• Korean Journal of Pharmacognosy
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• v.37 no.4 s.147
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• pp.307-313
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• 2006

Reactive oxygen species (ROS) and formation of advanced glycation end products (AGEs) play an important role in the pathogenesis of diabetic nephropathy by hyperglycemia. To find natural agents improving diabetic nephropathy, 63 natural resources which used to the treatment of diabetes mellitus in a folk remedy were investigated with an in vitro system employing radical scavenging activity and inhibitory activity of AGEs formation. In results, the extracts of Aspalathus linearis, Rubus coreanus, Rosa rugosa, and Epimedium koreanum significantly inhibited the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical with $IC_{50}$ values less than $10{\mu}g/ml$. The extracts of Zea mays, Cucurbita moschata, Cudrania tricuspidata, and Aspalathus linearis effectively reduced the formation of AGEs compared with the positive control $N-acetyl-_L-cystenine$ (NAC) and aminoguanidine (AG). In addition, the extracts of Aspalathus linearis, Commelina communis, Cornus officinalis, and Lespodeza cuneata showed the all inhibitory activity against DPPH radical and AGEs formation. Also, these resources definitely showed the radical scavenging activity against peroxynitrite $(ONOO^-)$ and hydroxyl radical $({\cdot}OH)$ relating to high glucose-induced ROS production. Thus, these results suggest that some natural resources may regulate the initiation and progression of diabetic nephropathy through inhibition of ROS production and AGEs formation.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.198.2-198.2
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• 2016

Reactive oxygen and nitrogen species (RONS) can be generated by using non-thermal atmospheric pressure plasma jet which have profound biomedical applications [1, 2]. In this work, reactive oxygen species like hydroxyl radical (OH) are generated by using non-thermal direct plasma jet above water surface using Ar gas and their properties have been studied using ultraviolet absorption spectroscopy. OH radicals are found to be generated simultaneously with the discharge current with concentration of $2.7{\times}1015/cm3$ at 7mm above water surface while their persistence time have been measured to be $2.8{\mu}S$. In addition, it has been shown that plasma initiated ultraviolets play a major role to generate RONS inside water. Further works are going on to measure the temporal behavior of OH and $O2^*-$.

• Korean Journal of Medicinal Crop Science
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• v.15 no.5
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• pp.335-338
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• 2007

Five samples (Bakwoonbae, Chungsilbae, Sandolbae, Dolbae, and Chuwhangbae) of Pyrus species differing in their origin of production were analyzed for total phenolic content, vitamin C content, and antioxidant activities. Two antioxidant activities were measured by the free-radical scavenging activity and reducing power method. Total phenolic content of the Chungsilbae extract (20.35 mg/g) was higher than those of other pears. Vitamin C content in five Pyrus species ranged from $420.32\;{\mu}g/g$ in Sandolbae to $659.75\;{\mu}g/g$ in Bakwoonbae. Chungsilbae also had the highest free radical scavenging activity (76.56%) and reducing power (0.35).

• 한국연소학회:학술대회논문집
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• 1997.06a
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• pp.1-11
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• 1997

The soot and OH radical distributions have been experimentally studied in ethylene and propane laminar diffusion flames. The integrated soot volume fraction was measured along the centerline of a flame using a laser light extinction method. Planar laser light scattering and PLIF techniques are employed for the soot and OH radical distribution measurements utilizing Nd:YAG laser and OPO, FDO system. The concentration of OH radical is rapidly decreased at the edge of sooting region, which implies the importance of OH radical species on the soot oxidation process. For ethylene flames, the addition of air in fuel moves the OH radical distribution towards the center line of a flame at the soot oxidation region, while the concentration of OH radical remains relatively high at the soot formation region. The interaction between soot particles and OH radicals becomes more active with fuel-air at the soot oxidation region. For propane flames, however, any indication of the increased interaction between soot particles and OH radicals with fuel-air was not noticed.

