• BMB Reports
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• 제40권6호
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• pp.1039-1049
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• 2007

Overdoses of acetaminophen cause hepato-renal oxidative stress. The present study was undertaken to investigate the protective effect of a 43 kDa protein isolated from the herb Cajanus indicus, against acetaminophen-induced hepatic and renal toxicity. Male albino mice were treated with the protein for 4 days (intraperitoneally, 2 mg/kg body wt) prior or post to oral administration of acetaminophen (300 mg/kg body wt) for 2 days. Levels of different marker enzymes (namely, glutamate pyruvate transaminase and alkaline phosphatase), creatinine and blood urea nitrogen were measured in the experimental sera. Intracellular reactive oxygen species production and total antioxidant activity were also determined from acetaminophen and protein treated hepatocytes. Indices of different antioxidant enzymes (namely, superoxide dismutase, catalase, glutathione-S-transferase) as well as lipid peroxidation end-products and glutathione were determined in both liver and kidney homogenates. In addition, Cytochrome P450 activity was also measured from liver microsomes. Finally, histopathological studies were performed from liver sections of control, acetaminophen-treated and protein pre- and post-treated (along with acetaminophen) mice. Administration of acetaminophen increased all the serum markers and creatinine levels in mice sera along with the enhancement of hepatic and renal lipid peroxidation. Besides, application of acetaminophen to hepatocytes increased reactive oxygen species production and reduced the total antioxidant activity of the treated hepatocytes. It also reduced the levels of antioxidant enzymes and cellular reserves of glutathione in liver and kidney. In addition, acetaminophen enhanced the cytochrome P450 activity of liver microsomes. Treatment with the protein significantly reversed these changes to almost normal. Apart from these, histopathological changes also revealed the protective nature of the protein against acetaminophen induced necrotic damage of the liver tissues. Results suggest that the protein protects hepatic and renal tissues against oxidative damages and could be used as an effective protector against acetaminophen induced hepato-nephrotoxicity.

• Advances in Traditional Medicine
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• 제7권4호
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• pp.357-362
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• 2007

Cytochrome P450 2C19 (CYP2C19) is a clinically important enzyme involved in the metabolism of therapeutic drugs, including (S)-mephenytoin, omeprazole, proguanil, and diazepam. Individuals are characterized as either extensive metabolizers (EM) or poor metabolizers (PM) on the basis of CYP2C19 enzyme activity. The PM phenotype occurs in 2-5% of Caucasians, but in 18-23% of Asians. To clarify the association between CYP2C19 polymorphisms and gastric cancer in Koreans, we investigated CYP2C19 genotypes ($CYP2C19^*1,\;{^*2},\;and\;^*3$) in 109 patients with gastric cancer and 211 controls. Normal ($CYP2C19^*1$) and defective alleles were detected with polymerase chain reaction/restriction enzyme analysis. CYP2C19 has three hereditary genotypes: homozygous EM, with high enzymatic activity; heterozygous EM, with moderate enzymatic activity; and PM, with no enzyme activity. We found that CYP2C19 heterozygous EM is more closely associated with gastric cancer than is homozygous EM. Because the CYP2C19 genotype varies in Koreans, a genotyping test is desirable to prevent gastropathy recurrence in patients before their doses of omeprazole are reduced during maintenance therapy.

• Toxicological Research
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• 제23권4호
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• pp.301-309
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• 2007

Paecilomyces tenuipes (PT), one of the Ascomycetes family, has been used for medicinal purposes due to its broad pharmacological activities. The present study was undertaken to investigate the hepatoprotective effects of PT water extracts against $CCl_4$-induced hepatotoxicity in primary cultures of adult rat hepatocytes. When the extract of PT was directly added into the culture medium at 1, 2, and 5 mg/ml, the extracts not only reduce the $CCl_4$-induced elevation of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase, and lipid peroxide, but also protect cultured hepatocytes from $CCl_4$-induced reduction of reduced glutathione, glutathione reductase, glutathione-S-transferase, glutathione peroxidase, catalase and superoxide dismutase. In addition, the effects of PT water extracts on cytochrome P450 enzymes were relatively marginal, indicating that the hepatoprotective effects of PT extract against $CCl_4$-induced toxicity might not be due to the inhibition of $CCl_4$ activation. In conclusion, the PT extracts were effective in protecting against $CCl_4$ induced hepatotoxicity in hepatocyte cultures, at least in part, by scavenging free radicals, and by modulating enzyme systems involved in cellular oxidative stress.

