Mutagenicity of water-soluble FePt nanoparticles in Ames test

A mutagenicity test was conducted on water-soluble FePt nanoparticles capped with tetramethylammonium hydroxide in a bacterial reverse mutation assay using Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537, and Escherichia coli strain WP2uvrA/pKM101, with and without metabolic activation by S9 mix in the preincubation method. Mutagenicity was weakly positive in the TA100 strain without S9 mix (maximum specific activity was 61.6 revertants/mg), but negative in other cases.     

Studies of the toxicological potential of tripeptides (L-valyl-L-prolyl-L-proline and L-isoleucyl-L-prolyl-L-proline): IX. Evaluation of the mutagenic potential of synthesized L-valyl-L-prolyl-L-proline in the Salmonella-Escherichia coli/microsome, incorporation assay

The objective of this study was to assess the mutagenic potential of a synthesized tripeptide, L-valyl-L-prolyl-L-proline (VPP), to induce mutational changes in Salmonella typhimurium LT2 strains TA1535, TA1537, TA98, and TA100, and Escherichia coli strain WP2uvrA in the classical Ames test protocol. Bacteria were exposed to plate concentrations of VPP of 0, 156.2, 312.5, 625, 1250, 2500, and 5,000 microg/plate in distilled water, in the presence and absence of Aroclor 1254-induced rat liver homogenate preparation (S9). Positive-control agents included sodium azide (TA100 and TA1535); 2-aminoanthracene (TA98, TA100, TA1535, TA1537, and WP2uvrA); 9-aminoacridine (TA1537); 2-nitrofluorene (TA98); and N-ethyl-N'-nitro-N-nitrosoguanidine (WP2uvrA) in DMSO. Incubations were conducted at 37 degrees C for about 48 h then revertant colonies were counted. All positive-control agents were consistently and unequivocally positive, but there was no evidence that VPP induced increases in the incidences of revertant colonies in any bacterial strain with and without metabolic activation. These findings were replicated in a second, confirmatory test performed with and without S9. The results of the experiments revealed no treatment-associated changes in the incidence of revertant colonies in any bacterial strain tested. These results support a conclusion that, under the experimental conditions described, there is no evidence that VPP possesses mutagenic potential.     

An investigation of the mutagenic activity of salamide – a major impurity of hydrochlorothiazide

Hydrochlorothiazide is a widely used antihypertensive agent and one of its major impurities, salamide (4-amino-6-chlorobenzene-1,3-disulphonamide), has a chemical structure containing a primary amino group, a functional group that has previously been reported to be associated with carcinogenic activity. It is known that hydrochlorothiazide purity is a challenging problem for the pharmaceutical industry. As there were no prior mutagenicity data for the impurity salamide, the aim was to investigate its mutagenicity in this study. Salamide was tested for mutagenic potential in Salmonella typhimurium TA98, TA100, TA 1535, TA 1537, and E. coli WP2 uvrA?+?E. coli WP2 [pKM101] strains at six different concentrations, the highest concentration being the 5000?μg/plate. In both the presence and absence of the metabolic activation system, no mutagenic activity was observed. Results indicated that salamide should be classified as an ordinary impurity and controlled according to Q3A(R2) and Q3B(R2) guidelines.     

Mutagenicity study of nine monoalkyl phthalates and a dialkyl phthalate using Salmonella typhimurium and Escherichia coli

Nine monoalkyl (C1-C8) phthalates and di-(2-ethylhexyl) phthalate (DEHP) were assayed for mutagenicity in two strains of Salmonella typhimurium (TA98 and TA100) and two strains of Escherichia coli WP2 try- (uvrA+ and uvrA-) with and without metabolic activation with S-9 mix. The procedure of Ames et al. (Mutation Res. 1975, 31, 347) was used, with minor modifications. None of the compounds tested showed any mutagenic activity, but all the monoalkyl phthalates showed some lethality towards the S. typhimurium strains, the most toxic being monoheptyl phthalate. A marginally lethal effect on the Salmonella strains was shown by DEHP, but only at the highest concentration tested (2000 micrograms/plate) and in the absence of S-9 mix.     

