• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.80-85
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• 2001

Various lines of evidence suggest that dietary components protect the initiation step of carcinogenesis. In this study, the ethylacetate (PGMEA), ethylether (PGMEE), butanol (PGMB) and aqueous (PGMA) soluble fractions of Punica granatum L. (PG) were screened for their growth inhibition using the MTT assay on HepG2, HeLa, C6, MCF-7 and HT-29 cells and for their activity to induce quinone reductase (QR) in HepG2 cells. Among various fractions of Punica granatum L., the PGMEE showed the strongest growth inhibition at 500 $\mu\textrm{g}$/mL which resulted 92.5% on Hela cell lines and 97.8% on C6 cell lines. The PGMEA and PGMB also showed significant growth inhibition. The assay of QR induction on HepG2 cells, grown in the presence of PGMEE at the concentration of 50$\mu\textrm{g}$/mL, was 1.4 times more effective compared with the control value of1.0. These results suggested that useful cancer chemoprevention materials could be isolated from PGMEE fraction of Punica granatum L.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.86-91
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• 2001

The anticarcinogenic effects of various food components on human cancer cells have received much attention in recent years. The precise effect and mechanisms of anticarcinogens in food materials on cancer cells have rarely been investigated. This study was carried out to determine the effects of Daucus carota L. leaf (DCL) extracts on cytotoxic and chemopreventive effect on human cancer cells. The experiment was conducted to determine cytotoxicity of Daucus carota L. leaf extracts on HepG2, Hela and MCF-7 cells by MTT assay. Among various partition layers of Daucus carota L. leaf, the ethylacetate partition layer (DCLMEA) at 500 $\mu\textrm{g}$/mL was shown to be most effective on MCF-7 cell lines. The four partition layers which are DCLM, DCLMH, DCLMB and DCLMH were less effecitve in inducing cytotoxicity than DCLMEA was. We also determined the induction of intracellular quinone reductase (QR) activity by adding DCL extracts on HepG2 cells. Among various partition layers of DCL extracts, DCLMH and DCLM were tested to be most effective with results such as 4.9 and 4.73 with a control value of 1.0.

• Journal of Plant Biotechnology
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• v.6 no.4
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• pp.259-264
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• 2004

The present study describes the ameliorating effect of $Ca^{++}\;on\;Cd^{++}$ toxicity on the germination, early growth of mungbean seedlings, nitrogen assimilation enzyme. s-nitrate reductase (NR), nitrite reductase (NIR), anti-oxidant enzymes (POD, CAT and SOD) and on the accumulation of hydrogen peroxide and sulphydryls. $Cd^{++}$ inhibited seed germination and root and shoot length of seedlings. While NR activity was down- regulated, the activities of NIR, POD and SOD were up- regulated with $Cd^{++}$ treatment. $Cd^{++}$ treatment also increased the accumulation of sulphydryls and peroxides, which is reflective of increased thiol rich proteins and oxidative stress. $Ca^{++}$ reversed the toxic effects of $Cd^{++}$ on germination and on early growth of seedlings as well as on the enzyme activities, which were in turn differentially inhibited with a combined treatment with calcium specific chelator EGTA. The results indicate that the external application of $Ca^{++}$ may increase the tolerance capacity of plants to environmental pollutants by both up and down regulating metabolic activities. Abbreviations: $Cd^{++}= cadmium,\;Ca^{++} = calcium$, NR= nitrate reductase, NIR=nitrite reductase, POD = peroxidse, SOD= superoxide dismutase, CAT= catalase, EGTA= ethylene glycol-bis( $\beta-aminoethyl ether$)-N,N,N,N-tetraacetic acid.

• Natural Product Sciences
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• v.10 no.1
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• pp.35-39
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• 2004

Aldose reductase (AR), the key enzyme of the polyol pathway, is known to play important roles in the diabetic complications. The inhibitors of AR, therefore, would be potential agents for the prevention of diabetic complications. In order to clarify the structural requirements of flavonoids for aldose reductase inhibitory activity, thirty flavonoids were examined. Among the thirty flavonoids, flavonols such as quercetin (5), reyneutrin (7), quercitrin (9), isoquercitrin (11), and avicularin (14) were found to exhibit much stronger AR inhibition. Lonicerin (10), amentoflavone (27) and sophoraflavanone B (30) were also showed strong inhibitory activity. Especially, quercitrin and reyneutrin exhibited the most inhibitory potency on rat lens (RL) AR. The results suggested that flavonol having the 7-hydroxyl and/or catechol moiety at the B ring exhibit strong activity. In addition, flavonols having 3-O-monosaccharide also showed stronger inhibition than free flavonols at the 3-position. These results suggested that quercitrin and reyneutrin are attributed to be the promising compounds for the prevention and/or treatment of diabetic complications.

