• Korean Journal of Pharmacognosy
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• v.32 no.3 s.126
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• pp.253-256
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• 2001

The present study was designed for the improvement of routine measurement of superoxide and hydroxyl radical scavenging activities utilized by a microplate reader. Superoxide radical scavenging activity by the ascorbic acid, which is a well-known superoxide scavenger, was determined in a dose-dependent manner. Hydroxyl radical scavenging activity by the thiourea, which is a well-known hydroxyl radical scavenger, was also well detected in a dose-dependent manner. Our results suggest that the use of microplate reader to assay the superoxide and hydroxyl radical scavenging activities improves the accuracy of data and enables the use of much smaller amounts of samples and/or reagents, with much simpler experimental procedure. Therefore, These methods appear to be suitable for screening of superoxide and hydroxyl radical scavenging activities in both the plant medicinal extracts and the isolated compounds.

• KSBB Journal
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• v.32 no.2
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• pp.140-145
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• 2017

The objective of this study was to compare antioxidant effects of different extracts of Salicornia bigelovii seed. DPPH radical scavenging activity, chelating activity of ferrous, superoxide anion radical-scavenging activity, hydroxyl radical scavenging activity, and contents of total polyphenol and flavonoid were measured for different extracts. Ethanol extract (10 mg/mL) was found to have the maximum DPPH radical scavenging and superoxide anion radical scavenging activities (65.26 and 62.36%, respectively). However, hot water extract (10 mg/mL) showed the highest hydroxyl radical scavenging and chelating activities (51.50 and 53.24%, respectively). Total phenolics and flavonoid contents in the ethanol extract were 522.8 and $480.35{\mu}g/mg$, respectively. They were 401.51 and $352.60{\mu}g/mg$, respectively, in the hot water extract. These results indicate that ethanol and hot water extracts of S. bigelovii seed have good potential to be used as a new source of antioxidants for functional foods, cosmetics, and pharmaceuticals.

• Food Science and Preservation
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• v.9 no.2
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• pp.253-259
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• 2002

The antioxidative and free radical scavenging activity of water extracts of dandelion were investigated. Antioxidative and radical scavenging activity were assessed by means of different tests; inhibition of peroxidation on linoleic acid model system, scavenging DPPH radical, scavenging of hydroxyl radical by chemiluminescence assay, scavenging of superoxide anion radical by EPR spectroscopy and scavenging of hydrogen peroxide. The leaf extract showed strong antioxidant activity in linoleic acid system. The antioxidant activity of water extracts of dandelion increased with increasing concentrations of extracts. The scavenging activity of the dandelion extracts, on inhibition of the DPPH radical, was related to the reaction time. Hydroxyl radical were generated by lenten reaction and dandelion extract was found to scavenge OH˙in a concentration-dependent manner. The water extract of leaf had effective scavenging activities on hydrogen peroxide and superoxide anion radical. From the these data, it is evident that water extract of dandelion leaf is an effective scavenger for OH˙, O$_2$¨, DPPH˙, hydrogen peroxide. And, the antioxidative effect observed is believed to be partly due to this radical scavenger activity.

• Journal of Microbiology and Biotechnology
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• v.20 no.4
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• pp.835-843
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• 2010

The objectives of this study were to investigate the effect of fermentation medium on the hydroxyl radical scavenging activity of exopolysaccharides from Inonotus obliquus by response surface methodology (RSM). A two-level fractional factorial design was used to evaluate the effect of different components of the medium. Corn flour, peptone, and $KH_2PO_4$ were important factors significantly affecting hydroxyl radical scavenging activity. These selected variables were subsequently optimized using path of steepest ascent (descent), a central composite design, and response surface analysis. The optimal medium composition was (% w/v): corn flour 5.30, peptone 0.32, $KH_2PO_4$ 0.26, $MgSO_4$ 0.02, and $CaCl_2$ 0.01. Under the optimal condition, the hydroxyl radical scavenging rate (49.4%) was much higher than that using either basal fermentation medium (10.2%) and single variable optimization of fermentation medium (35.5%). The main monosaccharides components of the RSM optimized polysaccharides are rhamnose, arabinose, xylose, mannose, glucose, and galactose with molar proportion at 1.45%, 3.63%, 2.17%, 15.94%, 50.00%, and 26.81%.

