• Asian-Australasian Journal of Animal Sciences
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• v.18 no.4
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• pp.567-573
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• 2005

This study aims to evaluate the antioxidative activities of cow-milk kefir and goat-milk kefir. Antioxidative mechanisms, including radical-scavenging effects, ferrous-ion chelating ability, reducing power and antioxidant activity, were investigated herein. Kefirs demonstrated significantly greater scavenging effects upon 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide radicals, an inhibition effect upon linoleic-acid peroxidation, and more substantial reducing power, but reduced glutathione peroxidase (GSH-Px) activity than was the case for milks. There was no significant difference between milks and kefirs as regards ferrous-ion chelating ability and superoxide dismutase (SOD) activity. These findings have demonstrated that kefirs possess antioxidant activity, thereby suggesting that kefirs are potential candidates for the role of useful natural antioxidant supplements for the human diet.

• Natural Product Sciences
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• v.14 no.4
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• pp.239-243
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• 2008

Equisetum hyemale L. has been prescribed widely as a traditional medicine for the treatment of inflammatory diseases such as rheumatoid arthritis, conjunctivitis, pyelonephritis. In order to identification the mechanism, we examined an antioxidant and anti-inflammatory activity of 85% methanol extract of E. hyemale. In this study E. hyemale exhibited strong scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical, superoxide radical, and nitric oxide. To elucidate the anti-inflammatory properties of E. hyemale, we investigated the inhibition effects of nitric oxide and IL-6 by E. hyemale in IFN-gamma and LPS-stimulated mouse peritoneal macrophages. E. hyemale suppressed nitric oxide, IL-6 production and iNOS expression dose-dependently without notable cytotoxic activity. These data suggest that E. hyemale might be useful in inflammatory diseases by inhibiting the free radicals and inflammatory mediators.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1156-1159
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• 2008

The antioxidant activity of hot water extracts of various parts, the leaf, stem, and root of Synurus deltoides was evaluated by various antioxidant assays, including total phenolic content, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, hydroxyl radical (${\cdot}OH$) scavenging, superoxide dismutase (SOD), and xanthine oxidase (XOI) activities. The various antioxidant activities were compared with the standard antioxidants such as L-ascorbic acid, $\alpha$-tocopherol, and butylated hydroxyanisole (BHA). Among the different plant parts, stem has been found to possess the highest activity in all tested model systems, the activity decreased in the order stems>roots>leaves. These results indicate that stem extract could be used as potential source of natural antioxidant.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.917-922
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• 2009

This study investigated the effects of steaming on the antioxidative activities of ray hydrolysates in vitro. Based on the results of 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, steamed ray hydrolysate possessed significantly higher antioxidative activities than raw ray hydrolysates (p<0.05). The 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity of steamed ray hydrolysate by pancreatin was slightly lower than raw ray hydrolysate at all concentrations. Raw ray hydrolysate displayed moderate hydroxyl radical scavenging activity, while steamed ray hydrolysate showed a greater increase in hydroxyl radical scavenging activity than raw ray hydrolysate at concentrations above 21.33 mg/mL, and it reached 58.21% at 42.67 mg/mL. The results of this study show that ray hydrolysates have potent free radical scavenging activities and reducing power, and the steaming has a partial impact on the antioxidative activity of ray hydrolysates.

• Culinary science and hospitality research
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• v.24 no.2
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• pp.103-111
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• 2018

The objectives of the present study were to examine the antioxidant activity of autofocusing fractions from egg white protein hydrolysates and obtain higher antioxidant peptide fraction, which could be applied to the food model system. Alkaline protease hydrolysate of egg white protein exerted higher antioxidant activities than other protein hydrolysates and were fractionated on the basis of the amphoteric nature of sample peptides by preparative isoelectric focusing without toxic solvents and reagents, which is termed autofocusing. Neutral and basic fractions showed higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than the acidic fractions. The acidic and neutral fractions showed higher hydroxyl (OH) radical scavenging activity and oxygen radical absorbance capacity (ORAC) values than the basic fractions. The acidic fractions showed higher metal chelating activity than basic fractions. Antioxidant activities of some autofocusing fractions except for ORAC showed higher compared to the crude hydrolysate. These results suggest that peptides fractions from egg white protein are effective antioxidant, and that autofocusing could be useful to increase antioxidant activity for application to food system.

• Biomolecules & Therapeutics
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• v.18 no.2
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• pp.191-196
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• 2010

In the course of screening for antioxidant compounds by measuring the radical scavenging effect on 1,1-diphenyl- 2-picrylhydrazyl (DPPH), a total extract of the twigs of Stewartia koreana (Theaceae) was found to show potent antioxidant activity. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of six phenolic compounds, ampelopsin (1), catechin (2), proanthocyanidin-A2 (3), fraxin (4), (2R, 3R)-taxifolin-3-${\beta}$-D-glucopyranoside (5), and (2S, 3S)-taxifolin-3-${\beta}$-D-glucopyranoside (6), as active principles. Their structures were elucidated by spectroscopic studies. Compounds 1-6 were isolated for the first time from this plant. Among them, three compounds 1-3 showed the significant antioxidative effects on DPPH, and riboflavin originated superoxide quenching activity. In riboflavin-nitrobluetetrazolium (NBT)-light system, compound 1 showed better superoxide quenching activity than vitamin C.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.448-453
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• 2000

During the screening of inhibitors of caspase-3 induction in U937 human monocytic leukemia cells from natural sources, Petasites japonicum, which showed a high level of inhibition was selected. The inhibiting compound was purified from the methanol extract by Sephadex LH-20 column chromatography and HPLC. The inhibitor was identified as [3-(3,4-dihydroxyphenyl)-2-oxopropyl]ester, petasiphenol, by spectroscopic methods of UV, EIMS, $^1H-NMR$, $^{13}C-NMR$ and HMBC. It showed a caspase-3 inducing inhibitory activity at $8\;{\mu}g/ml$ of $IC_{50}$ value with DNA fragmentation inhibition in U937 human leukemia cells. It also showed a free radical scavenging ability of 1,1-diphenyl-2-picrylhydrazyl.

