• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2002년도 Current Trends in Toxicological Sciences
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• pp.25-35
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• 2002

Transcription factor Nrf2 is essential for the antioxidant responsive element (ARE)-mediated induction of phase II detoxifying and oxidative stress enzyme genes. Detailed analysis of differential Nrf2 activity displayed in transfected cell lines ultimately led to the identification of a new protein, which we named Keap1, that suppresses Nrf2 transcriptional activity by specific binding to its evolutionarily conserved amino-terminal regulatory domain. The closest homolog of Keap1 is a Drosophila actin-binding protein called Kelch, implying that Keap1 might be a Nrf2 cytoplasmic effector. We then showed that electrophilic agents antagonize Keap1 inhibition of Nrf2 activity in vivo, allowing Nrf2 to traverse from the cytoplasm to the nucleus and potentiate the ARE response. We postulate that Keap1 and Nrf2 constitute a crucial cellular sensor for oxidative stress, and together mediate a key step in the signaling pathway that leads to transcriptional activation by this novel Nrf2 nuclear shuttling mechanism. The activation of Nrf2 leads in turn to the induction of phase II enzyme and antioxidative stress genes in response to electrophiles and reactive oxygen species.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.2973-2978
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• 2013

Maesil (Prunus mume Siebold & Zucc.), a member of the genus Rosaceae, has been reported to have antioxidative effects, as well as anticancer influence in many cancer lines. Thus, this present study was designed to investigate the inhibitory effect of fermented Maesil with probiotics against 7,12-dimethylbenz[a]anthracene (DMBA), 12-O-tetradecanoyl phorbol 13-acetate (TPA)-induced mouse skin carcinogenesis via its antioxidative potential. Mice were fed a diet containing fermented Maesil, containing either 1% (1% FM fed group) or 2% (2% FM fed group) along with probiotics following DMBA and TPA exposure. Continuous ingestion of the experimental feed markedly inhibited skin carcinogenesis, as evidenced by a marked decrease in papilloma numbers and epidermal hyperplasia as well as cellular proliferation and the percentage of proliferating-cell nuclear antigen positive cells. Also, the FM fed group showed an increase of total antioxidant capacity as well as an increased level of phase II detoxifying enzymes such as superoxide dismutase, concurrent with a decreased lipid peroxidation activity level. Taken together, these results suggest that fermented Maesil has the ability to suppress the development of DMBA-TPA induced skin carcinogenesis, via the reduction of lipid peroxidation, enhancing total antioxidant capacity and phase II detoxifying enzyme.

• BMB Reports
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• 제36권3호
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• pp.258-264
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• 2003

This study examined the effect of dietary polyunsaturated fatty acids (PUFA) that were supplemented with vitamin E on lipid peroxidation, glutathione-dependent detoxifying enzyme system activity, and lipogenic fatty acid synthase (FAS) expression in rat liver. Male Sprague-Dawley rats were fed semipurified diets containing either 1% (w/w) corn oil or 10% each of beef tallow, corn oil, perilla oil, and fish oil for 4 wk. Alpha-tocopherol was supplemented in perilla oil (0.015%) and fish oil (0.019%). Hepatic thiobarbituric acid reactive substances, an estimate of lipid peroxidation, were not significantly different among the dietary groups. The glutathione peroxidase, glutathione reductase, and glutathione S-transferase activities were all elevated by the polyunsaturated fats, especially fish oil. The activity of FAS was reduced in the polyunsaturated fat-fed groups in the order of fish oil, perilla oil, and corn oil. The mRNA contents decreased in rats that were fed the 10% fat diets, particularly polyunsaturated fats, compared with the rats that were fed the 1% corn oil diet. Similarly, the inhibitory effect was the greatest in fish oil. These results suggest that lipid peroxidation can be minimized by vitamin E; PUFA in itself has a suppressive effect on lipogenic enzyme.

