• Food Science and Preservation
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• v.19 no.2
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• pp.229-234
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• 2012

The antioxidant substance in black onion was identified. The assays that used 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazo line-6-sulphonic acid) ($ABTS^+$) radicals showed that the ethyl acetate fraction of black onion methanol extract had a higher level of radical-scavenging activity than the other fractions. Two antioxidative compounds were purified and isolated from the ethyl acetate fraction via column chromatographies of silica gel and Sephadex LH-20 using the guided DPPH radical-scavenging assay. The isolated compounds were identified as 3,4-dihydroxybenzoic acid (1) and quercetin (2) based on mass spectrometry and nuclear magnetic resonance. The isolated compounds showed a high level of DPPH and ABTS+ radical-scavenging activity. Compound 2 had a higher level of radical-scavenging activity than 1.

• Biomolecules & Therapeutics
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• v.19 no.3
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• pp.336-341
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• 2011

As part of an ongoing search for natural plants with antioxidant compounds by measuring the radical scavenging effect on 1,1-diphenyl- 2-picrylhydrazyl (DPPH), a total extract of the twigs of Galium spurium L. (Rubiaceae) was found to show potent antioxidant activity. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of nine compounds, asperulosidic acid methyl ester (1), asperuloside (2), caffeic acid (3), kaempferol-3-O-L-rhamnopyranoside (4), quercetin-3-O-[${\alpha}$-Lrhamnopyranosyl($1{\rightarrow}6$)-${\beta}$-D-glucopyranoside] (5), isorhamnetin-3-O-glucopyranoside (6), quercetin-3-O-${\alpha}$-L-rhamnopyranoside (7), kaempferol-3-O-[${\alpha}$-L-rhamnopyranosyl($1{\rightarrow}6$)-${\beta}$-D-glucopyranoside] (8), and quercetin (9). Their structures were elucidated by spectroscopic studies. Compounds 1, 3-8 were isolated for the first time from this plant. Among them, compounds 3 and 9 showed the significant radical scavenging effects on DPPH, and compounds 3 and 7 showed the potent riboflavin originated superoxide quenching activities.

• ALGAE
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• v.24 no.3
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• pp.179-184
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• 2009

Methanol crude extract of the sea grass Zostera marina L. and organic solvent fractions (n-hexane, chloroform, ethyl acetate, n-butanol, and water) were screened for antioxidant activity (total phenolic contents, DPPH scavenging activity, and reducing power) and antimicrobial activity against three human skin pathogens, two bacteria and a yeast; Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. Total phenolic contents and 2, 2- diphenyl-1-picrylhydrazyl (DPPH) scavenging activity were highest in the ethyl acetate fraction with 968.50 $\mu$g gallic acid equivalent per milligram of extract, and ca. 95% scavenging activity on the DPPH radicals at 10 mg $ml^{-1}$. In antimicrobial activity tests, MICs (Minimum Inhibitory Concentration) of each Zostera marina extract partitioned ranged from 1mg to 8 mg $ml^{-1}$ (extract/ 10% DMSO) against all three human skin pathogens. The MICs of the ethyl acetate and n-butanol fractions were the same with 1 mg $ml^{-1}$ against S. aureus and C. albicans. The ethyl acetate fraction of Z. marina does protect against free radicals and may be used to inhibit the growth of human skin pathogens.

• Journal of the Korean Wood Science and Technology
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• v.31 no.6
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• pp.67-72
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• 2003

The leaves of D. racemosum showed strong DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity and the order of the radical scavenging activity against DPPH radical is ethyl acetate (EtOAc) fraction>crude extracts>residue fraction>hexane fraction>ether fraction, under the experimental conditions. Since EtOAc fraction has highest antioxidative activity among these fractions, the isolation was performed from the EtOAc fraction of the leaves of D. racemosum and four phenolic compounds were isolated and identified as follows: methyl gallate, kaempferol, quercetin and quercitrin. The free radical scavenging activities of these compounds were 79.9%, 93.1%, 93.6% and 66.7% at 10 ㎍/ml, respectively. The IC₅₀ of compound 1, compound 2, compound 3 and compound 4 were 6.1, 4.1, 3.6 and 6.5 ㎍/ml, respectively. These compounds have higher antioxidative activity compared with reference compounds, ascorbic acid (IC₅₀ = 9.6 ㎍/ml).

