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.     

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.     

In vitro antimutagenicity of curcumin against environmental mutagens

The effects of curcumin, the yellow pigment of the spice, turmeric (Curcuma longa) on the mutagenicity of several environmental mutagens were investigated in the Salmonella/microsome test with or without Aroclor 1254-induced rat-liver homogenate (S-9 mix). With Salmonella typhimurium strain TA98 in the presence of S-9 mix, curcumin inhibited the mutagenicity of bidi and cigarette smoke condensates, tobacco and masheri extracts, benzo[a]pyrne and dimethyl benzo[a]anthracene in a dose-dependent manner. Curcumin did not influence the mutagenicity without S-9 mix of sodium azide, monoacetylhydrazine and streptozocin in strain TA100 nor of 4-nitrophenylenediamine in strain TA98. Our observations indicate that curcumin may alter the metabolic activation and detoxification of mutagens.     

Mutagenic activity of the condensates from thermal decomposition of different polyamides]

The mutagenic activity of the condensates from oxydative pyrolysis of various polyamides at 500, 800 and 1,000 degrees C has been searched for by AMES preincubation test in strains TA 98 and TA 100 with or without metabolic activation by an Aroclor 1254 induced rat liver microsomal S9mix fraction. All condensates are mutagenic in the presence of this fraction and most of them are far less or not mutagenic in the absence of S9mix. Strain TA 98 is more sensitive than strain TA 100 for detecting the mutagenic activity of these condensates. So, they mainly contain indirect mutagenic substances responsible for frameshift mutation. In all cases, mutagenic activity is maximum at 800 degrees C. This observation should draw the attention upon the genotoxic (carcinogenic) long term risk induced by thermal decomposition of plastics and then upon the necessary protection of firemen and others in charge of domestic or hospital solid waste incineration.     

Different results of the Salmonella umu test between three isomers of phenylenediamine (PDA) derivatives

A post-treatment assay of the umu test was performed to detect genotoxicity of 10 phenylenediamine (PDA) derivatives using Salmonella typhimurium TA1535/pSK1002 with/without S9 mix. Seven chemicals (o-PDA, 4-chloro-o-PDA, 4-nitro-o-PDA, p-PDA, 2-chloro-p-PDA, 2-nitro-p-PDA, and 2,5-diaminotoluene) showed positive results with S9 mix, but three chemicals (m-PDA, 4-chloro-m-PDA, and 2,4-diaminotoluene) were negative with and without S9 mix. Four of 7 chemicals (o-PDA, 4-chloro-o-PDA, 4-nitro-o-PDA, and 2-nitro-p-PDA) that gave positive results with S9 mix were also positive without S9 mix. These results indicate that the genotoxicity of PDA derivative possessing m-position amino substituents was not detected in the umu post-treatment assay using TA1535/pSK1002.     

3种促智药:石杉碱甲、茴拉西坦和吡乙酰胺的诱变作用和诱变协同作用

在鼠伤寒沙门菌/微粒体系统中测试了石杉碱甲、茴拉西坦和吡乙酸胺的诱变作用。结果表明,药物浓度从1μg-5mg/皿对TA97、TA98、TA100和TA1024个菌株,在无S_9代谢系统上所测的这3个药和有S_9代谢系统所测的石杉碱甲、茴拉西坦均未显示任何诱变作用。向拉西坦和吡乙酰胺在诱变协同实验中均不增加对-硝基喹啉在TA98上和甲基磺酸甲酯在TA100上诱发的回变数。ICR纯系小鼠骨髓微核试验,剂量高达1/2LD_(50)时不增加嗜多染红细胞的微核率,也无骨髓抑制作用.     

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.     

Mutagenicity of acrylonitrile.

Incubation of Salmonella typhimurium strains in an atmosphere of 0.2% gaseous acrylonitrile increased the numbers of his+ revertants/plate only in the presence of a fortified S9 liver fraction. The mutagenic effect was particularly pronounced with strains TA1530, TA1535 and TA1950 and much weaker with strains TA100, TA98 and TA1978. The results of bacterial fluctuation tests confirmed the necessity of the presence of S9 mix and showed the particular sensitivity of TA1530. The reversion rate varied with the S9 mix composition, the animal species utilized and the type of pretreatments applied to the animals. The mutagenicity of acrylonitrile in S. typhimurium is therefore microsome-mediated and is particularly discernable with strains sensitive to base-substitution mutagens.     

Non-mutagenicity of 2-methyl-2,3-epoxybutane and factors influencing the mutagenicity of 2,3-epoxybutane

The compound 2,3-epoxybutane (2,3-EB) is a direct mutagen for the base-pair-substitution-sensitive strains TA 1530, TA 1535 and TA 100, in the absence and in the presence of metabolic activation by liver S9-mix. Under the same experimental conditions, the 2-methyl derivative of 2,3-EB was not mutagenic, up to 10 mg per plate. The parent compound (2,3-EB) was more active on strain TA 1530 in the presence of liver S9-mix. This was observed at every epoxide concentration tested. The increase of mutagenicity depended on the S9 concentration, the mix composition and to a small extent on the method utilized.     