• Journal of Crop Science and Biotechnology
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• 제10권1호
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• pp.19-26
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• 2007

Glutathione S-transferases(GSTs, EC 2.5.1.18), glyoxalase-I(EC 4.4.1.5) and alliin lyase(alliinase, EC 4.4.1.4) are important enzyme systems in plant bodies. The first two are mainly detoxifying enzymes that utilize glutathione(GSH) in the defense mechanism, and the last one is mainly involved in secondary metabolism and relevant to sulfur compounds derived from GSH. The activities of the three enzymes have been investigated in soluble extracts of vegetable crops, including pumpkin, cabbage, broccoli, radish, carrot, potato, sweet potato, mungbean, and onion. GST activities were detected in all of the vegetables, and the extract of onion bulb exhibited the highest specific activity(648 nmol/min/mgP). The putative GSTs of most of the vegetables were found to be induced by ethanol. The activities of GSTs in onion bulb were found to be markedly inhibited by S-hexyl glutathione and were also inhibited by S-butyl glutathione and S-propyl glutathione. The anti-CmGSTF1 antiserum recognized a thick band for putative onion GST. The estimated glyoxalase-I activity level was also high in onion bulb(4540 nmol/min/mgP), indicating that the thick band detected by Western blot analysis might result from partial recognition of glyoxalase-I by the antiserum. The specific activities for glyoxalase-I were moderate in radish and carrot, and the extracts of other vegetables had rather low levels of activities. The extract of onion also showed the highest specific activity level for alliinase(2069nmol pyruvate/mgP). The extracts of other vegetables also had alliinase activities, although the estimated values were much lower than that of onion.

• Animal Bioscience
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• 제36권9호
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• pp.1403-1413
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• 2023

Objective: Intestinal alkaline phosphatase (IAP) maintains intestinal homeostasis by detoxifying bacterial endotoxins and regulating gut microbiota, and lipid absorption. Antibiotics administered to animals can cause gut dysbiosis and barrier disruption affecting animal health. Therefore, the present study sought to investigate the role of IAP in the intestinal environment in dysbiosis. Methods: Young male mice aged 9 weeks were administered a high dose of antibiotics to induce dysbiosis. They were then sacrificed after 4 weeks to collect the serum and intestinal organs. The IAP activity in the ileum and the level of cytokines in the serum samples were measured. Quantitative real-time polymerase chain reaction analysis of RNA from the intestinal samples was performed using primers for tight junction proteins (TJPs) and proinflammatory cytokines. The relative intensity of IAP and toll-like receptor 4 (TLR4) in intestinal samples was evaluated by western blotting. Results: The IAP activity was significantly lower in the ileum samples of the dysbiosis-induced group compared to the control. The interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha concentrations were significantly higher in the ileum samples of the dysbiosis-induced group. The RNA expression levels of TJP2, claudin-3, and claudin-11 showed significantly lower values in the intestinal samples from the dysbiosis-induced mice. Results from western blotting revealed that the intensity of IAP expression was significantly lower in the ileum samples of the dysbiosis-induced group, while the intensity of TLR4 expression was significantly higher compared to that of the control group without dysbiosis. Conclusion: The IAP activity and relative mRNA expression of the TJPs decreased, while the levels of proinflammatory cytokines increased, which can affect intestinal integrity and the function of the intestinal epithelial cells. This suggests that IAP is involved in mediating the intestinal environment in dysbiosis induced by antibiotics and is an enzyme that can potentially be used to maintain the intestinal environment in animal health care.

• Applied Biological Chemistry
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• 제31권3호
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• pp.241-248
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• 1988

