3-amino-1-methyl-5h-pyrido(4-3-b)indole and 2-amino-6-methyldipyrido(1-2-a-3--2--d)imidazole

Topics: Animals; Breast Neoplasms; Carbolines; Carcinogens, Environmental; Cattle; Colonic Neoplasms; Cooking; Food; Harmine; Head and Neck Neoplasms; Humans; Imidazoles; Male; Meat; Mutagens; Neoplasms; Nitrates; Nitrites; Nitrosamines; Prostatic Neoplasms

We have found that the exhaust gas from many incineration plants of municipal solid wastes (MSW) show significant mutagenic activities. The mutagenic activities of exhaust gas from incineration plants of the other wastes have not been studied in detail. Here, we analyzed the mutagenic activities and compounds in exhaust gas and ash from seven sludge incineration plants. Some samples of the exhaust gas from the sludge incineration plants showed high mutagenic activities; although, none of the ash residues showed mutagenic activities. There was no relationship between the mutagenic activities and furnace types, the plant size or the apparent residence time of the gas in the furnace. The mutagenic activities of the exhaust gas were produced during incomplete combustion at lower temperatures. Direct mutagenic activities without S9 mix were higher than indirect mutagenic activities with S9 mix which was made from rat liver homogenate and was used to test mutagenic activity after metabolism. These results are different to those of MSW incineration plants. We analyzed the mutagenic compounds in the exhaust gas by GC/MS after fractionation by HPLC, but they could not be identified. We found that the mutagenic compounds in the exhaust gas were different from the compounds that were produced from the MSW incineration plants. We believed that these mutagenic compounds might be non-volatile and more polar than the heterocyclic amines, Trp-P-2, Trp-P-1 and Glu-P-1, which are typical mutagenic compounds in sewage and sludge.

Topics: Animals; Carbolines; Carcinogens; Chemical Fractionation; Imidazoles; Incineration; Liver; Mutagenicity Tests; Rats; Refuse Disposal; Sewage; Vehicle Emissions

Antimutagenic and binding properties of 28 strains of Lactobacillus gasseri and 2 strains of Bifidobacterium longum on the mutagenicity of amino acid pyrolysates were investigated in vitro using a streptomycin-dependent (SD510) strain of Salmonella typhimurium TA 98. Four strains of L. acidophilus (SBT0274, SBT1703, SBT10239, and SBT10241) and 1 strain of B. longum (SBT 2928) exhibited the highest percentage of antimutagenicity and binding. These 5 strains were further optimized for other physical factors influencing the mechanism of binding, such as cell and mutagen concentration, pH, and incubation time. In all of the selected strains, 2 mg of cells bound with 88 to 95% of 0.2 mg of 3-amino-1,4 dimethyl-5H-pyrido[4,3-b]indole in 30 min at pH 7.0. Other amino acid pyrolysates, such as 3-amino-1-methyl-5H-pyrido[4,3-b]indole, 2-amino-6-methyldi-pyrido[1,2-a:3',2'-d]imidazole, 2-amino-3-methyl-imidazo[4,5,f]quinoline, and 2-amino-3,4-dimethyl-imidazo[4,5,f]quinoline were also tested for the binding ability of these strains. We observed that the complexity of the mutagens greatly influenced the binding properties. The binding of 3-amino-1,4 dimethyl-5H-pyrido[4,3-b]indole to the purified cell walls was very high compared with that of the crude cell wall, peptidoglycan, or the cell extract. Binding was inhibited when the cell walls were subjected to treatment with metaperiodate or trichloroacetic acid but not when they were subjected to treatment with lysozyme, trypsin, or proteinase K, reflecting the role of the carbohydrate component as a binding site.

Topics: Amino Acids; Antimutagenic Agents; Bifidobacterium; Binding Sites; Carbolines; Cell Wall; Chemical Phenomena; Chemistry, Physical; Hydrogen-Ion Concentration; Imidazoles; Lactobacillus; Mutagens; Periodic Acid; Quinolines; Time Factors; Trichloroacetic Acid

The ability of phthalic acid, phthalic acid anhydride, and various phthalate esters to enhance the mutagenicity of many amino acid pyrolysates was observed with the Ames test (Salmonella typhimurium TA98), but not the SOS Chromotest. Phthalate enhancement of the mutagenicity of 4-nitroquinoline-1-oxide, 2-nitrofluorene, and benzo[a]pyrene was not observed with either test. The mutagenicity-enhancing ability may be related to the induction of enzymes such as P450IIB, that metabolize amino acid pyrolysates. By quantitative structure activity relationship (QSAR) analysis, a good correlation was observed between the mutagenicity-enhancing activity of phthalates and their octanol-water partition coefficients.

