• Environmental Analysis Health and Toxicology
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• v.10 no.1_2
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• pp.47-54
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• 1995

To investigate and evaluated the scavenging and antioxidative effects of various flavonoids on paraquat induced toxicity, in vivo and vitro tests of eight flavonoids (catechin, epocatechin, flavone, chrysin, apigenin, quercetin, morin and biochanin A) were carried out. The generation of reactive oxygen substances(ROS) in PMS-NADH system $H_2O_2$ induced hemolysis and lipidperoxidation to blood, NADPH dependent lipidperoxidation to liver and lung microsome by paraquat were studied.The results are summerized as follows; 1) In the concentration ranges from 3.3 to 9.8$\mu$M of catechin,epicatechin, quercetin and biochanin A removed the 50% of DPPH radical scavenging effects. 2) In the concentration ranges from 0.60 to 1.86 mM of catechin, epicatechin, quercetin and biochanin A showed the inhibitory and antioxidative activity on superoxide anion which gernerated in PMA-NADH system. 3) In the concentration ranges from 0.12 to 0.49mM of catechin, epicatechin, quercetin and biochanin A showed the inhibitory and antioxidative activity on H202 which generated in PMA-NADH system. 4) In the concentration ranges from 0.6 x10$^{-5}$ to 6.3 x 10$^{-5}$mM of catechin, epicatechin, flavone, chrysin, quercetin and morin showed the inhibitory and antioxidative activity on $H_2O_2$ induced hemolysis to blood 5) All flavonoids tested exhibited inhibitory and antioxidative effects on paraquat induced liver and tung microsomal lipidperoxidation. Therefore, all flavonoids evaluated showed the useful compounds for scavenger and antioxidant on paraquat induced toxicity.

• Preventive Nutrition and Food Science
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• v.12 no.4
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• pp.191-196
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• 2007

We investigated radical scavenging effects and protective activities of fucoidan and alginic acid, active polysaccharide components from brown seaweeds, against peroxyl radical-induced oxidative stress under in vitro and cellular system. Fucoidan exerted strong radical scavenging effects against nitric oxide (NO) and superoxide anion $(O_2)$. On the other hand, alginic acid did not show inhibitory activity against NO and relatively weak $O_2{^-}$ scavenging effect. Additionally, alginic acid exhibited higher hydroxyl scavenging activity than fucoidan. Both fucoidan and alginic acid significantly enhanced cell viability against oxidative stress induced by 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH). At $1000{\mu}g/mL$ concentration of fucoidan and alginic acid, the viability was increased from 16.4% to 85.9% and 67.7%, respectively. In addition, fucoidan and alginic acid ameliorated the lipid peroxidation in LLC-PK1 cell induced by AAPH in a dose-dependent manner. In particular, fucoidan showed stronger inhibitory effect than alginic acid in the cellular system. The present study suggests that fucoidan and alginic acid may be promising antioxidants against oxidative stress induced by free radicals.

• Food Science and Preservation
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• v.13 no.3
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• pp.413-419
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• 2006

This study was investigated to analyze the antioxidant activity or extracts form Elaeagnus multiflora Thunb for development to the functional materials. The antioxidative activities of water ethanol and methanol extracts from the Elaeagnus multiflora Thunb were analyzed by electron donating ability (EDA), anti-oxidization activity, superoxide dismutase (SOD)-like activity, The superoxide anion radical-scavenging activity, and nitrite scavenging ability. The Etectron donating ability of methanol extract was higher in 1.0 mg/mL of extraction solution than those of ethers. The anti-oxidization activity of ethanol and methanol extracts by thiocyanate method using linolenic acid system was higher than those of the water extract. The SOD-like activity was increased with increase of the extract concentration in each extracts. The SOD-like activity was highest in 2.0 mg/mL of methanol extract. The superoxide anion radical-scavenging activity was increased with increase of the concentration in the ethanol extract and methanol extract. The nitrite scavenging ability of water extracts in 1.0 mg/mL of extraction soiution in pH 1.2 was higher than ethanol extrats and methanol extracts. The nitrite scavenging ability of all extracts was decreased according to increase of pH.

• Atmosphere
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• v.33 no.4
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• pp.367-385
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• 2023

The variabilities of precipitation and particulate matters (i.e., PM₁₀ and PM_2.5) and the scavenging efficiency of PMs by precipitation were quantified using long-term measurements in Seoul, Korea. The 21 years (2001~2021) measurements of precipitation and PM₁₀ mass concentrations, and the 7 years (2015~2021) of PM_2.5 mass concentrations were used. Statistical analysis was performed for each period (i.e., year, season, and month) to identify the long-term variabilities of PMs and precipitation. PM₁₀ and PM_2.5 decreased annually and the decreasing rate of PM₁₀ was greater than PM_2.5. The precipitation intensity did not show notable variation, whereas the annual precipitation amount showed a decreasing trend. The summer precipitation amount contributed 61.10% to the annual precipitation amount. The scavenging efficiency by precipitation was analyzed based on precipitation events separated by 2-hour time intervals between hourly precipitation data for 7 years. The scavenging efficiencies of PM₁₀ and PM_2.5 were quantified as a function of precipitation characteristics (i.e., precipitation intensity, amount, and duration). The calculated average scavenging efficiency of PM₁₀ (PM_2.5) was 39.59% (35.51%). PM₁₀ and PM_2.5 were not always simultaneously scavenged due to precipitation events. Precipitation events that simultaneously scavenged PM₁₀ and PM_2.5 contributed 42.24% of all events, with average scavenging efficiency of 42.93% and 43.39%. The precipitation characteristics (i.e., precipitation intensity, precipitation amount, and precipitation duration) quantified in these events were 2.42 mm hr^-1, 15.44 mm, and 5.51 hours. This result corresponds to 145% (349%; 224%) of precipitation intensity (amount; duration) for the precipitation events that do not simultaneously scavenge PM₁₀ and PM_2.5.