• Fisheries and Aquatic Sciences
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• v.25 no.6
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• pp.335-349
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• 2022

To optimize the hydrolysis conditions in the production of antioxidant hydrolysates from tuna cooking juice concentrate (TC) to maximize the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, TC containing 48.91% protein was hydrolyzed with Alcalase 2.4 L, and response surface methodology (RSM) was applied. The optimum hydrolysis conditions included a 2.2% (w/v) Alcalase concentration and 281 min hydrolysis time, resulting in the highest DPPH radical scavenging activity of 66.49% (0.98 µmol Trolox/mg protein). The analysis of variance for RSM showed that hydrolysis time was an important factor that significantly affected the process (p < 0.05). The effects of different drying methods (freeze drying, hot air drying, and vacuum drying) on the DPPH radical scavenging activity and amino acid (AA) profiles of TC hydrolysate (TCH) were evaluated. Vacuum-dried TCH (VD) exhibited an increase in DPPH radical scavenging activity of 81.28% (1.20 µmol Trolox/mg protein). The VD samples were further fractionated by ultrafiltration. The AA profiles and antioxidant activities in terms of the DPPH radical scavenging activity, 2,2'-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) radical scavenging activity, ferric reducing antioxidant power, and ferrous ion chelating activity were investigated. Glutamic acid, glycine, arginine, and cysteine were the major AAs found in the TCH fractions. The highest DPPH radical scavenging activity was found in the VD-1 fraction (< 5 kDa). The VD-3 fraction (> 10 kDa) exhibited the highest ABTS radical scavenging activity and ferric reducing antioxidant power. The ferrous ion chelating activity was the highest in VD-1 and VD-2 (5 to 10 kDa). In conclusion, this study provided the optimal conditions to obtain high antioxidant activities through TCH production, and these conditions could provide a basis for the future application of TCH as a functional food ingredient.

• Ocean and Polar Research
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• v.26 no.1
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• pp.59-64
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• 2004

As a part of our search for novel antioxidants from the seaweeds, we have investigated radical scavenging effect for their crude extracts using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, authentic peroxynitrite, and 3-morpholinsydnonimine (SIN-1), a peroxynitrite-generating species in vitro. Thirty-four seaweeds were screened for $ONOO^-$ and DPPH radical scavenging activities. A potent inhibitory effect against peroxynitrite generated by SIN-1 at $5{\mu}g/ml$ of methanol extracts was observed in order of Ishige okamurae(95.3%), Sargassum hemiphyllum(90.2%), Symphyocladia latiuscula(89.6%), Porphyra suborbiculata(86.7%), and Gelidium amamsii(85.9%), Also, a significant scavenging effect against direct authentic peroxynitrite was revekaled for methanol extracts of Ishige okamurae(66.2%) and Sargassum hemiphyllum(55.2%) and the acetone/methylene chloride(1:1) extract of Gigatina tenella (61.0%). In our measurement for evaluating the capacity to scavenge the stable free radical of DPPH, acetone/methylene chloride(1:1) extracts of Symphyocladia latiuscula, Gloiopeltis furcata, and Sargassum thunbergii and the methanol extract of Sargassum sp. showed an inhibitory potency of 85.8%, 82.8%, 74.1%, and 64.0%, respectively.

• Korean Journal of Medicinal Crop Science
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• v.13 no.2
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• pp.85-90
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• 2005

Phytochemical study on the EtOAc fraction from a MeOH extract of the leaves of Alnus hirsuta Rupr. led to the isolation of nine compounds betulin (1), betulinic acid (2), hirsutanonol (3), hirsutenone (4), quercetin (5), avicularin (6), gallic acid (7), hyperin (8), and daucosterol (9). Among them, six compounds 1, 2, 57, and 9 are report from this plant for the first time. All isolated compounds were evaluated for their antioxidant activity using DPPH radical scavenging capacity and inhibition effect on mitochondrial lipid peroxidation. Six phenolic compounds 3-8 were found to have potent antioxidant activity. Of which, compounds 3, 4 and 5 showed significant free radical scavenging activity with the $IC_{50}$ values of $18.3\;{\pm}\;2.5,\;15.7\;{\pm}\;3.8\;and\;23.5\;{\pm}\;3.1\;{\mu}m$, respectively. In addition, the compounds 3-8 exhibited inhibition effect on the mitochondrial lipid peroxidation with the $IC_{50}$ values of $88.0\;{\pm}\;6.5,\;12.6\;{\pm}\;1.2,\;8.0 \;{\pm}\;1.1,\;58.5\;{\pm}\;4.3,\;173.6\;{\pm}\;15.2,\;and\;75.0\; {\pm}\; 6.7\;{\mu}m$, respectively.