서양종(西洋種) 꿀벌(Apis mellifera L)에 대(對)한 살충제의 독성(毒性) 및 해독능력(解毒能力)을 조사(調査)하고 농약한계사용량(農藥限界使用量) 결정(決定)에 기여(寄與)하기 위하여 7가지 대표적(代表的)인 살충제의 꿀벌에 대한 독성(毒性)및 해독효소(解毒酵素)의 활성(活性)을 조사(調査)하였다. 효소활성(酵素活性)은 해독효소(解毒酵素)로 알려진 microsomal oxidases, glutathione S-transferases, esterases 와 DDT-dehydrochlorinase를 조사(調査)했고 성충(成？)일별의 중장(中腸)을 사용(使用)하여 측정(測定)하였다. $LC_{50}$치(値)의 측정결과(測定決果) 공시(供試) 살충제중(殺？劑中) DDT가 58ppm으로 독성(毒性)이 가장 낮았고 EPN이 1.61ppm으로 독성(毒性)이 가장 강(强)했다. 준치사농도(準致死濃度)의 농약(農藥)이 성충(成？)일벌의 microsomal oxidase에 미치는 영향은 malathion 및 permethrin 처리(處理)가 aldrin epoxidase 활성(活性)을 저해(沮害)시켰고 N-demethylase 활성(活性)은 diazinon 처리구(處理區)에서 증대(增大)되었다. Ghtathione S-transferarse(DCNB conjugation) 활성(活性)은 diazinon과 permethrin 처리구(處理區)에서 증대(增大)되었다. Esterase는 malathion 및 permethrin 처리구(處理區)에서 ${\alpha}-NA$ esterase활성(活性)의 저해(沮害)를 보였고 diazinon처리구(處理區)에서 carboxylesterase활성(活性)이 증대(增大)되었으며 AChE 활성(活性)은 거의 영향(影響)이 없었다. DDT-dehy drochlorinase활성(活性)은 carbaryl 및 permethrin 처리구(處理區)에서 증대(增大)되었다.

• Applied Biological Chemistry
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• 제41권4호
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• pp.228-234
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• 1998

An adaptive measure of photosynthetic cells to a condition identified with a reduction of cellular energy charge, caused by water deficit-induced impairment of photosynthetic ATP production, was investigated using hydroponically cultured rice seedlings. Water stress treatment of the seedlings resulted in a marked decrease in cellular ATP level, a significant increase in the content of NAD(H) and concurrent decrease in that of NADP(H) in shoots, which accompanied a decrease in the activity of NAD kinase (EC 2.7.1.23) that specifically converts NAD(H) to NADP(H). The decline in the enzyme activity was particularly evident in the $Ca^{2+}/calmodulin-dependent$ kinase, the major form of NAD kinase in plants, whereas the level of active calmodulin remained unchanged during water deficit. The ratio of $NADP^+$ to NADPH was maintained nearly constant and no increases were seen in the level of $H_2O_2$ and the activities of $superoxide/H_2O_2-detoxifying$ enzymes in shoots stress-treated for two days. Based on these results, it may be suggested that rice plants take a strategy to cope with an adverse situation of limited photophosphorylation created by water deficit in that cells facilitate ATP production through glycolysis and oxidative phosphorylation; in doing so, rice cells suppress NAD kinase activity, consequently up-sizing the NAD(H) pool at the expense of the NADP(H) pool. Several parameters associated with the stress symptoms are also of implicative that there is no overproduction of superoxide radical or the related active oxygen at least in rice seedlings.

• Toxicological Research
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• 제25권1호
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• pp.23-28
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• 2009

Some of the edible plants like apricot kernel, flaxseed, and cassava generate hydrogen cyanide (HCN) when cyanogenic glycosides are hydrolyzed. Rhodanese (thiosulfate: cyanide sulfurtransferases of TSTs; EC: 2.8.1.1) is a sulfide-detoxifying enzymes that converts cyanides into thiocyanate and sulfite. This enzyme exists in a liver and kidneys in abundance. The present study is to evaluate the conversion of apricot cyanogenic glycosides into thiocyanate by human hepatic (HepG2) and colonal (HT-29) cells, and the induction of the enzymes in the rat. The effects of short term exposure of amygdalin to rats have also been investigated. Cytosolic, mitochondrial, and microsomal fractions from HepG2 and HT-29 cells and normal male Spraque-Dawley rats were used. When apricot kernel extract was used as substrate, the rhodanese activity in liver cells was higher than the activity in colon cells, both from established human cell line or animal tissue. The cytosolic fractions showed the highest rhodanese activity in all of the cells, exhibiting two to three times that of microsomal fractions. Moreover, the cell homogenates could metabolize apricot extract to thiocyanate suggesting cellular hydrolysis of cyanogenic glycoside to cyanide ion, followed by a sulfur transfer to thiocyanate. After the consumption of amygdalin for 14 days, growth of rats began to decrease relative to that of the control group though a significant change in thyroid has not been observed. The resulting data support the conversion to thiocyanate, which relate to the thyroid dysfunction caused by the chronic dietary intake of cyanide. Because Korean eats a lot of Brassicaceae vegetables such as Chinese cabbage and radish, the results of this study might indicate the involvement of rhodanese in prolonged exposure of cyanogenic glycosides.

