• 한국물환경학회지
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• 제32권5호
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• pp.403-409
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• 2016

In this study, a TiO₂ nanotube was grown on a titanium plate by using anodic oxidation method for the evaluation of TiO₂ nanotube morphology. The TiO₂ nanotube was grown in an electrolyte containing ethylene glycol, 0.2 wt% of NH₄F and 2 vol% of H₂O. Applied voltage varied from 30 to 70 V and the morphology of the TiO₂ nanotube was observed. After anodization, a TiO₂ nanotube plate was immersed in 35℃ ethanol for 24 hours. Anatase and rutile crystal forms of TiO₂ nanoutbe were observed after annealing. 4-chrolobenzoic acid, a probe compound for OH radicals, was dissolved in H₂O in order to measure the OH radical. Liquid chromatography was used to check the concentration of the 4-chrolobenzoic acid. The OH radical generation by TiO₂ nanotube plate was proportionate to the length of the TiO₂ nanotube. Furthermore, when the number of TiO₂ nanotube plate increased, the OH radical generation increased as well.

• 동아시아식생활학회지
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• 제14권1호
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• pp.64-69
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• 2004

본 연구에서는 이미 항산화 효과로 알려져 있는 대두와 약성이 탁월한 약콩에서 AChE 활성 억제효과와 Free radical scavenger 효과를 노화로 인한 질병 예방효과에 대한 기초자료를 제공하고자 수행하였다. 1. 대두 열탕 추출물의 경우 저농도인 1, 0.1 mg/$m\ell$에서는AChE의 활성 억제 효과가 메탄을 추출물보다 높았다. (P<0.001) 2. 대두, 약콩 메탄올 추출물에서는 고농도인 5 mg/$m\ell$에서 각 시료의 효과가 62.0$\pm$2.43%, 65.0$\pm$3.29%로 비슷했으나 저농도인 0.1 mg/$m\ell$에서는 약콩의 경우 25.5$\pm$0.94%로 약콩이 대두에 비해 유의적인 AChE 억제효과를 나타냈다. (p<0.001) 3. 시간에 따른 Free radical scavenger효과는 비타민 C의 경우 시간에 따라 비슷한 효과를 보였으나 대두와 약콩은 incubating 시간에 따라 free radical 억제효과가 증가해 높은 항산화 효과를 볼 수 있었다. 4. 대두, 약콩 메탄올 추출물에서는 약콩이 고농도인 5mg/$m\ell$에서 약4배 정도의 효과를 보였으며 Free radical scavenger의 50%효과를 나타내는 $IC_{50}$/에서는 약 10배 정도로 높은 Free radical scavenger 효과를 나타내 약콩이 대두에 비해 유의적으로 높은 효과를 나타내었다. 결론적으로, 대두와 약콩의 추출물은 AChE 활성억제효과에 있어서 좋은 효과를 나타내며 또한 노화의 원인과 질병의 원인이 되는 free radical을 억제하는 효과를 가지고 있어 노인성 치매를 비롯하여 파킨슨씨병, 뇌허혈 및 뇌졸중과 같은 각종 노인성 질환예방에 도움이 될 것으로 보인다.

• Preventive Nutrition and Food Science
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• 제16권3호
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• pp.224-229
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• 2011

The radical scavenging activity and inhibition effect from lipid peroxidation induced by peroxyl radical of methanol extract from Perilla frutescens and its active compound, rosmarinic acid (RA), were investigated in vitro. The treatment of extract and RA scavenged 1,1-diphenyl-2-picrylhydrazyl, hydroxyl radical (${\cdot}OH$) and nitric oxide in a concentration-dependent manner. In particular, the extract and RA showed strong radical scavenging activity against ${\cdot}OH$, the most toxic and reactive radical. In addition, Perilla frutescens and RA effectively inhibited lipid oxidation induced by sodium nitroprusside and 2,2'-azobis(2-aminopropane) dihydrochloride, determined by the ferric thiocyanate method. The present results suggest that Perilla frutescens and RA play a protective role against oxidative stress induced by free radical and lipid peroxidation.

• Journal of Korean Society for Atmospheric Environment
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• 제19권E3호
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• pp.129-136
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• 2003

Effects of inorganic aerosols on the kinetics of the hydroxyl radical reactions with selected aliphatic alkanes have been investigated using the relative rate technique. The relative rates in the absence and presence of aerosols were determined for n-butane, n-pentane, n-hexane, n-octane, and n-decane. P-xylene was used as a reference compound. Inorganic aerosols including (NH$_4$)$_2$SO$_4$, NH$_4$NO$_3$, and NaCl aerosols at two different aerosol concentrations that are typical of polluted urban conditions were tested. Total surface areas of aerosols were 1400 (Condition I) and 3400 $\mu$$m^2$ cm$^{-3}$ (Condition II). Significant changes in the relative rates in the presence of the inorganic aerosols were not observed for the n-butanel/$.$OH, n-pentanel/$.$OH, n-hexanel/$.$OH, n-octanel/$.$OH, and n-decanel/$.$OH reactions versus p-xylenel/$.$OH reaction. These results suggest that the promoting effects depend on the semiconducting property of the aerosols and the nature of the organic compounds.