• Toxicological Research
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• 제8권2호
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• pp.265-272
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• 1992

Effects of repeated physical exercise on the carbon tetrachloride ($CCl_4$) hepatotoxicity were examined in adult female rats. Rats were introduced into a cylindrical rotating cage and forced to exercise for 1 hr each day, 6days/week, for 5 consecutive weeks at a speed starting from 10m/min, increased by 1m/min per day until the speed reached 27m/min. Significantly less body weight gain was observed in the exercise group suggesting that physical fitness had been induced in these animals. Eighteen hours following termination of the last exercise bout rats were treated with $CCl_4$(2 mmol/kg.ip). The $CCl_4$-induced heptotoxicity was significantly potentiated in the repeated exercise group compared to the resting sedentary animals as determined by changes in serum sorbitol dehydrogenase (SDH), glutamic oxaloacetic transaminase(GOT), glutamic pyruvic transaminase (GPT), and glucose-6-phosphatase(G-6-Pase) activities when measured 24hrs following the $CCl_4$ treatment. Hepatic drug metabolizing activity was determined in order to elucidate the underlying mechanism of potentiating action of the $CCl_4$ hepatotoxicity induced by repeated physical exercise. Repeated exercise increased the hepatic microsomal cytochrome P-450 contents and aminopyrine N-demethylase activity. The results suggest that the potentiation of $CCl_4$ hepatotoxicity by repeated exercise is associated with induction of the mixed function oxidase (MFO) enzyme system mediating the metabolism of $CCl_4$ to its active metabolite(s).

• Nutrition Research and Practice
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• 제2권2호
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• pp.80-84
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• 2008

Beneficial effects of dehydroepiandrosterone (DHEA) supplement on age-associated chronic diseases such as cancer, cardiovascular disease, insulin resistance and diabetes, have been reported. However, its mechanism of action in hepatocellular carcinoma in vivo has not been investigated in detail. We have previously shown that during hepatocellular carcinogenesis, DHEA treatment decreases formation of preneoplastic glutathione S-transferase placental form-positive foci in the liver and has antioxidant effects. Here we aimed to determine the mechanism of actions of DHEA, in comparison to vitamin E, in a chemically-induced hepatocellular carcinoma model in rats. Sprague-Dawley rats were administered with control diet without a carcinogen, diets with 1.5% vitamin E, 0.5% DHEA and both of the compounds with a carcinogen for 6 weeks. The doses were previously reported to have anti-cancer effects in animals without known toxicities. With DHEA treatment, cytosolic malate dehydrogenase activities were significantly increased by ${\sim}5$ fold and glucose 6-phosphate dehydrogenase activities were decreased by ${\sim}25%$ compared to carcinogen treated group. Activities of Se-glutathione peroxidase in the cytotol was decreased siguificantly with DHEA treatment, confirming its antioxidative effect. However, liver microsomal cytochrome P-450 content and NADPH-dependent cytochrome P-450 reductase activities were not altered with DHEA treatment. Vitamin E treatment decreased cytosolic Se-glutathione peroxidase activities in accordance with our previous reports. However, vitamin E did not alter glucose 6-phosphate dehydrogenase or malate dehydrogenase activities. Our results suggest that DHEA may have decreased tumor nodule formation and reduced lipid peroxidation as previously reported, possibly by increasing the production of NADPH, a reducing equivalent for NADPH-dependent antioxidant enzymes. DHEA treatment tended to reduce glucose 6-phosphate dehydrogenase activities, which may have resulted in limited supply for de novo synthesis of DNA via inhibiting the hexose monophophaste pathway. Although both DHEA and vitamin E effectively reduced preneoplastic foci in this model, they seemed to fimction in different mechanisms. In conclusion, DHEA may be used to reduce hepatocellular carcinoma growth by targeting NADPH synthesis, cell proliferation and anti-oxidant enzyme activities during tumor growth.

• Journal of Microbiology and Biotechnology
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• 제33권3호
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• pp.378-386
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• 2023

The CYP707A family genes encoding ABA 8'-hydroxylase catabolize abscisic acid (ABA), a plant stress hormone that plays an important role in stress condition, such as drought, heat, cold and salinity. Phaseic acid (PA) is a catabolic product of ABA. Recent studies have shown that PA is important for the physiological functions in plants. It is also a neuroprotective molecule that protects against ischemic brain injury in mice. To obtain enzymes for the PA production, four CaCYP707A genes (CaCYP707A1, CaCYP707A2, CaCYP707A3 and CaCYP707A4) were isolated from hot pepper. They were heterologously expressed in Escherichia coli. Among them, CaCYP707A2 showed significantly higher expression levels in both the membrane fraction and the soluble fraction. Preferred redox partners were investigated to improve the efficiency of CaCYP707A2's catalytic reaction, and NADPH-cytochrome P450 reductase (CPR) from hot pepper (CaCPR) was preferred over other redox partners (i.e., rat CPR and ferredoxin reductase/ferredoxin). The production of 8'-hydroxy ABA and PA by ABA hydroxylation activity was confirmed in CaCYP707A2 from both membrane and soluble fractions. Therefore, CaCYP707A2 is the first identified plant CYP protein that is expressed a soluble form in cytosolic fraction having stable activity. Taken together, we propose a new CYP707A protein with industrial applications for PA production without additional modifications in E. coli heterologous expression.

