• KSBB Journal
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• 제32권2호
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• pp.140-145
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• 2017

The objective of this study was to compare antioxidant effects of different extracts of Salicornia bigelovii seed. DPPH radical scavenging activity, chelating activity of ferrous, superoxide anion radical-scavenging activity, hydroxyl radical scavenging activity, and contents of total polyphenol and flavonoid were measured for different extracts. Ethanol extract (10 mg/mL) was found to have the maximum DPPH radical scavenging and superoxide anion radical scavenging activities (65.26 and 62.36%, respectively). However, hot water extract (10 mg/mL) showed the highest hydroxyl radical scavenging and chelating activities (51.50 and 53.24%, respectively). Total phenolics and flavonoid contents in the ethanol extract were 522.8 and $480.35{\mu}g/mg$, respectively. They were 401.51 and $352.60{\mu}g/mg$, respectively, in the hot water extract. These results indicate that ethanol and hot water extracts of S. bigelovii seed have good potential to be used as a new source of antioxidants for functional foods, cosmetics, and pharmaceuticals.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1907-1910
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• 2004

Generation of hydroxyl radical, one of their major active species in ozonation of water was directly observed with spin-trapping/electron spin resonance (ESR) technique using 5,5-dimethyl-pyrrolidine-1-oxyl (DMPO) as a spin-trapping reagent. Hydroxyl radical was trapped with DMPO as a stable radical, DMPO-OH. 80 mM of ozone produced $1.08{\times}10^{-6}$M of DMPO-OH, indicating that 1.4% of ${\cdot}$OH is trapped with DMPO if ${\cdot}$OH is produced stoichiometrically from ozone. Humic acid suppressed DMPO-OH generation in a dose-dependent manner. Generation rate of DMPO-OH was determined with ESR/stopped-flow measurement. Phenol derivatives increased the amount and generation rate of DMPO-OH, indicating that phenol derivatives enhance·OH generation during ozonation of water.

• Applied Biological Chemistry
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• 제46권1호
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• pp.32-38
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• 2003

시판되고 있는 두류 13종류의 70% 에탄을 추출물을 제조하여, 이들의 항산화 활성을 환원력, 지질과산화 억제 활성, superoxide radical 소저활성, hydroxyl radical 소거활성, mitomycin C로 유도된 DNA의 산화적 손상에 대한 억제활성을 지표로 조사하였다. 환원력은 예팥, 속피리, 유월콩 및 적두가 높았다. 지질과산화 억제능을 조사한 결과, linoleic acid 자동산화계를 이용한 실험계에서 모든 시료가 억제활성을 보인 반면, 토끼 적혈구막 지질과 산화에 대한 억제활성은 쥐눈이콩과 적두, 속피리에서만 관찰되었다. Superoxide radical 소거활성은 예팥, 나물콩, 적두, 쥐눈이콩에서 높게 나타났으며, hydroxyl radical 소거활성은 속피리, 청태, 예팥과 제비콩에서 높았다. Mitomycin C로 유도된 DNA의 산화적 손상에 대한 억제활성을 조사한 결과, 모든 품종들이 DNA의 산화적 손상을 억제할 수 있었으나, 특히 예팥, 쥐눈이콩, 나물콩, 녹두, 적두의 억제활성이 우수하였다. 이상의 실험결과에서 예팥, 적두, 쥐눈이콩, 속피리가 환원력, 지질과산화 억제, superoxide radical 및 hydroxyl radical 소거활성, DNA의 산화적 손상에 대한 억제활성 둥 항산화활성이 우수한 품종임을 알 수 있었다.

• The Korean Journal of Physiology and Pharmacology
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• 제2권3호
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• pp.369-376
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• 1998

This report shows that hydroxyl radical, generated by a Fenton reaction involving adenosine $5'-diphosphate/Fe^{2+}$ complex ($5-15\;{\mu}M$) and $H_2O_2$ ($2\;{\mu}M$), induced differentiation of HL-60 cells in a dose- and time-dependent manner. This is evidenced by the increases in 12-O-tetradecanoylphorbol 13-acetate- and fMLP-stimulated superoxide production capability. The cells exposed to hydroxyl radical for defined periods (24∼96 hr) continued to differentiate even after the hydroxyl radical generating system had been removed. The differentiated cells displayed fMLP-stimulated calcium mobilization and increased expression of myeloid-specific antigen CD11b and CD14. The extent of the differentiation was markedly reduced by desferrioxamine ($100\;{\mu}M$), dimethylthiourea (5 mM), N,N'-diphenyl-1,4-phenylenediamine ($2\;{\mu}M$), and N-acetyl-L-cysteine (5 mM). The induction of differentiation by hydroxyl radical was enhanced by 3-isobutyl-1-methylxanthine ($200\;{\mu}M$) and Ro-20-1724 ($8\;{\mu}M$), and inhibited by dipyridamole (2 ${\mu}M$). These results suggest that hydroxyl radicals may induce commitment of HL-60 cells to differentiate into more mature cells of myelomonocytic lineage through specific signal-transduction pathway that is modulated by phosphodiesterase inhibitors.

• 한국식품저장유통학회지
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• 제9권2호
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• pp.253-259
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• 2002

민들레 잎과 뿌리로부터 물추출물을 제조하여 항산화 활성 및 라디칼 소거활성을 분석하기 위하여 linoleic acid에 대한 과산화물 생성저해율, DPPH radical에 대한 소거활성, chemiluminescence를 이용한 hydroxyl radical에 대한 소거활성, EPR을 이용한 superoxide anion radical에 대한 소거활성및 hydrogen peroxide에 대한 소거활성을 측정하였다. 그 결과, 민들레 잎의 물추출물이 뿌리의 물추출물 보다 지방산에 대한 과산화물 생성 저해율이 높았고, DPPH radical, hydroxyl radical, superoxide anion radical 및 hydrogen peroxide에 대한 소거활성 역시 매우 높은 것으로 나타났다.

