• Journal of Nutrition and Health
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• v.32 no.4
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• pp.376-383
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• 1999

The effects of $\beta$-carotene substitutionl for vitamin A and the chronic consumption of ethanol of ethanol on hepatic folate metabolism were studied it rats. The substitution of $\beta$-carotene for vitamin A depressed hepatic 10-formyl-tetreahydrofolate dehydrogenase(10-formyl-tetrahydrofolate : NADP oxidoreductase, E.C. 1.5. 1.6)activity to 65% of controls(p<0.001) and enhanced hepatic 5, 10-methy-lenetetrahydrofolate reductase(E. C. 6.3.3.2)activity by 56% with respect to control levels(p<0.001). Hepatic activity of 10-formyltertrahydrofolate dehydrogenase was depressed to about half that of control levels by ethanol administration to rats(36% ethanol diet, p<0.001). The activity of 5, 10-methyleneterahydrofolate reductase was not changed by ethanol consumption. The increased activity of 5, 10-methyleneterahydrofolate reductase and the decreased activity of 10-formyltetrahydrofolate dehydrogenase appeared to decrease the level of nonmethyl folate conezyme and the rate of one-carbon metabolism. Plasma homocysteine concentrations were significantly higher in rats fed ethanol(p<0.01) o $\beta$-carotene(p<0.001) than in controls, which suggests that increased activity of 5, 10-methylenetetrahydrofolate reductase can depress homocysteine metabolism. We concluded that dietary substitution of $\beta$-carotene for vitamin A or chronic administration of ethanol resulted in changes in the activity of hepatic folate-dependent enzymes, which could affect the distribution of folate derivatives, plasma homocysteine levels and one-carbon metabolism.

• Journal of Life Science
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• v.21 no.3
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• pp.368-374
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• 2011

The relationship between MDHA reductase activity and ascorbate, dehydroascorbate, and hydrogen peroxide content was evaluated, and this experiment was conducted to determine the change of MDHA reductase activity and the level of steady-state mRNA abundance of MDHA reductase in lettuce leaves subjected to low temperature stress. MDHA reductase activity of chloroplastic and cytosolic fraction in lettuce leaves subjected to $4^{\circ}C$ for 24 hr increased, followed by a steady decrease during the duration of recovery to $20^{\circ}C$ for 48 hr. The content of ascorbate slowly increased during low temperature treatment, followed by a rapid increase during the duration of recovery to $20^{\circ}C$ for 48 hr, while dehydroascorbate content rapidly decreased. The relationship between MDHA reductase activity of chloroplastic and cytosolic fraction in lettuce leaves subjected to $4^{\circ}C$ and ascorbate content correlated positively ($R^2$=0.9240, 0.9108, respectively), but MDHA reductase activity of chloroplastic and cytosolic fraction and dehydroascorbate were reversely correlated ($R^2$=0.8638, 0.8980, respectively). Hydrogen peroxide content and MDHA reductase activity of chloroplastic and cytosolic fraction in lettuce leaves subjected to $4^{\circ}C$ correlated positively ($R^2$=0.9443, 0.9647, respectively). Northern blot analysis showed that the level of mRNA transcript of MDHA reductase was similar to total activity of MDHA reductase, and also that the level of mRNA of MDHA reductase after recovery to $20^{\circ}C$ for 24 hr decreased.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2003.11a
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• pp.46-46
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• 2003

Hypocholesterolemic peptide isolated from glycimin (11S protein) hydrolyzate by trypsin was purified and identified as LPYP and IAVPGEVA. To investigate the effects of phyiscal properties of side chains of the hypocholesterolemic activity, some of mutant peptides were designed and synthesized chemically. The structure related structures of each peptide were simulated and constructed and their conformations were observed by using spectropolarimeter. The hypocholesterolemic activities were monitored by assaying the inhibition of 3-hydroxy-3-methylglutaryl CoA reductase (HMG-CoA reductase) in vitro and by the determination of cholesterol content in mice serum. For LPYP derivatives, Hypocholesterolemic activity was lost when hydrophobic leucine residue at N-terminus was not so critical for maintaining hypocholesterolemic activity. For idealogical design of hypocholesterolemic peptides, the structure of HMG-CoA reductase are shown and inhibition mechanism of some peptides or inhibitors will be presented. For IAVPGEVA derivative inhibition of HMG-CoA reductase has been studied. For detail study of hypocholesterolemic activity, kinetic study of inhibition of peptides on HMG-CoA reductase and structural view of ligand binding should be investigated.