Mutagenicity tests on propiverine hydrochloride

1. The reverse mutation test was carried out on propiverine hydrochloride (P-4) at dose range of 5-500 micrograms/plate use Salmonella typhimurium strains, TA100, TA98, TA1535 and TA1537, and Escherichia coli strain WP2uvrA. As compared with solvent-treated control, no significant increases were observed in the number of revertant colonies in all tester strains in both systems with and without mammalian metabolic activation (S9 Mix). 2. The chromosomal aberration test was also carried out on P-4 using cultured Chinese hamster lung cells (CHL). The cells were treated with P-4 at the doses of 5, 10, 20 and 40 microM without S9 Mix and at 62.5, 125, 250 and 500 microM with S9 Mix. No significant differences were found in the incidence of structural- and numeral-aberrations of chromosomes in both systems with and without S9 Mix. 3. These results indicate that P-4 has no mutagenic activity.     

Participation of BER and NER pathways in the repair of DNA lesions induced at low N-nitrosodiethylamine concentrations

In the present work, we evaluated (p < 0.05) the participation of base excision repair (BER) and nucleotide excision repair (NER) mechanisms in repairing DNA lesions induced by N-nitrosodiethylamine (NDEA) at 1.5 ng/mL-36.5 microg/mL, through cell survival, in different single and double Escherichia coli DNA repair mutants (uvrA, uvrB, uvrC, fpg, nth, xthA, fpg/nth, uvrA/fpg, fpg/xthA, mutY, and fpg/mutY), using pre-incubation periods of 90 min. Mutant strains BH20 (fpg) and AB1886 (uvrA) showed microsomal enzyme (S9 mix) independent NDEA cytotoxicity. Cytotoxicity was also detected at lowest NDEA concentrations, in the presence of S9 mix, with strains BH980 (mutY) and BH990 (fpg/mutY). NDEA cytotoxicity, without S9 mix, was detected for mutant strains AB1884 (uvrC) and AB1885 (uvrB). Through SOS chromotest with 90 min of pre-incubation for uvrA and nth strains, only NER was shown to be required for repairing NDEA-induced lesions with or without metabolic activation. PQ37 and PQ66 strains, both uvrA mutants, showed different levels of NDEA sensitivity. The findings suggest that, under the used conditions, and at low concentrations, NDEA-induced lesions require both repair pathways.     

Implication of nitro group reduction in the mutagenic and chromosome damaging activities of 22 new 5-nitroisoquinolines by the Salmonella mutagenicity test and the cytokinesis-blocked micronucleus assay.

The mutagenic (MUT) and chromosome-damaging (CHR) activities of 22 potential antimalarial drugs (5-nitroisoquinoline derivatives) were evaluated by the Salmonella test and the cytokinesis-blocked micronucleus assay (CBMN). The Salmonella mutagenicity test was performed with and without metabolic activation (S9 mix) in S. typhimurium strains TA100 and YG1042 (an overproducing nitroreductase and O-acetyltransferase TA100 strain). The CBMN was carried out on human lymphocytes without metabolic activation. Four concentrations were tested: 1, 10, 100 and 1000 ng/ml. MUT was expressed as minimal mutagenic concentrations (MMC, microM) and CHR was expressed as minimal chromosome-damaging concentrations (MCDC, nM) to compare both activities. All the 5-nitroisoquinoline compounds were mutagenic in TA100. MMC ranged from 0.1 to 52.9 microM in TA100. A statistically significant decrease in MMC was observed in YG1042 (8 x 10(-3) to 3.5 microM), implicating reduction of the nitro group. Modulation of MUT by S9 mix was not significant in TA100 and YG1042. CHR was detected in 13 products for at least one concentration. Among the chromosome-damaging compounds, the MCDC ranged from 2.9 x 10(-3) to 3.6 nM. No relationship was found between MUT and CHR, suggesting two distinct pathways of DNA damage.     

