• International Journal of Vascular Biomedical Engineering
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• v.2 no.2
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• pp.1-9
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• 2004

The history of studies in biology regarding reactive oxygen species (ROS) is approximately 40 years. During the initial 30 years, it appeared that these studies were mainly focused on the toxicity of ROS. However, recent studies have identified another action regarding oxidative signaling, other than toxicity of ROS. Basically, it is suggested that ROS are reactive, and degenerate to biomolecules such as DNA and proteins, leading to deterioration of cellular functions as an oxidative stress. On the other hand, recent studies have shown that ROS act as oxidative signaling in cells, resulting in various gene expressions. Recently ROS emerged as critical signaling molecules in cardiovascular research. Several studies over the past decade have shown that physiological effects of vasoactive factors are mediated by these reactive species and, conversely, that altered redox mechanisms are implicated in the occurrence of metabolic and cardiovascular diseases ROS is a collective term often used by scientist to include not only the oxygen radicals($O2^{-{\cdot}},\;{^{\cdot}}OH$), but also some non-radical derivatives of oxygen. These include hydrogen peroxide, hypochlorous acid (HOCl) and ozone (O3). The superoxide anion ($O2^{-{\cdot}}$) is formed by the univalent reduction of triplet-state molecular oxygen ($^3O_2$). Superoxide dismutase (SOD)s convert superoxide enzymically into hydrogen peroxide. In biological tissues superoxide can also be converted nonenzymically into the nonradical species hydrogen peroxide and singlet oxygen ($^1O_2$). In the presence of reduced transition metals (e.g., ferrous or cuprous ions), hydrogen peroxide can be converted into the highly reactive hydroxyl radical (${^{\cdot}}OH$). Alternatively, hydrogen peroxide may be converted into water by the enzymes catalase or glutathione peroxidase. In the glutathione peroxidase reaction glutathione is oxidized to glutathione disulfide, which can be converted back to glutathione by glutathione reductase in an NADPH-consuming process.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.3
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• pp.163-168
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• 2003

The reactive oxygen species (ROS) are considered to be an important mediator in pancreatic ${\beta}$ cell destruction, thereby triggering the development of insulin-dependent diabetes mellitus. In the present study, HIV-1 Tat-mediated transduction of Cu,Zn-superoxide dismutase (SOD) was investigated to evaluate its protective potential against streptozotocin (STZ)-induced cytotoxicity in insulin-producing MIN6N cells. Tat-SOD fusion protein was successfully delivered into MIN6N cells in a dose-dependent manner and the transduced fusion protein was enzymatically active for 48 h. The STZ induced-cell destruction, superoxide anion radical production, and DNA fragmentation of MIN6N cells were significantly decreased in the cells pretreated with Tat-SOD for 1 h. Furthermore, the transduction of Tat-SOD increased Bcl-2 and heat shock protein 70 (hsp70) expressions in cells exposed to STZ, which might be partly responsible for the effect of Tat-SOD. These results suggest that an increased of free radical scavenging activity by transduction of Tat-SOD enhanced the tolerance of the cell against oxidative stress in STZ-treated MIN6N cells. Therefore, this Tat-SOD transduction technique may provide a new strategy to protect the pancreatic ${\beta}$ cell destruction in ROS-mediated diabetes.

• Korean Journal of Food Science and Technology
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• v.28 no.5
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• pp.865-869
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• 1996

Biological effect of aqueous extracts of 12 plants which showed superoxide dismutase (SOD)-like activity in vitro was evaluated using Drosophila melanogaster. Survival percentage of the flies was a criterion of effect when the flies were exported to paraquat, which generated superoxide anion radical in vivo. When flies were co-administered with paraquat and aqueous extracts of garlic, lettuce, kiwi, and nameko, they showed no defensive effect against of oxygen toxicity. If flies were exposed to 60 mM paraquat after adaptation to feed containing plant extracts with SOD-like activity for 10 days, however, survival percentage of flies fed with phytochemicals was $35{\sim}63%$ while that percentage of flies fed without phytochemical was only 11%. This result indicated that adaptation of flies to plant extracts with SOD-like activity could prevent the flies from oxidative injury. On the other hand, lettuce, kiwi, nameko, onion, persimmon, fern brake and cauliflower showed a reparative effect on an oxidative stress. Dropwort, shiitake, agaric mushroom and broccoli did not show such an effect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.402-407
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• 2018

