• Environmental Mutagens and Carcinogens
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• v.26 no.2
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• pp.48-52
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• 2006

Our investigation of the seaweed extracts, Ulva lactuca. The biological activities antioxidant, antimicrobial activity, antifungal and haemolytic activity of ethy-ether and ethyl-acetate extracts from the seaweed, Ulva lactuca were investigated. They were separately extracted using ethyl-ether and ethyl-acetate from dried samples at room temperature and freeze dried. Seaweed extracts were found to cause significant free radical scavenging effects on DPPH (1,1-diphenyl-2-picrylhydrazyl). Seaweed extracts had not significant haemolytic activity against human erythrocyte. This extracts exhibited in vitro broad-spectrum antimicrobial activity of gram-negative, gram-positive bacteria and without antifungal activity.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1299-1304
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• 2008

The potential antioxidant activities of different fractions from a 70% methanolic (MeOH) extract of Sonchus oleraceus were assayed in vitro. All of the fractions exception of n-hexane showed a strong antioxidant activity, especially the ethyl acetate (EtOAc) fraction, which showed the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity ($IC_{50}=19.25{\mu}g/mL$). The results of hydroxyl radical scavenging activity and a reducing power assay showed concentration dependence, the EtOAc fraction demonstrating a better result than the other fractions at the same concentration in the studies. Additionally, the fractions' total phenolic (TP) contents was measured, phenolic compounds such as tannic acid, p-coumatric acid, quercetin, epicathchin, and kaempferol being detected by high performance liquid chromatography (HPLC). Meanwhile, a regression analysis revealed a moderate-to-high correlation coefficient between the antiradical activity and the TP contents, suggesting that fractions obtained from the 70% MeOH extract of S. oleraceus are of potential use as sources of antioxidant material.

• YAKHAK HOEJI
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• v.47 no.6
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• pp.361-364
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• 2003

Acanthopanax species (Araliaceae) has been traditionally used as tonic, analgesic, stimulant of immune system, and replenishment of body function. The antioxidant activities of leaf and root bark of Acanthopanax species were determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and thiobarbituric acid reactive substances (TBARS) assay and relative electrophoretic mobility (REM) on human plasma low density lipoproteins (LDL). Acanthopanax divaricatus var. albeofructus and Acanthopanax for. nambunensis showed potent antioxidant activities.

• Journal of the Korean Wood Science and Technology
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• v.31 no.6
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• pp.40-44
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• 2003

This study was carried out to investigate the antioxidant activities of domestic trees grown in Korea. Based on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity method, the methanolic extracts of 23 species were screened in order to search for natural antioxidants. Among these species, Acer ginnala, Cotinus coggygria, Acanthopanax koreanum, Thea sinensis and Pinus densiflora showed stronger antioxidative activity comparing with reference compound, ascorbic acid.

• Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.13-20
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• 2015

Calculated chemical scores (computed in relation to the FAO/WHO reference protein) for salmon liver protein hydrolysates indicated that all amino acids (other than methionine and threonine) were present in adequate or excess quantities; thus, the raw liver material is a good source of essential amino acids. The hydrophobic amino acids contents in hydrolysates prepared from Oncorhynchus keta and O. gorbuscha were 38.4 and 39.1%, respectively. The proportion of released peptides exceeding 500 kDa was reduced when hydrolysates were treated with the commercial enzyme Alcalase, although proportions in the following MW ranges were elevated: 100-500 kDa and <50 kDa. The optimal conditions for enzymatic hydrolysis were as follows: pH 7.0, $50^{\circ}C$, and a reaction time of 1 h. Of the different proteases tested, Alcalase was the most efficient for production of salmon liver hydrolysate with the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity. The hydrolysates prepared from salmon liver had a balanced amino acid composition. The liver protein hydrolysates contained low molecular weight peptides, some of which may be bio-active; this bio-active potential should be investigated. Inhibition of the DPPH radical increased with increased degree of hydrolysis (DH), regardless of protease type. DPPH radical scavenging abilities, antithrombotic effects and ${\alpha}$-glucosidase enzyme inhibition effects of O. keta liver hydrolysate increased in a dose-dependent manner. Thus, salmon liver hydrolysate may be useful in functional food applications and as a source of novel products.

• Archives of Pharmacal Research
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• v.26 no.4
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• pp.279-285
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• 2003

In our ongoing study to identity antioxidants from natural sources, the antioxidant activity of Nelumbo nucifera stamens was evaluated for their potential to scavenge stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals, inhibit total reactive oxygen species (ROS) generation, in kidney homogenates using 2 ,7 -dichlorodihydrofluorescein diacetate (DCHF-DA), and scavenge authentic peroxynitrites ($ONOO^-$). A methanol (MeOH) extract of the stamens of N. nucifera showed strong antioxidant activity in the $ONOO^-$system, and marginal activity in the DPPH and total ROS systems, so were therefore fractionated with several organic solvents, such as dichloromethane ($CH_2 Cl_2$), ethyl acetate (EtOAc) and n-butanol (n-BuOH). The EtOAc soluble fraction, which exhibited strong antioxidant activity in all the model systems tested, was further purified by repeated silica gel and Sephadex LH-20 column chromatographies. Seven known flavonoids [kaempferol (1), kaempferol 3-Ο-$\beta$-D-glucuronopyranosyl methylester (2), kaempferol 3-Ο-$\beta$-D-glucopyranoside (3), kaempferol 3-Ο-$\beta$-D-galactopyranoside (4), myricetin 3 ,5 -dimethylether 3-Ο-$\beta$-D-glucopyranoside (5), kaempferol 3-Ο-$\alpha$-L-rhamnopyranosyl-(1$\rightarrow$6)-$\beta$-D-glucopyranoside (6) and kaempferol 3-Ο-$\beta$-D-glucuronopyranoside (7)], along with $\beta$-sitosterol glucopyranoside (8), were isolated. Compound 1 possessed good activities in all the model systems tested. Compounds 2 and 7 showed scavenging activities in the DPPH and $ONOO^-$ tests, while compounds 3 and 4 were only active in the $ONOO^-$ test. Conversely, compound 8 showed no activities in any of the model systems tested.