• Journal of Applied Biological Chemistry
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• v.53 no.1
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• pp.8-12
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• 2010

The antioxidant activity of hawthorn fruit (Crataegus pinnatifida Bunge var. typica Schneider) extracts was investigated by several in vitro antioxidants properties, including DPPH free radical scavenging activity, total phenolic and flavonoid contents, hydroxyl radical scavenging activity, reducing power activity, iron-chelating capacity and nitrite scavenging activity. Among the extracts in this study, the 70% EtOH extract showed higher antioxidant activity than the others. The $IC_{50}$ value of DPPH free radical scavenging activity was $99.26\;{\mu}g/mL$. Furthermore, the 70% EtOH extract also showed significantly high total phenolic and flavonoids contents and reducing power activity. However, the MeOH extract exhibited stronger effects on hydroxyl radical scavenging activity, iron-chelating capacity and nitrite scavenging activity. All the results implicated that, the hawthorn fruit may has the available potential to be utilize as a potential source of natural antioxidant.

• Preventive Nutrition and Food Science
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• v.11 no.1
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• pp.10-16
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• 2006

Radical scavenging and antioxidant activities of Laminaria japonica and fermented its extracts were evaluated. Freeze-dried L. japonica was fermented by Aspergillus oryzae and extracted with distilled water. The extract solution was mixed with ethanol and centrifuged. The supernatant was ethanol soluble fraction, non-polysaccharide fraction (ESF), and residue was ethanol insoluble precipitation, polysaccharide fraction (EIP). ESF was subjected to sequential fractionation with dichloromethane, ethyl acetate, butanol and water. To determine the radical scavenging and antioxidant activities of these, DPPH radical, hydroxyl radical, superoxide anion radical scavenging activities and linoleic acid oxidation were tested. Among the extracts, ESF of fermented L. japonica showed the highest radical scavenging activity. The ESF showed DPPH radical scavenging activity of 64.33% at concentration of $50{\mu}g/mL$. It was higher than 57.70% of vit. C. Ethyl acetate and butanol fraction had high value of radical scavenging and antioxidant activities, especially butanol fraction of fermented L. japonica was 79.48 % of hydroxyl radical scavenging activity at concentration of $50{\mu}g/mL$. The fermented L japonica had radical scavenging and antioxidant activities higher than L. japonica. These results suggest that fermented L japonica is healthy food having radical scavenging and antioxidant activities.

• Preventive Nutrition and Food Science
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• v.14 no.3
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• pp.195-200
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• 2009

This study was carried out to investigate the biological activities of star anise extracts obtained from four different solvents (water, methanol, ethanol and chloroform) by measuring total polyphenol and flavonoid contents, DPPH radical scavenging, hydroxyl radical scavenging, nitrite scavenging activity and antimicrobial activity. The methanol extract showed the highest extraction yield, followed by ethanol, water and chloroform. The properties of the extracting solvents significantly affected the total polyphenol content. Methanol extracts contained more total polyphenols than any other extracts. The highest DPPH radical scavenging activity was found in methanol extract. The hydroxyl radical and nitrite scavenging activity were highest in methanol and ethanol extracts. In antimicrobial activity, water extract showed stronger activities than methanol and ethanol extract against Micrococcus luteus and Bacillus subtilis, and no inhibitory effects on Gram negative bacteria were found in all extracts at the concentration used.