Evaluation of the mutagenic and genotoxic potential of ubiquinol

Ubiquinol (the reduced form of coenzyme Q(10)) is the two-electron reduction product of ubiquinone (the oxidized form of coenzyme Q(10)), and has been shown to be an integral part of living cells, where it functions as an antioxidant in both mitochondria and lipid membranes. To provide information to enable a Generally Regarded as Safe (GRAS) evaluation for the use of ubiquinol in selected foods, a series of Organisation of Economic Cooperation and Development (OECD) and good laboratory practice (GLP) toxicological studies was conducted to evaluate the mutagenic and genotoxic potential of Kaneka QH brand of ubiquinol. Ubiquinol did not induce reverse mutations in Salmonella typhimurium strains TA100, TA1535, TA98, and TA1537 and Escherichia coli WP2uvrA at concentrations up to 5000 mu g/plate, in either the absence and presence of exogenous metabolic activation by rat liver S9. Likewise, ubiquinol did not induce chromosome aberrations in Chinese hamster lung fibroblast (CHL/IU) cells in short-term (6-h) tests with or without rat liver S9 at concentrations up to 5000 mu g/ml or in a continuous (24-h) treatment test at concentrations up to 1201 mu g/ml. Finally, no mortalities, no abnormal clinical signs, and no significant increase in chromosome damage were observed in an in vivo micronucleus test when administered orally at doses up to 2000 mg/kg/day. Thus, ubiquinol was evaluated as negative in the bacterial reverse mutation, chromosomal aberration, and rat bone marrow micronucleus tests under the conditions of these assays.     

Genotoxicity studies of cefmatilen hydrochloride hydrate (S-1090)

Cefmatilen hydrochloride hydrate (S-1090), a new non-ester type of orally active cephem antibiotic synthesized in Shionogi Research Laboratories, was evaluated for its genotoxic potential using three assay systems. In a reverse mutation test with bacteria of Salmonella typhimurium TA100, TA1535, TA98, and TA1537, and Escherichia coli WP2uvrA using the preincubation method, the number of revertant colonies in the S-1090 treated plates was almost equal to that in the negative control plates in all strains with and without metabolic activation system with S9 mix (maximum dose, 100 micrograms/plate in TA98). In a chromosomal aberration test with cultured Chinese hamster lung cells (CHL/IU), S-1090 did not induce structural chromosome aberrations or polyploid cells either in the absence or presence of S9 mix up to the 50% growth inhibition doses. The potential of inducing clastogenicity and/or disruption of mitotic apparatus in vivo by S-1090 was evaluated by a micronucleus test with bone marrow cells of male Jc1:ICR mice. S-1090 suspended in 0.5% aqueous methylcellulose was administered by oral gavage up to 2000 mg/kg/day in single and double dosing groups. No induction of micronucleated polychromatic erythrocytes was observed 24 hr after the last dosing in each group. As all three genotoxicity tests showed negative responses, S-1090 is thought to have no genotoxic potential.     

The antimutagenic activity of Lavandula angustifolia (lavender) essential oil in the bacterial reverse mutation assay.

Essential oils from Melaleuca alternifolia (tea-tree oil) and Lavandula angustifolia (lavender oil) are commonly used to treat minor health problems. Tea-tree oil possesses broad-spectrum antimicrobial activity, and is increasingly used for skin problems. Lavender oil, traditionally used as an antiseptic agent, is now predominantly used as a relaxant, carminative, and sedative in aromatherapy. Despite their growing use no data are available on their mutagenic potential. In this study, after determining the chemical composition of tea-tree oil and lavender oil, by gas-chromatography and mass spectrometry, we investigated their mutagenic and antimutagenic activities by the bacterial reverse mutation assay in Salmonella typhimurium TA98 and TA100 strains and in Escherichia coli WP2 uvrA strain, with and without an extrinsic metabolic activation system. Neither essential oil had mutagenic activity on the two tested Salmonella strains or on E. coli, with or without the metabolic activation system. Conversely, lavender oil exerted strong antimutagenic activity, reducing mutant colonies in the TA98 strain exposed to the direct mutagen 2-nitrofluorene. Antimutagenicity was concentration-dependent: the maximal concentration (0.80 mg/plate) reduced the number of histidine-independent revertant colonies by 66.4%. Lavender oil (0.80 mg/plate) also showed moderate antimutagenicity against the TA98 strain exposed to the direct mutagen 1-nitropyrene. Its antimutagenic property makes lavender oil a promising candidate for new applications in human healthcare.     

Antimutagenic effect of essential oil of sage (Salvia officinalis L.) and its monoterpenes against UV-induced mutations in Escherichia coli and Saccharomyces cerevisiae.