Topics: 1-Octanol; 4-Nitroquinoline-1-oxide; Benzo(a)pyrene; Carbolines; Cytochrome P-450 CYP2B1; Cytochrome P-450 Enzyme System; Drug Synergism; Enzyme Induction; Esters; Fluorenes; Imidazoles; Mutagenesis; Mutagenicity Tests; Mutagens; Octanols; Oxidoreductases; Phthalic Acids; Quinolines; Structure-Activity Relationship; Water

Osteogenic Disorder Shionogi (ODS) rats, which cannot synthesize ascorbic acid due to a deficiency of L-gulonolactone oxidase, become scorbutic when not supplied with dietary ascorbic acid. We used the deficient rats to study the effects of ascorbic acid on the amount of cytochrome P450 enzymes in liver microsomes. The total amount of hepatic cytochrome P450 in ODS rats deprived of ascorbic acid was lower by approximately 40%, whereas ODS rats fed with ascorbic acid and the wild strain had the same level of total hepatic cytochrome P450. Western blot analysis for various forms of cytochrome P450 in liver microsomes indicated that the amount of CYP1A2 was significantly higher in ascorbic acid deficient rats. On the other hand, amounts of CYP2B2 and 3A were lower, and those of CYP2E1 and CYP2C6/11 were unaffected. In accordance with the higher amount of CYP1A2, Northern blot analysis showed increased expression of CYP1A2 mRNA. The capacity of microsomes to produce mutagens from 2-amino-6-methyl-dipyrido[1,2-a:3',2'-d]imidazole acetate (Glu-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole acetate (Trp-P-2) was higher in scorbutic ODS rats by the Ames test. These results indicate that the effects of ascorbic acid deficiency on the expression of cytochrome P450 in ODS rat livers are form-specific and that the increased CYP1A2 is associated with increased metabolic activation of promutagens in the scorbutic state.

Topics: Animals; Ascorbic Acid Deficiency; Base Sequence; Biotransformation; Body Weight; Carbolines; Cytochrome P-450 CYP1A2; Cytochrome P-450 Enzyme System; Electron Transport; Imidazoles; Male; Microsomes, Liver; Molecular Sequence Data; Mutagens; NADPH-Ferrihemoprotein Reductase; Oligonucleotide Probes; Organ Size; Oxidoreductases; Rats; Rats, Mutant Strains

The fried food mutagens IQ, MeIQ, Glu-P-1 and Trp-P-2 were treated with nitrite at pH 3.0 for 1 h at 37 degrees C. The resulting reaction mixtures were tested for mutagenicity towards Salmonella typhimurium TA97, TA98, TA100 and TA1535. Glu-P-1 and Trp-P-2 were readily converted to weak or non-mutagenic deaminated compounds, whereas IQ and MeIQ were converted to extremely strong mutagenic derivatives in both the presence and the absence of rat liver S9 mix. The mutagenicity of MeIQ in TA98 was enhanced by nitrite up to 3-fold, while that of nitrosated MeIQ was further enhanced by S9 mix up to 15-fold. The nitrosation products of MeIQ were resolved into 7 bands by TLC on silica gel plate. Bands I, III, V and VI were highly mutagenic to both TA98 and TA100. The experimental results suggest that the non-enzymatic formation of direct-acting mutagens from indirect-acting mutagens such as IQ or MeIQ might be physiologically important, especially with regard to the etiology of human gastrointestinal tract tumors.

Topics: Amines; Carbolines; Chromatography, Thin Layer; Drug Interactions; Imidazoles; Mutagenicity Tests; Mutagens; Nitrites; Nitrosation; Quinolines

The binding of mutagenic pyrolyzates to cell fractions from some gram-negative intestinal bacteria and to thermally treated bacterial cells was investigated. 3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) were effectively bound by several of the bacterial cells. The cell wall skeletons of all bacteria effectively bound Trp-P-1 and Trp-P-2. Their cytoplasmic fractions retained Trp-P-1 and Trp-P-2, but to a lesser extent than the cell wall skeletons. 2-Amino-3-methylimidazo[4,5-f]quinoline (IQ) was not found in their cytoplasmic fractions. These cell wall skeletons also bound 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), 2-amino-5-phenylpyridine (Phe-P-1), IQ, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQX). The amount of each mutagen bound differed with the type of mutagen and the bacterial strain used. The outer membrane of Escherichia coli IFO 14249 showed binding of about 123.7 micrograms/mg of Trp-P-2, and its cytoplasmic membrane bound 57.14 micrograms/mg. Trp-P-2 bound to the bacterial cells was extracted with ammonia (5%), methanol, and ethanol but not with water.

