• Journal of Applied Biological Chemistry
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• v.58 no.2
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• pp.109-112
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• 2015

Fruits of Rhus parviflora were extracted with 80% aqueous methanol (MeOH), and the concentrated extract was partitioned using ethyl acetate (EtOAc), n-butanol (n-BuOH), and $H_2O$, successively. Purification of EtOAc fraction led to isolation of fifteen polyphenols of which structures were identified by spectroscopic methods including 2D-NMR. Most compounds apart from compound 10 inhibited low density lipoproteinoxidation within $IC_{50}$ value of $10{\mu}M$. Among compounds, taxifolin (2), quercetin 3-O-${\alpha}$-L-rhamnopyranoside (13), agathisflavone (5) sulfuretin (4), and aureusidin (3) showed $IC_{50}$ values 0.9, 0.8, 5.8, 2.9, and $2.4{\mu}M$ which were of highly significant in comparison positive control butylated hydroxytoluene with $IC_{50}$ value of $2.1{\mu}M$. The results indicate fruits of R. parviflora as a source of antihypercholesterolemic compounds.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2537-2543
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• 2011

A self-assembled Al-bridged diiminopyridine-based ligand (3) was synthesized and characterized by FT-IR, ESI-MS and NMR spectroscopy. Electron spectral titrations were performed to confirm the formation of a novel trinuclear bis(imino)pyridyl iron(II) complex (4) upon addition of $FeCl_2$ into Al-bridged ligand 3 in methanol solution. Simultaneously, a typical bis(imino)pyridine-iron(II) complex (2) was synthesized and fully characterized. The X-ray crystal study of the iron(II) complex 2 disclosed a five-coordinate, distorted square-pyramidal structure with the tridentate N^N^N ligand and chlorides. The optimal molecular structure of 4 was obtained by means of molecular mechanics, which showed that each iron atom in the complex 4 is surrounded by two chlorides, a tridentate N^N^N ligand and one oxygen atom, supporting considerations about the possibility of six-coordinate geometry from MMAO or the ethylene access. A comparison of 4 with the reference 2 revealed a remarkable decrease of the catalytic activity and MMAO consumption (activity up to $0.41{\times}10^3\;kg\;{mol_{Fe}}^{-1}h^{-1}bar^{-1}$, Al/Fe = 650 for 4 and $7.02{\times}10^3\;kg\;{mol_{Fe}}^{-1}h^{-1}bar^{-1}$, Al/Fe = 1600 for 2).

• KSBB Journal
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• v.19 no.1
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• pp.57-61
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• 2004

A peroxynitrite is formed when superoxide and nitric oxide exist at near eqimolar ratio in biological systems. Although not a free radical by chemical nature, peroxynitrite is a powerful oxidant having a wide array of tissue damaging effects ranging from lipid oxidation and inactivation of enzymes and ion channels through protein oxidation and nitration to inhibition of mitochondrial respiration. During our search for new antioxidizing components from natural resources, twenty salt marsh plants were screened for their ONOO and DPPH radical scavenging activities. Among them, methanol extract of Rosa rugosa, lxeris tamagawaensis, Erigeron annus, Tetragonia tetragonoides, Imperata cylindrica, and Suaeda japonica inhibited more than 85% of peroxynitrite produced by 3-morpholinsydnonimine (SIN-1) at a concentration of 5 $\mu\textrm{g}$/$m\ell$. In addition, Rosa rugosa, Artemisia capillaris, Erigeron annus and Ixeris tamagawaensis showed significant scavenging effect against DPPH (1,1-diphenyl-2-picrylhydrazyl radical).

• The Korea Journal of Herbology
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• v.23 no.4
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• pp.121-134
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• 2008

Objectives: Melia toosendan(MT) has been used as a traditional Korean herbal medicine, and today it is used as a medication for colic, side aches, heartache and other disorders of liver. The aim of this study was to determine whether fractionated extracts of MT inhibit free radical generation such as DPPH radical, superoxide radical and nitric oxide, production of nitrite, an index of NO, PGE2, iNOS, COX-2 and proinflammatory cytokines in lipopolysaccharide(LPS)-treated RAW 264.7 macrophages. Methods: MT extract prepared with methanol, and then fractionated with hexane, dichloromethane, ethylacetate, n-butanol and water. Inhibitory effect of MT onto free radical generation was determined by measuring DPPH, superoxide anions and nitric oxide scavenging activities in vitro. Cytotoxic activity of extracts on RAW 264.7 cells was measured using 5-(3-caroboxymeth-oxyphenyl)-2H-tetra-zolium inner salt(MTS) assay. Intracelluar oxidation was analysed by DCF-DA assay. The nitric oxide(NO) production was measured by Griess reagent system. The levels of iNOS and COX-2 expression were confirmed by western blot. And pro inflammatory cytokines were measured by ELISA kit. Results: Our results indicated that fractionated extracts, especially dichloromethane and ethyl acetate extracts, significantly inhibited free radical generation, the LPS-induced $H_2O_2$, NO, $PGE_2$ production and iNOS, COX-2 expression accompanied by an attenuation of TNF-${\alpha}$, IL-1${\beta}$ and IL-6 formation in macrophages. Conclusions: These results indicate that dichloromethane and ethyl acetate extracts of MT have potential as an agent of chronic inflammatory diseases.

