• Asian Pacific Journal of Cancer Prevention
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• v.16 no.8
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• pp.3371-3376
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• 2015

Pigmented rice bran has been suggested to be a valuable source of beneficial phytochemicals. We investigated genotoxic and anti-genotoxic effects of purple rice bran extract (PRBE) in rats using a liver micronucleus assay. Purple rice bran was extracted with methanol, obtaining large amounts of phenolic compounds, including anthocyanins and small amounts of gamma-oryzanol. The experimental protocols were divided into two sets. Male rats were divided into three groups. Group 1 was a negative control, while Groups 2 and 3 were fed with 100 and 500 mg/kg bw of PRBE, respectively, for 28 days. PRBE had no effect on micronucleus formation or xenobiotic metabolizing enzymes in rat liver. Experiments concerning the effect of PRBE on $AFB_1$ showed that PRBE significantly lessened the amount of micronucleated hepatocytes in $AFB_1$ treated rats. Furthermore, it modulated metabolic activation of $AFB_1$ metabolism in the liver by suppressing activity and protein expression of CYP1A2, CYP3A and CYP 450 reductase, and enhancing phase II enzymes including GST and UGT. Overall, purple rice bran extract was not genotoxic in rats. It exhibited anti-genotoxicity by modulation some xenobiotic enzymes active in $AFB_1$ metabolism.

• Toxicological Research
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• v.23 no.1
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• pp.73-78
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• 2007

To evaluate the immuno-toxicity of magnolia extracts, mutagenicity of Salmonella, chromosome aberration of Chinese hamster ovary (CHO) cells and micronucleus formation in rats were examined. Magnolia extracts at the concentrations of $312{\sim}5,000{\mu}g/plate$ did not induce mutagenicity in Salmonella typhimurium TA 98, TA 100 and TA 1535 with and without metabolic activation of S-9 mixture. In chromosome aberration assay, Magnolia extracts at the concentrations of $50{\sim}800{\mu}g/plate$ did not cause a significant chromosome aberration in CHO cells with and without metabolic activation of S-9 mixture. Magnolia extracts were treated with dose of 0.5, 1 and 2 g/kg in ICR mice. After 48 hours, the frequencies of the micro-nucleided polychromasia erythrocytes (MNPCE) were determined in bone marrows isolated from the mice. Magnolia extracts did not increase the incidence of polychromasia erythrocytes of bone marrow in ICR mice. These results show that Mgnolia extracts did not induce any harmful genotoxic effects.

• Environmental Analysis Health and Toxicology
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• v.28
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• pp.3.1-3.8
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• 2013

Objectives We investigated the genotoxic effects of 40-59 nm silver nanoparticles (Ag-NPs) by bacterial reverse mutation assay (Ames test), in vitro comet assay and micronucleus (MN) assay. In particular, we directly compared the effect of cytochalasin B (cytoB) and rat liver homogenate (S9 mix) in the formation of MN by Ag-NPs. Methods Before testing, we confirmed that Ag-NPs were completely dispersed in the experimental medium by sonication (three times in 1 minute) and filtration ($0.2{\mu}m$ pore size filter), and then we measured their size in a zeta potential analyzer. After that the genotoxicity were measured and especially, S9 mix and with and without cytoB were compared one another in MN assay. Results Ames test using Salmonella typhimurium TA98, TA100, TA1535 and TA1537 strains revealed that Ag-NPs with or without S9 mix did not display a mutagenic effect. The genotoxicity of Ag-NPs was also evaluated in a mammalian cell system using Chinese hamster ovary cells. The results revealed that Ag-NPs stimulated DNA breakage and MN formation with or without S9 mix in a dose-dependent manner (from $0.01{\mu}g/mL$ to $10{\mu}g/mL$). In particular, MN induction was affected by cytoB. Conclusions All of our findings, with the exception of the Ames test results, indicate that Ag-NPs show genotoxic effects in mammalian cell system. In addition, present study suggests the potential error due to use of cytoB in genotoxic test of nanoparticles.