• Journal of Ginseng Research
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• v.20 no.1
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• pp.106-110
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• 1996

The present study was undertaken to elucidate the effects of ginseng components on rat lens aldose reductase activity. Ginseng total saponin (GTS) exhibited inhibitory activities on rat lens aldose reductase in a dose-dependent manner. Among ginsenosides, Rf and Rgl showed potent inhibitory activities on rat lens aldose reductase. Lipid soluble fraction also inhibited rat lens aldose reductase activities. These data suggest that ginseng components inhibit rat lens aldose reductase activity in vitro.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.247-264
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• 1997

501 preschool children from 4 to 6 years were examined for their salivary reductase activity and caries experience by Resazurin Disc Test and dental examination respectively. We asked the parents about their children's oral hygiene habits, between-meal eating habits, and physical exercise habits by the questionnaire. Toothbrushing frequency had negative relation to salivary reductase activity and caries experience. Caries experience was low when parents did toothbrushing for children, when teeth were brushed at bedtime, and when fluoride toothpastes were used. Salivary reductase activity and caries experience were high in bread & cookies group, chocolates & candies group, milk & soft drink group, and fruits & vegetables group in order. Caries experience was high in case of irregular between-meal eating. Sweet food eating frequency had positive relation to caries experience. Caries activity was low in case of eating homemade non-sweet between-meals. Salivary reductase activity and caries experience were low when gum-chewing frequency was high. Salivary reductase activity and caries experience were high when the amount of physical exercise was low.

• Archives of Pharmacal Research
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• v.18 no.3
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• pp.206-212
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• 1995

New hypolipaemic agents, in which substituted indazole nucleus is connected to tetrahydro-4-hydroxy-2H-pyran-2-one by a two-carbon bridge, were designed and synthesized to show significant inhibitory activity against microsomal HMG-CoA reductase in rat liver.

• Journal of Life Science
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• v.24 no.3
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• pp.227-233
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• 2014

Effects of p-coumaric acid (p-CA), benzoic acid (BA), and salicylic acid (SA) on the activities of glutathione reductase and catalase were studied in in vitro grown tobacco plants. After culturing the tobacco plants in MS medium containing $10^{-5}$ mM of p-CA, BA, and SA, the increase in the activities of two enzymes, glutathione reductase and catalase, were compared from day 20 to day 50 day, with an interval of 10 days. The growth of the tobacco plants treated with p-CA, BA, and SA was the highest on day 50. Analysis of the effect of the three substances on the activity of glutathione reductase showed that BA and p-CA decreased the activity of the enzyme compared with a control, and SA increased the activity of the enzyme. All of them showed the highest activity on day 40. SA increased the activity of catalase, but BA and p-CA reduced the activity of this enzyme. In all the experimental groups, the activity was the highest on day 40. In conclusion, p-CA and BA appear to promote the growth of tobacco plants. The growth was the best on day 50, but the activity of the antioxidative enzyme was inhibited. On the contrary, SA seemed to inhibit the growth of the tobacco plants but to promote the activity of glutathione reductase and catalase. The growth of the plants treated with SA was best on day 40.

• Natural Product Sciences
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• v.7 no.2
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• pp.38-44
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• 2001

NAD(P)H:quinone reductase (QR), known as DT-diaphorase, is a kind of detoxifying phase II metabolic enzyme catalyzing hydroquinone formation by two electron reduction pathway from quinone type compounds, and thus facilitating excretion of quinoids from human body. With the usefulness of QR induction activity assay system for the modulation of toxicants, in the course of searching for cancer chemopreventive agents from natural products, the methanolic extracts of approximately two hundreds of oriental medicines were primarily evaluated using the induction potential of quinone reductase (QR) activity in cultured murine Hepa1c1c7 cells. As a result, several extracts including Hordeum vulgare, Momordica cochinchinensis, Strychnos ignatii, Houttuynia cordata, and Polygala japonica were found to significantly induce QR activity. In addition, the methylene chloride fraction of H. vulgare, one major dietary food source, showed potent induction of QR activity $(CD=6.4{\mu}g/ml)$. Further study for isolation of active principles from these lead extracts is warranted for the discovery of novel cancer chemopreventive agents.

• Archives of Pharmacal Research
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• v.24 no.6
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• pp.597-600
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• 2001

Based on the potential cancer chemoprebentive activity of resveratrol, a trihydroxystilbene with the induction of quinone reductase activeity this study was designed to determine if stilbene-related compounds were inducers of phase ll detoxifying metabolic enzyme quinone reductase (QR) in the mouse hepatoma Hepa 1c1c7 cells. Among the thirteen compounds tested, several compounds including 3,4,5,3',5'-pentamethoxy-trans-stibene were found to potentially induce QR activity in this cell line. In addition, substitution with 3-thiofurane ring instead of phenyl ring in the stilbene skeleton also exhibited potential induction of QR activity. This result will give primary information to design the potential inducers of QR activity in the stilbene analogs.

• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.725-730
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• 2003

Three recombinant Saccharomyces cerevisiae strains showing different levels of xylose reductase activity were constructed to investigate the effects of xylose reductase activity and glucose feed rate on xylitol production. Conversion of xylose to xylitol is catalyzed by xylose reductase of Pichia stipitis with cofactor NAD(P)H. A two-substrate fermentation strategy has been employed where glucose is used as an energy source for NADPH regeneration and xylose as substrate for xylitol production. All recombinant S. cerevisiae strains Yielded similar specific xylitol productivity, indicating that xylitol production in the recombinant S. cerevisiae was more profoundly affected by the glucose supply and concomitant It generation of cofactor than the xylose reductase activity itself. It was confirmed in a continuous culture that the elevation of the glucose feeding level in the xylose-conversion period enhanced the xylitol productivity in the recombinant S. cerevisiae.