• Journal of the Korean Wood Science and Technology
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• v.36 no.6
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• pp.159-167
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• 2008

This study was carried out to investigate the potential promise of Chamaecyparis obtusa oil as a natural antioxidant. C. obtusa oil and its fractions were subjected to screening for their antioxidant activities by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and ammonium thiocyanate method. In the first case, $IC_{50}$ value of the C. obtusa oil was determined as $40{\mu}{\ell}/m{\ell}$. At $0.5{\mu}{\ell}/m{\ell}$ concentration level, free radical scavenging effect of fraction G determined as 66.94% was the highest among the fractions of C. obtusa oil. In the ammonium thiocyanate method, essential oil of C. obtusa and its fraction C, D, and E showed activities of 72.0%, 71.2%, 71.9% and 71.1%, respectively. Fraction G, most active fraction, was mainly consisted of $\alpha$-terpineol, elemol, widdrol and $\alpha$-cadinol.

• Journal of Applied Biological Chemistry
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• v.65 no.3
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• pp.221-230
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• 2022

We investigated the antioxidant and anti-inflammatory effects of silymarin. The antioxidant activity was evaluated using 1,1-diphenyl-1-picrylhydrazyl radical (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals scavenging assays. Silymarin scavenged 71% of DPPH radicals and 78% of ABTS radicals at a concentration of 1 mg/mL, respectively. Silymarin effectively inhibited the oxidative damage of DNA, and the oxidative modifications of human serum proteins and Cu,Zn-SOD. Also silymarin effectively inhibited H₂O₂- and LPS-induced cell death as well as the generation of reactive oxygen species and DNA fragmentation by H₂O₂ and LPS. The results suggested that silymarin might be an effective natural antioxidant and anti-inflammatory material.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.4 s.48
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• pp.499-502
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• 2004

DPPH radical-generating system was used to evaluate the antioxidant properties of the Rosaceae. The inhibitory effects of ethanolic extracts from Rosaceae plants were investigated on melanin biosynthesis which is closely related to hyperpigmentation. Of the Rosaceae extracts, Prunus sargentii, Rubus coreanus, Chaenomeles sinensis, Photinia glabra and Pyrus pyrifolia showed a potent inhibition of tyrosinase, the enzyme which converts 3-(3,4-dihydroxyphenyl) alanine (dopa) to dopachrome in the melanin biosynthetic process. Furthermore, MMT assay was used to check the cytotoxicity of extracts on the human foreskin fibroblast cell line, Hs68. Among the Rosaceae, bark of Prunus sargentii, bark wood of Photinia glabra and all parts or Chaenomeles sinensis showed more than $50\%$ inhibition of mushroom tyrosinase activity at 100 ug/mL and more than $80\%$ of strong DPPH radical-scavenging activity at 10 ug/mL. In audition to, they had no cytotoxic activity on Hs68. These results suggest that these extracts might be except a controler in pigmentation.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.165-170
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• 2003

The antioxidative activity of antioxidative substances produced from several bacterial strains isolated from fermented foods were tested by $DPPH\;({\alpha},{\alpha}'-diphenyl-{\beta}-picrylhydrazyl)$ free radical scavenging activity. One of the strains showing the highest antioxidative activity was identified as Bacillus sp. based on the morphological, biochemical, physiological characteristics, and 16S rRNA sequence, and named FF-7. The most optimal medium condition for the production of antioxidative substance from Bacillus sp. FF-7 was 2% galactose as carbon source and l% tryptone as nitrogen source. The antioxidative substance produced from FF-7 in these cultural medium was also tested by in vitro experimental models, the peruxidation of linoleic acid and the peroxidation of rat tissues microsomes by using thiobarbituric acid (TBA) for assay of free malondialdehyde production. The antioxidative activity against lipid peroxidation of rat tissues microsomes was shown in the following order; brain 97.50% > heart 79.95% > kidney 77.84% > spleen 77.47% > testis 69.96% > liver 62.45%. The antioxidative substance produced from FF-7 on linoleic acid peroxidation by IBA method was effectively inhibited during four days, and 0.05% BHT (butylated hydroxytoluene) used comparative control was also effectively inhibited. Results showed that the highest antioxidative activity by DPPH method of antioxidative substance produced from Bacillus sp. FF-7 was obtained by supplementing 2% galactose as carton source and l% tryptone as nitrogen source in cultured medium, this substance effectively inhibited the formation of TBARS in brain microsome in vit개 system and in linoleic acid peroxidation.