• The Korean Journal of Food And Nutrition
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• v.33 no.2
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• pp.210-214
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• 2020

In this study, polyphenol and flavonoid contents were measured, and DPPH, OH, H₂O₂ radical scavenging activity, and the α-amylase inhibitory activity were measured to study the antioxidant activity of 70% ethanol extract from Morinda citrifolia L. The polyphenol and flavonoid contents of noni 70% ethanol extract were 29.52 GAE/g and 12.48 CE/g, respectively. Also, the IC₅₀ values of DPPH, hydroxyl radical, and hydrogen peroxide scavenging activity of 70% ethanol extract from noni were 18.70 mg/mL, 26.45 mg/mL, and 35.67 mg/mL, respectively. Measurement of the α-amylase inhibitory activity of 70% ethanol extract from noni showed 45% inhibitory activity at 10 mg/mL.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.6
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• pp.319-326
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• 2011

Quercetin-3-O-${\beta}$-D-glucuronopyranoside (QGC) is a flavonoid glucoside extracted from Rumex Aquaticus Herba. We aimed to explore its protective effect against ethanol-induced cell damage and the mechanism involved in the effect in feline esophageal epithelial cells (EEC). Cell viability was tested and 2',7'-dichlorofluorescin diacetate assay was used to detect intracellular $H_2O_2$ production. Western blotting analysis was performed to investigate MAPK activation and interleukin 6 (IL-6) expression. Exposure of cells to 10% ethanol time-dependently decreased cell viability. Notably, exposure to ethanol for 30 min decreased cell viability to 43.4%. When cells were incubated with $50{\mu}M$ QGC for 12 h prior to and during ethanol treatment, cell viability was increased to 65%. QGC also inhibited the $H_2O_2$ production and activation of ERK 1/2 induced by ethanol. Pretreatment of cells with the NADPH oxidase inhibitor, diphenylene iodonium, also inhibited the ethanol-induced ERK 1/2 activation. Treatment of cells with ethanol for 30 or 60 min in the absence or presence of QGC exhibited no changes in the IL-6 expression or release compared to control. Taken together, the data indicate that the cytoprotective effect of QGC against ethanol-induced cell damage may involve inhibition of ROS generation and downstream activation of the ERK 1/2 in feline EEC.

• Journal of Microbiology and Biotechnology
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• v.29 no.9
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• pp.1401-1411
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• 2019

Mycobacterial cell walls comprise thick and diverse lipids and glycolipids that act as a permeability barrier to antibiotics or other chemical agents. The use of OH radicals from a non-thermal plasma jet (NTPJ) for the inactivation of mycobacteria in aqueous solution was adopted as a novel approach. Addition of water vapor in a nitrogen plasma jet generated OH radicals, which converted to hydrogen peroxide ($H_2O_2$) that inactivated non-pathogenic Mycobacterium smegmatis and pathogenic Mycobacterium tuberculosis H37Rv. A stable plasma plume was obtained from a nitrogen plasma jet with 1.91 W of power, killing Escherichia coli and mycobacteria effectively, whereas addition of catalase decreased the effects of the former. Mycobacteria were more resistant than E. coli to NTPJ treatment. Plasma treatment enhanced intracellular ROS production and upregulation of genes related to ROS stress responses (thiolrelated oxidoreductases, such as SseA and DoxX, and ferric uptake regulator furA). Morphological changes of M. smegmatis and M. tuberculosis H37Rv were observed after 5 min treatment with $N_2+H_2O$ plasma, but not of pre-incubated sample with catalase. This finding indicates that the bactericidal efficacy of NTPJ is related to the toxicity of OH and $H_2O_2$ radicals in cells. Therefore, our study suggests that NTPJ treatment may effectively control pulmonary infections caused by M. tuberculosis and nontuberculous mycobacteria (NTM) such as M. avium or M. abscessus in water.

• Korean Journal of Agricultural Science
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• v.49 no.2
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• pp.175-184
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• 2022

