• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.1
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• pp.165-170
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• 2007

Pyungwi-san(PWS) have been using as a basic prescription of digestive disorder in Korean traditional medicine. This study was performed to examine the in vitro antioxidant activity of the extract using different antioxidant tests including by 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging, superoxide anion radical scavenging, metal chelating hydrogen peroxide scavenging, lipid peroxydation protective effect and scavenging effect of nitric oxide and peroxynitrite. Herbal-acupuncture solution of PWS(PWS-HS) exhibited a concentration-dependent inhibition of DPPH radical adduct formation and it showed dose-dependent free radical scavenging activity onto superoxide anions. In addition, the result of metal chelating hydrogen peroxide scavenging and ammonium thiocyanate experiments showed that PWS-HS was an active scavenger of hydroxyl radicals. Furthermore, it was also found to be effective in scavenging nitric oxide and peroxynitrite, well-known cytotoxic species that can oxidize several cellular components such as proteins, lipids and DNA.

• Journal of Environmental Science International
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• v.21 no.7
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• pp.845-853
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• 2012

Diethyl phthalate (DEP) is widely spread in the natural environment as an endocrine disruption chemicals (EDs). Therefore, in this study, ultrasound (US) and ultraviolet (UVC), including various applied power density (10-40 W/L), UV wavelengths (365 nm, 254 nm and 185 nm) and frequencies (283 kHz, 935 kHz) were applied to a DEP contaminated solution. The pseudo-first order degradation rate constants were in the order of $10^{-1}$ to $10^{-4}\;min^{-1}$ depending on the processes. Photolytic and sonophotolytic DEP degradation rate also were high at shortest UV wavelength (VUV) due to the higher energy of photons, higher molar absorption coefficient of DEP and increased hydroxyl radical generation from homolysis of water. Sonolytic DEP degradation rate increased with increase of applied input power and the dominant reaction mechanism of DEP in sonolysis was estimated as hydroxyl radical reaction by the addition of t-BuOH, which is a common hydroxyl radical scavenger. Moreover, synergistic effect of were also observed for sonophotolytic degradation with various UV irradiation.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2129-2140
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• 2017

Silibinin is the major active component of silymarin, extracted from the medicinal plant Silybum marianum. Silibinin has potent antibacterial activity; however, the exact mechanism underlying its activity has not been elucidated. Here, we investigated the novel mechanism of silibinin against Escherichia coli. Time-kill kinetic assay showed that silibinin possess a bactericidal effect at minimal inhibitory concentration (MIC) and higher concentrations (2-and 4-fold MIC). At the membrane, depolarization and increased intracellular $Ca^{2+}$ levels were observed, considered as characteristics of bacterial apoptosis. Additionally, cells treated with MIC and higher concentrations showed apoptotic features like DNA fragmentation, phosphatidylserine exposure, and caspase-like protein expression. Generally, apoptotic death is closely related with ROS generation; however, silibinin did not induce ROS generation but acted as a scavenger of intracellular ROS. These results indicate that silibinin dose-dependently induces bacterial apoptosis-like death, which was affected by ROS depletion, suggesting that silibinin is a potential candidate for controlling bacteria.

• Biomolecules & Therapeutics
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• v.17 no.4
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• pp.395-402
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• 2009

Insulin appears to play a role in brain physiology, and disturbances of cerebral insulin signalling and glucose homeostasis are implicated in brain pathology. The objective of the present study was to investigate the protective effects of insulin under conditions of oxidative stress induced by hydrogen peroxide ($H_2O_2$) in C6 glial cells. Insulin at concentration of $10^{-7}$ M could prevent 12 h $H_2O_2$-induced cell death. The formation of reactive oxygen species (ROS), nitric oxide (NO) and 2-thiobarbituric acid-reactive substances (TBARS) were significantly scavenged by insulin pre-treatment in C6 glial cells after $H_2O_2$-induced oxidative stress. Insulin significantly stimulated the phosphorylation of Akt in the cells and the activation of Akt was maintained in response to insulin under $H_2O_2$ incubation for 12 h. In conclusion, these results provide evidence that insulin acts as a free radical scavenger and stimulating Akt activity. These data suggest that insulin may be effective in degenerative diseases with oxidative stress.