• Journal of the Korean Applied Science and Technology
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• v.36 no.3
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• pp.985-994
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• 2019

Muberry (Morus alba L.) leaves fermented with Hericium erinaceum mycelium (MA-HE) were assessed for the protection against oxidative modification of antioxidant enzymes, Cu,Zn-superoxide dismutase(SOD) and ceruloplasmin(CP). MA-HE were shown to significantly inhibited oxidative modifications and inactivations of Cu,Zn-SOD and CP induced by peroxyl radical. Antioxidant activity of MA-HE evaluated using peroxyl radical scavenging assays. MA-HE showed 44.03% of peroxyl radical scavenging activity at $100{\mu}g/mL$. Thus, MA-HE protect the antioxidant enzymes from oxidative damage by the scavenging peroxyl radicals. The results suggested that MA-HE was effectively removed reactive oxygen species in cells, thereby protecting cytotoxicity caused by oxidative stress.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1135-1139
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• 2017

Spatial distribution of chemical species in flame is a important indicator understanding the flame structure and combustion characteristics, and optical emission spectroscopy has been widely used for the measurement because of its simple and non-intrusive methodology. In this study, we suggest the feasibility of the measurement of chemical species (OH radical) distribution in rocket plume using optical emission spectrometer which was developed for the spatially resolved measurement along the line-of-sight. In order to predict the ground state concentration of species from the measured emission intensity by optical emission spectrometer, we consider thermal and chemical excitation mechanisms in flame, and assume thermodynamic equilibrium for the thermally excited species. We also present the spatial resolution and the correction of collection characteristics of the optical emission spectrometer depending on object distance.

• Korean Journal of Plant Resources
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• v.21 no.2
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• pp.128-133
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• 2008

This study was conducted to compare the antioxidative effects of Dendranthema zawadskii var. latilobum (Maxim.) Kitam and D. zawadskii var. yezoense (Maek.) Y.M. Lee & H.J. Choi due to the harvest date. Harvested samples at May 9th (early), July 17th (middle) and September 3rd (late stage) were extracted with 80% ethanol, and biological activities and antioxidant substance contents were detected. The earlier harvested samples showed the higher moisture contents and extraction yields. DPPH radical scavenging effect of early harvested D. zawadskii var. latilobum (Maxim.) Kitam ($RC_{50}$ = $0.128\;mg\;{\cdot}\;mL^{-1}$) was similar to BHT ($0.121\;mg\;{\cdot}\;mL^{-1}$). ABTS radical scavenging effects of both species harvested at early stage were higher than that of ascorbic acid which was well-known natural antioxidant. However, both species harvested at late stage showed the highest $Fe^{2+}$ chelating effect, but it was lower than that of EDTA. Total polyphenol and flavonoid contents of both species were higher when samples were harvested earlier stage. However, both species harvested at early stage contained more total polyphenols (79.93 and $75.10\;mg\;{\cdot}\;g^{-1}$) than flavonoids (57.84 and $54.91\;mg\;{\cdot}\;g^{-1}$).

• FLOWER RESEARCH JOURNAL
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• v.17 no.4
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• pp.271-278
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• 2009

The attempts to develop natural antioxidants have been made with aerial part of 16 Compositae species by analyzing their phenolic compound contents, scavenging activities on 1,l-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals, ferrous ion chelating effects and inhibition effects on peroxidation of linoleic acids. Total polyphenol and flavonoid contents were highest in Matricaria recutica. Scavenging activity on DPPH and ABTS radicals were highest with extracts of Echinacea angustifolia and Serratula coronata var. insularis f. insularis, respectively. Aerial palt extracts of all species showed lower DPPH scavenging activity than ascorbic acid and 2,6-Di-tert-butyl-4-methylphenol (BHT). But Serratula coronata var. insularis f. insularis demonstrated higher ABTS scavenging activity than ascorbic acid and BHT. In Hieracium pilosella, Echinacea angustifolia, Matricaria reculica extracts showed higher ABTS scavenging activity than BHT. Ferrous ion chelating effects was highest with Matricaria recutica extract, but the effects were much lower than ethylenediaminetetraacetic acid (EDTA). The inhibition activity in lipid peroxidation of linoleic acids was highest in Eupatorium japonicum with 90.06% inhibition 4 days after reaction and 40.52% after 24 days. This demonstrated higher inhibition activity and longer lasting than BHT. Aerial part of Matricaria recutica for extraction source, rather than flower, has higher potential for antiox.idant material. In conclusion, development of natural antioxidants in Compositae is possible by studying antioxidant activity of each species.