Mutagenic and antimutagenic potential of essential oil (EO) of cultivated sage (S. officinalis L.) and its monoterpenes: thujone, 1,8-cineole, camphor and limonene against UVC-induced mutations was studied with Salmonella/microsome, E. coli WP2, E. coli K12 [Simi?, D., Vukovi?-Gaci?, B., Knezevi?-Vukcevi?, J., 1998. Detection of natural bioantimutagens and their mechanisms of action with bacterial assay-system. Mutat. Res. 402, 51-57] and S. cerevisiae D7 reversion assays. The toxicity of EO differed, depending on the strain used. The most sensitive were permeable strains TA100, TA102, E. coli K12 IB112 and non-permeable WP2. Mutagenic potential of EO and monoterpenes was not detected, with or without S9. EO reduced the number of UV-induced revertants in a concentration-dependent manner, reaching 50-70% of inhibition at the maximum non-toxic concentrations: 3 microl/plate (TA102), 5 microl/plate (WP2), 7.5 microl/plate (IB112), 30 microl/plate (E. coli K12 SY252) and 60 microl/plate (D7). The metabolic activation had no effect on antimutagenic potential of EO. Similar toxicity of monoterpenes was observed in TA100, E. coli SY252 and D7, with the exception of limonene (less toxic to D7). Reduction of UV-induced revertants by non-toxic concentrations of monoterpenes, tested with SY252 and D7, reached 40-50% at 15-20 microl/plate of thujone, 10 microl/plate of cineole and 1-10 microg/plate of camphor. Limonene showed antimutagenic effect only in D7. Our data recommend sage monoterpenes for further chemoprevention studies.     

Mutagenic activity of organic esters are likely to form from bromo-2 ethanol generated during fumigation using ethylene oxide

The mutagenic potencies of 13 bromoethyl esters of natural organic acids, have been studied, by Ames's test (strains TA 98 and TA 100, with and without system of metabolisation, S9 mix). None of the 8 bromoethyl esters of linoleic, oleic, palmitic, stearic, lauric, myristic, cinnamic and fumaric acids is genotoxic. On the other hand the 5 others derived from gallic, oxalic, tartric acids (strain TA 100 with and without S9 mix), malic and citric acids (strain TA 100 with S9 mix) are mutagenic, the ester of gallic acid giving still a doubtful mutagenic response; their mutagenic potencies are 2 to 3 times smaller than that of bromo-2 ethanol. This observation, complemently with the mutagenicity of some organic esters of the chloro-2 ethanol, proves the potential danger of ethylene oxide used for the fumigation of foods or vegetables and medicinal plants containing much chloride and/or bromide.     

Mutagenicity studies on N-nitrosated products of the Maillard browning reaction: N-nitroso-fructose-amino acids

The N-nitroso derivatives of D-fructose-L-glycine, D-fructose-L-alanine, D-fructose-L-phenylalanine, D-fructose-L-serine, Dfructose-L-aspartic acid and D-fructose-L-tryptophan (a mixture of alpha-N-nitroso-D-fructose-L-tryptophan and 'indolyl-nitrosamine'-D-fructose-L-tryptophan) were tested for mutagenicity in five auxotrophic strains of Salmonella typhimurium with and without metabolic activation (S-9 mix). The alanine, phenylalanine and aspartic acid compounds were not mutagenic. The glycine and serine compounds showed a very low but reproducible increase in the numbers of his+ revertants in strain TA1535 without S-9 mix. The mixture containing both nitrosated D-fructose-L-tryptophan compounds was mutagenic in all five strains, with or without metabolic activation. The alpha-N-nitroso-D-fructose-L-tryptophan component of the mixture, which is nitrosated at the amino group, was isolated and tested without S-9 mix. It was mutagenic in three strains. Unnitrosated D-fructose-L-amino acids, D-fructose, and the individual L-amino acids were non-mutagenic when tested under those conditions for which a positive response had been obtained with the corresponding nitrosated compounds. These results indicate the potential value of developing analytical methods to identify alpha-N-nitroso-D-fructose-L-tryptophan in food or food extracts that are to be screened for mutagenic components.     

Antimutagenic and anticlastogenic effects of Turkish Black Tea on TA98 and TA100 strains of Salmonella typhimurium (in vitro) and mice (in vivo)

Context: Black tea has been reported to have significant antimutagenic and anticarcinogenic properties associated with its polyphenols theaflavins (TF) and thearubigins (TR). Similarly, Turkish black tea (TBT) also contains a considerable amount of TF and TR.

