morin), 캠퍼롤(kaempferol) 순이었다. 쿼세틴, 피세틴, 7,8-디하이드록시플라본은 부틸하이드록시 아니솔(butyl hydroxyl anisole)보다 더 높은 항산화 능력을 가졌다. 쿼세틴은 플라보노이드와 이소플로보노이드 중에서 TEAC 값이 가장 높았고 뒤이어 3-하이드록시플로본(3-hydroxyflavone), 피세틴, 7,8-디하이드록시플라본과 모린 순이었다. 다른 나머지 플라보노이드와 이소플라보노이드는 트롤록스 보다 더 약한 $ABTS^+$ 분해능력(scavenging potential)을 가졌다. 테스트된 13개 플라보노이드/이소플라보노이드에서 이소플라보노이드는 플라보노이드보다 매우 약한 항산화 능력을 보였다.

• 한국미생물·생명공학회지
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• 제40권3호
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• pp.208-214
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• 2012

본 연구는 왕겨를 이용한 항산화, 항노화에 효과적인 초액을 대량생산하여 기능성을 검증하고 왕겨초액 내의 기능성물질을 분석하여 사업화의 가능성을 타진하고자 하였다. 정제된 왕겨초액을 분획하여 기능성이 확인된 부분을 HPLC 기기를 이용하여 확인한 결과 caffeic acid 외에 7종의 polyphenol 유래물질에서 기능성을 확인하였다. 기능성 화장품소재 시험으로는 세포 생존율 측정(MTT assay), 주름개선 (collagenase inhibition assay, elastase inhibition assay), 미백(tyrosinase inhibition assay), 항산화 시험(DPPH free radical scavenging assay, SOD-like activity, xanthine oxidase inhibition assay)이 실시하였다. 피부주름형성은 콜라겐의 합성과 분해가 중요한 원인으로 작용한다고 알려져 있지만, 최근 많은 연구에서 엘라스틴의 재형성과 분해 또한 주름형성 기전에서 중요한 작용을 하는 것으로 보고되고 있다. 왕겨초액은 $100{\mu}L/mL$의 농도에서 collagenase 저해효과가 100%, elastase 저해효과가 55% 이상으로 주름개선 효과가 우수하였다. 왕겨초액은 $100{\mu}L/mL$의 농도에서 tyrosine에 대한 tyrosinase 저해효과가 80% 이상으로 미백효과가 우수하게 나타났다. DPPH radical 소거율, xanthine oxidase 저해와 SOD-like 활성을 이용하여 항산화 효과를 측정하였다. 왕겨초액 $100{\mu}L/mL$의 농도에서 DPPH radical 소거율이 80%, xanthine oxidase 저해효과가 80%, 그리고 SOD-like 활성이 100%를 나타내었다. 따라서 본 연구를 통하여 정제 왕겨초액을 이용한 산업화를 위한 가능성을 타진하여 효과가 좋음을 확인할 수 있었다. 이와 같은 결과로 왕겨초액을 이용한 기능성 화장품의 소재로 뿐만 아니라, 식품 및 의약외품의 품목허가를 통하여 고부가가치의 상품화소재로의 가능성이 있다고 사료됩니다.

• 한국자원식물학회지
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• 제22권4호
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• pp.323-329
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• 2009

기능성 옥수수 수염을 가지는 옥수수 계통을 선발하기 위해 다양한 자식계통과 F1을 대상으로 옥수수 수염의 항산화 성분과 항산화능을 측정하였다. 측정결과, 총 페놀 함량, 총 플라보노이드 함량의 경우 각각 980${\sim}$2,420 mg 100 $g^{-1}$, 1,532${\sim}$3,274 mg 100 $g^{-1}$의 범위를 나타내었다. 안토시아닌의 고유영역인 517 nm에서의 흡광도는 0.05에서 0.76까지의 범위를 보였다. 옥수수 수염의 항산화 성분과 DPPH, ABTS, FRAP assay에서 얻어진 항산화능간의 상관관계를 분석한 결과, ABTS와 FRAP assay에서 옥수수 수염의 항산화 활성과 페놀성물질 및 안토시아닌간의 상관계수가 유의하게 높았다. 옥수수 수염의 안토시아닌을 추출하는 용매가 산성이라는 점과 안토시아닌의 DPPH 용액과의 가시영역 파장에서의 간섭을 고려할 때, DPPH 보다는 ABTS assay나 FRAP assay가 더 적합한 항산화능 측정 방법이 될 것이다. 이들 중 특히 ABTS assay는 옥수수 수염의 주요한 기능성 성분인 안토시아닌과 플라보노이드 및 페놀성 물질과 모두 높은 상관성을 보여 옥수수 수염의 종합적인 항산화능을 평가하고 우수 계통을 선발하는데 적합한 측정 방법이 될 것으로 사료된다. 본 실험에서 안토시아닌 함량과 페놀 함량이 높고 ABTS assay와 FRAP assay에서 모두 높은 항산화능을 보여준 S15은 고 기능성 품종 육종 및 옥수수 수염을 이용한 기능성 소재 개발에 이용될 수 있을 것이다. 또한 옥수수 수염의 항산화능 측정에 대한 항산화 실험의 적합성 연구는 우수한 옥수수 수염을 선발하는데 도움이 될 것이다.

• 한국식품영양학회지
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• 제24권4호
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• pp.713-719
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• 2011

The antioxidant activities of the ethanol extract of Arctium lappa were assessed by measuring the 1,1-diphenyl-2-picrylhydrazyl( DPPH) radical scavenging effect, inhibition of $Fe^{2+}$-induced lipid peroxidation, inhibition of malondialdehyde(MDA)-bovine serum albumin(BSA) conjugation reaction and antimutagenic capacities using the Ames test. The DPPH radical scavenging activity and inhibition of $Fe^{2+}$-induced lipid peroxidation of the $Arctium$ $lappa$ ethanol extract significantly increased in a dose-dependent manner. In the radical scavenging assay using DPPH, the $IC_{50}$ of the Arctium lappa extract was 296 ${\mu}g$/assay(1.29 mg of dry sample). In addition, the $IC_{50}$ in the inhibition of $Fe^{2+}$-induced lipid peroxidation was 1,759 ${\mu}g$/assay(7.65 mg of dry sample). This extract also significantly inhibited the MDA-BSA conjugation reaction with an $IC_{50}$ of 57.58 mg/assay(250 mg of dry sample). However, no inhibitory effects against the direct and indirect mutagenicities in $Salmonella$ Typhimurium TA98 and TA100 were observed. Based on these results, the ethanol extract of $Arctium$ $lappa$ was shown to display considerable antioxidative activities.