Mutagenicities of indole and 30 derivatives after nitrite treatment

Indole and 7-derivatives, L- and D-tryptophan and 9 derivatives, and beta-carboline (norharman) and 11 derivatives were tested for mutagenicity to Salmonella typhimurium TA100 and TA98 after nitrite treatment. 1-Methylindole, which is present in cigarette smoke condensate (Grob and Voellmin, 1970; Hoffmann and Rathkamp, 1970), was the most mutagenic to TA100 without S9 mix after nitrite treatment, inducing 615,000 revertants/mg. 2-Methylindole, 1-methyl-DL-tryptophan, harmaline and (-)-(1S,3S)-1,2-dimethyl-1,2,3,4-tetrahydro-beta-carboline-3- carboxylic acid also showed strong mutagenicity after nitrite treatment, inducing 129,000, 184,000, 103,000 and 197,000 revertants/mg, respectively. These mutagenic potencies were comparable with those of benzo[alpha]pyrene, 3-methylcholanthrene and 2-amino-9H-pyrido[2,3-b]indole (A alpha C) (Sugimura, 1982). Of 31 compounds tested, 22 were mutagenic after nitrite treatment. Since various indole compounds are ubiquitous in our environment, especially in plants, the presence of their mutagenicities after nitrite treatment warrants further studies, including those on their in vivo carcinogenicities.     

Mutagenicities of nitrosated carboline derivatives

Food-borne amines have been considered as the potential precursors of endogenous carcinogenic N-nitroso compounds in humans. A compound which yields a direct mutagen after nitrite treatment was isolated from soy sauce and was identified as 1-methyl-1,2,3,4-tetrahydro-2-carboline-3-carboxylic acid (MTCA) (Wakabayashi, et al., 1983). The mutagenicities of other carboline derivatives such as harman, norharman, harmaline, harmalol, harmine, and harmol were studied. Like MTCA, the nitrosated carboline derivatives showed higher mutagenic activity as compared to their corresponding parent compounds. The demethylated analogue of MTCA, 1,2,3,4-tetrahydro-2-carboline-3-carboxylic acid was synthesized and its nitrosated products were shown to be mutagenic to Salmonella typhimurium TA 100 and TA 98. The potent mutagen Trp-P-2 is a typical 3-carboline derivative. The mutagenicity of Trp-P-2 was suppressed remarkably after nitrosation. Several 3-carboline derivatives also showed the similar property. Nitrosation of MTCA gave several derivatives which were isolated and showed direct mutagenicity to Salmonella typhimurium TA 98. Further characterization of these new carboline derivatives is in progress.     

Mutagenicities of quinoline and its derivatives.

Quinoline, recently reported to be carcinogenic in rats [12], was mutagenic to Salmonella typhimurium tester strains TA100 and TA98 in the presence of the metabolic activation system S-9 mix. 2-Chloroquinoline, a non-carcinogen [12], was non-mutagenic with or without S-9 mix. 8-Hydroxyquinoline, which is t known to be carcinogenic, was mutagenic with S-9 mix to both bacterial strains. The mutagenicities of 17 other quinoline derivatives that are not known to be carcinogenic were tested, and 12 of these compounds were mutagenic.     

Mutagen formation on nitrite treatment of indole compounds derived from indole-glucosinolate

The mutagenicities of 8 indole compounds (indole-3-acetonitrile, indole-3-carbinol, indole-3-acetamide, indole-3-acetic acid, 3-methylindole, indole-3-aldehyde, indole-3-carboxylic acid and indole) derived from indole glucosinolate were studied by mutation tests on Salmonella typhimurium TA98 and TA100 and Escherichia coli WP2 uvrA/pKM101 with and without S9 mix. None of the 8 indole compounds were mutagenic, but they became mutagenic on these 3 tester strains when treated with nitrite at pH 3. The nitrite-treated indole compounds were mutagenic without metabolic activation system (S9 mix), and their mutagenicities were decreased by the addition of S9 mix.     

Combinatorial synthesis of libraries of indole derivatives

The synthesis of two indole derivative libraries is described. 2-Acyl-3-amino-indoles 4 can easily be accessed by treatment of the intermediates 3 with bases in a one-pot reaction sequence whereas the reaction of the isolated intermediates 5 (R(3)=aromatic-, heteroaromatic, or cycloalkyl) with acid chlorides yielded the novel indole derivatives 6. The products were purified by reversed phase column chromatography and obtained in multi-milligram quantities in acceptable yields.     

Biotransformation of indole derivatives by mycelial cultures

Biotransformation of tryptophan to tryptamine and 3-methyl-indole by Psilocybe coprophila was performed. On the other hand, Aspergillus niger was able to transform tryptophan to 5-hydroxy-tryptophan. P. coprophila biotransformed 5-hydroxy-tryptophan to 5-hydroxytryptamine. These results prove once more that fungi are good tools to establish hydroxyindole derivatives.     

Mutagenicities of nitrofuran derivatives on a bacterial tester strain with an R factor plasmid

Many nitrofuran derivatives are known to be mutagenic on Escherichia coli WP2 but not on Salmonella typhimurium TA1535, TA1536, TA1537 or TA1538. Ames and coworkers recently obtained a new tester strain of S. typhimurium, TA100, by putting an R factor plasmid, pKM101, into TA1535. We found that all the mutagenic nitrofuran derivatives previously found to be mutagenic on E. coli WP2 were mutagenic on this new strain (TA100).     

