• Preventive Nutrition and Food Science
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• v.10 no.1
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• pp.46-51
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• 2005

The protective effect of Acanthopanax senticosus (AS) extract on alloxan-induced pancreatic β-cell damage was investigated in HIT T-15 cells, a Syrian hamster pancreatic β-cell line. Alloxan caused the pancreatic β-cell damage through the generation of reactive oxygen free radicals, increased DNA fragmentation, and decreased cellular NAD/sup +/ levels. The β-cell damage was significantly prevented by the pretreatment with water soluble extract of AS roots. These results suggest that the protective effect of AS extract, on alloxan-induced β-cell damage, is primarily due to the inhibition of the generation of reactive oxygen free radical species (ROS) by alloxan.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.1016-1022
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• 2012

In order to investigate the effects of 70% EtOH extract obtained from Hovenia dulcis Thunberg on enzymes relating reactive oxygen intermediate, cancer-stricken animals induced by DEN (N,N-diethylnitrosamine) were recovered by administering the extract of Hovenia dulcis Thunberg. It showed that there was no effect on the generation of superoxide radical by the extract of Hovenia dulcis Thunberg. However, considering the increase of the activity of Cu, Zn-SOD and Mn-SOD in the tested animal class, the extract of Hovenia dulcis Thunberg could participate directly in removing of superoxides. The experimented-animals treated with the extract of Hovenia dulcis Thunberg showed an increase in the activity of the enzymes, catalase and glutathione peroxidase, which can eliminate hydrogen peroxide pertained in liver tissue. The extract of Hovenia dulcis Thunberg seemed to have some factors that accelerate the oxidation. Also, the extract of Hovenia dulcis Thunberg showed effects on the enzymes relating to the active oxygen toxicity which could be an indicator of aging and body toxicity.

• Korean Journal of Pharmacognosy
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• v.36 no.1 s.140
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• pp.34-37
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• 2005

Reactive oxygen species (ROS) are known to cause oxidative modification of DNA, proteins, lipids and small cellular molecules and are associated with tissue damage and are the contributing factors for inflammation, aging, cancer, arteriosclerosis, hypertension and diabetes. We screened the anti-oxidants in V79-4 hamster lung fibroblast cells induced by hydrogen peroxide with eighteen pure compounds isolated from natural products. Allantoin, brassicasterol, and hypaconitine were found to strongly scavenge intracellular reactive oxygen species, which is measured by dichlorodihydrofluorescin diacetate method (DCHF-DA), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical.

• Korean Journal of Veterinary Research
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• v.39 no.2
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• pp.287-293
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• 1999

Isoeugenol, one of the phenylpropanoid derivatives has been known to inhibit the lipid peroxidation via scavenging effect on hydroxyl or superoxide radical production. We examined whether isoeugenol has a inhibitory effect against N-methyl-D-aspartate(NMDA)-, oxygen/glucose deprivation- and xanthine/xanthine oxidase(X/XO)-induced neurotoxicity or NMDA-induced $^{45}Ca^{+2}$ uptake elevation in primary mouse vertical cultures. We also evaluated whether isoeugenol exhibits inhibitory action on NMDA-induced convulsion in mice. Isoeugenol ($30{\sim}300{\mu}M$) attenuated NMDA- and X/XO-induced neurotoxicity by 11~85% and 83~92%, respectively. In the oxyge/glucose deprivation(60 min)-induced neurotoxicity, isoeugenol significantly(p<0.05) reduced by 32% at the maximal concentration. However, it failed to ameliorate NMDA-induced $^{45}Ca^{+2}$ uptake elevation. Isoeugenol(0.5g/kg, i.p.) delayed 6.5 times on the onset time of convulsion evoked by NMDA($0.1{\mu}g$) compared to that of control. These results suggest that the neuroprotective action of isoeugenol may be ascribed to the modulation of massive generation of reactive oxygen species(ROS) occurred during the ischemic or excitotoxic damage, not by directly affecting the NMDA receptor.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.5 s.248
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• pp.397-404
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• 2006

Effects of surface defect distribution on flame instability during flame-surface interaction are experimentally investigated. To examine chemical quenching phenomenon which is caused by radical adsorption and recombination processes on the surface, thermally grown silicon oxide plates with well-defined defect density were prepared. ion implantation technique was used to control the number of defects, i.e. oxygen vacancies. In an attempt to preferentially remove oxygen atoms from silicon dioxide surface, argon ions with low energy level from 3keV to 5keV were irradiated at the incident angle of $60^{\circ}$. Compositional and structural modification of $SiO_2$ induced by low-energy $Ar^+$ ion irradiation has been characterized by Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). It has been found that as the ion energy is increased, the number of structural defect is also increased and non-stoichiometric condition of $SiO_x({\le}2)$ is enhanced.

• Journal of the Korean Chemical Society
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• v.67 no.1
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• pp.33-41
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• 2023

Nanocrystallne WO₃ and MoO₃ with several different sizes and crystal structures were prepared by simple acid precipitation and subsequent heat treatment. The photochromic (PC) properties of these samples were comparatively investigated in powder state by monitoring diffuse reflectance spectral changes after bandgap irradiation. The PC effect of hexagonal WO₃ and monoclinic WO₃ strongly depended upon crystallite size rather than crystal structure. The smaller the crystallite size, the better the PC effect. However, orthorhombic WO·H₂O and MoO₃ having hexagonal and orthorhombic structures did not follow this trend. One consistent result for all WO₃ and MoO₃ samples is that the heat treatment in air, which changes crystallinity, whether it changes the crystal structure or only the crystallite size, reduces the PC effect. Since the thermal treatment reduces the surface oxygen defect sites, we believe that the PC effect of WO₃ and MoO₃ depends critically on the surface oxygen defect sites that serve as deep trap sites for photogenerated electrons and oxygen radical holes. We also found that the proton insertion claimed by double charge injection model is not critical for the PC effect.

• Korean Journal of Microbiology
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• v.30 no.6
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• pp.460-465
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• 1992

The effect of PSOD expression on lacZ-sodP fusion (pYK4) was explored in Escherichia coli sodA sodB mutants (QC774) under oxidative stress. In this system, although .betha.-galactosidase activity was not fully induced by isopropyl-1-thio-.betha.-galactosidase (IPTG) and was inhibited by glucose, functional PSOD was under lacZ promotor control and was induced by IPTC, lactose, PQ and copper isons, finally, the results show that higher PSOD expression leel was consistently importnat in defending against superoxide radicals.

• Proceedings of the Korean Nutrition Society Conference
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• 2003.05a
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• pp.301.2-301.2
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• 2003

• YAKHAK HOEJI
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• v.43 no.6
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• pp.703-708
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• 1999

The effect of antioxidants on photochemical reaction of pefloxacin by UVB (290~320 nm) was investigated and the possible mechanism of phototoxicity on the skin was also studied. The photo-degradation of pefloxacin by UVB was suppressed by cysteine, reduced glutathione and ascorbic acid, but was promoted by ${\alpha}-tocopherol$. Squalene, accounts for more than 10% of skin surface lipids, was peroxidized by pefloxacin through both radical and singlet oxygen mechanism.

• Proceedings of the Korean Nutrition Society Conference
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• 2001.05a
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• pp.306.2-306
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• 2001