• Applied Biological Chemistry
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• v.46 no.1
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• pp.32-38
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• 2003

Seventy percent ethanolic extracts from commercially available 13 legumes were made to investigated their antioxidative activities by determining the reducing power, inhibitory effect on lipid peroxidation, scavenging activity against both superoxide radical and hydroxyl radical, together with inhibitory activity toward mitomycin C-induced oxidative damage of DNA. High level of reducing powers were detected in Yepat, Sokpiri, Yuweol-bean and Jeokdu. Inhibitory effects on lipid peroxidation were found ubiquitously in all extracts examined when employing the linoleic acid autoxidation system, whereas, only 3 legumes, Yepat, Namul-bean and Jeenuni-bean, were revealed marked inhibition in rabbit erythrocyte-ghost membrane lipid peroxidation system. Yepat, Namul-bean, Jeokdu and Jeenuni-bean showed great scavenging activities on superoxide radical, on the other hand, high level of hydroxyl radical scavenging activities were demonstrated in Sokpiri, Chungtae, Yepat and Jebi-bean. Ubiquitous inhibitory effects on mitomycin C-induced oxidative damage on DNA were found in all extracts tested, Among them, however, Yepat, Jeenuni-bean, Namul-bean, Nokdu and Jeokdu showed the higher level of inhibition. Taken together, we could assign Yepat, Jeokdu, Jeenuni-bean and Sokpiri, for the legume species highly functional on overall antioxidative activity.

• Archives of Pharmacal Research
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• v.27 no.9
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• pp.947-953
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• 2004

The antioxidative and hepatoprotective potentials of two anthraquinones, alaternin (2-hydroxy-emodin) and emodin, to scavenge and/or inhibit hydroxyl radicals generated by the Fenton reaction and to protect tacrine-induced cytotoxicity in human liver derived HepG2 cells were evaluated, respectively. The inhibitory activity on hydroxyl radical generated in a cell-free chemical system (FeSO$_4$/$H_2O$$_2$) was investigated by a fluorescence spectrophotometer using a highly fluorescent probe, 2$^1$,7$^1$-dichlorofluorescein. The hydroxyl radical scavenging activity was determined by electron spin resonance spectroscopy using 5,5-dimethy-1-pyrroline-N-oxide as hydroxyl radicals trapping agents. Tacrine-induced HepG2 cell toxicity was determined by a 3-［4,5-dimethylthiazole-2yl］-2,5-diphenyltertrazolium bromide assay. Although the scavenging activity of alaternin on hydroxyl radical was similar to that of emodin in dose-dependent pat-terns, the inhibitory activity exhibited by the former on hydroxyl radical generation was stron-ger than that of the latter, with $IC_{50}$/ values of 3.05$\pm$0.26 $\mu$M and 13.29$\pm$3.20 $\mu$M, respectively. In addition, the two anthraquinones, alaternin and emodin showed their hepatoprotective activ-ities on tacrine-induced cytotoxicity, and the EC$_{50}$ values were 4.02 11M and 2.37 $\mu$M, respec-tively. Silymarin, an antihepatotoxic agent used as a positive control exhibited the EC$_{50}$ value of 2.00 $\mu$M. These results demonstrated that both alaternin and emodin had the simultaneous antioxidant and hepatoprotective activities.ies.

• The Korean Journal of Food And Nutrition
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• v.28 no.2
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• pp.295-301
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• 2015

Biological compounds such as crude saponin and total polyphenol were determined in Allium hookeri roots and leaves. In addition, activities of DPPH radical scavenging activity, hydroxyl radical scavenging activity, ${\alpha}$-amylase inhibition activity and nitrite scavenging were detected in concentrates of 70% ethanol extracts of Allium hookeri roots and leaves. The crude saponin content of the roots and leaves were 4.28 mg/g, and 4.17 mg/g, respectively. Total polyphenol and total flavonoid content was higher in leaves than roots. Furthermore the DPPH radical scavenging activity and hydroxyl radical scavenging activities of leaves was higher than roots. For ${\alpha}$-glucosidase inhibitory activity, 70% ethanol extracts of Allium hookeri roots and leaves showed 60% activity inhibition at a 10 mg/mL concentration. Nitrite scavenging abilities under acidic conditions were most effective for Allium hookeri leaves extracts. These results suggested that Allium hookeri leaves might be used as the components of health functional food.