• Journal of Life Science
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• v.12 no.5
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• pp.549-554
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• 2002

Taraxacunf mongofieum Hand-Mass aqua-acupuncture solution (TMAS) was prepared and investigated og, the effect on initiation of carcinogenesis. The following effe.Is as a blocking agent were measured. .(a) Indu.ction of quinone reductase, (b) Induction of glutathione S-transferase activity (c) Increase of reduced glutathione. TMAS was potent inducer of quinone reductase in Hepa Iclc7 murine hepatoma cells. Clutathione S-transferase activity was increased with TMAS. In addition glutathione levels were increased about 1.6-fold with TMAS in cultured murine hepatoma Hepa Iclc7 cells.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.5
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• pp.580-593
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• 1992

Cholesterol have many essential functions as a component of cellular and subcellular membranes, metabolic precursor of bile acids and steroid hormones, and obligatory part of the metabolic systems involved in DNA synthesis and cell division. These essential funtions demand a continuous and appropriate supply of cholesterol to the tissues. Body cholesterol pool is maintained by the balance of acquirement from diets, de novo synthesis, and excretion either as bile acids or neutral steroids. In these metabolic process, cholesterol biosynthesis is controlled by the change in the activity of 3-hydroxy-3methylglutaryl coenzyme A (HMG-CoA) reductase. Under most physiological or nutritional situations, the activity of this enzyme is adroitly regulated to maintain tissue cholesterol balance. Excess cholesterol accumulation in the cells induces the decrease in the number of LDL-receptor, followed by the increase in the level of serum LDL-cholesterol. Increase in the level of serum cholesterol appears to be an important determinant for the incidence of the coronary heart disease. Dietary intervention may be helpful in alleviating an increase in the level of serum cholesterol or body cholesterol pool.

• Journal of Microbiology and Biotechnology
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• v.23 no.12
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• pp.1699-1707
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• 2013

During the fermentative production of 1,3-propanediol under high substrate concentrations, accumulation of intracellular 3-hydroxypropionaldehyde will cause premature cessation of cell growth and glycerol consumption. Discovery of oxidoreductases that can convert 3-hydroxypropionaldehyde to 1,3-propanediol using NADPH as cofactor could serve as a solution to this problem. In this paper, the yqhD gene from Klebsiella pneumoniae DSM2026, which was found encoding an aldehyde reductase (KpAR), was cloned and characterized. KpAR showed broad substrate specificity under physiological direction, whereas no catalytic activity was detected in the oxidation direction, and both NADPH and NADH can be utilized as cofactors. The cofactor binding mechanism was then investigated employing homology modeling and molecular dynamics simulations. Hydrogen-bond analysis showed that the hydrogen-bond interactions between KpAR and NADPH are much stronger than that for NADH. Free-energy decomposition dedicated that residues Gly37 to Val41 contribute most to the cofactor preference through polar interactions. In conclusion, this work provides a novel aldehyde reductase that has potential applications in the development of novel genetically engineered strains in the 1,3-propanediol industry, and gives a better understanding of the mechanisms involved in cofactor binding.

• Korean Journal of Pharmacognosy
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• v.42 no.2
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• pp.187-194
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• 2011

Aldose reductase (AR), the key enzyme in the polyol pathway, plays an important role in the development of the diabetic complications. None of Aldose reductase Inhibitor (ARI) has achieved worldwide use because of limited efficacy or undesirable side effects. Therefore, evaluating natural sources for ARI potential may lead to the development of safer and more effective agents against diabetic complications. Fifty two Chinese herbal medicines have been investigated for inhibitory activities on AR. Among them, twelve herbal medicines, Artemisia anomala (aerial part), Centella asiatica (aerial part), Scutellaria baicalensis (root), Senecio chrysanthermoides (whole plant), Gleditsia japonica (twig), Zizyphus jujube (twig, leaf), Citrus aurantium (fruit), Hydnocarpus anthelmintica (fruit), Potaninia mongolica (aerial part), Tribulus terrestris (fruit), Artemisia apiacea (aerial part) and Eclipta prostrate (aerial part) exhibited a significant inhibitory activity against AR. Particularly, Artemisia anomala, Centella asiatica and Scutellaria baicalensis showed four times more potent inhibitory activity than the positive control, 3,3-tetramethyleneglutaric acid (TMG).

• Journal of Microbiology
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• v.34 no.2
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• pp.206-213
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• 1996

NADH-quinone reductase was purified 22-fold from the cytosolic fraction of Streptomyces sp. Imsnu-1 to apparent hemogenity, with an overall yield of 9%, by the purification procedure consisting of ammonium, sulfate precipitation and DEAE Sephacryl S-200 and DEAE 5 PW chromatographies. Thes molecular mass of the enzyme determined by gel filtration chromatography was found to be 110 kDa. SDS-PAGE revealed that the enzyme consists of two sugunits with a molecular mass of 54 kDa. The enzyme contained 1 mol of FMN per subunit as a cofactor. The $A_{272}$ A$_{457}$ ratio was 6.14 and the molar extinction coefficients were calculated to be 20, 800 and 25, 400M$^{-1}$ $cm^{-1}$ / AT 349 AND 457 nm, respectively. The N-terminal sequence of the enzyme contained the highly conserved fingerprint of ADP-binding domain. The enzyme used NADH as an electron donor and various quinones as electron acceptors. Cytochrome c was practically inactive. Air-stable flavin semiquinone was produced by the addition of NADH to the enzyme. Also, naphthosemiquinone was detected in the reaction mixture containing the enzyme.

• Animal cells and systems
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• v.1 no.4
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• pp.583-587
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• 1997

Incubation of an NADPH-dependent succinic semialdehyde reductase from bovine brain with N-bromosuccinimide (NBS) resulted in a time-dependent loss of enzyme activity. The inactivation followed pseudo-first-order kinetics with the second-order rate constant of $6.8\times{10}^3$ $M^-1$ $min^{-1}$. The inactivation was prevented by preincubation of the enzyme with substrate succinic semialdehyde, but not with coenzyme NADPH. There was a linear relation-ship between oxindole formation and the loss of enzyme activity. Spectro-photometric studies indicated that about one oxindole group per molecule of the enzyme was formed following complete loss of enzymatic activity. It is suggested that the catalytic function of succinic semialdehyde reductase is modulated by binding of NBS to a specific tryptophan residue at or near the substrate binding site of the enzyme.