• KSBB Journal
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• v.18 no.3
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• pp.165-169
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• 2003

The antioxidative activity of Portulaca oleracea was tested using in vitro experimental models. Antioxidative activities were determined by measuring DPPH radical scavenging activity and lipid peroxide using 2-thiobarbituric and (TBA). The crude extract was sequentially partitioned with n-hexane, 15% aq. MeOH, EtOAc, n-BuOH, $H_2O$. A remarkable antioxidative effect was observed in the EtOAc and n-BuOH fractions. The DPPH radical scavenging effect ($IC_{50}$=17.90 $\mu\textrm{g}$/ml) of the n-BuOH soluble fraction was comparable with that of the natural antioxidant, $\alpha$-tocopherol ($IC_{50}$=6.99 $\mu\textrm{g}$/ml) and the inhibition effect of lipid peroxidation in mouse liver homogenate was similar to that of the natural antioxidant, L-ascorbic acid at a concentration of 1.0 mg/ml to 5 mg/ml.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.4
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• pp.252-259
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• 2006

Extracts which were prepared by four different extractions - 80% methanol extracts (ME) at high ($70^{\circ}C$) and a room temperature ($20^{\circ}C$), respectively and aqueous extracts (AE) at both temperatures with the residue after the methanol extracts - of 10 green, 19 brown and 25 red seaweeds collected in Jeju Island coast were examined for their DPPH free radical scavenging activity using a ESR (electron spin resonance) spectroscopy. A variety of the extracts showed positive scavenging effect against DPPH free radical (except the green seaweeds). Among the extracts, the brown seaweed extracts exhibited the highest scavenging activity. Especially, Sargassum spp. of the brown seaweeds have remarkable scavenging activities - both methanolic and aqueous at the both temperatures ($20^{\circ}C$ and $70^{\circ}C$). On the other hand, ME showed better scavenging activity than AE in the red seaweed extracts. These results indicate that autogenous seaweeds in Jeju will be potential natural antioxidants for functional food compounds.

• Korean Journal of Pharmacognosy
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• v.35 no.4 s.139
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• pp.338-345
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• 2004

Scavenging effects of DPPH radical and hydroxyl radical, inhibition of linoleic acid oxidation, inhibition of NO synthesis and iNOS expression were tested with extracts and chromatographic subfractions of Canavalia lineata obtained at Jeju island. Chloroform extract and its subfractions gave moderate effects on scavenging DPPH radical and hydroxyl radical, They also inhibited linoleic acid oxidation, and NO synthesis. Inhibition of NO synthesis resulted from the repression of iNOS gene expression. Ethyl acetate extract and its subfractions showed excellent effects on scavenging DPPH radical and hydroxyl radical, while they were cytotoxic.

• Biomedical Science Letters
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• v.14 no.3
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• pp.193-198
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• 2008

In order to evaluate on the effect of kaempferol on the cytotoxicity of oxygen tree radicals, XTT assay was performed to determine the cell viability after skin fibroblasts derived from human (Detroit 51) that were treated with various concentrations of hydrogen peroxide $(H_2O_2)$. And also, the effect of kaempferol on the cytotoxicity induced by H202 that was examined by cell viability, lactate dehydrogenase (LDH) activity and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity in these cultures. $H_2O_2$ decreased cell viability in dose-dependent manner in these cultures and the $XTT_{90}\;and\;XTT_{50}$ values were determined at concentration of $35{\mu}M\;and\;90{\mu}M$ of $H_2O_2$ after skin fibroblasts derived from human were treated with $15{\sim}90{\mu}M$ of $H_2O_2$ for 6 hours, respectively. $H_2O_2$ was highly toxic on cultured skin fibroblasts derived from human by toxic criteria of Brenfreund and Puerner (1984). In the protective effect of kaempferol on $H_2O_2$-induced cytotoxicity, kaempferol increased DPPH radical scavenging activity and significantly decreased LDH activity. From these results, it is suggested that oxygen tree radical, $H_2O_2$, was highly toxic on cultured skin fibroblasts derived from human, and also kaempferol of flavonoid showed the protection on $H_2O_2$-induced cytotoxicity.

• Korean Journal of Medicinal Crop Science
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• v.21 no.3
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• pp.197-203
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• 2013

We studied the total polyphenol content, DPPH radical scavenging activity, hydroxyl radical scavenging activity and ${\alpha}$-glucosidase inhibition of water extracts from 17 medicinal plants. Total polyphenol contents ranged from 10.0 (Coix lachryma-jobi L, CL) ~ 279.7 (Perilla sikokiana, PS)mg/g. The water extract from medicinal plants were evaluated for its free radical scavenging activities and compared with a commercial antioxidant, ascorbic acid. DPPH radical scavenging activity of Pyrus pyrifolia (PP), Chamaecyparis obtusa L. (COL), Chamaecyparis obtusa F. (COF), and PS were higher than positive control. Higher hydroxyl radical scavenging activity were shown in Acanthopanax senticosus (AS) and Cordyceps militaris (CM) than the other plants. The highest anti-${\alpha}$-glucosidase activity was observed in Cornus officinalis (CO) and Paeonia suffruticosa Andrews (PSA) water extracts. PSA showed not only the higher DPPH radical scavenging activity but also the anti-${\alpha}$-glucosidase activity. The results of our study that PP, COL, COF, PS, AS, CM, CO and PSA could be potential candidates for natural antioxidants.