• Natural Product Sciences
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• v.4 no.2
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• pp.105-114
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• 1998

The antimutagenic activity of a methanol extract of Ecklonia stolonifera (Laminariaceae) against aflatoxin $B_1\;(AFB_1)$ was demonstrated with the Salmonella typhimurium assay. The numbers of revertants per plate decreased significantly when this extract was added to the assay system using S. Salmonella typhimurium TA100. The methanol extract also exhibited significant inhibitory effects on the micronuclei formation in mouse peripheral blood reticulocytes and the DNA damage in mouse spleen lymphocytes induced by N-methyl-N-nitrosourea (MMU) and benzo(a)pyrene (B(a)P). The MeOH extract was then sequentially partitioned with $CH_2Cl_2,\;CH_2Cl_2$ insoluble intermediate, EtOAc, n-BuOH, and $H_2O$. All fractions possessed antimutagenic activity but the $H_2O$ fraction was inactive. Among active fractions, the EtOAc and $CH_2Cl_2$ insoluble intermediate fractions showed the highest activity. Column chromatography using $SiO_2$ and Sephadex LH-20 yielded phloroglucinol from the EtOAc fraction. Phloroglucinol also demonstrated significant antimutagenic activity, and inhibitory effects on the micronuclei formation in mouse peripheral blood reticulocytes and DNA damage in mouse spleen lymphocytes induced by MMU and B(a)P.

• YAKHAK HOEJI
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• v.48 no.2
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• pp.111-116
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• 2004

The ethanol extracts of mixed vegetables (Bioactive Vegetables, BV), mixed fruits (Bioactive Fruits, BF) and their liquid formulation (Chungpae Plus , CP) were evaluated for their antioxidative and antigenotoxic activities. They were shown to possess the significant free radical scavenging effect against 1,1-diphenyl-2-picryl hydrazine (DPPH) radical generation and were revealed to show the inhibitory effect of lipid peroxidation as measured by malondialdehyde (MDA) formation although the potencies were not higher than those of vitamin C. They did not possess any pro-oxidant effect on bleomycin-Fe(III) dependent DNA degradation, whereas vitamin C showed strong pro-oxidant effect. Furthermore, oral administration of BV and BF inhibited micronucleated reticulocyte (MNRET) formation of mouse peripheral blood induced by KBrO3 treatment in vivo. CP also showed significant inhibition under same experimental condition. Therefore, the liquid formulation (CP) containing BV and BF may be a useful natural antioxidative and antigenotoxic agent by scavenging free radicals, inhibition of lipid peroxidation and protecting chromosomal damage.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.3
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• pp.211-216
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• 2016

Micronucleus test is genotoxicity assay for detection of micronuclei in the cytoplasm of interphase cells. The reduction and replacement of in vivo toxicity testing on animals require the development of in vitro models to predict the genotoxicity or other tests for cosmetic products. In this study, we evaluated a genotoxicity assay for topically applied chemicals using a three-dimensional human reconstructed skin model, KeraSkin$^{TM}$. Two genotoxins, mitomycin C (MMC) and methyl methanesulfonate (MMS), induced significant dose-related increases in cytotoxicity and micronuclei induction in the skin model. In contrast, two non-genotoxins, 4-nitrophenol (4-NP) and trichloroethylene (TCE), induced cytotoxicity but not micronucleus formation. In conclusion, micronucleus test using human skin model may be useful for predicting in vitro genotoxic potentials of cosmetic products.

• Journal of Preventive Medicine and Public Health
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• v.30 no.3 s.58
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• pp.555-566
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• 1997

This study was carried out to evaluate the cytotoxicity of rock wool fibers(RWFs) such as cell division disturbance, chromosomal and DNA damage, and mutagenicity using cultured cells. RWFs were the man made mineral fibers. In order to find the correlation between the cytotoxicity of RWFs and the phagocytic capacity of cells, the phagocytic processes were observed using scanning electron microscope. Cell division disturbance by RWFs was evaluated by the formation of multinucleated giant cells. The chromosomal damage was evaluated by the micronucleus formation. For the evaluation of oxidative DNA damage, 8-hydroxy-2'-deoxyguanosine (8-OH-dG) formation was measured utilizing calf thymus DNA. Mutagenicity was determined by the point mutation of HGPRT and the effect of RWFs on cell transformation was also observed. 1. Compared with the results of chrysotile, RWFs were no or little effect on the cell growth according to the results done by the tests of cell proliferation inhibition and relative plating efficiency. 2. The frequency of multinucleated giant cell formation was increased by the treatment of RWFs and it was dose-dependent. However, the effect of RWFs was weaker than that of chrysotile. 3. The number of micronuclei formed in the RWFs treated cells was between those of cells treated with chrysotile and those of untreated cells. 4. The 2 fold increase in the formation of 8-OH-dG in calf thymus DNA was observed in the cells treated with RWFs in the presence of $H_2O_2$. On the other hand, chrysotile had no effect on the 8-OH-dG formation. 5. RWFs had no effect on the HGPRT point mutation and cell transformation. These results showed that RWFs could induce chromosomal damage, cell division disturbance and oxidative DNA damage in the RWFs treated cells.