• 한국약용작물학회지
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• 제15권1호
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• pp.21-25
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• 2007

해당화 뿌리는 우리나라 민간에서 당뇨병 치료제로 사용되는 약용식물이다. Bromobenzene으로 간독성을 유발한 흰쥐에 뿌리에서 분리한 화합물인 (+)-catechin을 경구투여하여 bromobenzene대사계에 미치는 효소활성을 간독성 물질인 bromobenzene 3,4-oxide 생성에 관여하는 효소인 aminopyrine N-demetylase와 aniline hydroxylase와 독성 epoxide 대사중간체를 무독화 시키는 epoxide hydrolase와 glutathione S-transferase에 활성을 관찰하였다. (+)-Catechin의 투여가 aminopyrine N-demetylase, aniline hydroxylase 및 glutathione S-transferase에 활성에는 영향을 주지 못하였으나, epoxide hydrolase는 positive control로 사용한 ascorbic acid에 미치지 못하지만, bromobenzene 처리군 보다 39% 효소활성을 회복 시켰다. 따라서, (+)-catechin은 간독성 물질을 무독화시키는 epoxide hydrolase의 활성을 회복시켜 간보호 활성을 나타냄을 알 수 있었으며, 해당화에서 분리한 사포닌 성분인 rosamultin도 이효소의 활성을 증가시킴으로 인해 보호활성을 나타내는 것으로 보고된바 있다.

• 대한약리학회지
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• 제26권2호
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• pp.185-192
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• 1990

Diallyl disulfide의 간손상 예방효과를 검토할 목적으로 mouse에 bromobenzene을 투여해 간 손상의 model을 만든 다음 실험을 행하였을 때, diallyl disulfide를 전처치한 실험군이 대조군에 비하여 간손상의 정도가 경미하게 나타났다. 한편 diallyl disulfide의 간손상예방 효과 기전을 구명할 목적으로 bromobenzene의 활성화 및 해독 관련 효소들의 활성을 검토하였을때 활성화 효소인 aniline hydroxylase와 해독 효소의 일종인 epoxide hydrolase의 활성은 diallyl disulfide 전처치에 의해 변동이 없었으나, 나머지 해독 효소인 glutathione S-transferase의 활성은 유의 하게 증가되었고 이의 포합인자인 glutathione의 함량도 증가하였다. 또한 diallyl disulflde에 의한 glutathione S-transferase 활성 증가현상이 어떠한 기전으로 나타나는지 검토 하였을때, diallyl disulfide를 전처치 함으로서 Km치는 별다른 차이가 없었으나 Vmax치는 대단히 증가하였다. 그러나 시험관내에서 diallyl disulfide의 첨가농도를 증가시켰을 때에는 효소활성은 변하지 않았다. 이러한 실험결과들을 종합해 볼 때, diallyl disulfide 전처치에 의한 bromobenzene이 유도한 간손상의 예방효과는 diallyl disulfide가 bromobenzene의 독성 중간 대사산물인 bromobenzene 3,4-oxide를 해독하는 glutathione S-transferase 단백의 합성을 유도함으로서 나타난 결과로 사료되어지나 이점에 대해서는 추후 계속적인 연구 검토가 행해져야 할것이다.