• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.135-139
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• 1999

A new effective and economic method was developed, removing interferences such as chlorophyll and lipid from leaves with small amounts of reagents and solvents in order to analyse PAHs(Polycyclic Aromatic Hydrocarbons). The extract from a soxhlet containing $4{\sim}5g$ of leaves and 100ml of dichlormethane and refluxed for 20 hrs was concentrated and eluted with 60ml of a hexane:dichloromethane (1:1) mixture through a column of 9mm wide inner diameter and 130mm long, packed from the bottom with 2.5g of $Al_2O_3$, 1.5g of $SiO_2$and 2g of anhydrous $Na_2SO_4$. The eluent was concentrated and loaded on a GPC column of 20mm wide inner diameter and 280mm long, packed with 12g of Bio-beads. The column was washed with 37ml of the hexane:dichloromethane(1:1) mixture. Another 43ml of the mixture was eluted as a PAH fraction and collected. This eluent was concentrated under gentle nitrogen to $50{\mu}l$ and analysed using GC-MS. The recoveries, obtained by comparing with the amounts of the internal standards of deuterated PAHs were $43.3{\sim}107.5%$(RSD $2.2{\sim}9.5%$).

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.2
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• pp.236-241
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• 1997

Inhibitory effects of several edible plant extracts against 3-hydroxy-3-methylglutaryl coenzyme A(HMG-CoA) reductase, a rate-limiting enzyme in the biosynthesis of cholesterol, were screened. Inhibition rates of $10{\sim}15%$ were observed with hot water extracts of Allium fistulosum, Allium sativum and Cucurbita maxima. Methanol extracts of Aster scaber, Allium sativum, Zingiber officinale, Oenanthe javanica and Angelica keiskei effectively reduced the enzyme activity with inhibition rates of $29{\sim}51%$. The methanol extract of Angelica keiskei was fractionated sequentially with chloroform, ethyl acetate and n-butanol. Of the fractions ethyl acetate fraction showed the highest inhibition against the enzyme. $Luteolin-7-O-{\beta}-D-glucoside$ and hyperoside isolated from the ethyl acetate fraction of Angelica keiskei inhibited the enzyme activity by 65.5% and 14.8%, respectively, at the concentration of $30{\mu}M$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.5
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• pp.659-666
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• 1995

Fucoidans were isolated from Hizikia fusiformis and Sargassum fulvellum and characterized on their chemical properties. Crude fucoidans were extracted at $65^{\circ}C$ for 1hr with acid solution of pH 2.0, and cetylpyridinum chloride was used for partial purification. The yields of partially purified fucoidans were $2.51\%$ for H. fusiformis, and $65\%$ for S. fulvellum, respectively. The partially purified fucoidans were separated into 3 fractions by DEAE-Sephadex A-25 ion exchange column chromatography and the major fractions were refractionated with fractional preripitation with ethanol. $60-70\%$ ethanol precipitated fraction(P-70) of H. fusiformis and $60-65\%$ ethanol precipitated fraction(P-65) of S. fulvellum turned out to be homogeneous by cellulose acetate electrophoresis and gel filtration chromatography. The molar ratios of fucose, galactose, and sulfate In the purified fucoidans were 1 : 0.66 2.74 for H. fusiformis and 1 : 0.24. 1.46 for 5. fulvellum. The averaged molecular weights of the purified fucoidans from H. fusiformis and S. fulvellum were 26,000 and 105,000, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.8
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• pp.979-984
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• 2008

The stems of P etasites japonicus were extracted with ethanol and then partitioned with hexane, chloroform, ethyl acetate, n-butanol and water, successively. The antioxidant potency of five crude fractions were determined using (1) 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, (2) thiobarbituric acid reactive substances (TBARS) assay in the linoleic acid model system, and (3) lipoxygenase inhibition assay. Among the crude fractions, the ethyl acetate fraction exhibited the most potent antioxidant effect. By activity-guided fractionation, compound PJ-4 was isolated from the ethyl acetate fraction through the repeated silica gel open column chromatography. The chemical structure of the isolated compound was determined as kaempferol by $^1H-$ and $^{13}C$-NMR analysis and its antioxidative capacity was further investigated. DPPH radical scavenging activity of the compound was 65.76% at the concentration of $100 \;{\mu}g/mL$. The inhibitory activity of the compound against lipid peroxidation and lipoxygenase exhibited 43.47% and 58.60%, respectively at the concentration of $100\;{\mu}g/mL$. The result suggests that the compound may serve as a useful natural antioxidant and furthermore indicates the possibility of developing the stems of Petasites japonicus as a natural antioxidant source.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.1
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• pp.17-22
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• 1977