• Biomolecules & Therapeutics
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• v.8 no.1
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• pp.32-37
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• 2000

Recently new soybean saponins with D DMP (2,5-dihydroxy-6-methyl-2,3,- dihydro-4H-pyran-4-one) moiety have been isolated from legumes. The purpose of this study is to characterize ROS scavenging activities of DDMP saponins ($\alpha$g, $\beta$g saponin) isolated from Glycine max (L.) Merrill. The scavenging activity on OH was examined in terms of lipid peroxidation in the rat liver homogenates and the same activity on $O_2$ was also determined in the xanthine-xanthine oxidase system, respectively. Up to 0.25 mg DDMP saponins ($\alpha$g and $\beta$g saponins) did not cause any significant effects on the prevention of lipid peroxidation as compared with the control group. In terms of superoxide scavenging activities, 0.25 and 0.5 mg $\alpha$g saponin inhibits only 2.6% and 5.5% (p<0.05) of the control group, respectively. However, $\alpha$g saponin dose-dependently (p<0.01, r=0.955) inhibits the formation of superoxide radical unto 21.3% of the control group with a maximal dose of 0.5 mg (p<0.01), equivalent to 0.17 units of superoxide dismutase activity.

• Journal of Applied Biological Chemistry
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• v.44 no.2
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• pp.87-91
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• 2001

Extracts from Geum japonicum (Bammu in Korean) were analyzed for their antioxidative activities and scavenging effects on free radicals. The ethyl acetate fraction of G. japonicum methanol extract (EFGJ) showed a remarkable scavenging activity on the 1,1-diphenyl-2-picrylhydrazyl radical. EFGJ also showed excellent antioxidative activity on linoleic acid during long-period storage and on rat liver microsome peroxidation system, and good anti-peroxidation effect on lipid in Rancimat system using lard, palm oil, and perilla oil, as compared with BHT and ${\alpha}$-tocopherol. Varying effects of antioxidative activity of the EFGJ on various fatty acids were observed. The prevention of linoleic acid and linolenic acid peroxidation was superior to ${\alpha}$-tocopherol, but inferior to BHT. The methanol extract of G. japonicum did not show mutagenicity as revealed through SOS chromotest. Based on the results, the extracts of G. japonicum may be useful source as natural antioxidants.

• YAKHAK HOEJI
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• v.49 no.1
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• pp.86-91
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• 2005

Flavonoids are class of polyphenolic compounds widely distributed in the plant kingdom, which display a variety of biological activities, including antiviral, antithrombotic, antiinflammatory, antihistaminic, antioxidant and free-radica 1 scavenging abilities. The antioxidant enzyme (AOE) system plays an important role in the defense against oxidative stress insults. To determine whether flavonoid, myricetin can exert antioxidative effects not only directly by modulating the AOE system but also scavenging free radical, we investigated the influence of the flavonoid myricetin on cell viability, different antioxidant enzyme activities, ROS level and the expression of different antioxidant emzyme in B16F10 murine melanoma cells. Myricetin in a concentration range from 6.25 to $50\;{\mu}M$ decreased superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzyme activities, but catalase (CAT) activity was increased. In the myricetin-treated group, ROS levels were decreased dose-dependently. Antioxidant enzyme expression was measured by RT-PCR. Myricetin treatment of B16F10 cells increased catalase expression. Expression levels of copper zinc superoxide dismutase (CuZn SOD) were not affected by exposure of myricetin. Manganese superoxide dismutase (Mn SOD) and GPx expression levels decreased slightly after myricetin treatment. In conclusion, the antioxidant capacity of myricetin was due to CAT and free-radical scavenging.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.22-24
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• 2008

This paper presents a numerical model of internal flows in a lubricant supplying and scavenging flow path of an aero-engine lubrication system. The numerical model was built in the General Analysis Software of Aero-engine Lubrication System, GASLS, developed by Northwestern Polytechnical University. The lubricant flow flux, pressure and temperature distribution at steady state were calculated. GASLS is a general purpose computer program employed a 1-D steady state network algorithm for analyzing flowrates, pressures and temperatures in a complex flow network. All kinds of aero-engine lubrication systems can be divided into finite correlative typical elements and nodes from which the calculation network be developed in GASLS. Special emphasis is on how to use combined elements which is a type of typical elements to replace some complex components like bearing bores, accessory gearboxes or heat exchangers. This method can reduce network complexity and improve calculation efficiency. Final computational results show good agreement with experimental data.

• Bulletin of the Korean Chemical Society
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• v.22 no.4
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• pp.362-366
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• 2001

To show the effects of metallothionein (MT) on the activity of enzymes involved in the removal of reactive oxygen species, MT has been added to the assay systems of superoxide dismutase (SOD), catalase and peroxidase. We have used assay systems of SOD based on NADPH oxidation and nitrite formation from hydroxylammonium chloride as an assay of superoxide breakdown rate. The two assay systems showed different results at the high concentration of MT. MT showed the scavenging of superoxide in the SOD assay system in the presence and absence of SOD. MT added to the SOD assay system behaved as an activator of SOD, but apo-MT behaved as an inhibitor. When MT was added to the assay system in the presence of a fixed amount of SOD, the breakdown rate of superoxide increased. The effects of MT on the decomposition of hydrogen peroxide and the activity of catalase and peroxidase decomposing hydrogen peroxide were evaluated. MT decreased the activities of catalase and peroxidase. We have concluded that the function of MT as an antioxidant might effect the level of superoxide scavenging and not the level of hydrogen peroxide.

• 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.