• 대한약리학회지
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• 제21권1호
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• pp.34-48
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• 1985

항균제 nitrofurantion에 의한 폐독작용의 생화학적 기전을 규명하기 위한 연구 일환으로 in vitro에서 폐장 microsome 지질의 과산화 및 반응성 산소 radical $(O^{-}_{2}{\cdot},\;H_2O_2,\;OH{\cdot},\;^1O_2)$의 생성에 대한 nitrofurantion의 영향과 양자 간의 상호 관련성을 검토하였다. Nitrofurantion은 호기성 반응 조건에서 돼지 폐장 microsome의 NADPH 의존성 지질 과산화를 용량 의존적으로 증가시킬 뿐 아니라 $O^{-}_{2}{\cdot},\;H_2O_2$ 및 두 radical의 상호 작용으로 2차적으로 형성되는 $OH{\cdot}$의 생성 또한 촉진하였으며 $^1O_2$생성은 관찰되지 않았다. 이와 같은 폐장 microsome지질 과산화 증가는 SOD 및 catalase에 의하여 억제될 뿐만 아니라 $OH{\cdot}$ 제거 물질인 mannitol, thiourea에 의하여도 현저히 억제되었으며, $^1O_2$ 제거 물질에 의하여는 영향을 받지 않았던 한편 염기성 반응 조건에서는 nitrofurantoin에 의한 지질 과산화가 관찰되지 않았다. 이상의 결과로 미루어 보아 nitrofurantoin은 폐장 microsome의 NADPH 의존적이 반응성산소 radical $(O^{-}_{2}{\cdot},\;H_2O_2$ 및 $OH{\cdot})$의 생성을 증가시키며 이들 중 특히 $OH{\cdot}$ 에 의한 microsome막 지질 과산화를 촉진하는 것으로 결론지었고, 이와 같은 in vivo 현상은 nitrofurantion의 in vitro 폐독작용의 기전을 설명하는 일부가 될 것으로 사료하였다.

• 농업과학연구
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• 제50권3호
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• pp.569-580
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• 2023

The aim of this study was to investigate the antioxidant effects of O. robusta stem extract (ORE) and to determine the total polyphenol and flavonoid contents. Free radical scavenging properties were evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid)), and ·OH (hydroxyl radical) scavenging assays. Total polyphenol and flavonoid contents were measured using Folin-Ciocalteu reagent and aluminum chloride colorimetric methods, respectively. Active compounds of ORE were determined using high-performance liquid chromatography (HPLC). The results of the study showed that ORE exhibited DPPH, ABTS, and ·OH radical scavenging activities in a dose-dependent manner. Especially, 1,000 ㎍/mL of ORE showed the strongest radical scavenging properties against DPPH, ABTS, and ·OH. ORE contained total polyphenol content of 57.4 mg GAE/g and total flavonoid content of 5.4 mg QE/g, which may contribute to their antioxidant effects. As a result of HPLC, the contents of active compounds in ORE, dihydrokaempferol (0.65 ㎍/mL), and 3-O-methylquercetin (1.10 ㎍/mL) were confirmed. In conclusion, ORE may be useful as a functional material with antioxidant properties.

• 대한화학회지
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• 제39권4호
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• pp.237-243
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• 1995

Anthraquinone이 유기용매에서 광반으에 의하여 반응 중간체로 생성하는 짧은 수명의 중성 세미퀴논 라디칼과 음이온 라디칼을 시간분해 ESR법에 의하여 측정하였다. 2-2-propanol (PrOH)과 triethylamine (TEA) 10:1 혼합 용매에서 광반응에 의하여 생성하는 중성 anthrasemiquinone 라디칼(AQH${\cdot}$)과 음이온 라디칼 (AQH${\cdot}$)의 CIDEP 스펙트럼을 측정하였다. 생성한 AQH${\cdot}$은 반감기가 0.8 ${\mu}sec$로 수명이 아주 짧았으며, AQ${\cdot}$-은 안정하여 cwESR의 측정이 가능하였다. 스핀분극된 음이온 라디칼(AQ${\cdot}$-*)의 분극소멸 속도 상수는 $2.6{\times}10^5\; sec^{-1}$이고, 음이온 라디칼의 소멸은 1차 반응으로 속도상수가 $3.0{\times}10^2\; sec^{-1}$이다. 혼합용매에 TEA가 2% 미만일 때 CIDEP가 일어나지 않았다. 벤젠과 TEA 혼합용매에서는 반감기 3.0 ${\mu}sec$의 중성 anthrasemiquinone 라디칼의 CIDEP가 측정되었다. 그러나, cwESR은 측정되지 않았다. PrOH, TEA 또는 벤젠만의 용매로서는 CIDEP와 ESR을 측정할 수 없었다.