• Journal of Life Science
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• v.12 no.2
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• pp.144-150
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• 2002

This experiment was designed to investigate the antioxidant effects of Chrysanthemum coronarium L. (CC) fractions on the liposomal phospholipid membranes. The sample CC was extracted and fractionated into five different types, methanol (CCMM), hexane (CCMH), ethylacetate (CCMEA), butanol (CCMB), and aqueous (CCMA) fractions. The antioxidant activities of CC fractions in oxidized dilinoleoylphosphatidylcholine (DLPC) liposomes were examined by spectrophotometry measuring conjugated dienes. The oxidation indices of five CC fractions exhibited weaker antioxidant activities than that of BHT in oxidized DLPC liposomes, however, showing much similar antioxidant activities of $\alpha$-tocopherol in the oxidized DLPC liposomes, which is known as a potent antioxidant. Among CC fractions, CCMM and CCMA in oxidized DLPC liposomes showed rather effective than $\alpha$-tocopherol after 2 h. These results strongly indicate that bioactive substances in CC fractions have a kind of function as potent antioxidants against biomembrane oxidation.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1137-1144
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• 2013

$TiO_2$ composites with seven different carbon materials (activated carbons, graphite, carbon fibers, single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene oxides, and reduced graphene oxides) that are virgin or treated with nitric acid are prepared through an evaporation method. The photocatalytic activities of the as-prepared samples are evaluated in terms of $H_2$ production from aqueous methanol solution (photo-catalytic reduction: PCR) and degradation of aqueous pollutants (phenol, methylene blue, and rhodamine B) (photocatalytic oxidation: PCO) under AM 1.5-light irradiation. Despite varying effects depending on the kinds of carbon materials and their surface treatment, composites typically show enhanced PCR activity with maximum 50 times higher $H_2$ production as compared to bare $TiO_2$. Conversely, the carbon-induced synergy effects on PCO activities are insignificant for all three substrates. Colorimetric quantification of hydroxyl radicals supports the absence of carbon effects. However, platinum deposition on the binary composites displays the enhanced effect on both PCR and PCO reactions. These differing effects of carbon materials on PCR and PCO reactions of $TiO_2$ are discussed in terms of physicochemical properties of carbon materials, coupling states of $TiO_2$/carbon composites, interfacial charge transfers. Various surface characterizations of composites (UV-Vis diffuse reflectance, SEM, FTIR, surface area, electrical conductivity, and photoluminescence) are performed to gain insight on their photocatalytic redox behaviors.

• Journal of Korean Vacuum Science & Technology
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• v.2 no.2
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• pp.63-77
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• 1998

The oxidation of NiAl(110) was investigated in the temperature regime between 300K and 1300 K using LEED (low energy electron diffraction), TPD (temperature programmed desorption) and HREELS (high resolution electron energy loss spectroscopy). The adsorption of N2O and O2 up to reconstructions. Stepwise annealing of the oxygen-saturated sample from 600 K to 1300K in UHV (ultra-high vacuum,) results in firstly the onset of randomly oriented then finally fairly well-ordered. 5 ${\AA}$ Al2O3 film with quasi-hexagonal periodicity. Ordered thicker oxide films of 18-30 ${\AA}$ seem to be grown on this interfacial oxide layer by direct oxidation of sample at elevated temperature between 1150 and 1300 K because of the LEED pattern consisting of new broad hexagonal spots and the previous 5 ${\AA}$ spots. Although the periodicity of surface oxygen arrays shows no significant change from an hexagonal close-packing, the O-O distance changes from ∼3.0 ${\AA}$ film to ∼2.9 ${\AA}$ for thicker oxides. with the appearance of Auger parameter, for the 5${\AA}$ film can be described better as an interfacial oxide layer. The observation of three symmetric phonon peaks can be also a supporting evidence for this phase assignment since thicker oxide films on the Same Ni2Al3(110) show somewhat different phonon structure much closer to that of the ${\gamma}$-Al2O3. The adsorption/desorption of methanol further proves the preparation of less-defective and/or oxygen-terminated Al2O3 films showing ordered phase transitions with the change of oxide thickness between 5 ${\AA}$ to 30 ${\AA}$.