• 한국식품영양학회지
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• 제28권1호
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• pp.40-46
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• 2015

Hamcho (Salicornia herbacea) extracts were evaluated for total polyphenol content, antioxidant and pro-oxidant activities. The total polyphenol content was 1.81 g and 0.72 g per 100 g of dried sample in water and ethanol extracts respectively. Both water and ethanol extracts of Hamcho significantly exhibited antioxidant activity. The scavenging activity of hydroxyl radical was 13.8~26.2% and 14.2~16.0% in water and ethanol extracts respectively. The inhibitory effect of conjugated diene formation was 24.6~39.1% and 28.4~39.6% in water and ethanol extracts respectively. However, pro-oxidative effect was also observed in the Hamcho extracts. The Hamcho water extract showed the pro-oxidant effect by enhancing the formation of hydroxyl radical and conjugated diene. The ethanol extract of Hamcho induced conjugated diene formation at 0.5 mg/mL but not at 1 mg/mL. The hydroxyl radical formation was not induced by the Hamcho ethanol extract. Taken together, these results show that Hamcho extracts can act as pro-oxidants by generating hydroxyl radical or conjugated diene in addition to their antioxidant properties. Therefore, this study suggests that the physiological properties of Hamcho and its use as food materials should be considered with caution because antioxidant dietary plants such as Hamcho possess possible adverse effects induced by pro-oxidant activity.

• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.835-843
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• 2010

The objectives of this study were to investigate the effect of fermentation medium on the hydroxyl radical scavenging activity of exopolysaccharides from Inonotus obliquus by response surface methodology (RSM). A two-level fractional factorial design was used to evaluate the effect of different components of the medium. Corn flour, peptone, and $KH_2PO_4$ were important factors significantly affecting hydroxyl radical scavenging activity. These selected variables were subsequently optimized using path of steepest ascent (descent), a central composite design, and response surface analysis. The optimal medium composition was (% w/v): corn flour 5.30, peptone 0.32, $KH_2PO_4$ 0.26, $MgSO_4$ 0.02, and $CaCl_2$ 0.01. Under the optimal condition, the hydroxyl radical scavenging rate (49.4%) was much higher than that using either basal fermentation medium (10.2%) and single variable optimization of fermentation medium (35.5%). The main monosaccharides components of the RSM optimized polysaccharides are rhamnose, arabinose, xylose, mannose, glucose, and galactose with molar proportion at 1.45%, 3.63%, 2.17%, 15.94%, 50.00%, and 26.81%.

• 생약학회지
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• 제35권4호통권139호
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• pp.338-345
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• 2004

Scavenging effects of DPPH radical and hydroxyl radical, inhibition of linoleic acid oxidation, inhibition of NO synthesis and iNOS expression were tested with extracts and chromatographic subfractions of Canavalia lineata obtained at Jeju island. Chloroform extract and its subfractions gave moderate effects on scavenging DPPH radical and hydroxyl radical, They also inhibited linoleic acid oxidation, and NO synthesis. Inhibition of NO synthesis resulted from the repression of iNOS gene expression. Ethyl acetate extract and its subfractions showed excellent effects on scavenging DPPH radical and hydroxyl radical, while they were cytotoxic.

• Journal of Photoscience
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• 제9권2호
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• pp.138-141
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• 2002

A photo-labile compound which is bioinactive but, upon irradiation with light, yields bioactive species is called as "caged compound". Photolysis of caged compounds generating bioactive species, has become a general method to produce a desired amounts of bioactive species in the specific time interval at the desired place or area of the target biological systems. For this purpose, we designed and synthesized caged hydroxyl radical., "Photo-Fenton Reagent" NP-IIl. NP-IIl has a strong absorption maximum at 377 nm and yields hydroxyl radicals upon UV light irradiation. The antioxidant activity of the ${\alpha}$ -lipoic acid and other naturally occurring compounds has been examined by using NP-IIl as a molecular probe. For example, upon photoirradiation of NP-lII with BSA or apolipoprotein of human low density (LDL), the significant oxidative modifications were observed in both cases. The oxidation was completely suppressed in the presence of ${\alpha}$-lipoic acid, which clearly demonstrates the strong hydroxyl radical scavenging activity of ${\alpha}$-lipoic acid. Other applications of NP-lII will also be described

• 한국환경보건학회지
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• 제35권6호
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• pp.532-537
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• 2009

The tropospheric ozone production mechanism for the gas phase additive oxidation reaction of hydroxyl radical (OH) with isoprene (2-methyl-1,3-butadiene) has been studied using cavity ring-down spectroscopy (CRDS) at total pressure of 50 Torr and 298 K. The applicability of CRDS was confirmed by monitoring the shorter (~4%) ringdown time in the presence of hydroxyl radical than the ring-down time without the photolysis of hydrogen peroxide. The reaction rate constant, $(9.8{\pm}0.1){\times}10^{-11}molecule^{-1}cm^3s^{-1}$, for the addition of OH to isoprene is in good agreement with previous studies. In the presence of $O_2$ and NO, hydroxyl radical cycling has been monitored and the simulation using the recommended elementary reaction rate constants as the basis to OH cycling curve gives reasonable fit to the data.