• Korean Journal of Plant Resources
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• v.19 no.3
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• pp.405-410
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• 2006

A series of aqueous or methanol extracts from four different Korean salad plants were assayed to determine their allelopathy and antioxidant activity. The extracts applied on filter paper in a Petri-dish bioassay significantly inhibited root growth of against alfalfa (Medicago sativa) seedlings. Leaf extracts from 40 g dry tissue $L^{-1}$ of Aster yomena was most phytotoxic to alfalfa root growth, and followed by that of Cirsium japonicum, Taraxacum officinale, and Ixeris dentate. Methanol extracts of plants dose-dependently increased DPPH free radical scavenging activity in vitro. Antioxidant activity of methanol extracts from the same plant species was investigated, and the result showed high DPPH free radical scavenging activity in Cirsium japonicum, Aster yomena, and Ixeris dentate, however, in Taraxacum officinale was least activity. By means of HPLC analysis, chlorogenic acid, p-coumaric acid, and total phenolics with 7.68, 17.47 and 18.64 mg, $100g^{-1}$, respectively, showed the highest amounts in methanol extracts from Cirsium japonicum leaves. These results suggest that Compositae salad plants contain water-soluble substances with allelopathic potential as well as antioxidant activity.

• Food Engineering Progress
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• v.15 no.3
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• pp.221-229
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• 2011

Optimization study of the hot water extraction for enhancing antioxidative activity from Auricularia auricula was performed by Taguchi approach using orthogonal matrix $L_9(3^4)$ method. The correlation between DPPH radical scavenging activity and the components of samples extracted from different extraction conditions were also analyzed. The correlation coefficient between DPPH radical scavenging activity and melanin content of A. auricula were 0.93, indicating 'good correlation'. The optimum extraction conditions was obtained at the extraction time of 1 hr. temperature of $85^{\circ}C$, solid: water ratio of 1: 40(w/v) and frequency of 2 times. Under these conditions, values of maximum DPPH free radical scavenging activity and melanin contents of A. auricula were $67.21{\pm}2.17$ and $52.94{\pm}2.10 mg/g$, respectively. Melanin content of 1.6 times and DPPH free radical scavenging effect of 130% were enhanced by optimization.

• Archives of Pharmacal Research
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• v.20 no.5
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• pp.496-500
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• 1997

A strong antioxidant activity, which was measured by the radical scavenging effect on 1, 1-diphenyl-2-picrylhydrazyl(DPPH) radical, was detected in the methanol extract of Salvia miltiorrhiza Bunge (Labiatae). By activity-directed fractionation, compounds 1 and 2 were isolated as antioxidant principles of S. miltiorrhiza. Compounds 1 and 2 were identified as dimethyl lithospermate and 3-(3, 4-dihydroxyphenyl)lactamide, respectively, on the basis of spectral data. The radical scavenging effect of compounds 1 and 2 on DPPH radical exceeded that of L-ascorbic acid which is a well known antioxidant. These two compounds also showed prominent inhibitory activity against free radical generation in dichlorofluorescein (DCF) method and cytoprotective effect against t-BHP in cultured liver cell.

• Korean Journal of Clinical Laboratory Science
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• v.43 no.3
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• pp.98-104
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• 2011

To evaluate the physioactivity of Salicornia herbacea L. (SH), which are obtained from Sunchon bay as wild plants, an SH extract was prepared by freeze drying to obtain SH, and by cold drying to obtain SH. For the evaluation of their bioactivities, cell viability and antioxidative effect were measured. The XTT assay was adopted to measure cell viability after C6 glioma cells were treated with various concentrations of reactive oxygen species (ROS) and hydrogen peroxide ($H_2O_2$) for 8 hours. The DPPH-radical scavenging activity was also measured for the antioxidative effect. In this study, the $XTT_{50}$ value of $H_2O_2$ was determined at $30{\mu}M$ which was highly toxic based on the cytotoxic criteria by Borenfreund and Puerner. The protective effect of SH extract significantly increased cell viability compared with $H_2O_2$-treated group. Its antioxidative effect showed a significant DPPH-radical scavenging activity at concentrations of $1-100{\mu}g/mL$, while SH extract showed highly a DPPH-radical scavenging activity at only $100{\mu}g/mL$. From these results, $H_2O_2$ was highly toxic in cultured C6 glioma cells, and SH extract was effective in the prevention of cell damage by its antioxidative effect.

• The Korean Journal of Community Living Science
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• v.15 no.4
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• pp.11-16
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• 2004

This study was conducted to find the powerful free radical scavenging effect in methanol extracts from 35 kinds of Korean medicinal plants obtained from the Plant Extract Bank as natural plant products. Antioxidant activity of the plant extracts was determined by measuring the scavenging effect of 1,1-diphenyl-2-picryl hydrazyl radical (DPPH). In the screening of plant extracts tested, at 200 ppm level, almost all plantex tracts showed significantly high antionidant activity. In the reinvestigation of 15 kinds of Korean medicinal plants at 50 ppm level selected as good sources with good free radical scavenging effect at 200 ppm level, the DPPH scavenging effects were similar to those of L-ascorbic acid in whole plant extract of Fragaria yezoensis (90.4％), in the plant stems and roots extract of Gingko biloba, and the leaves extract of Rhododendron mucronulatum var. ciliatum (90％). The fruits extract of Cornus officinalis showed the strongest antioxidant activity (95％). These results suggest that the methanol extracts from Korean medicinal plants can be a potential source of antioxidants that can be used to control oxidative stress in the body, But further study is needed to measure their safety for consumption