Objective: This study investigated the mutagenic, antimutagenic and anticlastogenic properties of TBT.

Materials and methods: The mutagenic and antimutagenic effects of TBT (10 to 40000?μg/plate) were investigated in vitro on Salmonella strains TA98 and TA100 with and without S9 fraction. Anticlastogenic effect was studied at concentrations of 300–1200?mg/kg TBT extract by chromosomal aberrations (CA) assay from bone marrow of mice.

Results: The results of this study did not reveal any mutagenic properties of TBT. On the contrary, TBT extract exhibited antimutagenic activity at >1000?μg/plate concentrations in TA98 strain with and without S9 activation (40% inhibition with S9 and 27% without S9). In TA100 strain, the antimutagenic activity was observed at?>20,000?μg/plate TBT extracts without S9 activation (28% inhibition) and at >1000?μg/plate with S9 activation (59% inhibition). A significant decrease in the percentage of aberrant cells (12.33%?±?1.27) was observed in dimethylbenz(a)anthracene (DMBA) plus highest concentration (1200?mg/kg) of TBT extract-treated group when compared to only DMBA-treated group (17.00%?±?2.28).

Discussion and conclusion: Results indicated that TBT can be considered as genotoxically safe, because it did not exert any mutagenic and clastogenic effects. As a result, TBT exhibited antimutagenic effects more apparently after metabolic activation in bacterial test system and had an anticlastogenic effect in mice.     

Preclinical studies on safety of fullerene upon acute oral administration and evaluation for no mutagenesis

Fullerenes characterized as an antioxidant are believed to reduce various reactive chemical species, such as free radicals, and their characteristic features have been disclosed to furnish many useful medical technologies. Despite the numerous applications for the biological efficacy of fullerenes, less is known about the toxicity of fullerenes in mammals. Hence, the protocol was designed to determine the acute oral median lethal dose and evaluate the acute toxicity of fullerenes when administrated as a single dose to Sprague-Dawley rats. In an acute toxicity test, fullerenes were administered once orally to a single group of male and female at a dose level of 2000 mg/kg. No deaths were observed and the body weights in both sexes of 2000 mg/kg group increased in a similar pattern to the control group. Genotoxicity of fullerenes was also assessed in a bacterial reverse mutation assay (Ames test) and the chromosomal aberration test in cultured Chinese hamster lung (CHL/IU) cells. Although structural chromosomal aberrations were induced at up to 5000 microg/mL, there was no significant increase in the frequency of chromosomal aberrations at any dose level regardless of presence of S9. Fullerenes did not cause genetic damage in Salmonella typhimurium TA100, TA1535, TA98 and TA1537 and Escherichia coli WP2uvrA/pKM101. These results indicate that fullerenes are not of high toxicological significance.     

Mutagenic activity of surface soil and quantification of 1,3-, 1,6-, and 1,8-dinitropyrene isomers in soil in Japan

To clarify the mutagenic potential of nonagricultural surface soil in Japan, 110 soil samples were collected from five geographically different areas between November 1996 and March 1997, and organic extracts of the soil samples were examined by the Ames/Salmonella assay. Most of the soil extracts showed mutagenicity toward both strains TA98 and TA100 in the presence and/or absence of a mammalian metabolic activation system (S9 mix), suggesting that surface soil is largely contaminated with environmental mutagens. Soil samples collected at Hekinan, Kobe, and Osaka were highly mutagenic toward both strains, and their potencies toward TA98 without S9 mix were extremely high, inducing more than 12 000 revertants per gram of soil. On the other hand, soil samples from Muroran showed strong mutagenicity toward TA100 with S9 mix. Furthermore, 1, 3-dinitropyrene (DNP), 1,6-DNP, and 1,8-DNP in soil samples collected at 10 sampling sites in three metropolitan areas were quantified by fluorometric detection of the corresponding diaminopyrene isomers using high-performance liquid chromatography (HPLC). Three DNP isomers were detected in all soil samples, and the amounts of 1,3-, 1,6-, and 1,8-DNP isomers in the soil samples were 12-3270, 14-5587, and 13-6809 pg/g, respectively. The gross amount of three DNP isomers in surface soil collected at Hekinan was more than 10 ng per gram of soil. The highest contribution ratios of DNP isomers to the mutagenicity of soil extracts were observed for the samples collected at Osaka, and the total of the contribution ratios of three DNP isomers was about 50%. These results suggest that surface soil is largely contaminated with mutagenic compounds and that DNP isomers are one class of major mutagenic and carcinogenic compounds contaminating surface soil.     