Topics: Bacteroides fragilis; Carbolines; Cell Wall; Chromatography, High Pressure Liquid; Citrobacter freundii; Escherichia coli; Gram-Negative Bacteria; Hot Temperature; Imidazoles; Mutagens; Pseudomonas putida; Quinolines

The binding ability of bovine milk caseins with mutagenic heterocyclic amines was investigated. Binding was determined with 2 mg of casein and 20 micrograms of heterocyclic amine in .40 ml of pH 7.4, 50 mM phosphate buffer, at 37 degrees C, in a shaker for 10 min. The unbound heterocyclic amine in protein-free ultrafiltrate was analyzed by HPLC. The binding ability of whole casein, alpha s-casein, beta-casein, and kappa-casein, respectively, was 90.08, 83.06, 90.92, and 96.70% with 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole; 85.48, 51.54, 63.62, and 82.71% with 3-amino-1-methyl-5H-pyrido[4,3-b]indole; and 87.03, 59.77, 97.04, and 88.30% with 2-amino-6-methyldipyrido[1,2-a:3',2'-d]-imidazole. Higher binding of 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole and 3-amino-1-methyl-5H-pyrido[4,3-b]indole to alpha s-casein, beta-casein, and kappa-casein was observed at pH above 7.4, and the binding was inhibited at pH below 6.5. The maximum binding of 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole to these caseins was at pH 6.6 and 7.4. The binding was inhibited at alkaline pH above 8.5 and acidic pH below 6.5.

Topics: Animals; Carbolines; Caseins; Cattle; Hydrogen-Ion Concentration; Imidazoles; Mutagens

The presence of 2 kinds of components in brewed and instant coffee that could remove and destroy heterocyclic amine mutagens was demonstrated. The component that could remove the mutagens was insoluble fiber composed of hemicellulose. The fiber could tightly adsorb the mutagens Trp-P-1, Trp-P-2, Glu-P-1 and A alpha C, and those generated in roasted coffee beans. The component that could destroy the mutagens was high-molecular-weight soluble polyphenolics. They might be converted into quinone derivatives in the presence of molecular oxygen. The quinone derivatives might destroy the mutagens. The fibers and the polyphenolics in one cup of brewed or instant coffee had the capacity to remove and destroy a substantial amount of the mutagens in pyrolysates of foodstuffs.

Topics: Amines; Anisoles; Benzoquinones; Caffeic Acids; Carbolines; Chlorogenic Acid; Coffee; Coumaric Acids; Gallic Acid; Hydrogen-Ion Concentration; Hydrolyzable Tannins; Imidazoles; Mutagenicity Tests; Mutagens; Phenols; Polysaccharides; Salmonella typhimurium

The binding of mutagenic pyrolyzates to freeze-dried cells of Streptococcus cremoris Z-25 was investigated in human gastric juice and compared with the ability of these pyrolyzates to bind in distilled water (pH 6.30). The pH of donated gastric juice ranged from 1.2 to 7.8. Binding that occurred in gastric juice was pH dependent, and binding was affected by NaCl, CaCl2, and MgCl2. Les sof Trp-P-2 was bound in gastric juice at low pH (1.2, 1.48, and 2.1) than at pH 4 to 8. The strain bound simultaneously Trp-P-1, Trp-P-2, and Glu-P-1. The maximum amounts of Trp-P-2 bound to S. cremoris Z-25 were approximately 47.50 micrograms/mg of cells. Freeze-dried cells treated at 120 degrees C for 15 min or 80 degrees C for 3 h showed increased binding of Trp-P-2. However, binding decreased 10% after heating at 120 degrees C for 15 min. Cells nonthermally killed by gastric juice (pH 1.5) had the same Trp-P-2 binding capacity as viable cells. Lactobacillus acidophilus IFO 13951 and Bifidobacterium bifidum IFO 14252 representation of the intestinal bacteria nonthermally killed by gastric juice also showed larger binding of Trp-P-2.

