• Natural Product Sciences
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• 제1권1호
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• pp.55-60
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• 1995

In the course of evaluation of hepatoprotective components against alcohol-induced toxicity from Aloe spp., the methanol extract was found to cause a significant inhibition of rat liver cytosolic alcohol dehydrogenase activity. Systematic fractionation of active tractions monitored by bioassay led to isolation of four compounds; aloe-emodin, aloenin, ethylidene-aloenin and ${\beta}-sitosterol$, which were estimated as active principles for inhibition of c-ADH and c-ALDH activities in vitro.

• 대한의생명과학회지
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• 제8권2호
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• pp.83-88
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• 2002

To investigate the skin toxicity of xylene, xylene (25 mg/$\textrm{cm}^2$) has been sequentially applied to the rat skin for four days. On the light microscopic examination, epithelium was left out with infiltration of inflammatory cells in border with dermis, and formation of new epithelial layer was shown under the inflammatory zone. Application of xylene to the rat skin showed the marked rise of cutaneous xanthine oxidase activity whereas, He activities of oxygen free radical scavenging enzymes, superoxide dismutase and glutathione S-transferase, were significantly declined. Furthermore, the content of cutaneous glutathione was more and less decreased in rat skin applied with xylene. In conclusion, these results suggest that a part of oxygen free radical may be responsible for morphological changes in skin by applying xylene to the rat skin.

• 한국환경성돌연변이발암원학회지
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• 제26권3호
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• pp.86-88
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• 2006

Cytochrome P450 1A2 (CYP1A2) is a xenobiotic metabolizing enzyme that is tissue-specifically expressed in the mammalian liver. In this study, the extent of CYP1A2 promoter methylation was analyzed to determine its potential role in the regulation of CYP1A2 in diethylnitrosamine (DEN)-induced mouse liver tumors. CYP1A2 mRNA was under-expressed about three fold in DEN-induced liver tumors compared to age-matched control livers. The CYP1A2 promoter was hypermethylated in DEN-induced liver tumors compared to controls, especially in a promoter domain close to the coding region. These results suggest that promoter methylation is involved in the regulation of CYP1A2 in mouse liver tumors.

• 생약학회지
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• 제27권1호
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• pp.47-52
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• 1996

A triterpenoid(melianone) and a limonoid(28-deacetyl sendanin) were isolated from the chloroform fraction of Meliae toosendan Fructus, the rippen fruits of Melia toosendan SIEB. et ZUCC.(Meliaceae) and were applied to serial experiments to clarify the liver protective activities. We found that the compounds promoted slightly the drug metabolizing enzyme activities and decreased serum transaminase activities which was elevated by carbon tetrachloride intoxication. And also they slightly increased the secretion of bile juice in rat.

• 미생물학회지
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• 제19권3호
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• pp.137-141
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• 1981

Occurrence and distribution of sucrose metabolizing enzymes in oral streptococci had been studied. In these studies, the carbohydrate component of the culture medium had been glucose. I have extended these studies by analyzing bacterial culture supernatants for the relative content of hexosyltransferases, namely glucosyl and fructosyltransferase. As a carbohydrate, fructose was used. The growth measured for nine oral streptococci (Strptococcus mutans strains BHT, ING, AHT, 6715, LM-7, and SL-1 ; Streptococcus sanguis 903, 9811, and M-5) varied. The level of glucosyltansferase activity also varied among S. mutans strains, and its level in S. sanguis was relatively low. Fructosyltansferase activity of the various strains fluctuated more than of glucosyltransferase. S.mutans strain LM-7 had significantly higher level of both enzymes. As a whole, fructose-grown cultures had generally an agreeable trend of enzyme activity to those from glucose-grown cultures.