• The Journal of Korean Medicine
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• v.28 no.1 s.69
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• pp.148-158
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• 2007

Objective : The objective of this study was to investigate the antioxidant effects of Mori Folium extract. Methods Total antioxidant status was examined by total antioxidant capacity(TAC) and total antioxidant response(TAR) against potent free radical reactions. The effect of Mori Folium extract was examined by measuring total phenolic content, concentration at which 1,1-dipheny1-2-picrylhydrazyl(DPPH) radical scavenging activity was inhibited, inhibitory effect on lipid peroxidation, and the effect on reactive oxygen species(ROS) generation. Results : 1. TAC and TAR of Mori Folium extract at the concentration of 5 mg/ml were 1.61 and 1.24 mM Trolox equivalents, respectively. 2. Total phenolic content of Mori Folium extract at the concentration of 5 mg/Ml was 1.70 mM gallic acid equivalent. 3. Concentration of Mori Folium extract at which DPPH radical scavenging activity was inhibited by 50% was 2.29 m9/m4 as compared to 100% by Pyrogallol solution as a reference. 4. The inhibitory effect of the extract on lipid peroxidation was examined using rat liver mitochondria induced by FeSO$_4$/ascorbic acid. Mori Folium extract at the concentration of 10 mg/ml significantly decreased thiobarbituric acid reactive substances(TBARS) concentration. The extract prevented lipid peroxidation in a dose-dependent 5. The effect of Mori Folium extract on reactive oxygen species(ROS) generation was examined using a celt-free system induced by hydrogen peroxide FeSO$_4$. Addition of 1 mg/ml of Mori Folium extract significantly reduced dichlorofluorescein(DCf) fluorescence. The extract caused concentration-dependent attenuation of the increase in DCF fluorescence, indicating that the extract significantly prevented ROS generation in vitro. Conclusion ; The antioxidant effects of Mori Folium extract seem to be due, at least in part, to the prevention offree radical-induced oxidation, fllowed by inhibition of lipid peroxidation.

• Korean Journal of Medicinal Crop Science
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• v.18 no.3
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• pp.201-207
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• 2010

This study was carried out to obtain the information on the antioxidant activity of Phyllanthus. We compared and analyzed three indigenous collections of Phyllanthus: species from Korea, Brazil and Paraguay. Total phenolic acid contents were $1.93{\pm}0.015$ mg/mL in KCS (Korean Collection Species), $1.65{\pm}0.003$ mg/mL in PCS (Paraguay Collection Species) and $1.49{\pm}0.003$ mg/mL in BCS(Brazil Collection Species). In both DPPH radical scavenging activities and SOD-liked activities, KCS was the highest ($67.25{\pm}0.03%,\;78.38{\pm}1.17%$). KCS were also the highest in hydroxyl radical scavenging activities ($95.80{\pm}0.17%$). It turned out that there was no meaningful difference between BCS ($81.64{\pm}0.23%$) and PCS ($81.54{\pm}0.04%$). As for hydrogen radical scavenging activities, there was no statistically meaningful difference between KCS ($36.44{\pm}0.24%$) and BCS ($36.31{\pm}0.33%$) and it was the lowest in PCS ($33.72{\pm}0.15%$). Our results showed that KCS excelled the others not only in antioxidant activity but also in other beneficial effects. This encouraging results may be potentially useful in developing Phyllanthus urinaria L. variety which contains lots of functional elements such as total phenolic acid.