Topics: Calcium Chloride; Carbolines; Freeze Drying; Gastric Juice; Hot Temperature; Humans; Hydrogen-Ion Concentration; Imidazoles; Magnesium Chloride; Mutagens; Sodium Chloride; Streptococcus

In order to evaluate the effect of carcinogenic heterocyclic amines on the stimulus-reaction system of human cells, we examined the effect of 5 kinds of carcinogenic heterocyclic amines including 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), 2-amino-dipyrido[1,2-a:3',2'-d]imidazole (Glu-P-2), 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) on human lymphocyte (4 x 10(5) cells/ml) blast transformation induced by 0.125% phytohemagglutinin (PHA). Both Trp-P-1 and Trp-P-2 exhibited an inhibitory effect on the lymphocyte proliferation stimulated by PHA at the final concentration of 1.0-5.0 and 1.0-10 microM, respectively. The concentrations of Trp-P-1 and Trp-P-2 causing 50% inhibition were 3.1 and 5.1 microM, respectively. However, the other carcinogenic heterocyclic amines examined did not show any inhibitory effect on lymphocyte mitogenesis even at a final concentration of 10 microM. Viabilities of lymphocytes were more than 90% (n = 3 x 5) when 5 kinds of carcinogenic heterocyclic amines (0.1 ml) were respectively added at the final concentration of 10 microM to the lymphocyte culture medium (4 x 10(5) cells/0.9 ml).

Topics: Amines; Carbolines; Carcinogens; Dose-Response Relationship, Drug; Hot Temperature; Humans; Imidazoles; Lymphocyte Activation; Lymphocyte Culture Test, Mixed; Mathematics; Phytohemagglutinins; Tryptophan

The mutagenic activation of various promutagens by liver microsomes from dogs, monkeys and humans was investigated. Dog liver microsomes efficiently catalyzed the mutagenic activation of Trp-P-2 and Glu-P-1 followed by IQ and AAF. Monkey liver microsomes were most active in the activation of IQ followed by Glu-P-1, AAF and Trp-P-2. Although there were remarkable individual differences, human liver microsomes were found to be most active in the mutagenic activation of IQ followed by Trp-P-2, Glu-P-1 and AAF. Antibodies against rat P-448-H inhibited the mutagenic activation of Glu-P-1, Trp-P-2 and IQ in rat and dog liver microsomes, and Glu-P-1 and Trp-P-2 in monkey liver microsomes. The activation of Glu-P-1 and IQ in human liver microsomes was also strongly inhibited by anti-P-448-H antibodies. The amounts of cytochrome P-450 cross-reactive with anti-P-448-H antibodies in human liver microsomes highly correlated with the capacity to activate Glu-P-1, Trp-P-2 and IQ but not AAF.

Topics: 2-Acetylaminofluorene; Animals; Biotransformation; Carbolines; Cross Reactions; Cytochrome P-450 CYP1A2; Cytochrome P-450 Enzyme System; Cytochromes; Dogs; Female; Haplorhini; Humans; Imidazoles; Male; Microsomes, Liver; Mutagens; Quinolines; Rats; Rats, Inbred Strains; Salmonella typhimurium; Species Specificity

Trp-P-1, Trp-P-2, MeA alpha C, A alpha C, Glu-P-1, Glu-P-2, Lys-P-1, IQ and Phe-P-1 were tested for tumour initiating activity in a two-stage skin carcinogenesis model using 12-O-tetradecanoylphorbol-13-acetate (TPA) as the promoter. The total initiating doses were 20 mg for Trp-P-1, Trp-P-2, Glu-P-1 and Glu-P-2, 40 mg for MeA alpha C and A alpha C, 5 mg for Lys-P-1, 7.5 mg for IQ and 100 mg for Phe-P-1. 7,12-Dimethylbenz[a]anthracene was used as a positive control compound at a total dose of 100 micrograms. All compounds were topically applied twice weekly for 5 weeks on the dorsal skin, and then followed by similar TPA administration for 47 weeks. Trp-P-2 induced skin tumours in 30% of the mice (0.35 tumours/mouse), and Trp-P-1, MeA alpha C and Phe-P-1 in 10-20% (0.20-0.25 tumours/mouse). The smaller amounts of Lys-P-1 and IQ applied induced tumours at an incidence of 10 and 5% respectively. No tumours appeared in the groups treated with test chemicals alone or TPA alone. Statistical analysis according to either the Fisher exact test or Peto trend test revealed significant differences for tumour appearance in the Trp-P-1, Trp-P-2, MeA alpha C and Phe-P-1 followed by TPA groups as compared with that given TPA alone. The data were used to generate ID50 (50% initiating dose) values for each of the compounds.

