• The Journal of Dong Guk Oriental Medicine
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• v.6 no.1
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• pp.163-176
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• 1997

This study was undertaken to determine whether Juglandis Semen extraction(JS) has a protective effect against the lung cell injury caused by oxidant, t-butythydroperoxide(t-BHP) and $H_2O_2$ in rabbit lung slices. JS significantly prevented an increase in water content induced by t-BHP. Similarly, JS significantly prevented the lipid peroxidation induced by t-BHP. Cellular concentration of glutathione, and the activities of catalase and superoxide dismutase were significantly not altered by 5% JS. However, JS at 5% concentration significantly increased the glutathione peroxidase activity in oxidant-treated and control tissues. JS decreased directly the production of superoxide or hydroxyl radical. These results indicate that JS prevents the cell injury and lipid peroxidation induced by oxidants in the lung. Such an antioxidant effect is attributed to enhancement of major endogenous antioxidant defence systems such as glutathione peroxidase and direct inhibition of oxygen free radical production.

• Toxicological Research
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• v.23 no.2
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• pp.143-150
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• 2007

Although animal and epidemiological studies have suggested oxidative stress as an etiological factor in pathogenesis including cancer, inflammation, sepsis, fibrosis, cardiovascularlneurodegenerative diseases and aging-related disorders, conflicting results have been obtained in clinical trial with antioxidants. The reason for this discrepancy remains unknown but may be due, in part, to the lack of a validated assay system for evaluating antioxidant capacity. The antioxidant activity of a series of sugar alcohols against peroxyl radicals, hydroxyl radicals and peroxynitrites was determined by the total oxy-radical scavenging capacity (TOSC) assay and cell-based assay using H4IIE cells. Specific TOSC values calculated from the slope of the linear regression for erythritol, xylitol, sorbitol or mannitol against peroxyl radicals was $2.1{\pm}0.2,\;3.7{\pm}0.3,\;9.1{\pm}0.3$ or $8.7{\pm}1.1$ TOSC/mM, respectively. Specific TOSC values for erythritol, xylitol, sorbitol or mannitol against peroxynitrite was $1.9{\pm}0.3,\;3.9{\pm}0.4,\;7.8{\pm}0.7$ or $7.7{\pm}0.5$ TOSC/mM, respectively. These results suggest that oxy-radical scavenging capacity is dependent on the number of aliphatic hydroxyl group in sugar alcohols of monosaccharide. Tert-butylhydroperoxide (t-BHP)-induced cell toxicity determined by MTT assay was marginally attenuated by 10 mM erythritol, but completely inhibited by 10 mM xylitol, 2 mM sorbitol or 0.75 mM maltitol, a disaccharide alcohol. Oxidative stress markers, such as glutathione (GSH) and malondial-dehyde (MDA) levels, were measured in t-BHP-treated cells using HPLC equipped with a fluorescence detector and a reverse phase column. Erythritol did not change the levels of GSH and MDA in H411E cells treated with t-BHP. The t-BHP-induced changes in cellular GSH and MDA levels were ameliorated by 10 mM xylitol and completely blocked by 10 mM sorbitol and maltitol. These results indicate that sugar alcohols protect cells against oxidative stress via scavenging oxy-radical and suggest that TOSC assay in conjunction with cell-based assay is a valid method for evaluating antioxidant capacity of natural and synthetic chemicals.

• Nutrition Research and Practice
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• v.4 no.1
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• pp.3-10
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• 2010

This study was performed to investigate the effect of desalinated underground seawater (named as 'magma seawater', MSW) of Jeju Island in Korea on lipid metabolism and antioxidant activity. MSW was collected from underground of Han-Dong in Jeju Island, and freely given to high fat diet (HFD)-fed C57BL/6 mice for 10 weeks. Although there were no significant differences in the body weight changes and plasma lipid levels, hepatic triglyceride levels were significantly lower in the MSW group than in the normal tap water (TW)-drunken control group. Furthermore, the activity of fatty acid synthase (FAS) was significantly decreased and carnitine palmitoyltransferase (CPT) activity was increased in MSW group compared to TW group. Similarly, real-time PCR analysis revealed that mRNA expressions of lipogenic genes were lowered in MSW groups compared to the control group. In a morphometric observation on the liver tissue, accumulation of fats was remarkably reduced in MSW group. Meanwhile, in vitro assay, tree radical scavenging activity measured by using diphenylpicrylhydrazyl (DPPH) was increased in MSW group. The 2'-7'-dichlorofluorescein diacetate (DCF-DA) staining followed with fluorescent microscopy showed a low intensity of fluorescence in MSW-treated HepG2 cells, compared to TW-treated HepG2 cells, which indicated that the production of reactive oxygen species by tert-butyl hydroperoxide (t-BHP) in HepG2 cells was decreased by MSW treatment. The antioxidant effect of MSW on t-BHP-induced oxidative stress in HepG2 cells was supported by the increased activities of intracellular antioxidant enzymes such as catalase and glutathione reductase. From these results, we speculate that MSW has an inhibitory effect on lipogenesis in liver and might play a protective role against cell damage by t-BHP-induced oxidative stress.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.153-160
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• 2013