Mutagenicity studies of benzidine and its analogs: structure-activity relationships.

The Ames SALMONELLA:/microsome assay was employed to test the mutagenicity of benzidine and its analogs using strains TA98 and TA100 in the presence and absence of Aroclor 1254-induced rat S9 mix. 3,3'-Dichlorobenzidine-2HCl and 4,4'-dinitro-2-biphenylamine were directly mutagenic to TA98, while 4,4'-dinitro-2-biphenylamine was directly mutagenic to both TA98 and TA100 in the absence of S9 mix. 2-Aminobiphenyl, 3-aminobiphenyl, and 3,3'-5,5'-tetramethylbenzidine were not mutagenic in either strains in the presence or absence of S9. In the presence of S9 mix, 4-aminobiphenyl, benzidine, 3, 3'-dichlorobenzidine-2HCl, 3,3'-dimethoxybenzidine, 3,3'-4, 4'-tetraaminobiphenyl, o-tolidine, N, N-N', N'-tetramethylbenzidine, and 4,4'-dinitro-2-biphenylamine were mutagenic to TA98; 4-aminobiphenyl, 3,3'-dichlorobenzidine-2HCl, 3, 3'-dimethoxybenzidine, and 4,4'-dinitro-2-biphenylamine were mutagenic to TA100. Physicochemical parameters of these compounds including oxidation potentials, the energy difference between the lowest unoccupied molecular orbital and the highest occupied molecular orbital, ionization potentials, dipole moment, relative partition coefficient, and basicity did not correlate with their bacterial mutagenic activities.     

Ames mutagenicity tests of products from a heated potato-starch system

A charred sample was prepared from potato starch heated with ammonium carbonate at 600°C in a flask under a nitrogen stream. The water produced was collected and extracted with methylene chloride. The basic fraction obtained from the extract exhibited strong mutagenicity in Ames assays using Salmonella typhimurium strains TA98 or TA100 with metabolic activation (rat-liver S-9 mix). The basic fraction was further fractionated by silica gel column chromatography and subsequently by Scphadex column chromatography. Some of the resulting fractions exhibited strong mutagenic activities in S. typhimurium strain TA98 with S-9 mix.     

Mutagenicity of the products obtained from heated milk systems

Methylene chloride extracts of the browning reaction products prepared from model systems consisting of major milk components (casein and/or lactose, and non-fat dried milk) were tested for mutagenicity in the Ames Salmonella/microsome assay. Samples obtained by heating aqueous solutions of these components under either neutral or basic (pH 10) conditions exhibited no significant mutagenic activity when tested with or without S-9 mix. The addition of common food additives, such as sodium nitrite, butylated hydroxyanisole and butylated hydroxytoluene, to the aqueous solutions did not enhance the mutagenic activity of the browning samples. On the other hand, the tar samples prepared by heating the same milk components in the dry state exhibited strong mutagenicity, primarily to Salmonella typhimurium strain TA98 and only with S-9 mix. A casein/lactose mixture and non-fat dried milk were also heated with baking soda in the dry state. The presence of the baking soda enhanced the mutagencity of the browning products; the tar from the non-fat dried milk heated with baking soda was the most potently mutagenic of all the samples towards strain TA98 and also produced a positive response in strain TA100 in the presence of S-9 mix.     

Mutagenicity and antimutagenicity of teas used in popular medicine in the salmonella/microsome assay

Plant species are widely used in tea form in Brazil, but little is known about scientific aspects of the effect of these aqueous extracts on human health or on genetic material. Mutagenic and antimutagenic activities of three plant species, Vitex montevidensis Cham. (Lamiaceae), Gochnatia cordata Less. (Asteraceae) and G. polymorpha (Asteraceae) in the Salmonella/microsome assay were evaluated. No mutagenic activity was found for base-pair substitution (TA100) and frameshift mutations (TA98) in the three extracts studied. Low indexes of mutagenesis inhibition induced for the V. montevidensis extract with the sodium azide mutagen and results of co-mutagenesis with 4-oxide-1-nitroquinoline were observed for the three extracts evaluated without addition of a rat liver metabolic system fraction (S9 mix). Assays with S9 mix showed significant antimutagenic properties against mutagenesis induced by 2-aminofluorene, both for TA98 (67% of the assays) and for TA100 (100% of the assays). This protective activity was possibly related to properties described for flavonoids and/or tannins acting as potential inactivators of enzymes involved in the mutagen metabolism.     

Bacterial mutagenicity of extracts of the baked and raw Agaricus bisporus mushroom.

Aqueous extracts of baked and raw Agaricus bisporus (AB) mushroom were tested for mutagenic activity in Salmonella typhimurium strains TA1535 and TA1537. The extracts were studied with and without metabolic activation by Aroclor-induced rat liver S9 mix. The extracts of the baked and raw AB exhibited a dose related mutagenic activity with and without activation in strain TA1535. Similar findings were obtained in strain TA1537, although the net revertant values were of lower magnitude. Because humans mainly consume the cultivated mushroom AB in baked form, the implications of the findings are self-evident.     

