• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.3
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• pp.326-333
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• 1984

The oxidation rate of krill lipids is very slow and no peroxides are accumulated even after long storage. By means of various chromatographic techniques and mass spectrophotometry, the primary antioxidant has been identified as ${\alpha}$-tocopherol. The phospholipid fractions did not show any antioxidative activity but peroxide-decomposing properties of total lipids depended upon the phospholipid contents. The peroxide-decomposing activities of phospholipids were due to the presence of polar materials generated during the storage. The most peroxide-decomposing fractions of oxidized krill lecithin by DEAE-cellulose column chromatography was low-molecule fraction (mean molecular weight: 182) and high-molecule fraction (mean molecular weight: 1942) was the next. The separation of peroxide-decomposing properties from low-molecule fraction was achieved by partitioning between chloroform and methanol/water. The methanol/water fraction showed strong peroxide-decomposing activities and main component of this fraction was assumed hydroxyamine compounds derived from choline.

• Biomedical Science Letters
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• v.16 no.3
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• pp.161-167
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• 2010

In this study, the biological activities of Glycyrrhiza uralensis were investigated, including antioxidative, fibrinolytic, thrombin inhibitory, and a-glucosidase inhibitory activity. The hot water extract of Glycyrrhiza uralensis was fractionated into hexane, $CHCl_3$, ethyl acetate, butanol, and water fractions, and each of these fractions were assayed individually. The water fraction showed the highest extraction yield of 19.45% (w/w). Using the DPPH method, the free radical scavenging activity was to be the strongest in the $CHCl_3$ fraction at 89.3%. Using the fibrin plate method, only the butanol fraction showed a substantial plasmin activity of 0.62 units/ml. In thrombin inhibitory activity tests, a 100-fold dilution of the ethyl acetate fraction showed the strongest activity of 46.9%. In the a-glucosidase inhibitory activity assay, a 100-fold dilution of the $CHCl_3$ fraction showed the strongest activity of 80.6%. In conclusion, the combined results of this study demonstrate that the extracts of Glycyrrhiza uralensis can be used as a material for the development of biofunctional foods for diabetics.

• Preventive Nutrition and Food Science
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• v.15 no.1
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• pp.36-43
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• 2010

The purpose of this study was to investigate the phenolic acid, proanthocyanidin (PAs), and flavonol glycoside contents, as well as the antioxidant activities of pine needle extracts from six species of young pine trees. The extracts were prepared from Section Pinus (Diploxylon): P. densiflora, P. sylvestris, P. pinaster and P. pinea, and Section Strobus (Haploxylon): P. koraiensis and P. strobus. Phenolics were extracted from pine needles with 80% acetone to obtain the soluble free fraction, and insoluble residues were digested with 4 M NaOH to obtain bound ethyl acetate and bound water fractions. Phenolics were analyzed by HPLC, and the hydrophilic antioxidant activity was measured using oxygen radical absorbance capacity (ORAC). Total phenolic and flavonoid contents of the soluble free fraction were higher than those of the bound ethyl acetate and bound water fractions. The main phenolics were monomers and polymers of PAs in the soluble free fraction, and phenolic acids and flavonol glycosides in bound ethyl acetate fraction. Flavonol glycosides found in different species of pine needles were qualitatively similar within fractions, but composition varied among Pinus sections. High levels of kaempferol arabinoside and an unknown compound were present in all Strobus species. The soluble free fraction had the highest antioxidant activity, followed by bound ethyl acetate and bound water fractions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.6
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• pp.1321-1325
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• 1999

The inhibitory effect of Ramaria botrytis on the mutagenicity in Salmonella assay and cytotoxicity on cancer cell were studied. Ramaria botrytis methanol extracts showed antimutagenic effects of 60~90% on B(a)P and AFB1 in S. typhimurium TA98 and TA100. These extracts showed 73~85% antimutagenicity on TA100 against MNNG. The methanol extracts with strong antimutagenic activities were further fractionated by ethylacetate and water, the ethylacetate fraction were found to be stronger antimutagen icity against MNNG than water fraction. Ramaria botrytis methanol extracts and ethylacetate fraction revealed the highest cytoxicity against HT 29 human colon adenocarcinoma cells in which cell growth was inhibited by 57~88% and 69~94% at 0.25~1.0mg/ml, respectively. These methanol extract and ethyl acetate fraction exhibited 53~79% and 66~87% inhibition against HepG2 human hepatocarcinoma cells, respectively. But water fraction showed only 10~24% inhibition. However, these extract and fractions did not show cytotoxic effect against human chang liver cells. From these results, it is considered that Ramaria botrytis has stronger antimutagenic and anticancer effects in vitro.

• Korean Journal of Pharmacognosy
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• v.42 no.2
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• pp.195-200
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• 2011

In this study, we investigated on antioxidative activity, tyrosinase inhibitory activity and nitric oxide(NO) production inhibitory activity in the hot water extract of Taraxacum coreanum and its fractions. The total polyphenol and flavonoid contents of the extract were found to be 65.42 mg/g and 9.83 mg/g, respectively. And the total polyphenol and flavonoid contents of the ethyl acetate fraction were found to be 168.23 mg/g and 31.92 mg/g, respectively. In DPPH radical scavenging ability, $SC_{50}$ values of the ethyl acetate and butanol fraction were exhibited 64.65 ${\mu}g/ml$ and 277.42 ${\mu}g/ml$, respectively. Moreover, ethyl acetate fraction showed higher inhibitory activity than other samples in tyrosinase inhibitory activity. In NO production inhibitory activity, the extract and its fractions showed NO production inhibitory effect. Especially, the ethyl acetate, chloroform and butanol fraction was exhibited higher NO production inhibitory activity than other samples. As a result, the ethyl acetate and butanol fraction from the water extract of T. coreanum could be applicable to functional materials for skin-related fields.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.6
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• pp.429-445
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• 2008