The peel from seven types of citrus was extracted with 80% methanol, and their phenolic compound content, oxygen radical absorbance capacity (ORAC), inhibitory activities of nitric oxide (NO), and reactive oxygen species (ROS) production induced by LPS and t-BHP in LPS-activated RAW 264.7 cells were measured. Total phenolic content was high in Yungkyool, Cheonhyehyang, and Jinkyool (30.6, 30.2, and 28.2 mg GAE/g, respectively), while total flavonoid content was high in Yungkyool and Jinkyool (30.3 and 25.5 mg RE/g, respectively). ORAC was the highest at 1,076 mM TE/g in Yungkyool, followed by Cheonhyehyang (1,012), Jinkyool (984), and Hallabong (914). High inhibitory activity against NO production was shown in Cheonhyehyang, Yungkyool, and Jinkyool with $IC_{50}$ values of 215.3, 259.2, and 328.9 ${\mu}g/mL$, respectively. LPS-induced ROS production was inhibited by 16.4% and 12.8% in Hallabong and Jinkyool, while t-BHP-induced ROS production was inhibited by 28.7%, 26.1%, and 26.6% in Jinkyool, Hallabong, and Cheonhyehyang, respectively. Correlation coefficients between total phenolic, total flavonoid content, and ORAC were 0.884 and 0.855. Inhibitory activity against NO production showed higher correlation with total phenolic content than total flavonoid content. It was concluded that citrus peels had potent antioxidant activities and could be used as natural antioxidants in the food and pharmaceutical industries.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.870-875
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• 2015

Diesel engines are widely used due to superior power and fuel consumption, however there are many challenges in exhaust gas management. Exhaust gas recirculation (EGR) is the most effective technique for reducing mono-nitrogen oxide (NOx) emissions in a diesel engine, in comparison with other catalytic technologies. In addition, the technology has a number of advantages in terms of economic efficiency and implementation. In this study, the effects on the power and exhaust characteristics of diesel engines equipped with EGR systems were investigated. It was found that as the EGR rate increased, horsepower expressed as IHP and BHP decreased. The net effect of the application of EGR was measured at various engine speeds. EGR technology caused decreases in BHP of around 9% during low engine speed and 3.5% during high engine speed. Additionally, NOx emissions reduced as the EGR rate increased, and increased as engine speed increased. However, smoke emissions increased as the EGR rate increased, and decreased as engine speed increased. The optimum operating conditions and ERG rate to simultaneously achieve minimum NOx and smoke emissions were investigate. It was found that as the EGR rate increased, optimal operating speed for minimal NOx and smoke also increased. Keywords: Diesel engine, Exhaust gas recirculation, Power perfomance, Emission characteristics, NOx, Smoke

• Land and Housing Review
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• v.4 no.4
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• pp.361-370
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• 2013

The purpose of this paper is to appraise Bogeumzari Housing Program(BHP) which is providing public housing of different types for the target brackets on a matching system basis. Especially, on government's announcing BHP plan with the designation of several Bogeumzari districts in Seoul Metropolitan area, they raised a question about target groups' receiving the benefits of BHP plan and this paper focuses on the question. We tried to analyze two topics. First one is about the exorbitant windfall profits to the future potential residents derived from low price or rental cost of Bogeumzari Housing in comparison with neighborhood's market price. Second one is the low possibility of low-moderate income household's access to absolutely high price Bogeumzari Housing that is because the market price is so high in some area. BHP includes not only long-term public rental hosing(Permeant rental housing, National rental housing) for low income households but also other types of public rental housing(10-year rental housing, shared-ownership rental housing) for moderate income households. So, in this study we tried to find out the affordability of each bracket in three public housing types, which are public sales housing(condominium), 10-year rental housing and shared-ownership rental housing. Through analyzing the housing affordability by types, regions, size, we tried to seek the answer to the controversy and propose policy implications related to the future public housing programs.