• Korean Journal of Medicinal Crop Science
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• v.13 no.5
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• pp.227-232
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• 2005

The antioxidant effect of methanol extract (ME) and water extract (WE) from Clematis trichotoma was evaluated as primary study to scavenge stable 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), inhibited iron-induce lipid peroxidation in linoleic acid emulsion, peroxidation of liposome induced by $Fe^{3+}/H_2O_2/ascorbie$ acid, and on $Fe^{2+}/H_2O_2$ induced the mitochondrial lipid peroxidation. In secondary study, five flavonoids as luteolin (1), quercetin (2), apigenin (3), hirsutrin (4), kaempferol-3-O-glucoside were isolated (5). Among them, compounds 1 and 2 showed good activities in all the model systems. Compound 3 exhibited moderate antioxidant activities in both radical scavenging and these lipid peroxidation systems tested. Compound 4 showed significant inhibitions in liposome peroxidation and compound 5 displayed weak inhibition in all four tested systems. All the results presented herein indicate that products of C. trichotoma maybe useful in inhibiting membrane lipid peroxidation and preventing free radical-linked diseases.

• Journal of Pharmacopuncture
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• v.13 no.1
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• pp.79-85
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• 2010

Objective: This experimental study was performed to investigate the anti-inflammation and anti-oxidant effects of Sopungdojeok-tang(SPDJT) and Samulsopung-san(SMSPS) which were used to treat patient with atopic dermatitis Methods: Anti-inflammation and anti-oxidant effects of SPDJT and SMSPS were measured by the inhibitory ability of Nitric oxide(NO) production and the scavenging for 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical. Results: 1. SPDJT and SMSPS were not showed cell toxicity. 2. In inhibitory effects against NO production, all groups of SPDJT were showed anti-inflammation, but all groups of SMSPS were not showed anti-inflammation. There were statistical significances between $20{\mu}g/m\ell$ and 4, $10{\mu}g/m\ell$ in SPDJT groups. 3. In DPPH radical scavenging activity, all groups of SPDJT and all groups of SMSPS were showed anti-oxidant effects. There were statistical significances between $20{\mu}g/m\ell$ SPDJT group and 4, $10{\mu}g/m\ell$ SMSPS groups. Conclusion: These results suggest that the SPDJT groups are better than the SMSPS groups in antiinflammation and anti-oxidant effects.

• Preventive Nutrition and Food Science
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• v.10 no.1
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• pp.92-94
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• 2005

The flavonoids kaempherol and epicatechin, and a proanthocyanidin fraction were isolated from the seed of allspice (Pimenta dioica). Their structures were determined by chemical and spectral analyses. Antioxidant activities of kaempherol, epicatechin and the proanthocyanidin fraction were tested using the reaction with the stable radical diphenyl-p-picrylhydrazyl (DPPH) and exhibited IC/sub 50/ values of 7.83, 4.27 and 2.92 g/mL, respectively. These results demonstrate that allspice proanthocyanidins and flavonoids might act as effective antioxidants.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.854-858
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• 2005

Methanol and water crude extracts, crude polysaccharides and crude polysaccharides-free of water crude extracts from Shiitake mush-room (Lentinus edodes) were investigated for their antioxidant capacity in total polyphenolics and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. Total polyphenolics in the crude polysaccharides-free of water crude extracts were higher than that of the other ones. And crude polysaccharides-free of water crude extracts and water crude extracts show high on DPPH free radical scavenging activity. Positive correlations were found between total polyphenolics and their antioxidant activity.

• YAKHAK HOEJI
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• v.46 no.4
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• pp.237-241
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• 2002

Polyphenoloxidase activity (PPO) in the leaves of Erechitites hieracifolia was estimated by Warburg's manometric method. The emzyme was most reactive toward chlorogenic acid followed by caffeic acid. Diethyldithiocarbamate and potassium cyanide were shown powerful inhibition rate to the polyphenoloxidase from the leaves of Erechitites hieracifolia. We confirmed antioxidant activity of the leaves of Erechitites hieracifolia by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging method. Electrophorectic isoenzyme banding patterns of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were observed by native PAGE. The correlation of PPO and antioxidant enzymes is not investigated yet. That is need to further study.

• Archives of Pharmacal Research
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• v.25 no.4
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• pp.449-452
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• 2002

The antioxidant activity of Juniperus chinensis (Cupressaceae) was determined by measuring the radical scavenging effect on DPPH (1,1-diphenyl-2-picrylhydrazyl). The methanolic extract of J. chinensis heartwood showed the strong antioxidant activity. The antioxidant activity of n-BuOH soluble fraction was stronger than that of the others, and the fraction was subjected to purification by repeated silica gel and Sephadex LH-20 column chromatography. Quercetin, naringenin, taxifolin, aromadendrin and isoquercitrin were isolated from the n-BuOH fraction. Their structures were elucidated by physico-chemical and spectroscopic studies.