• 약학회지
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• 제33권1호
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• pp.54-63
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• 1989

Examination of the subacute toxicity of captafol showed that. 1) In the captafol administered group, the body weight was significantly decreased but the amounts of AST, ALT, LDH, BUN, TG in serum were remarkably elevated in comparision to those of the control group. 2) In captafol treated animals, the amount of cytochrome P-450 and the activity of NADPH-cytochrome c reductase in liver and in kidney were decreased, but TAB value in serum and in liver and total ATPase activity in liver and in kideny were found to be remakably elevated. 3) When captafol administered with ethanol to the group, the group showed elevated serum levels of AST, ALT and BUN but the amount of cytochrome P-450 and the activity of NADPH-cytochrome c reductase in liver and in kidney were decreased as the group which was treated with captafol only.

• 대한의생명과학회지
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• 제12권4호
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• pp.439-442
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• 2006

To evaluate the postmortem changes in activities of oxygen free radical metabolizing enzymes, the rats were sacrificed with cervical dislocation and were kept in an incubator at $25^{\circ}C$, 70% of humidity for 12 hours. The activities of aniline hydroxylase, catalase, glutathione-S-transferase and superoxlde dismutase were decreased with the time. On the other hand, the activity and type conversion ratio (type D ${\to}$type O) of hepatic xanthine oxidase (XO) were gradually increased. From these changes of XO, the estimation of death time (mathematical equation) could be determined with the least square method. To clarify the cause of increasing XO activity, enzyme kinetics were examined. The Km values of XO were decreased with the time. In conclusion, the determination of liver XO activity might be used for the estimation of death time in the early postmortem period.

• Archives of Pharmacal Research
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• 제12권3호
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• pp.196-200
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• 1989

The methanolic extract of the Rhizome of Curcuma zedoaria exhibited a significant prolongation of hexobarbital (HB)-induced hypnosis. Through liquid chromatography of an ether soluble fraction. monitoring by bioassay, three sequiterpenes, germacrone (A), curzerenone (B) and germacrone epoxide (C) were isolated as active consituents. A single treatment (100-200 mg/kg, i.p.) of each compound showed not only a significant prolongation of HB-induced sleeping time but also a significant inhibition of aminopyrine N-demethylase activity in mice, and further exhibited a typical type I binding spectra with oxidized rat hepatic cytochrome P-450 induced by phenobarbital. All of the compounds provoked a sleep episode at a subhypnotic dose of HB, implying that they possess CNS depressant properties.

• 한국환경보건학회지
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• 제28권2호
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• pp.71-80
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• 2002

To evaluate the skin toxicity of topical cyclohexane application (25mg/$\textrm{cm}^2$) was sequentially applied to the rat skin for four days. On the histopathological findings in the light micrographs, neutrophils and engulfed neutrophils are seen, and many cytoplasmic processes were appeared in proliferated layer whereas in the dermis area, increased numbers of fibroblast, accumulation of neutrophil and lipid droplets are demonstrated. On the other hand, applying the cyclohexane to the rat skin led to the remarkable rise of cutaneous xanthine oxidase activity and similar activities of superoxide dismutase and glutathione peroxidase and glutathione content and declined activity of glutathione S-transferase compared with control group. Especially the remarkably decreased activity of aniline hydroxylase (AH) was appeared in skin as little as scarcely determined. Furthermore, the applying the cyclohexane to skin led to the significantly increased activity of hepatic AH and alcohol dehydrogenase. These results indicate that oxygen free radical and intermediate metabolite of cyclohexane may be responsible for structural changes in skin by cyclohexane application to rat skin.

• International Journal of Oral Biology
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• 제40권4호
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• pp.217-221
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• 2015

Cariogenic Streptococcus mutans encounters a variety of host defense factors produced in oral cavity. Nitric oxide (NO) and NO-mediated reactive nitrogen species are potential antimicrobials of innate immunity that can threaten the fitness of S. mutans in their ecological niches. Streptococcal strategies to detoxify cytotoxic NO, which allow S. mutans to persist in caries or other environments of the oral cavity, remain unknown. In this study, we directly measured NO consumption rates of S. mutans isolated in Korea. Surprisingly, all S. mutans strains were unable to consume exogenous NO efficiently, while an intracellular parasite Salmonella enterica serovar Typhimurium expressing the NO-metabolizing enzyme flavohemoglobin consumed most of the NO. This result suggested that S. mutans has alternative detoxification systems for tolerating NO-induced nitrosative stresses.