• Archives of Pharmacal Research
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• v.21 no.6
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• pp.683-687
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• 1998

We have examined in vitro and in vivo radioprotective effects of a well-known thiol-containing compound, dithiothreitol (DTT). The treatment of both 0.5 and 1mM of DTT significantly increased clonogenic survival of ${\gamma}$-ray irradiated Chinese hamster (V79-4) cells. In order to investigate the possible radioprotective mechanism of DTT, we measured gamma-ray induced chromosome aberration by micronucleus assay. In the presence of 0.5mM or 1mM DTT, the frequencies of micronuclei were greatly reduced in all dose range examined (1.5-8 GY). Slightly higher reduction in micronucleus formation was observed in 1mM DTT-treated cells than in 0.5mM DTT-treated cells. In addition, incubation with both 0.5 and 1mM of DTT prior to gamma-ray irradiation reduced nucleosomal DNA fragmentation at about same extent, this result suggests that treatment of DTT at concentrations of 0.5 and 1mM reduced radiation-induced apoptosis. In vivo experiments, we also observed that DTT treatment reduced the incidence of apoptotic cells in mouse small intestine crypts. In irradiated control group 4.4${\pm}$0.5 apoptotic cells per crypt were observed. In DTT-administered and irradiated mice, only 2.1${\pm}$0.4 apoptotic cells per crypt was observed. In vitro and in vivo data obtained in this study showed that DTT reduced radiation-induced damages and it seems that the possible radioprotective mechanisms of action of DTT are prevention of chromosome aberration.

• Environmental Analysis Health and Toxicology
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• v.30
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• pp.14.1-14.7
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• 2015

Objectives Cigarette smoking is associated with carcinogenesis owing to the mutagenic and genotoxic effects of cigarette smoke. The aim of this study was to evaluate the mutagenic and genotoxic effects of Korean cigarettes using in vitro assays. Methods We selected 2 types of cigarettes (TL and TW) as benchmark Korean cigarettes for this study, because they represent the greatest level of nicotine and tar contents among Korean cigarettes. Mutagenic potency was expressed as the number of revertants per ${\mu}g$ of cigarette smoke condensate (CSC) total particulate matter whereas genotoxic potency was expressed as a concentration-dependent induction factor. The CSC was prepared by the International Organization for Standardization 3308 smoking method. CHO-K1 cells were used in vitro micronucleus (MNvit) and comet assays. Two strains of Salmonella typhimurium (Salmonella enterica subsp. enterica ; TA98 and TA1537) were employed in Ames tests. Results All CSCs showed mutagenicity in the TA98 and TA1537 strains. In addition, DNA damage and micronuclei formation were observed in the comet and MNvit assays owing to CSC exposure. The CSC from the 3R4F Kentucky reference (3R4F) cigarette produced the most severe mutagenic and genotoxic potencies, followed by the CSC from the TL cigarette, whereas the CSC from the TW cigarette produced the least severe mutagenic and genotoxic potencies. Conclusions The results of this study suggest that the mutagenic and genotoxic potencies of the TL and TW cigarettes were weaker than those of the 3R4F cigarette. Further study on standardized concepts of toxic equivalents for cigarettes needs to be conducted for more extensive use of in vitro tests.

• Toxicological Research
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• v.23 no.3
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• pp.245-251
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• 2007

Water extract of Cordyceps militaris grown upon Protuetja dreujtarsis (CMPD) was examined for the genetic toxicity-bacterial mutagenicity, chromosome aberration, and micronucleus formation. For mutagenicity assay, bacterial reversion test with Salmonella typhimurium TA98, TA100, TA1535, TA 1537, and E. coli WP2uvrA were performed. The extract at the concentrations of $50{\sim}5,000{\mu}g/plate$ did not induce mutagenicity at all. Chromosome aberration test was performed by using Chinese lung (CHL) cells. There was no significant chromosome aberration in CHL cells with S-9 mixture at the concentrations of $312.5{\sim}1,250{\mu}g/ml$ of the extract and without S-9 mixture at the concentrations of $1.2{\sim}19.5{\mu}g/ml$ of the extract. For micronucleus test, ICR mice were treated with the extract at the dose of 0.5, 1, and 2g/Kg. The frequencies of the micronucleated polychromatic erythrocytes (MNPCE) in bone marrow preparations of the extract-treated group were not increased compared to the untreated control group. Taken together, our results show that water extract of CMPD did not induce any harmful genotoxicity.