• Natural Product Sciences
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• 제7권2호
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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.

• 생약학회지
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• 제34권4호통권135호
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• pp.314-317
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• 2003

Inhibitory effects of the whole extract and isolated compounds from the leaves of Vaccinium koreanum (Ericaceae) on rat lens aldose reductase (RLAR) and on platelet aggregation were investigated for the prevention or the treatment of chronic diabetic complications. Arbutin, isolated from n-butanol fraction of methanol extract, exhibited a potent inhibitory effects on rat platelet aggregation induced by ADP $(IC_{50}=0.12\;{\mu}M)$ and collagen $(IC_{50}=0.039\;{\mu}M)$ and showed same inhibitory activities with positive control, tetramethylene glutaric acid, on RLAR.

• 약학회지
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• 제54권6호
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• pp.466-473
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• 2010

A series of $3{\beta}$-substituted 5-androstene-$17{\beta}$-carboxamides were synthesized from analogs of $3{\beta}$-hydroxy-5-androstene-$17{\beta}$-carboxylic acid (1) with tert-butylamine, N,N-diethylamine and 3-aminopyridine and some compounds were epoxidized with mCPBA. A rat prostate testosterone $5{\alpha}$-reductase inhibitory activity of synthesized compounds was assessed by radioimmunoassay using [1,2,6,7-3H]-testosterone as substrate. All synthesized compounds showed lower activity than finasteride and the N-(3-pyridino)-$3{\beta}$-carboxycarbonyloxy-5-androstene-$17{\beta}$-carboxamide (12) showed weak inhibitory activity ($IC_{50}$: $2.4{\times}10^{-7}M$).

• Biomolecules & Therapeutics
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• 제1권1호
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• pp.93-97
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• 1993

We have previously reported that an NADPH-dependent succinic semialdehyde reductase was purified homogeneously from bovine brain by several chromatographic procedures, and was found to be a monomeric protein with a molecular mass of 28 kDa (Cho et al., Eur. J. Biochem. 1993). Since succinic semialdehyde is an important intermediate in the ${\gamma}$-aminobutyrate(GABA) shunt and GABA level is associated with various forms of human neurological disorders, we have investigated the effects of anticonvulsant drugs on the succinic semialdehrde reductase. Among the drugs tested, sodium valproate and diphenylhydantoin inhibited the enzyme activity, while some other drugs, barbiturate and chlorpromazine, had no inhibitory effects on the enzyme activity. The purified enzyme was also injected as an immunogen into Balb/c mice to obtain monoclonal antibodies (mob) and several mobs to the protein were produced from the fusion experiments.

• KSBB Journal
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• 제6권1호
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• pp.55-61
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• 1991

The objective of this in vitro study is to screen a possible inhibitor, originated from some chinese herb medicines, of 3-hydroxy-3-methylglutaryl Coenzyme A (HMG-CoA) reductase that is the major regulatory enzyme of hepatic cholesterol biosynthesis. Fourteen kinds of herbal plant were extracted with water and evaporated for prescreening. The methanol extracts of the effective 3 kinds (9 species) were fractionated with chloroform, ethylacetate, butanol and water, and vacuum evaporated. The degree of inhibition of the extracts to HMG-CoA reductase activity was calculated by the spectrophotometric method using microsomal protein of Saccharomyces cerevisiae ATCC 42949 as an enzyme source. Among these samples, marked inhibitory effects were observed in the extracts of ethylacetate and chloroform fractions of the Rosa rugosa roots, and those of butanol, ehtylacetate and water fractions of pine leaves. Also, the inhibitory effects of the extracts obtained from buckwheat shell and the roots of Rosaceae were found.

• 생약학회지
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• 제32권2호통권125호
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• pp.168-174
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• 2001

Induction of phase II enzymes is a major mechanism of chemoprevention. The induction levels of quinone reductase (QR) activity in cultured murine hepatoma (Hepa 1c1c7) cells by 80%-methanol extracts of traditional medicinal plants were measured. Among the tested 81 plants, the extracts of Aralia continentalis, Magnolia obovata, and Viscum album were found to induce QR activities over 250%. The maximum induction levels obtained were 401.9%, 270.5%, and 301.8% by treatments of the extracts of A. continentalis $(318\;{\mu}g/ml)$, M. obovata $(53.8\;{\mu}g/ml)$ and V. album $(80.6\;{\mu}g/ml)$, respectively. These QR induction activities were more potent than those of the known QR inducers, t-butylhydroquinone (170.1%) and ${\beta}-naphthoflavone$ (320.0%).

• Natural Product Sciences
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• 제9권1호
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• pp.34-37
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• 2003

We examined methanol extracts prepared from the Korean plants for their inhibitory effects on rat lens aldose reductase (RLAR) activity in vitro. Among 41 plant extracts, the extracts of Lagerstroemia indica, Punica granatum, Eurya japonica, Liquidambar styraciflua, and Vitis coignetiae exhibited highest inhibitory potency, even more potent than tetramethylene glutaric acid (TMG), known as one of typical aldose reductase inhibitors $(IC_{50}\;value,\;0.51\;{\mu}g/ml)$. Especially, the extract of Lagerstroemia indica (Lythraceae), exhibited the most inhibitory potency $(IC_{50}\;value,\;0.069\;{\mu}/ml)$ on RLAR.

• Journal of Microbiology
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• 제44권4호
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• pp.461-465
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• 2006

The occurrence of thioredoxin reductase (NAD(P)H: oxidized-thioredoxin reductase, EC 1.6.4.5, TrxR) in five mesophilic species of Deinococcus was investigated by PAGE. Each species possessed a unique TrxR pattern, for example, a single TrxR characterized D. radiopugnans while multiple forms of TrxR occurred in other Deinococcal spp. Most of TrxRs occurring in Deinococcus showed dual cofactor specificity, active with either NADH or NADPH, although the NADPH specific-TrxR was observed in D. radiophilus and D. proteolytic us.

• Korean Journal of Acupuncture
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• 제20권1호
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• pp.39-43
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• 2003

괴화약침액이 간세포의 quinone reductase, glutathione S-transferase 와 환원형 glutathione의 활성에 미치는 영향을 살펴 본 결과 괴화약침액은 암예방 효소인 Phase II enzyme을 유의성 있게 증가 시켰다. 따라서 괴화약침액은 암예방에 효과가 있는 것으로 사료된다.

• Journal of Ginseng Research
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• 제15권2호
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• pp.139-143
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• 1991

This study investigated the relations between the photosynthetic rate and the activities of antioxidatile enzymes, glutathione reductase, ascorbate free radical reductase, ascorbate peroxidase, glutathione peroxidase, and ascorbate oxidase, in the leaves of Panax ginseng. Under the normal cultivation condition, Panax in showed lower g1utathione reductase and ascorbate free radical reductase activities the Glycine max. But P ginseng showed higher 91utathione Peroxidase, ascorbate Peroxidase, and ascorbate oxidase activities than C. Panax. Therefore, P. ginseng showed weak activities of reductases for the reduction of the oxidized antioxidants. Under the light intensity of 25 KLux, the reductases showed a decrease of over 75% after 24 hours. But the peroyoxidases decreased about 40%. These results showed that the decrease of reductases acitivities was consistent with the decrease of photosynthetic rate. Therefore, we consider that the regulation of antioxidative enzymes or the application of exogenous antioxidants will be effective means for the protection of photodamage in p. ginseng.