• Journal of Microbiology and Biotechnology
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• 제34권3호
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• pp.725-734
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• 2024

CYP102A1 from Bacillus megaterium is an important enzyme in biotechnology, because engineered CYP102A1 enzymes can react with diverse substrates and produce human cytochrome P450-like metabolites. Therefore, CYP102A1 can be applied to drug metabolite production. Terpinen-4-ol is a cyclic monoterpene and the primary component of essential tea tree oil. Terpinen-4-ol was known for therapeutic effects, including antibacterial, antifungal, antiviral, and anti-inflammatory. Because terpenes are natural compounds, examining novel terpenes and investigating the therapeutic effects of terpenes represent responses to social demands for eco-friendly compounds. In this study, we investigated the catalytic activity of engineered CYP102A1 on terpinen-4-ol. Among CYP102A1 mutants tested here, the R47L/F81I/F87V/E143G/L188Q/N213S/E267V mutant showed the highest activity to terpinen-4-ol. Two major metabolites of terpinen-4-ol were generated by engineered CYP102A1. Characterization of major metabolites was confirmed by liquid chromatography-mass spectrometry (LC-MS), gas chromatography-MS, and nuclear magnetic resonance spectroscopy (NMR). Based on the LC-MS results, the difference in mass-to-charge ratio of an ion (m/z) between terpinen-4-ol and its major metabolites was 16. One major metabolite was defined as 1,4-dihydroxyp-menth-2-ene by NMR. Given these results, we speculate that another major metabolite is also a mono-hydroxylated product. Taken together, we suggest that CYP102A1 can be applied to make novel terpene derivatives.

• Biomolecules & Therapeutics
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• 제6권3호
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• pp.247-255
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• 1998

Carbon tetrachloride (CCI$_4$) induces the hepatotoxicity due to the reactive free radicals generated by cytochrome P-450 (CYP-450) enzyme, which result in destabilization of cellular membrane. Diltiazem, a calcium channel blocking agent, has been known to suppress the CYP-450 enzyme activities. To study the effect of diltiazem in $CCl_4$-treated rats, we measured the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and glutathione S-transferase (GST), contents of bilirubin, albumin, total protein, cholesterol, triglyceride, blood urea nitrogen, creatinine malondialdehyde and calcium. Also we conducted liver histopathologic examinations. Diltiazem, when administered 1 hour prior to CCI$_4$ treaeent, significantly reduced the activities of ALT and AST, the contents of microsomal malondialdehyde and calcium in liver and microsome as compared with those of $CCl_4$-treated rats. In addition, histopathologic examination showed that diltiazem prevented the development of centrilobular necrosis induced by CCI$_4$ in liver tissue. Our results suggested that diltiazem could inhibit the formation of free radicals and the influx of calcium. Therefore diltiazem may be applied to suppress the liver damage caused by $CCl_4$.

• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2001년도 춘계심포지움 및 학술발표회
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• pp.137-137
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• 2001

It is it well known fact that the most relevant toxic emissions such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-1ike polychlorinated biphenyls (PCBs) are produced from incinerators. Induction of cytochrome P450IA1 catalyzed 7-ethoxyresorufin 0-deethylase (EROD) activity in mammalian cell culture (EROD-microbioassay) is a selective and sensitive parameter used for the quantification of dioxin-like compounds. (omitted)

• Food Science and Biotechnology
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• 제18권1호
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• pp.245-248
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• 2009

Present study was investigated the hepatic effects of equol on the 7,12-dimethylbenz(a)anthracene (DMBA)-induced enzymatic activity and expression of CYP1A1 and CYP1B1 in mice. Equol was administered orally at 5 and 25 mg/kg BW for 4 weeks. Subsequently, mice pretreated with equol received DMBA intragastrically twice a week for 2 weeks. DMBA induced CYP1 activity as well as the expression of CYP1A1 and CYP1B1. Each of these effects was significantly reduced by equol in dose-dependent manner (p<0.05). Equol also reduced the relative AhR mRNA expression, similar to its effect on CYP1A1. These results suggest that equol modulates the CYP1A1 through a reduction of AhR expression in mice treated with DMBA.