In the present paper, the effect of sodium sulfite treatment on tile inhibition of browning reactions occurring in the storage of dried oyster was tested and the supplementary effect of antioxidantsaddedwasalsomentioned. Dried oysters treated with sodium sulfite solutions as described in the previous paper(Lee and Choi, 1977) were stored in the bottles with silica gel bags at room temperature with or without the application of antioxidants. The ethanol solution of an antioxidant mixture(BHA, BHT, plus, synergists) was sprayed on the surface of cooked oyster before drying. The density of brown pigment was determined spectrophotometrically by measuring the absorbance at 420 and 440 nm of both fractions of pigment extract, namely chloroform-methanol and water soluble fractions, which represent the brown color developed by fat oxidation and Maillard reactions respectively. TBA value was also measured for the oxidative rancidity in oysters during the storage. It appeared from the results that the 0.5 M sodium sulfite-60minute treated samples showed better effect after 150 day storage at room temperature. Controlling tile pH of treating solutions, did not reveal so much different in inhibitory effect in the aspect of color but a more reduction of tyrosine and reducing sugar was resulted with acidic solution than with alkaline solution. The development of brown color in dried oyster seemed to be leaded rather by the oxidative rancidity of lipids than sugar-amino reactions particularly in a long-term storage since the browning of chloroform-methanol fraction progressed more rapidly than of water. soluble fraction. The application of antioxidant, therefore, could largely retard the browning of the product as appeared in the results that sodium sulfite treated oyster with addition of antioxidant kept the best color during the storage.

• Korean Journal of Pharmacognosy
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• v.33 no.3 s.130
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• pp.177-181
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• 2002

This study was carried out to investigate the antioxidative activities of Rosa davurica Pall for the purpose of development of novel antioxidant from natural products. Antioxidant activities of four different parts of Rosa davurica Pall such as fruit, leaf, stem and root were examined by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. The methanol extract from the root of Rosa davurica Pall showed the highest antioxidative activity among 16 samples tested. And, we also tested radical scavenging effects of 5 different extract compartments(Hexane, $CHCl_3$, EtOAc, BuOH and $H_2O$ fraction). EtOAc and BuOH fractions from the root of Rosa davurica Pall exhibited antioxidative activities higher to those of natural, ${\alpha}-tocopherol$ or synthetic antioxidants, BHT. The antioxidative substance of EtOAc fraction from the root of Rosa davurica Pall was successively purified with silica gel adsorption column chromatography and Sephadex LH-20 column chromatography. The purified active substance was isolated as crystal and identified as (+)-catechin by $^{l}H-NMR$ and $^{13}C-NMR$. This compound exhibited DPPH radical scavenging activity with the $IC_50$ value of $1.7\;{\mu}g/ml$. In the analysis of catechin content, the leaf extracts contained the highest catechin, and fruit extracts contained the lowest catechin. Considering antioxidative activity on DPPH assay, the extracts of Rosa davurica Pall showed a possibility to be used as a new material for natural antioxidant and functional food.

• Journal of Plant Biology
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• v.35 no.2
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• pp.117-123
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• 1992

The effect of benzyladenine (BA) on lipid peroxidation and compositions of total insoluble proteins and chloroplast thylakoid protein from wheat primary leaves during senescence in the dark was studied. BA ($10^{-5}\;M$) treatment prevented conspicuously the loss of chlorophyll content and soluble and insoluble leaf protein contents in senescing wheat leaf segments during 4-day dark incubation. Under the BA treatment, especially, the level of insoluble protein was highly maintained than that of soluble protein. Also, the increase of malondialdehyde (MDA: the peroxidation product of membrane lipids) content was inhibited in the BA treated leaves. Three major polypeptide bands in quantity corresponding to 57, 26 and 12 KD molecular weight were clearly resolved with other minor bands by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) in the insoluble protein fraction. The insoluble protein profiles of the control leaves showed a remarkable decrease in the intensity of the 57 and 12 KD band except for 26 KD band in the 72 h dark incubation. This loss during dark incubation was reduced by BA treatment. More than 20 polypeptides were resolved in the chloroplast thylakoid membrane fraction with the most prominent bands which are 59 and 57 KD ($\alpha\;and\;\beta$ subunit of coupling factor: CF) and 26 KD (apoprotein of LHCP). The changes in thylakoid protein profile during 72 h dark incubation showed the rapid degradation in control, but this degradation was prevented in quantity by BA treatment. The above results suggested that BA would inhibit the peroxidation of membrane lipids, thereby preventing the loss of membrane proteins which led to the maintenance of the membrane integrity including chloroplast thylakoid.