Topics: Animals; Carbolines; Female; Imidazoles; Mice; Mutagens; Quinolines; Skin Neoplasms; Tetradecanoylphorbol Acetate

The first step in metabolic activation of mutagenic and carcinogenic heterocyclic amines has been elucidated to be N-hydroxylation by cytochrome P-448. N-Hydroxyamino compounds are further activated to form N-O-acyl derivatives that readily react with DNA. The adducts between the metabolites of Trp-P-2 and Glu-P-1 and DNA were shown to have a C8-guanylamino structure. In the case of Glu-P-1, modification of guanine in GC clusters occurred preferentially. Glutathione transferases and myeloperoxidase were shown to inactivate some heterocyclic amines or their active metabolites. Hemin and fatty acids bind to and inactivate them. Fibers and other factors from vegetables also work to inactivate heterocyclic amines. Nitrite at low pH also degraded some heterocyclic amines, but those with an imidazole moiety were resistant. Glu-P-1 induced intestinal tumors in a high incidence when fed orally to rats. When 14C-Glu-P-1 was administered by gavage into rats about 50% and 35% were excreted into feces and urine, respectively, within 24 hr. When the bile was collected, around 60% of radioactivity was excreted into it within 24 hr. In the bile, N-acetyl-Glu-P-1 was identified as one of the metabolites of Glu-P-1. It showed a mutagenic activity of about one fourth that of Glu-P-1 with S9 mix. Some radioactivity was also detected in the blood. At 24 hr after administration, most of the radioactivity was found to be bound to erythrocyte beta-globins and serum proteins including albumin.

Topics: Animals; Base Composition; Biotransformation; Blood Proteins; Carbolines; Carcinogens; DNA; Food; Food Contamination; Hot Temperature; Imidazoles; Inactivation, Metabolic; Mutagens; Neoplasms, Experimental; Protein Binding; Rats

Carcinogenicities of mutagenic heterocyclic amines in cooked foods have been tested in CDF1 mice and F344 rats of both sexes. Eight heterocyclic amines--Trp-P-1, Trp-P-2, Glu-P-1, Glu-P-2, MeA alpha C, A alpha C, IQ, and MeIQ--were given to mice and/or rats at 0.02 to 0.08% in the diet continuously. In mice, all heterocyclic amines tested were demonstrated to be carcinogenic. Hepatocellular carcinomas were induced in a high incidence in all groups treated with heterocyclic amines. Hemangioendothelial sarcomas were also induced by Glu-P-1, Glu-P-2, MeA alpha C, and A alpha C. Most hemangioendothelial sarcomas were located in the interscapular brown adipose tissue. In mice given IQ, forestomach and lung tumors were also observed in a high incidence. Carcinogenicity tests on MeIQ are ongoing, and interim data by week 83 show that MeIQ also induces forestomach tumors in addition to liver tumors. In rats, hepatocellular carcinomas were induced by Trp-P-1, Glu-P-1, Glu-P-2, and IQ. In rats given Glu-P-1, Glu-P-2, and IQ, adenocarcinomas in the small and large intestines, squamous cell carcinomas in the Zymbal gland and clitoral gland were also observed in a high incidence.

Topics: Animals; Carbolines; Carcinogens; Female; Food Contamination; Heterocyclic Compounds; Hot Temperature; Imidazoles; Male; Mice; Neoplasms, Experimental; Quinolines; Rats

3-Amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1) are potent mutagen/carcinogens isolated from pyrolyzates of tryptophan and glutamic acid, respectively, and they have been found to exist in many cooked foods. Trp-P-2 and Glu-P-1 bind to DNA covalently after metabolic activations. The compounds are oxidized to the corresponding hydroxylamines (N-OH-Trp-P-2 and N-OH-Glu-P-1) by microsomes. N-OH-Trp-P-2 and N-OH-Glu-P-1 are the proximate forms of Trp-P-2 and Glu-P-1, respectively. They are further activated by cytosol to the O-acyl derivatives, which bind covalently with DNA. The structures of the modified nucleic acid bases were identified as 3-(C8-guanyl)amino-1-methyl-5H-pyrido[4,3-b]indole (Gua-Trp-P-2) and 2-(C8-guanyl)amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Gua-Glu-P-1). These initial events caused by Trp-P-2 and Glu-P-1 were established chemically, both in vitro and in vivo.