• Ocean and Polar Research
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• v.43 no.3
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• pp.113-126
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• 2021

In the present study, the halophyte C. falcatum extract and its solvent fractions (n-hexane, 85% aqueous methanol, n-butanol, and water) were evaluated for antioxidant and anti-inflammatory activities. Antioxidative ability was measured by DPPH radical, intracellular reactive oxygen species (ROS) and peroxynitrite scavenging, DNA oxidation inhibition, and ferric reducing antioxidant power (FRAP). For DPPH radical and peroxynitrite scavenging, DNA oxidation inhibition, and FRAP, 85% aq.MeOH and n-BuOH fractions showed significant scavenging activity. For production of intracellular ROS in HT-1080 cells, 85% aq.MeOH fraction showed the highest scavenging activity. In addition, anti-inflammatory activity was also assessed by measuring the inhibitory effect against mRNA expression of pro-inflammatory factors (NO, IL-1β, IL-6 and COX-2) in LPS-stimulated Raw 264.7 macrophages. For NO production, crude extract exhibited a strong inhibitory effect at a concentration of 100 ㎍/ml. For mRNA expression of pro-inflammatory cytokines (IL-1β, IL-6, and COX-2), n-BuOH greatly suppressed expression levels of IL-1β and IL-6 at 100 ㎍/ml concentration while 85% aq. MeOH fraction significantly inhibited that of COX-2 even at 100 ㎍/ml. These results suggest that C. falcatum may be used as a potential source for the development of a natural antioxidant or anti-inflammatory agent.

• Journal of Life Science
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• v.21 no.5
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• pp.746-752
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• 2011

The contents of bioactive materials (e.g. polyphenolics compounds, flavonoids, minerals, and fatty acids) and antioxidative activities (DPPH (${\alpha}$,${\alpha}$'-diphenyl-${\beta}$-picrylhydrazyl) free radical scavenging activity, peroxidation of linoleic acid and rat hepatocyte microsome, and Fe/Cu reducing power) were tested by in vitro experimental models using water, ethanol and methanol extracts of leaves (TOL) and fruits (TOF) from Thuja orientalis. Methanol extract from TOL showed the highest extraction yield (12.90%) as well as contents of polyphenolic compounds (16.02%) and flavonoids (0.25%). Major minerals were Ca, K, and Mg. Major fatty acids were palmitic and lauric acids in TOL and palmitic and decanoic acids in TOF. In oxidation of in vitro models using DPPH free radical scavenging activity, Fe/Cu reducing power, $Fe^{2+}$/ascorbate-induced linolenic acid peroxidation by ferric thiocyanate and thiobarbituric acid (TBA) methods, and autooxidation of rat hepatic microsomes membrane, anti-oxidative activities were stronger in all extracts of TOL than in those of TOF in a dose-dependent manner. From these results, methanol extract of TOL was shown to have the most potent anti-oxidative properties and the highes content of antioxidative compounds such as polyphenolic compounds and flavonoids.

• Food Science and Preservation
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• v.17 no.1
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• pp.107-116
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• 2010

We prepared extracts from Ulmus davidiana (root, Korean source; URK) and Ulmus davidiana (bark, Korean source; UBK). URK extracts obtained with all tested solvents showed the highest antioxidant effects on fish oils. Both treatments containing 0.1% (v/v) extract from URK and UBK each showed that peroxide values of 30 meq/kg were maintained for 6 h and levels of 40 meq/kg were apparent for up to 18 h, indicating that antioxidative activity seemed to sustain during all tested time periods. Compared with commercial antioxidants, butanol and methanol extracts diluted to 0.05% (v/v) had similar antioxidative effects. Water and butanol UBK extracts diluted to 0.1% (v/v) both showed the highest antioxidative activities. After addition of metal ions, methanol and butanol URK extracts diluted to 0.1% (v/v) showed enhanced antioxidative activity. UBK ethanol extracts displayed superior antioxidative activity and a constant peroxide value throughout storage. However, in the case of Perilla oil, $\alpha$-tocopherol which is known as a natural antioxidant did not show any antioxidative activity except in the BHT. Methanol and butanol URK extracts diluted to 0.2% (v/v) showed superior antioxidative activities throughout the experiment. A methanolic UBK extract (0.2%, v/v) also had a similarly increased antioxidative effect. In tests involving addition of metal ions to all extracts, the methanolic UBK extract (0.2%, v/v) showed excellent antioxidative activity. When lard was tested, antioxidant levels did not differ significantly among extracts prepared using four different solvents at either 0.05% or 0.1% concentrations (both v/v). Addition of metal ions at levels of 0.05% or 0.1% (w/v) to these extracts had no significant additive effect on oxidation.