• Journal of the Mineralogical Society of Korea
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• v.25 no.4
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• pp.283-293
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• 2012

In order to have better insights into the chemical differentiation of Earth from its magma ocean phase to the current stratified structure, detailed information of crystallization kinetics of silicate melts consisting of the magma ocean is essential. The structural transitions in oxide glasses and melts upon crystallization provide improved prospects for a systematic and quantitative understanding of the crystallization processes. Here, we report the $^{27}Al$ 3QMAS NMR spectra for sol-gel synthesized $Al_2O_3$ glass with varying temperature and annealing time. The NMR spectra for the amorphous $Al_2O_3$ show well-resolved Al coordination environments, characterized with mostly $^{[4,5]}Al$ and a minor fraction of $^{[6]}Al$. The fraction of $^{[5]}Al$ in the alumina phase decreases with increasing annealing time at constant temperature. The NMR results of $Al_2O_3$ phases also imply that multiple processes (e.g., crystallization and/or changes in structural disorder within glasses) could involve upon its phase transition. The current results and method can be useful to understand crystallization kinetics of diverse natural and multi-component silicate glasses and melts. The potential result may yield atomic-level understanding of Earth's chemical evolution and differentiation from the magma ocean.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.842-849
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• 1997

This study was designed to investigate the antioxidative activity of enzymatic hydrolysates prepared from defatted anchor muscle by various pretenses. In these hydrolysates, the hydrolysates derived from pepsin and Protamex showed the strongest antioxidative activity. Enzymatic hydrolysates also showed the synergistic effects on antioxidative activity of $\alpha-tocopherol$, and almost no change in butylated hydroxytoluene (BHT). Peroxidation of metal ions $(Fe^{3+},\;Cu^{2+})$ was inhibited by enzymatic hydrolysates. Ten fractions (P-1 to P-10) were fractionated from the peptic hydrolysates by Amberlite IR-120 and Bio-gel P-2 column chromatography. The maximum antioxidative activity was observed in the traction P-2 (fraction No. $26\~31$). In amino acid composition of before and after hydrolysis of defatted anchovy muscle and the active fractions (P-2), contents of aspartic arid and glutamic acid were increased, but alanine, cysteine, tyrosine and phenylalanine were decreased.

• Korean Journal of Veterinary Research
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• v.41 no.1
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• pp.21-28
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• 2001

The protein of the bovine, horse and dog erythrocyte membrane were analyzed by polyacrylamide gel eletrophoresis in sodium dodecyl sulfate and their relation to the sedimentation rate of animal erythrocytes were investigated by treating the erythrocytes with proteinases such as trypsin and chymotrypsin. Protein content in erythrocyte membrane was in human, in Jindo dog, in cattle and in horse, showing similar in among. The erythrocyte sedimentation rates bovine erythrocytes from Hostein and Korean native cattle were very slow compared with the human one(1/7 as slow as the human one) as reported previously. Although the general protein profiles of the bovine erythrocyte membranes were almost similar to that of human, bovine erythrocyte membranes showed one additional protein band, called band Q in this study, which migrated electrophoretically to the mid-position between band 2 and band 3 in human erythrocyte membranes. The erythrocyte sedimentation of race horse were very fast compared with the human one are reported previously. Although the general protein profiles of the race horse erythrocyte membranes were almost similar to that of human, band 3 content was showing higher in race horse(34.7%) than in human(25.3%). The general protein profile of the Jindo dog erythrocyte membrane was almost similar to the human patterns, Jindo dog erythrocyte membranes showed one absent protein band. It was band 7. The glycoprotein profiles of the bovine erythrocyte membranes revealed by periodic acid-Schiff(PAS) stain showed a marked difference from that of human. The PAS-1(glycophorin) and PAS-2(sialoglycoprotein) present in human erythrocyte membrane were almost absent from the bovine erythrocyte membranes showed a strong PAS-positive band near the origin of the electraphorograms, which is named as PAS-B in this study. The PAS-1 and PAS-2 present in human erythrocyte membrane were almost absent from race horse erythrocyte membranes, but PAS-2 was more in only race horse from that of human. The PAS-1 and PAS-2 were absolutely absent from the Jindo dog erythrocyte membrane. These results suggest the slow sedimentation rate of bovine erythrocytes is due in part to the presence of band Q protein fraction and PAS-B glycoprotein in the bovine erythrocytes, and that the fast sedimentation rate of race horse erythrocyte is due in part to the presence of more band 3 protein fraction and PAS-E glycoproteins in the race horse erythrocytes.