• Food Science and Preservation
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• v.6 no.1
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• pp.121-135
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• 1999

Effective synthetic antioxidants such as butylated hydroxyanisole(BHA) and butylated hydroxytoluene(BHT) have been widely used in the food industry, but they are suspected to be toxic and carcinogenic effects. Therefore, the development of safely available natural antioxidants such as ascorbic acid, ${\alpha}$-tocopherol, ${\beta}$-carotene, flavonoids and selenium is essential. In particular, flavonoids, 2-phenyl-benzo-${\alpha}$-pyrones, are polyphenolic compounds that occur ubiquitously in food of plant origin. flavonoids occur in foods generally as O-glycosides with sugars bound usually at the C\ulcorner position. And variations in their heterocyclic ring gibes rise to flavones, flavonols, flavanones, flavanols, catechins, anthocyanidins, chalcone and isoflavones. Vegetables, fruits, and beverages are the main dietary sources of the flavonols, primarily as quercetin, kaempferol, and myricetin and the corresponding flavones, apigenin and luteolin. These flavonoids have biological activity such as antioxidant, anti-inflammatory, antithrombotic, antimutagenic, anticarcimogenic antiallergic and antimicrobial activity effects in vitro and in vivo. Flavonoids posses strong antioxidant activities acting as oxygen radicals scavenger, metal chelators and enzyme inhibitor. The antioxidant activity of flavonoids is determined by their molecular structure and more specially, by the position and degree of hydroxylation of the ring structure. All flavonoids with the 3`, 4`-dihydroxy(ortho-dihydroxy) posses marked antioxidant activity. And antioxidant activity increases with the number of hydroxyl groups substituted on the A-and B-rings. There is as yet no certainty about the effect of the presence of a double bond between C\ulcorner and C\ulcorner on the antioxidant activity of flavonoids.

• 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.

• Proceedings of the KSAR Conference
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• 2000.10a
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• pp.5-6
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• 2000

Nitric oxide (NO) is a simple combined molecule of oxygen and nitrogen, and has a wide variety of action on the physiological and pathophysiological function of the body. It is a key transducer of the vasodilator message from the endothelium to vascular cells. However, its different roles have been elucidated by numerous researches, which was undertaken in the 80's and 90's. Three types of NO synthase were involved in synthesizing NO and they are identified in different tissues and cells including macrophage, endothelial cells and even tumor cells. In the late 90's, we undertook a number of researches for elucidating the effect of NO on embryo development, since developmentally arrested bovine embryos contained large amount of NO metabolites in their cytoplasm. Subsequently, we found that the addition of a spontaneous NO donor to culture medium markedly inhibited embryo development and that its inhibitory role was independent of embryonic genome activation. Research was focused to find a way to prevent the inhibitory action of NO on embryo development and demonstrated that the addition of hemoglobin, a NO scavenger, to embryo culture medium greatly stimulated in vitro-development of bovine and mouse embryos. Based on these research outcomes, we developed a NO action-free culture system for embryos and other tissues. The efficacy of such system has subsequently been confirmed by achieving the high rates of preimplantation development and blastocyst formation in the NO action-free culture of mouse and bovine embryo. In this article, we briefly introduced the nature of NO and our research outcomes on the role of NO in embryo development.