• Herbal Formula Science
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• v.31 no.4
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• pp.231-243
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• 2023

Objectives : Jasminum officinale L. var. grandiflorum is used as a traditional or folk remedy in China to treat arthritis, hepatitis, duodenitis, conjunctivitis, gastritis, and diarrhea. In this study, we aimed to study the hepatocyte protective activity and molecular mechanism of Jasminum officinale L. var. grandiflorum aqueous extract (JGW) using HepG2 hepatocyte cell lines. Methods : HepG2 cells were pretreated with diverse concentrations of JGW, and then the cells were exposed to tert-butyl hydroperoxide (tBHP) for inducing oxidative stress. Hydrogen peroxide (H₂O₂) production, glutathione (GSH) concentration, mitochondrial membrane potential (MMP) and cell viability were measured to investigate hepato-protective effects of JGW. Phosphorylation of AMP-activated protein kinases (AMPK), acetyl coenzyme A carboxylase (ACC) and effects of compound C on cell viability were examined to observe the role of AMPK on JGW-mediated cytoprotection. Results : Pretreatment with JGW (10-300 ㎍/mL) significantly suppressed cytotoxicity induced by tBHP in a concentration dependent manner and reduced the expression of cleaved PARP and cleaved caspase-3 proteins related to apoptosis in HepG2 cells. In addition, pretreatment with JGW significantly prevented the increase in H₂O₂ production, GSH depletion, and lower MMP induced by tBHP. Treatment with JGW (30 minutes of incubation and concentrations of 100 and 300 ㎍/mL) increased the phosphorylation of AMPK and ACC and treatment with compound C, a chemical inhibitor of AMPK, inhibited the cytoprotective effect of JGW. Conclusions : Our results demonstrated that JGW may protect hepatocytes from oxidative stress via activation of AMPK.

• BMB Reports
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• v.42 no.10
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• pp.648-654
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• 2009

Overexpression of phospholipid hydroperoxide glutathione peroxidase (PHGPx) genes has been reported to play an important role in protecting host cells from oxidative injury in several model systems. A radish phospholipid hydroperoxide glutathione peroxidase (RsPHGPx) known to have high catalytic activity was applied to mouse 3T3 fibroblasts to determine the protective effects of PHGPx against oxidative injury triggered by hydroperoxides such as hydrogen peroxide ($H_2O_2$), tert-butyl hydroperoxide (t-BHP) and phosphatidylcholine hydroperoxide (PCOOH). We observed that preincubation of cells with RsPHGPx significantly increased cell viability, reduced levels of malondialdehyde (MDA), inhibited generation of reactive oxygen species (ROS), and maintained natural cell shapes after treatment with $H_2O_2$, t-BHP or PCOOH, indicating that the exogenous RsPHGPx can act as an effective hydroperoxide-scavenger and may also protect target cells from oxidative damage. These results suggest the possibility for use of RsPHGPx as a therapeutic protectant.

• Korean Journal of Pharmacognosy
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• v.38 no.3 s.150
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• pp.287-290
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• 2007

Phytochemical investigation of the MeOH extract of the dried stem barks of Fraxinus rhynchophylla Hance (Oleaceae), as guided by cytoprotective activity against tert-butyl hydroperoxide (t-BHP)-induced cell injury in mouse hippocampal HT22 cells, furnished two coumarins, esculetin (1) and fraxetin (2). Compounds 1 and 2 had the significant cytoprotective effects on t-BHP-induced cellular oxidative injury in HT22 cells. Furthermore, compounds 1 and 2 showed potent DPPH radical scavenging effect, exhibiting $IC_{50}$ values of 14.68 and 9.64 ${\mu}M$, respectively.

• Journal of Acupuncture Research
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• v.20 no.4
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• pp.209-219
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• 2003

This study was performed to determine if Juglandis semen extract(JSE) has free radical scavenging and antioxidant activities. Superoxide anion generation by xanthine oxidase/xanthine and in neutrophils activated by phorbol-12, 13-dibutyrate was inhibited by JSE and its effect was dose-dependent. JSE also inhibited generation of $H_2O_2$ induced by glucose oxidase/glucose and in opossum kidney cells treated with antimycin A. JSE exerted a direct $H_2O_2$ scavenging effect. Exposure of opossum kidney cells to 1mM tBHP caused a significant increase in lipid peroxidation, which was prevented by JSE. JSE also prevented tBHP-induced LDH release. These data suggest that JSE has free radical scavenging and antioxidant activities. However, further studies should be carried out to find the active ingredient(s) of JSE that exerts radical scavenging action.