Two-phase compressible flow fields of air-water are investigated numerically in the fixed Eulerian grid framework. The phase interface is captured via volume fractions of each phase. A way to model two phase compressible flows as a single phase one is found based on an equivalent equation of states of Tait's type for a multiphase cell. The equivalent single phase field is discretized using the Roe‘s approximate Riemann solver. Two approaches are tried to suppress the pressure oscillation phenomena at the phase interface, a passive advection of volume fraction and a direct pressure relaxation with the compressible form of volume fraction equation. The direct pressure equalizing method suppresses pressure oscillation successfully and generates sharp discontinuities, transmitting and reflecting acoustic waves naturally at the phase interface. In discretizing the compressible form of volume fraction equation, phase interfaces are geometrically reconstructed to minimize the numerical diffusion of volume fraction and relevant variables. The motion of a projectile in a water-filled tube which is fired by the release of highly pressurized air is simulated presuming the flow field as a two dimensional one, and several design factors affecting the projectile movement are investigated.

• YAKHAK HOEJI
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• v.51 no.6
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• pp.500-507
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• 2007

To investigate the possibility of development as a whitening agent using bamboo extracts (Phyllostachys nigra var. henonis), we measured DPPH assay, NBT/XO assay, intracellular ROS scavenging assay, tyrosinase assay and MSH-induced melanin production in B-16 cells. Bamboo extracts had dose-dependently anti-oxidant activity in DPPH, NBT/XO and intracellular ROS assay. Bamboo extracts appear to inhibit xanthine oxidase directly. Bamboo extracts inhibited not only purified tyrosinase activity but also inhibited tyrosinase activity and melanin production in B16 melanoma cells stimulated by $1{\mu}M\;{\alpha}$-MSH. Anti-oxidant activity and cytotoxicity of ethyl acetate fraction was more potent than those of water fraction, whereas whitening effect of water fraction was stronger than ethyl acetate fraction. Therefore, these results suggest that water fraction of bamboo extracts may be useful for the development as whitening agents reducing cytotoxicity.

• The Korean Journal of Food And Nutrition
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• v.34 no.3
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• pp.289-294
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• 2021

The antioxidant activity and α-glucosidase inhibitory activity of the solvent fraction fractionated from the methanol extract of Saururus chinensis Baill were examined. As a result of measuring the yields of methanol, hexane, chloroform, ethylacetate, butanol, and water fractions, the extraction yield of fraction was 18.60, 3.38, 24.03, 7.75, 8.11 and 62.57%, respectively. The total polyphenol content of the methanol extract of Saururus chinensis Baill was 13.40, 4.62, 7.39, 31.24, 25.76 and 5.64 mg GAE/g, respectively. DPPH radical scavenging activity (IC_50%) results were 20.81, 5.47, 10.15, 22.63, 19.68 and 21.06 ug/mL, respectively, and hydroxyl radical scavenging activity (IC_50%) results were 15.81, 2.69, 8.84, 12.80, 3.70 and 3.39 ug/mL. Hydrogen peroxide scavenging activity scavenging activity measurement (IC_50%) showed 33.63, 8.88, 16.93, 32.84, 33.79, and 33.71 ug/mL in methanol, hexane, chloroform, ethyl acetate butanol, and water fractions, respectively. The α-glucosidase inhibitory activity of the solvent fraction fractionated with the methanol extract of 300 sec was measured for the α-glucosidase inhibitory activity of methanol, hexane, chloroform, ethyl acetate butanol, and water fraction, respectively, 15.85, 10.84, 15.74, 24.90, 2.58 and 35.70%.

• Korean Journal of Food Science and Technology
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• v.39 no.4
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• pp.447-451
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• 2007

This study was carried out to examine the antioxidant activity of Gynostemma pentaphyllum Makino. Using the DPPH method, we found that free radical scavenging activity was strong in all the fractions except the water fraction of the water extract (GPW) and ethanol extract (GPE) of G pentaphyllum Makino. Pseudo-SOD activity was highest in the diethyl ether fraction of the ethanol extract, while the other fractions of the ethanol and water extracts were lower. For xanthine oxidase inlribition activity, the diethyl ether fraction and butanol fraction of GPW, and the diethyl ether fraction and butanol fraction of GPE, showed activities over 80%. Nitrite scavenging ability was strong (over 60%) in all the GPW and GPE fractions. The diethyl ether fraction and butanol fraction of GPW had more effective nitrite scavenging abilities than the other extract fractions. These results suggest that the extracts of G pentaphyllum Makino can be used as a functional material in a tea or drink.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2626-2631
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• 2007

Air-water two phase natural circulation flow in the T-HERMES (Thermo-Hydraulic Evaluation of Reactor cooling Mechanism by External Self-induced flow)-1D experiment has been evaluated to verify and evaluate the experimental results by using the RELAP5/MOD3 computer code. The RELAP5 results have shown that an increase in the coolant inlet area leads to an increase in the water circulation mass flow rate. However, the water outlet area does not effective on the water circulation mass flow rate. As the coolant outlet moves to a lower position, the water circulation mass flow rate decreases. The water level is not effective on the water circulation mass flow rate. As the height increases in the air injection part, the void fraction increases. However, the void fraction in the upper part of the air injector maintains a constant value. An increase in the air injection mass flow rate leads to an increase in the local void fraction, but it is not effective on the local pressure.