Topics: Animals; Biotransformation; Carbolines; Carcinogens; DNA; Imidazoles; Liver; Mutagens; Rats

The involvement of four forms of cytochrome P-450 in the activation of the promutagens, 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-amino-6-methyl-dipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-aminofluorene and 4-aminobiphenyl has been investigated using a Salmonella test system. A high-spin form, P-448 II-a, catalysed the activation of IQ and Glu-P-1 28 and 12 times faster, respectively, than a low-spin form, P-448 II-d, whereas benzo[a]pyrene was metabolized to the phenols 60 times faster by P-448 II-d than P-448 II-a. Both P-448 II-a and P-448 II-d were highly active in the activation of Trp-P-2 and 2-aminofluorene. Treatment of CDF1 mice with polychlorinated biphenyls (PCB) increased the microsomal-activating ability for the promutagens in various degrees. More than a ten-fold increase was observed with Trp-P-2, while the increase was only two-fold with IQ. No sex-related difference was observed for the hepatic microsomal activating ability of male and female CDF1 mice for Trp-P-2, Glu-P-1 or IQ. These results indicate that more than two forms of cytochrome P-450, which are inducible by treatment with PCB or 3-methylcholanthrene, mediate the metabolic activation of heteroaromatic amines in rats and mice.

Topics: Amines; Aminobiphenyl Compounds; Animals; Benzo(a)pyrene; Biotransformation; Carbolines; Cytochrome P-450 Enzyme System; Female; Fluorenes; Imidazoles; Male; Mice; Microsomes, Liver; Mutagens; Polychlorinated Biphenyls; Quinolines

The potent mutagens 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2, 62450-07-1), 2-amino-6-methyldipyrido-[1,2-a:3', 2'-d]imidazole (Glu-P-1, 67730-11-4) and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ, 76180-96-6), isolated from pyrolysates of tryptophan and glutamic acid and from broiled sardines, respectively, were effectively degraded by chlorinated tap water with a concomitant loss of mutagenicity toward Salmonella typhimurium TA98 and TA100. The half-life of 10 microM IQ in the presence of 1.5 ppm of residual chlorine was less than 10 sec; those of Glu-P-1 and Trp-P-2 were 0.5-1 and 2-3 min, respectively. This means that a glass of chlorinated tap water (150 ml) containing 1.5 ppm of residual chlorine can break down about 200 micrograms of these pyrolysate mutagens within a couple of minutes.

Topics: Carbolines; Cell Survival; Chlorine; Cooking; Hot Temperature; Imidazoles; Mutagenicity Tests; Mutagens; Quinolines; Salmonella typhimurium; Spectrophotometry, Ultraviolet; Water Supply

Hydroxyamino, nitroso and nitro derivatives of 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), mutagens-carcinogens produced on pyrolysis of amino acids, were synthesized from Trp-P-2 and Glu-P-1. 3-Hydroxyamino-1-methyl-5H-pyrido[4,3-b]indole (N-OH-Trp-P-2) and 2-hydroxyamino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (N-OH-Glu-P-1) were obtained with good yields by controlled catalytic reduction of 3-nitro-1-methyl-5H-pyrido[4,3-b]indole and 2-nitro-6-methyldipyrido[1,2-a:3',2'-d]imidazole. Subsequent oxidation of N-OH-Trp-P-2 and N-OH-Glu-P-1 with gamma-manganese dioxide yielded 3-nitroso-1-methyl-5H-pyrido[4,3-b]indole and 2-nitroso-6-methyldipyrido[1,2-a:3',2'-d]imidazole. All six synthesized compounds were mutagenic to Salmonella typhimurium TA98 without mammalian activation systems. The mutagenic activities of hydroxyamino and nitroso derivatives were identical for both S. typhimurium TA98 and TA98NR, the nitroreductase deficient strain. However, nitro derivatives were essentially mutagenic only towards S. typhimurium TA98.