• Biomedical Science Letters
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• v.11 no.4
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• pp.441-446
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• 2005

The molecular mechanism of ischemia/reperfusion injury remains unclear. Reactive oxygen species (ROS) are implicated in cell death caused by ischemia/reperfusion in vivo or hypoxia in vitro. Poly (ADP-ribose) polymerase (PARP) activation has been reported to be involved in hydrogen peroxide-induced cell death in renal epithelial cells. This study was therefore undertaken to evaluate the role of P ARP activation in chemical hypoxia in opossum kidney (OK) cells. Chemical hypoxia was induced by incubating cells with antimycin A, an inhibitor of mitochondrial electron transport. Exposure of OK cells to chemical hypoxia resulted in a time-dependent cell death. In OK cells subjected to chemical hypoxia, the generation of ROS was increased, and this increase was prevented by the $H_2O_2$ scavenger catalase. Chemical hypoxia increased P ARP activity and chemical hypoxia-induced cell death was prevented by the inhibitor of PARP activation 3-aminobenzamide. Catalase prevented OK cell death induced by chemical hypoxia. $H_2O_2$ caused PARP activation and $H_2O_2-induced$ cell death was prevented by 3-aminobenzamide. Taken together, these results indicate that chemical hypoxia-induced cell injury is mediated by PARP activation through H202 generation in renal epithelial cells.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2005.04a
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• pp.131-148
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• 2005

This study is peformed to investigate the effect of water extract from Vaccinium uliginosum L., on melanin production in B 16 melanoma cells, procollagen production and matrix metalloproteinase-1(MMP-1) inhibition in human fibroblast cells. One hundred grams of the Vaccinium uliginosum L. was extracted with 2000 mL of water($90^{\circ}C$, 16h, 2times). The water extracts were lyophilized and stored at $4^{\circ}C$ until used. Dry weight yields of extracts of Vaccinium uliginosum L. were $3\%$(w/w). Extracts from Vaccinium uliginosum L. showed scavenger activities on DPPH radical, superoxide anion radical, hydroxyl radical, hydrogen peroxide and singlet oxygen radical. And these substances inhibited release of cyiokines from human keratinocyte after UV B exposure. Therefore we confirmed that extracts from Vaccinium uliginosum L. had antioxidative effect. These substances inhibited purified tyrosinase activity and melanogenesis in B 16 melanoma cells treated/untreated IL-$1{\alpha}$. Moreover this extract stimulated procollagen production and inhibited MMP-1 production in human fibroblast cells treated/untreated IL-$1{\beta}$. Therefore we confirmed that extracts from Vaccinium uliginosum L. had whitening effect. And these substances decreased degree of wrinkle in hairless mouse skin that induced by UV B irradiation. Therefore we confirmed that extracts from Vaccinium uliginosum L. had anti-wrinkle effect. From the above results, it is possible that Vaccinium uliginosum L. may be developed to be an anti-melanogenesis agent and anti-wrinkle agent.

• The Journal of Internal Korean Medicine
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• v.27 no.1
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• pp.178-187
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• 2006

Objectives : Peroxynitrite $(ONOO^-),\;{\cdot}O_2^-$ and nitric oxide (NO) are cytotoxic species that can oxidize several cellular components such as proteins, lipids and DNA. It has been implicated in the aging process and age-related disease such as Alzheimer's disease, rheumatoid arthritis, cancer and atherosclerosis. The aim of this study was to investigate $ONOO^-$ scavengactivities, and that of its precursors, NO and ${\cdot}O_2^-$ of Samjunghwan. Methods : To investigate $ONOO^-,\;NO,\;{\cdot}O_2^-$ scavenging activities, fluorescent probes, namely 2',7'-dichlorodihydrofluorescein diacetate (DCFDA), 4,5-diaminofluorescein (DAF-2) and dihydrorhodamine 123 (DHR 123) were used. Results : Samjunghwan markedly scavenged authentic $ONOO^-,\;{\cdot}O_2^-$ and NO. It also inhibited $ONOO^-$ induced by .02' and NO which are derived from SIN-I. Furthermore, Samjunghwan inhibited $ONOO^-$, ${\cdot}O_2^-$ and NO generation in LPS-treated ICR mouse kidney postmitochondria. Conclusions : These results suggest that Samjunghwan is an effective $ONOO^-,\;{\cdot}O_2^-$ and NO scavenger, and that this substance has a potential role as an inhibitor of aging process, and in therapy against age-related diseases.