The present study investigated the neuroprotective effects of Coreopsis lanceolate extract against hydrogen-peroxide (H₂O₂)-induced oxidative damage and cell death in pheochromocytoma 12 (PC12) cells. Reactive oxygen species (ROS), 2,2'-azinobis (3-ethylbebzothiazoloine-6-sulfonic acid) diammonium salt, and 1,1-diphenyl-2-picrrylhydrazyl radical scavenging activities, as well as the expression levels of proteins associated with oxidative damage and cell death were investigated. According to the results, C. lanceolate extract exhibited inhibitory activity against intracellular ROS generation and cell-damaging effects induced by hydroxyl radicals in a dose-dependent manner. Total phenolic and flavonoid contents were 22.3 mg·g^-1 gallic acid equivalent and 16.2 mg·g^-1 catechin equivalent, respectively. Additionally, a high-performance liquid chromatography (HPLC) assay based on the internal standard method used to detect phenolic compounds. The phenolic compounds identified in C. lanceolata extract contained (+)-catechin hydrate (5.0 ± 0.0 mg·g^-1), ferulic acid (1.6 ± 0.0 mg·g^-1), chlorogenic acid (1.5 ± 0.0 mg·g^-1), caffeic acid (1.2 ± 0.0 mg·g-1), naringin (0.9 ± 0.0 mg·g^-1), and p-coumaric acid (0.5 ± 0.0 mg·g^-1). C. lanceolata extract attenuated pro-apoptotic Bax expression levels and enhanced the expression levels of anti-apoptotic Bcl-2, caspase-3, and caspase-9 proteins. Therefore, C. lanceolata is a potential source of materials with neuroprotective properties against neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases.

• Journal of the Korean GEO-environmental Society
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• v.12 no.9
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• pp.55-61
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• 2011

This study investigate the use of ultraviolet(UV) light with hydrogen peroxide($H_2O_2$) for Methyl Tert Butyl Ether(MTBE) degradation in photolysis reactor. The process in general demands the generation of OH radicals in solution at the presence of UV light. These radicals can then attack the MTBE molecule and it is finally destroyed or converted into a simple harmless compound. The MTBE removal by photolysis were mathematically described as the independent variables such as irradiation intensity, initial concentration of MTBE and $H_2O_2$/MTBE ratio, and these were modeled by the use of response surface methodology(RSM). These experiments were carried out as a Box-Behnken Design(BBD) consisting of 15 experiments. Regression analysis term of Analysis of Variance(ANOVA) shows significantly p-value(p<0.05) and high coefficients for determination values($R^2$=94.60%) that allow satisfactory prediction of second-order regression model. And Canonical analysis yields the stationery point for response, with the estimate ridge of maximum responses and optimal conditions for Y(MTBE removal efficiency, %) are $x_1$=25.75 W of irradiation intensity, $x_2$=7.69 mg/L of MTBE concentration and $x_3$=11.04 of $H_2O_2$/MTBE molecular ratio, respectively. This study clearly shows that RSM is available tool for optimizing the operating conditions to maximize MTBE removal.

• Journal of dental hygiene science
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• v.19 no.3
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• pp.198-204
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• 2019

Background: Oxidative stress is a known to be associated with in the pathogenesis of many inflammatory diseases, including periodontitis. Ursolic acid is a pentacyclic triterpenoid with has antimicrobial, antioxidative, and anticancer properties. However, the role of ursolic acid in the regulating of osteogenesis remains undetermined. This study was aimed to elucidate the crucial osteogenic effects of ursolic acid and its ability to inhibit oxidative stress by targeting the immediate early response 3 (IER3)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. Methods: Cell proliferation was determined using water-soluble tetrazolium salt assay, cell differentiation was evaluated by alkaline phosphatase (ALP) activity, and formation of calcium nodules was detected using alizarin red S stain. Generation of reactive oxygen species (ROS) was determined using by DCFH-DA fluorescence dye in hydrogen peroxide ($H_2O_2$)-treated MG-63 cells. Expression levels of IER3, Nrf2, and heme oxygenase-1 (HO-1) were analyzed using western blot analysis. Results: Our results showed that ursolic acid up-regulated the proliferation of osteoblasts without any cytotoxic effects, and promoted ALP activity and mineralization. $H_2O_2$-induced ROS generation was found to be significantly inhibited on treatment with ursolic acid. Furthermore, in $H_2O_2$-treated cells, the expression of the early response genes: IER3, Nrf2, and Nrf2-related phase II enzyme (HO-1) was enhanced in the presence of ursolic acid. Conclusion: The key findings of the present study elucidate the protective effects of ursolic acid against oxidative stress conditions in osteoblasts via the IER3/Nrf2 pathway. Thus, ursolic acid may be developed as a preventative and therapeutic agent for mineral homeostasis and inflammatory diseases caused due to oxidative injury.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.3
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• pp.95-101
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• 2008

Purpose: Hydrogen peroxide which is one of the reactive oxygen species has been seen to cause various diseases, various cellular disinfections, gene transformation and cell death. The goals of this study were to determine the protective effect of EGCG against $H_2O_2$-induced apoptotic death in conjunctival cell lines. Methods: We measured cell viability by MTT assay and analyzed DNA fragmentation to check up a distinctive feature in cell death and measured the removal ability of free radicals by DPPH free radical scavenging assay and evaluated the oxygen free radical's quantity in the cell by DCFH-DA assay. The mRNA expression in the cell were examined by RT-PCR. Results: Cell viability and free radical scavening activites was significantly increased in dose dependently after cell was exposed to EGCG. And DNA fragmentation and intracellular ROS was decreased. It was showed the mRNA expression which increase of bcl-2, bcl-xL expression and decrease of bax expression. Conclusions: From these results, it suggests that EGCG has an antioxidant effect and protects conjunctival cell lines from the $H_2O_2$-mediated apoptosis through the modulation of the mRNA expression.