Topics: Carbolines; Hydroxylamines; Imidazoles; Indicators and Reagents; Mutagenicity Tests; Mutagens; Mutation; Nitro Compounds; Nitroso Compounds; Salmonella typhimurium; Structure-Activity Relationship

Pyrolysates of tryptophan (Trp-P-2) and glutamic acid (Glu-P-1) are known mutagens in in vitro short term mutagenicity tests, and have also shown carcinogenic effects in long term animal studies. The present study demonstrates that they also produce mutations in somatic cells. This result demonstrates the ability of the test to detect carcinogenic and mutagenic compounds.

Topics: Animals; Carbolines; Carcinogens; Female; Hair Color; Imidazoles; Indoles; Injections, Intraperitoneal; Litter Size; Male; Mice; Mutagenicity Tests; Mutagens; Mutation; Pregnancy

The activities of pyrolysis products for initiating or promoting preneoplastic lesions were tested. In experimental series I, N-2-fluorenylacetamide (2-FAA) was used as an initiator or a promoter and 3-amino-1,4-dimethyl-5H-pyrido-[4, 3-b] indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido [4, 3-b] indole (Try-P-2), 2-amino-6-methyldipyrido [1,2-a:3', 2'-d] imidazole (Glu-P-1) or 2-amino-dipyrido [1, 2-a:3', 2'] imidazole (Glu-P-2) was administered at a fixed dose and for the same period in the initiation stage or the promotion stage. Animals were subjected to partial hepatectomy or treated with carbon tetrachloride (CCl4) to increase the induction of gamma-glutamyl transpeptidase (gamma-GT) positive foci. Trp-P-1 and Glu-P-2 administered in either the initiation or promotion stage significantly increased the induction of gamma-GT positive foci (p less than 0.001). Glu-P-1 increased the induction of gamma-GT positive foci (P less than 0.001) when administered in the initiation stage but it was not effective when administered during the promotion stage. In experimental series II, animals were given a single dose of these chemicals at one of three different dose levels with partial hepatectomy and then were fed with 2-FAA and given a single dose of CCl4. Trp-P-1, Glu-P-1 and Glu-P-2 caused dose-dependent inductions of gamma-GT positive foci.

Topics: 2-Acetylaminofluorene; Animals; Carbolines; Enzyme Induction; gamma-Glutamyltransferase; Imidazoles; Liver; Liver Regeneration; Male; Mutagens; Rats; Rats, Inbred F344

Topics: Carbolines; Cell Division; Cytokinins; Imidazoles; Indoles; Mutagens; Nicotiana; Plant Development; Plants; Plants, Toxic

The mutagenic aromatic amines Trp-P-1, Trp-P-2 and Glu-P-1, isolated frm pyrolysates of tryptophan and glutamic acid, at the concentration of 0.025 mM were treated with 0.05 mM nitrite at various pH values at 37 degrees C. The resulting reaction mixtures were tested for mutagenicity towards Salmonella typhimurium TA98 and TA100. When treated with nitrite at this physiologically realistic concentration, these mutagenic aromatic amines were readily converted to extremely weak or non-mutagenic deaminated compounds. These deaminated products were identified as the corresponding hydroxy compounds by mass and proton magnetic resonance spectroscopies. Comparative kinetic studies were made on the disappearance of the mutagenic aromatic amines. The half-life (t1/2 of Glu-P-1 on treatment with nitrite at pH 1.6 was less than 5 min, and those of Trp-P-1 and Trp-P-2 were 95 and 105 min, resp.

Topics: Amines; Animals; Carbolines; Deamination; Glutamates; Imidazoles; Mutagenicity Tests; Mutagens; Nitrites; Rats; Salmonella typhimurium; Tryptophan

Two potent mutagens, 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), isolated from a tryptophan pyrolysate, and 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), isolated from a glutamic acid pyrolysate, modified calf thymus DNA in the presence of rat liver microsomes. The major base modified by Trp-P-2 was identified wih 3-(3-guanyl)amino-1-methyl-5H-pyrido[4,3-b]indole. The major base modified by Glu-P-1 was identified with 2-(8-guanyl)amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole. N-acetoxy-Glu-P-1 efficiently modified DNA without microsomes.

Topics: Animals; Biotransformation; Carbolines; Cattle; DNA; Imidazoles; Indoles; Microsomes, Liver; Mutagens; Rats; Thymus Gland