In this study, we investigated the antioxidative effects of AY by measuring 1.1-Diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical ($^{\cdot}OH$), and superoxide radical ($O_2{^-}$) scavenging activities in vitro. AY was extracted with ethanol and then partitioned with n-hexane, methylene chloride ($CH_2Cl_2$), ethylacetate (EtOAc) and n-butanol (n-BuOH). In the DPPH radical scavenging assay, AY at concentrations of 10 to $100{\mu}g/mL$ dose-dependently increased inhibition of DPPH oxidation, with the EtOAc fraction of AY showing the highest DPPH radical scavenging activity fractions. The $^{\cdot}OH$ radical scavenging activities of the extract and four fractions of AY increased by over 80% at a concentration of $50{\mu}g/mL$. In particular, the IC50 value of the EtOAc fraction was $0.03{\mu}g/mL$, which was the lowest value among all fractions. We also found that the EtOAc fraction of AY was better at $O_2{^-}$ radical scavenging than other fractions. Taken together, these results suggest that AY, especially the EtOAc fraction, can be used as a natural antioxidant against free radicals.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.503-511
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• 2023

The aim of this study was to investigate in vitro antioxidant activities of defatted Camellia japonica L. seeds (DCJS). The DCJS were extracted using ethanol and then fractionated with butanol (BuOH), ethyl acetate (EtOAc), chloroform, and hexane. To evaluate antioxidant activity of extract and fractions from DCJS, we investigated free radical scavenging activities such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺), hydroxyl radical (^•OH), and superoxide anion (O₂^-) radicals. The five extract and fractions of DCJS dose-dependently increased DPPH, ABTS⁺ and O₂^- radical scavenging activities. The BuOH fraction of DCJS showed the highest free radical scavenging activities among other extract and fractions. The contents of total polyphenol and flavonoid in BuOH fraction of DCJS were 23.26 mg GAE/g and 32.39 mg QE/g, respectively. The polyphenol and flavonoids contents of BuOH fraction has highest than other extract and fractions. In addition, BuOH and EtOAc fraction of DCJS contained 102.37 and 165.05 ㎍/g of camelliaside B, respectively. Therefore, DCJS has higher antioxidant activity and may be useful as a natural antioxidant material.

• 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.

• Proceedings of the Korean Biophysical Society Conference
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• 1998.06a
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• pp.26-26
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• 1998

Superoxide dismutases are metalloenzymes catalyzing the dimutation of superoxide anion radical to hydrogen peroxide and molecular oxygen. Examples of enzymes containing Cu, Mn and Fe as the redox-active metal have been characterized. Recently, an SOD containing one Ni atom per subunit was reported.(omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.145.1-145.1
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• 2003

Oxidative stress has been implicated in a range of disease states, including end-stage renal failure treated with hemodialysis [Westhuyzen J. et al, 2003]. Free radicals react with biological molecules and destroy the structure of cells, which eventually causes free-radical induced disease such as cancer, renal failure, aging, etc. Exogenous or endogenously produced nitric oxide (NO) inhibits superoxide-stimulated urea permeability. In the inner medulla, superoxide generation by local oxidases may stimulate urea transport, and the role of endogenous No may be to dampen this effect by decreasing superoxide levels ［Zimpelmann J. et al, 2003 (Epub ahead of print)］. (omitted)

• Toxicological Research
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• v.17 no.1
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• pp.33-39
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• 2001

To evaluate the skin toxicity oj topical toluene application, toluene (35 mg/$cm^2$) was sequentially applied to the portion rat skin for five days. The topical toluene application resulted in increased xanthine oxidase activity and CYP content, and significantly decreased superoxide dismutase and glutathione peroxidase activities at five days in rat skin. Especially catalase activity was remarkably decreased in toluene-applied rat skin. And benzylalcohol dehydrogenase activity showed also a significant decrease in toluene-applied skin. On the other hand, histopathological ultrastructural examination revealed disrupted epidermal basement membrane, rared intercellular adhensions and degenerated keratin layer due to topical toluene application. Increased deposit of cerrous perhydroxide resulted from reaction with $H_2O_2$was abserved in toluene-treated animals. These results indicate that oxygen free radical may be responsible for ultrastructural changes in skin tissue by toluene application to rat skin.

• Journal of the Korean Home Economics Association
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• v.42 no.5
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• pp.193-203
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• 2004

This study examined the changes in the chemical components and antioxidant activity of Ecklonia cava according to the drying methods. As chemical components, the concentrations of minerals(K, Ca, Na, Mg, Fe, Cu, Mn and Zn), vitamins(vitamin C, ${\beta}$-carotene and ${\alpha}$-tocopherol) and the total polyphenols were analyzed. In additions, the antioxidant activity was determined by measuring the free radical(DPPH radical, superoxide anion radical, hydroxyl radical and hydrogen peroxide) scavenging activity and the linoleic acid peroxidation inhibitory activity. The mineral content was not affected by the drying methods. However, more vitamins were lost and the total polyphenol concentration was reduced as a result of sun-drying than by the other drying methods used. More of the total polyphenol was preserved by freezing-drying than by any of the other drying methods, which meant that there was a higher antioxidant activity after freeze drying.