Mutagenicity Assay in Salmonella for Thirteen 2-Substituted-1H-phenanthro (9,10-d) Imidazoles

Abstract

Some 2-substituted-1H-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.     

Macrocyclic musk compounds--an absence of genotoxicity in the Ames test and the in vivo Micronucleus assay

Three synthetic macrocyclic musks, ethylene dodecanedioate, ethylene brassylate, and cyclopentadecanolide, which are widely used as ingredients of perfume fragrances, were tested for genotoxicity. In this report we present results from two different studies, the flow-cytometer-based micronucleus assay in peripheral blood of mice and the Salmonella/microsome test with TA 97, TA 98, and TA 100. Female NMRI and male CD 1 mice were intraperitoneally injected with one of the three macrocyclic musk compounds. Three different doses (0.1-1.6 g/kg bw) of each of the compounds were tested. Blood samples were collected on two occasions from each mouse and the frequency of micronucleated polychromatic erythrocytes (fMPCE) was determined. Neither of the compounds caused a significant difference from the control fMPCE. No mutagenic effect with and without S9 mix in the tested Salmonella strains was observed. The presence of S9 mix reduced the killing effect of high doses.     

Ames mutagenicity tests of overheated brewed coffee

Five kinds of coffee samples were prepared from a commercial drip-grind coffee in order to examine the mutagenicity of brewed coffee using the Ames test. The samples prepared were a thick coffee syrup, coffee solid residues, dichloromethane and ethanol extracts of solid residues, a dichloromethane extract of a distillate from normally heated brewed coffee and dichloromethane extracts of distillates from overheated (150–300°C) brewed coffee. The samples were tested for mutagenicity towards Salmonella typhimurium strains TA98 and TA100 both with and without metabolic activation (S-9 mix). Only the extracts of the distillates obtained from coffee heated to 150° or 300°C exhibited mutagenicity towards strain TA98 with S-9 mix.     

Mutagenicity evaluation of riot control agent o-chlorobenzylidene malononitrile (CS) in the Ames Salmonella/microsome test.

o-Chlorobenzylidene malononitrile (CS), a riot control agent, was evaluated for its possible mutagenic activity in the Ames Salmonella/mammalian microsome mutagenicity test. Five histidine-deficient (His-) mutant tester strains of Salmonella typhimurium--TA97a, TA98, TA100, TA102 and TA104--were used. The liquid preincubation procedure was used with metabolic activation (presence of S9 mixture) and without metabolic activation (absence of S9 mixture). For the experiments with metabolic activation, three different concentrations of S9 fraction (supernatant of Aroclor 1254-induced rat liver homogenate at 9000 g)--5%, 15% and 30% in S9 mixture--were used. Along with mutagenic activity, CS was also evaluated for cytotoxic activity in all the five tester strains of Salmonella typhimurium, both in the presence and absence of S9 mixture. The mutagenic and cytotoxic activities of CS were assessed by counting the His+ revertant colonies and by counting the microcolonies (His-, auxotrophs in the background lawn), respectively, and the respective mean values were compared with the relative negative (solvent) control. A dose range of 12.5-800 micrograms plate-1 for CS did not induce a mutagenic response either in the presence or absence of S9 mix. No change in the negative mutagenic response of CS has been observed even in the presence of an elevated level of S9 fraction in the S9 mix. A dose of 200 micrograms plate-1 for CS was found to be cytotoxic by decreasing the surviving cells as well as His+ revertant colonies; however, the effect was reduced in the presence of an elevated level of S9 fraction in the S9 mix.     

Genotoxicity testing of sodium formononetin-3′-sulphonate (Sul-F) by assessing bacterial reverse mutation,chromosomal aberrations and micronucleus tests

As part of a safety evaluation, we evaluated the potential genotoxicity of sodium formononetin-3′-sulphonate (Sul-F) using bacterial reverse mutation assay, chromosomal aberrations detection, and mouse micronucleus test. In bacterial reverse mutation assay using five strains of Salmonella typhimurium (TA97, TA98, TA100, TA102 and TA1535), Sul-F (250, 500, 1000, 2000, 4000 μg/plate) did not increase the number of revertant colonies in any tester strain with or without S9 mix. In a chromosomal assay using Chinese hamster lung fibroblast (CHL) cells, there were no increases in either kind of aberration at any dose of Sul-F (400, 800, and 1600 μg/mL) treatment groups with or without S9 metabolic activation. In an in vivo bone marrow micronucleus test in ICR mice, Sul-F at up to 2000 mg/kg (intravenous injection) showed no significant increases in the incidence of micronucleated polychromatic erythrocytes, and the proportion of immature erythrocytes to total erythrocytes. The results demonstrated that Sul-F does not show mutagenic or genotoxic potential under these test conditions.     

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.