• Journal of Applied Biological Chemistry
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• v.65 no.4
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• pp.405-412
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• 2022

Echinodorus cordifolius (L.) is an aquatic plant in the family Alismataceae. The anti-skin aging activity of E. cordifolius (L.) has not been yet reported. Therefore, the objective of the present study was to prepare 70% ethanol extract (ECEE) from E. cordifolius (L.) and investigate their antioxidant and anti-hyaluronidase activities for confirm the potential of anti-skin aging. ECEE showed good activities of DPPH, hydrogen peroxide scavenging, and hyaluronidase inhibition, with EC₅₀ and IC₅₀ values of 31.4, 300, and 450 ㎍/mL, respectively. ECEE also significantly improved cell viability and inhibited intracellular reactive oxygen species dose-dependently against 1 mM hydrogen peroxide-induced oxidative stress in immortalized human keratinocytes (HaCaT cells). Furthermore, ECEE upregulated hyaluronic acid (HA)-synthesizing enzyme hyaluronan synthase 2 (HAS2) expression level, but downregulated expression level of HA-degrading enzyme hyaluronidase 2, resulting in increased HA production in HaCaT cells. Taken together, these results suggest that ECEE shows antioxidant and anti-hyaluronidase potential and could be a functional cosmetic ingredients for anti-skin aging.

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.582-588
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• 2009

Direct electron transfer of hemoglobin (Hb) in the chitosan (CTS) and $TiO_2$ nanoparticles (nano-$TiO_2$) composite films was achieved by using a room temperature ionic liquid of 1-butyl-3-methylimidazolium hexafluorophosphate ($BMIMPF_6$) modified carbon paste electrode (CILE) as the basal electrode. UV-Vis and FT-IR spectroscopy indicated that Hb in the film retained the native structure. Electrochemical investigation indicated that a pair of well-defined quasi-reversible redox peaks of Hb heme Fe(III)/Fe(II) was obtained with the formal potential located at -0.340 V (νs. SCE) in pH 7.0 phosphate buffer solution (PBS). The electrochemical parameters such as the electron transfer coefficient (α), the electron transfer number (n) and the standard electron transfer rate constant ($k_s$) were got as 0.422, 0.93 and 0.117 $s^{-1}$, respectively. The fabricated CTS/nano-$TiO_2$/Hb/CILE showed good electrocatalytic ability to the reduction of trichloroacetic acid (TCA) and hydrogen peroxide ($H_2O_2$), which exhibited a potential application in fabricating a new kind of third generation biosensor.

• Journal of Ginseng Research
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• v.47 no.2
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• pp.311-318
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• 2023

Background: The beneficial effects of compound K (CK) on different chronic diseases have been shown to be at least related to antioxidant action. Nevertheless, since its antioxidant activity in human retinal pigment epithelial (RPE) cells is still unknown, here we investigated whether CK alleviates oxidative stress-stimulated damage in RPE ARPE-19 cells. Methods: The cytoprotective consequence of CK in hydrogen peroxide (H₂O₂)-treated cells was evaluated by cell viability, DNA damage, and apoptosis assays. Fluorescence analysis and immunoblotting were performed to investigate the inhibitory action of CK on reactive oxygen species (ROS) production and mitochondrial dysfunction. Results: H₂O₂-promoted cytotoxicity, oxidative stress, DNA damage, mitochondrial impairment, and apoptosis were significantly attenuated by CK in ARPE-19 cells. Furthermore, nuclear factor erythroid 2-related factor 2 (Nrf2) phosphorylation level and its shuttling to the nucleus were increased, which was correlated with upregulated activation of heme oxygenase-1 (HO-1). However, zinc protoporphyrin, a blocker of HO-1, significantly abrogated the preventive action of CK in H₂O₂-treated ARPE-19 cells. Conclusion: This study indicates that activation of Nrf2/HO-1 signaling by CK plays an important role in rescuing ARPE-19 cells from oxidative cellular damage.