Expression of recombinant human cytochrome P450 1A2 inEscherichia coli bacterial mutagenicity tester strain

Human cytochrome P450 1A2 is one of the major cytochrome P450s in human liver. It is known to be capable of activating a number of carcinogens such as arylamines and heterocyclic amines. In order to develop the new bacterial mutagenicity test system with human P450, a full length of human P450 1A2 cDNA inserted into pCW bacterial expression vector was introduced toEscherichia coli WP2 uvrA strain which is a well-knownE. coli strain for bacterial reverse mutagenicity assay. Expressed human P450 1A2 showed typical P450 hemoprotein spectra. Maximum expression was achieved at 48 hrs after incubating at 30°C in terrific broth containing ampicillin, IPTG and other supplements. High level expression of P 450 1A2 inE. coli WP2 uvrA membranes was determined in SDS-PAGE. The well-known mutagens 2-aminoanthracene and MelQ increased the revertant colonies ofE. coli WP2 uvrA expressing human P450 1A2 without an exogenous rat hepatic post-mitochondrial supernatant (S9 fraction) in a dose-dependent manner. The results show that the functional expression of human P450 in bacterial mutagenicity tester strain will provide a useful tool for studying the mechanism of the mutagenesis and carcinogenesis of new drugs and environmental chemicals.     

Mutagenicity study of gadobenate dimeglumine formulation (E7155) (1)--Reverse mutation assays in S. typhimurium and E. coli tester strains

The ability of gadobenate dimeglumine formulation (E7155) to cause gene mutations was assessed in five strains of Salmonella typhimurium (TA100, TA1535, TA98, TA1538, and TA1537) and a strain of Escherichia coli (CM891; WP2, uvrA-, pKM101) using the Ames test (agar plate assay). The results suggest that E7155 is non-mutagenic towards these bacterial tester strains.     

Mutagenicity assay in Salmonella for thirteen 2-substituted-1 H-phenanthro (9,10-d) imidazoles

Some 2-substituted-1 H-phenanthro [9,10-d] imidazole compounds synthesized as a predrugs were tested in mutagenicity assays in Salmonella strains TA97, TA98, and TA100 using a plate incorporation assay both with and without S9 mix. The 10 substances were mutagenic in TA97 and five of them were mutagenic only with metabolic activation, whereas one of them did not require the addition of S9. The eight substances were mutagenic in TA98 only with S9. For TA100, seven substances showed positive results both with and without S9, however another four required S9, whereas only one of them did not required metabolic activation. In summary, all of 13 substances derived from phenanthro [9,10-d] imidazole were found to be mutagenic for at least one or two of the three strains and their mutagenicity are discussed.     

Mutagenic potentials of Amberlite XAD-2-resin extracts obtained from river and drinking waters in the Northwest district of Chiba, Japan

Amberlite XAD-2 resin extracts of river and drinking water sampled from the Northwest district of Chiba Prefecture in each month during the period from January to December 2008 were investigated to characterize and determine their mutagenic potentials and polycyclic aromatic hydrocarbon (PAH) levels. The extracts from the river water were shown to be mutagenic in Salmonella typhimurium TA98 (a flameshift mutagen) without S9 mix, with higher mutagenic responses in summer and early fall seasons. While the drinking water extracts exhibited weak mutagenicity in both the TA98 and TA100 strains (a base-pair substitution mutagen) without S9 mix, with high mutagenic responses in fall and early winter seasons. GC/MS determinations of the water concentrates showed some seasonal scatter in PAH levels in river water. In contrast, comparatively high concentrations of PAHs were observed for drinking water samples collected during warmer seasons. Statistical studies revealed that there is a lower correlation between the levels of flameshift mutagenicity and the concentrations of PAH in the river water concentrations, but a higher correlation between them in the drinking water samples.