• 대한기계학회논문집B
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• 제21권11호
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• pp.1393-1402
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• 1997

Characteristics of the lifted flame which is generated by issuing of the fuel through the miniature nozzle, d = 0.164 mm, are studied using the planar laser induced fluorescence technique. OH radical is excited on the $Q_{1}$(8) line of the $A^{2}$.SIGMA.$^{+.leq.X2}$ .PI.(1, 0) band transition (283.55 nm) and LIF signals are captured at the bands of (0, 0) and (1, 1) transition (306 ~ 326 nm) using the filters and ICCD camera. Hydroxyl radical (OH) profile for nozzle attached flame shows that OH radical populations at the flame sides and flame tip are larger than those at the base. But for the lifted flame (tribrachial flame) case, those are larger at the flame base than at the flame tip and flame sides. The OH radical is more dense near the center line of flame base at the blowing out. This fact proves the Chung and Lee's blowout theory-blowout occurs when the flame is anchored at the flame axis. axis.

• Food Science and Biotechnology
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• 제18권1호
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• pp.124-129
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• 2009

Antioxidant activities of the extract of red seaweed, Polysiphonia morrowii, were evaluated using several in vitro assay systems. Activity-guided fractionation revealed that the 90% MeOH fraction of the P. morrowii extract exhibited the highest antioxidant activity, and that this fraction had a high total phenolic content ($135.7{\pm}5.0\;mg$ gallic acid/g extract). Therefore, the antioxidant activities of the 90% MeOH fraction against 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical, reducing power, ferrous chelating, and hydrogen peroxide were investigated. The results revealed that the antioxidant activities of the 90% MeOH fraction were similar and/or superior to that of commercial antioxidants such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). In addition, the ability of the 90% MeOH fraction to inhibit oxidative damage to DNA was assessed by measuring the conversion of the supercoiled pBR322 plasmid DNA to the open circular form. The 90% MeOH fraction was found to significantly protect this hydroxyl radical-induced DNA damage in a dose-dependent manner. Taken together, these findings suggest that the 90% MeOH fraction of P. morrowii extract and/or its constituents has the potential for use as a new bioresource of antioxidants.

• Food Science and Biotechnology
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• 제16권1호
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• pp.90-98
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• 2007

The antioxidant activities of water ($H_2O$) and ethanol (EtOH) extracts from hamcho (Salicornia herbacea L.) juice and cake prepared by enzymatic treatments were evaluated by in vitro assays against DPPH, superoxide, and hydroxyl radicals. Among the $H_2O$ and EtOH extracts from five different carbohydrases treated, the EtOH extract from viscozyme-treated hamcho cake had higher yield and phenolic content, and exhibited the strongest radical scavenging activity against DPPH ($IC_{50}=186.91\;{\mu}g/mL$), superoxide ($IC_{50}=87.54\;{\mu}g/mL$), and hydroxyl radicals ($IC_{50}=367.07\;{\mu}g/mL$). Antioxidant assay-guided fractionation and purification of the EtOH extract led to isolation and identification of five phenolic compounds, procatechuic, ferulic and caffeic acids, quercetin, and isorhamnetin. Most of these phenolic compounds exhibited considerable DPPH, superoxide, and hydroxyl radical scavenging activities, and in particular, caffeic and ferulic acids had stronger superoxide and hydroxyl radical scavenging activities than the well-known antioxidant radical scavenger, (+)-catechin (p<0.05). Quercetin and isorhamnetin were the primary compounds responsible for the strong antioxidant activity in the EtOH extract of the viscozyme-treated hamcho cake. Meanwhile, these five phenolic compounds were detected in the EtOH extract of the viscozyme-treated hamcho cake at the following levels (dry base of hamcho); procatechuic acid (1.54 mg%), caffeic acid (6.87 mg%), ferulic acid (8.45 mg%), quercetin (12.63 mg%), and isorhamnetin (6.65 mg%). However, three of these phenolic compounds (procatechuic, caffeic acid, and ferulic acids) were detectable in the $H_2O$ extract of viscozyme-treated hamcho juice. These results suggest that the EtOH extract of viscozyme-treated hamcho cake may be a potential source of natural antioxidants.