• Korean Journal of Weed Science
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• v.14 no.1
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• pp.8-15
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• 1994

The mode of safening action and potency of the 1, 8-naphthalic anhydride(NA) were investigated in corn(Zea mays) and soybean(Glycine max) treated with herbicide bensulfuron[2-{{{{{(4,6-dimethoxy-2-pyrimidinyl)amino}carbonyl}amino}sulfonyl}methyl}benzoic acid] and imazaquin[2-{4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl} 3-quinolinonecarboxylic acid]. Seed dressing with 0.2%(w/w) NA showed successful protection in corn against injury from herbicide bensulfuron and imazaquin but not in soybean. Safening factors of NA against bensulfuron and imazaquin were 10.2 and 5.0, respectively, in corn, while they were both 1.3 in soybean. In vivo, Glutathione-S-transferase(GST) activity of NA-treated corn and soybean increased 1.8-and 1.3-fold, respectively, but the activity was not affected by the herbicides in vitro. Acetolactate synthase(ALS) levels of NA-treated corn was increased 1.3-fold, but not changed in soybean. Tolerance of ALS activity to the herbicides was slightly greater in ALS obtained from NA-treated corn than that from the untreated, whereas the difference was not found in soybean. A significant increase of ACCase due to NA occurred in corn, but not in soybean. The herbicides did not affect in vitro ACCase activity.

• Applied Biological Chemistry
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• v.35 no.5
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• pp.367-374
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• 1992

This study was performed to investigate effects of probable detoxifying enzyme activity and toxicity by pesticides and their combinations in the fresh water fish. Seven pesticides including IBP, isoprothiolane, cartap, ridomil, chlorothalonil, captafol and endosulfan were subjected to investigate for their acute toxicites and synergism possibilities. The $LC_{50}$ value of endosulfan was the lowest at showing 0.0079 ppm and that of metalaxyl was the highest as showing 40 ppm over. The synergism effects of relative pesticides were observed in the combinations of isoprothiolane+IBP and isoprothiolane+cartap. The changes of glycogen contents in fish liver were assayed for 5 pesticides and its highest inhibition effect of glycogen showed in IBP treated fish. The activity of probable detoxifying enzymes including carboxylesterase (CE), glutathion S-transferase (GST) and lactate dehydrogenase (LDH) were assayed in carp liver at dose of sublethal concentrations. Effects of pesticides on changes in each enzyme activities were as follows: carboxylesterase (CE) activities were the highest in IBP and gtutathion S-transferase (GST) activities were the highest in iosoprothiolane+IBP. Both activities of carboxylesterase (CE) and glutahtion S-transferase (GST) were increased by 5 chemicals. The highest LDH activity showed in isoprothiolane treated fish, while the lowest activity was observed in isoprothiolane+cartap. Sublethal exposure to cartap and isoprothiolane+cartap in carp exerted various effects on LDH activity.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.749-755
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• 2014

Background: Purple rice has become a natural product of interest which is widely used for health promotion. This study investigated the preventive effect of purple rice extract (PRE) mixed diet on DMH initiation of colon carcinogenesis. Materials and Methods: Rats were fed with PRE mixed diet one week before injection of DMH (40 mg/kg of body weight once a week for 2 weeks). They were killed 12 hrs after a second DMH injection to measure the level of $O^6$-methylguanine and xenobiotic metabolizing enzyme activities. Results: In rats that received PRE, guanine methylation was reduced in the colonic mucosa, but not in the liver, whereas PRE did not affect xenobiotic conjugation, with reference to glutathione-S-transferase or UDP-glucuronyl transferase. After 5 weeks, rats that received PRE with DMH injection had fewer ACF in the colon than those treated with DMH alone. Interestingly, a PRE mixed diet inhibited the activity of bacterial ${\beta}$-glucuronidase in rat feces, a critical enzyme for free methylazoxymethanol (MAM) release in the rat colon. These results indicated that purple rice extract inhibited ${\beta}$-glucuronidase activity in the colonic lumen, causing a reduction of MAM-induced colonic mucosa DNA methylation, leaded to decelerated formation of aberrant crypt foci in the rat colon. Conclusions: The supplemented purple rice extract might thus prevent colon carcinogenesis by the alteration of the colonic environment, and thus could be further developed for neutraceutical products for colon cancer prevention.

• Molecular & Cellular Toxicology
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• v.1 no.4
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• pp.268-274
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• 2005

Bromobenzene (BB) is well known hepatotoxicant. Also, BB is an industrial solvent that arouses toxicity predominantly in the liver where it causes centrilobular necrosis. BB is subjected to Cytochrome P450 mediated epoxidation followed by either conjugation with glutathione, enzymatic hydrolysis or further oxidation. In this study, we focused on BB-induced gene expression at non-hepatotoxic dose. Mice were exposed to two levels of BB, sampled at 24 h, and hepatic gene expression levels were determined to evaluate dose dependent changes. When examining the toxic dose of BB treated group in other previous studies, genes related to heat shock protein, oxidative stress, and drug metabolism are expressed. Compared to these results, our study, in which non-toxic dose of BB was administrated, showed similar patterns as the toxic conditions above. The purpose of the study was to select genes that showed changes in relation to the differing dose through confirmation of the difference within transcriptomic boundaries, but those that are not detected by the existing classic toxicology tools in non-hepatotoxic dose.

• Journal of Life Science
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• v.24 no.1
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• pp.98-103
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• 2014

NAD(P)H quinone oxidoreductase 1 (NQO1) is a flavoprotein that catalyzes the two electron reduction of diverse substrates, including quinones. It uses NADH or NADPH as a cofactor for enzymatic machinery. In the metabolism of quinones, NQO1 has two conflicting functions because of the different stability of converted hydroquinones. The stable form of hydroquinone is excreted from cells by conjugation with glutathione or glucuronic acid. The unstable form of hydroquinone induces cell death by induction of oxidative stress and DNA damage. Certain quinones known as bio-reductive agents have a cytotoxic function following reduction by NQO1. Bio-reductive agents, such as ${\beta}$-lapachone or mitomycin C, induce the depletion of NAD(P)H and the generation of oxidative stress in an NQO1-dependent manner. NQO1 is highly expressed in several cancer tissues. Therefore, NQO1 is a good therapeutic target for cancer treatment with bio-reductive agents.