• 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.

• Toxicological Research
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• v.26 no.4
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• pp.321-327
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• 2010

The ability of 80% ethanol extracts from five medicinal plants, Aralia continentalis, Paeonia suffruticosa, Magnolia denudata, Anemarrhena asphodeloides, and Schizonepeta tenuifolia, to neutralize hydroxyl radical, peroxyl radical and peroxynitrite was examined using the total oxyradical scavenging capacity (TOSC) assay. Peroxyl radical was generated from thermal homolysis of 2,2'-azobis(2-methylpropionamidine) dihydrochloride (ABAP); hydroxyl radical by an iron-ascorbate Fenton reaction; peroxynitrite by spontaneous decomposition of 3-morpholinosydnonimine N-ethylcarbamide (SIN-1). The oxidants generated react with $\alpha$-keto-$\gamma$-methiolbutyric acid (KMBA) to yield ethylene, and the TOSC of the substances tested is quantified from their ability to inhibit ethylene formation. Extracts from P. suffruticosa, M. denudata, and S. tenuifolia were determined to be potent peroxyl radical scavenging agents with a specific TOSC (sTOSC) being at least six-fold greater than that of glutathione (GSH). These three plants also showed sTOSCs toward peroxynitrite markedly greater than sTOSC of GSH, however, only P. suffruticosa revealed a significant hydroxyl radical scavenging capacity. Seven major active constituents isolated from P. suffruticosa, quercetin, (+)-catechin, methyl gallate, gallic acid, benzoic acid, benzoyl paeoniflorin and paeoniflorin, were determined for their antioxidant potential toward peroxynitrite, peroxyl and hydroxyl radicals. Quercetin, (+)-catechin, methyl gallate, and gallic acid exhibited sTOSCs 40~85 times greater than sTOSC of GSH. These four components also showed a peroxynitrite scavenging capacity higher than at least 10-fold of GSH. For antioxidant activity against hydroxyl radical, methyl gallate was greatest followed by gallic acid and quercetin. Further studies need to be conducted to substantiate the significance of scavenging a specific oxidant in the prevention of cellular injury and disease states caused by the reactive free radical species.

• 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%.

• 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.

• ALGAE
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• v.20 no.1
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• pp.69-75
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• 2005

Hizikia fusiformis is well known edible brown seaweed both in Korea and Japan. It has been intensively studied due to its pronounced health benefits. In this study, the radical scavenging (antioxidative) activities of its hydrophilic phlorotannin constituents were studied. An aqueous extract/original extract (OE) of H. fusiformis was initially prepared with heat, enzymes and pH control treatments. Then the original extract was further fractionated (with methylene chloride and methanol) and crude hydrophilic phlorotannin extract (CHPE) was prepared. The radical scavenging activities of both OE and CHPE were determined by using electron spin resonance (ESR) spectrophotometric assays such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and alkyl radical assays. The CHPE reported significantly (p < 0.05) higher total phenolic (phlorotannins) content (1.23 mg ${\cdot}ml^{-1}$) than that of the OE (0.21 mg ${\cdot}ml^{-1}$). Both OE and CHPE have reported good radical scavenging activities and those activities were dose-dependent. The CHPE have demonstrated significantly higher radical scavenging activities than that of the OE. In comparison, the DPPH radical (6 $\times$ 10$^{-5}$ M) scavenging activities of all the CHPE concentrations (0.25, 0.5 and 1 mg ${\cdot}ml^{-1}$) tested were significantly higher (37.3, 78.2 and 91.6%, respectively) than that of the OE counterparts (11.4, 34.6 and 61.7%, respectively). Alkyl radical scavenging percentages of CHPE at 0.0625, 0.125, 0.25 and 0.5 mg${\cdot}ml^{-1}$ were significantly higher (34.3, 69.2, 80.4 and 88.7%, respectively) than that of the OE (16.6, 41.4, 62.3 and 77.4%, respectively). The percentages of hydroxyl radical scavenging activities of CHPE at the concentrations of 0.25, 0.5 and 1 mg ${\cdot}ml^{-1}$ were 32.5, 59.4 and 84.2 % respectively. Moreover, the hydroxyl radical scavenging activity of OE was quite lower than that of the CHPE. Therefore, these results suggest that the hydrophilic phlorotannins of H. fusiformis are potential radical scavengers thus, a great source of antioxidative nutraceuticles.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.1041-1045
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• 2007

Heated onion juice was partitioned using the solvents hexane, chloroform, ethyl acetate, and butanol. The ethyl acetate fraction showed the strongest scavenging effect on the ABTS radical. The antioxidant activities of the ethyl acetate fraction from raw and heated onion (120, 130, and $140^{\circ}C$) were evaluated using radical scavenging assays. Radical and nitrite scavenging activities were higher in heated onion than raw onion, and the higher the temperature of heat treatment, the greater the radical and nitrite scavenging activities. Heated onion ($140^{\circ}C$, 2 hr) was more effective than raw onion, having higher DPPH radical scavenging (5.7-fold), hydroxyl radical scavenging (6.4-fold), superoxide radical scavenging (2.3-fold), hydrogen peroxide scavenging (11.8-fold), and nitrite scavenging (4.3-fold) activities. Onion increased its physiologically active materials after heating, and in this regard, heated onion can be used as biological material for the manufacture of health foods and supplements.

• 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.

• Preventive Nutrition and Food Science
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• v.10 no.4
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• pp.326-332
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• 2005

A methanol extract of mulberry cake prepared from mulberry fruits (Morus spp.) was shown to have strong scavenging activities against DPPH, superoxide and hydroxyl radicals. Eleven phenolic compounds were isolated from the mulberry cake by a combination of Diaion HP-20, silica gel (or polyamide), Sephadex LH-20 column chromatographies, preparative HPLC and TLC. Their chemical structures were characterized as procatechuic acid (PCA), caffeic acid (CA), cyanidin 3-O-$\beta$-D-glucopyranoside (CyG) and cyanidin $3-O-\beta­D-rutinoside$ (CyR), rutin (RT), isoquercitrin (IQT), astragalin (AG), quercetin (QT), morin (MR), di-hydroquercetin (DHQ), and 4-prenylmoracin (PM) by spectral analysis and the published data. Most of the phenolic constituents were effective scavengers of DPPH, superoxide and hydroxyl radicals, and especially caffeic acid and 4-prenylmoracin showed potent superoxide and hydroxyl radical scavenging activity, in which their activities were higher than that of the well-known antioxidant, BHT (p< 0.05). Dehydroquercetin and quercetin also exhibited strong superoxide and hydroxyl radical scavenging activities. These results suggest that mulberry cake containing antioxidant phenolic compounds may be useful as natural antioxidants in functional foods and cosmetics.