Change in mutagenic activity of genistein after a nitrite treatment

This study examined the mutagenic activity of genistein after a nitrite treatment under acidic conditions. Nitrite-treated genistein exhibited mutagenic activity toward Salmonella typhimurium strains TA 100 and TA 98 with or without S9 mix. Nitrite-treated genistein was demonstrated by electron spin resonance to generate radicals. An instrumental analysis showed 3'-nitro-genistein to have been formed in the reaction mixture. However, 3'-nitro-genistein did not exhibit mutagenic activity toward the S. typhimurium strains, suggesting that other mutagens might also have been formed in the reaction mixture. The clastogenic properties of nitrite-treated genistein and 3'-nitro-genistein were examined by a micronucleus test with male ICR mice. Nitrite-treated genistein and 3'-nitro-genistein showed a significantly higher frequency of micronucleated reticulocytes in mice than in the control group. These results suggest that a daily oral intake of genistein and nitrite through foodstuffs might induce the formation of various mutagenic compounds in the body.     

gem-Dithioacetylated indole derivatives as novel antileishmanial agents

In this communication we report a serendipitously discovered hybrid molecule 1, combining fragment of 3 (an in vivo active antileishmanial molecule) with H₂S donor moiety (known for bimodal behavior of cytoprotection and apoptosis), as antileishmanial agent. Compound 1 suppresses 99.82% parasitemia of L. donovani infected macrophages at 12.5 μg/ml without even deforming them (CC₅₀ > 100 μg/ml). This compound appears cytotoxic for intracellular amastigotes while cytoprotective to host macrophages. The concept can be utilized to develop high therapeutic index NCE (New Chemical Entities) for other macrophage mediated diseases like tuberculosis and cancer.     

Mutagenicities of N-acyl-N-arylhydroxylamines for Salmonella

The N-formyl, N-acetyl and N-propionyl derivatives of N-hydroxy-trans-4-aminostilbene (N-OH-AS), N-hydroxy-4-aminobiphenyl (N-OH-ABP) and N-hydroxy-2-aminonaphthalene (N-OH-AN) were synthesized and examined for their mutagenicities in Salmonella typhimurium TA 98. The N-formyl derivatives were direct-acting mutagens possibly due to hydrolysis, either spontaneously or by bacterial enzymes to hydroxylamines. Their mutagenicities were enhanced by rat liver microsomes and cytosol. All acetyl and propionyl derivatives required activation by either liver cytosol or microsomes. NADPH slightly decreased the microsome-mediated mutagenicities of the N-acyl derivatives of N-OH-AN. However, it greatly enhanced the cytosol-mediated mutagenicities of these hydroxamic acids, probably due to stabilization of their hydroxylamine derivatives. The mutagenicities reported here do not correlate with previously reported carcinogenicity data. Thus, data obtained in Salmonella mutagenicity studies may not necessarily directly reflect carcinogenic potential in mammalian systems due to the different mechanisms of activation.     

Synthesis and biological activity of 8beta-substituted hydrocodone indole and hydromorphone indole derivatives.

The 8beta-unsubstituted and substituted analogues of hydrocodone indole and hydromorphone indole were synthesized and their binding affinities to opioid receptors were determined. Introduction of an 8beta-methyl group into the indolomorphinan nucleus increased affinity at all opioid receptors. 6,7-Dehydro-4,5alpha-epoxy-8beta-methyl-6,7,2',3'-indolomorphinan (9) was found to be a delta antagonist with subnanomolar affinity (0.7 nM) for the delta-opioid receptor, and to have good delta-selectivity (mu/delta=322).     

Isolation of mutagenic beta-carboline derivatives after nitrite treatment of maillard reaction mixtures and analysis of these compounds from foodstuffs and human urine

Mixtures of carbohydrate decomposition products and L-tryptophan were incubated at pH 7.0 and 37 degrees C for 4 weeks. These mixtures exhibited mutagenic activity toward S. typhimurium TA 100 without metabolic activation after a nitrite treatment at pH 4.0. Four beta-carboline derivatives were isolated as premutagens from mixtures of methylglyoxal and furfural. These premutagens were also found to be contained in daily foodstuffs and human urine samples.     

Mutagenicities of N-nitrosamines on Salmonella.

The mutagenic activities of 11 N-nitrosamines were tested using Salmonella typhimurium TA100 and TA98. All the carcinogenic N-nitrosamines were mutagenic on TA100 with a drug-activating system from the rat liver, whereas N,N-diphenylnitrosamine, a non-carcinogen, was not mutagenic. None of the N-nitrosamines was mutagenic on TA98, except N,N-diethylnitrosamine which was weakly mutagenic. To detect the mutagenicity of N,N-dimethylnitrosamine, the pre-incubation of bacteria and N,N-dimethylnitrosamine with S-9 Mix before if was poured onto plates was obligatorily required. Dimethyl sulfoxide inhibited the mutagenic effect of N,N-dimethylnitrosamine.