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PubMed1986

Mutagenicity of 3,4-diphenyl-5-nitrofuran analogs in Salmonella typhimurium.

A new series of chemicals comprising eight different 3,4-diphenyl-substituted furan analogs, namely, methyl-3,4-diphenyl-2-furoate, methyl-3,4-diphenyl-5-nitro-2-furoate, 3,4-diphenyl-5-nitro-2-furoic acid, 3,4-diphenyl-5-nitro-2-acetylfuran, 3,4-diphenyl-5-nitro-2-bromoacetylfuran, 2-amino-4-(3,4-diphenyl-5-nitro-2-furyl)thiazole, 2-acetyl-amino-4-(3,4-diphenyl-5-nitro-2-furyl)thiazole and 2-formyl-amino-4-(3,4-diphenyl-5-nitro-2-furyl)thiazole were synthesized and their mutagenic activities tested in Salmonella typhimurium. The structure--activity relationship studies revealed that for mutagenic activity the nitro group is essential and that the potency of activity is greatly altered by the nature of the substituent at the 2-position of the furan ring. The mutagenic activities of these chemicals were generally much higher in TA100 compared to TA98. The relative order of activities for 2-substituted, 3,4-diphenyl-5-nitrofurans were COOCH3 greater than COCH2BR greater than COCH3 greater than COOH in S. typhimurium TA100. 3,4-Diphenyl-5-nitro-2-bromoacetylfuran was equally active in nitroreductase-proficient (TA98, TA100) and in nitroreductase-deficient (TA98NR, TA100NR) strains. In contrast, the acetyl and carboxymethyl ester analogs were relatively less active in nitroreductase-deficient strains. Mutagenic activities of 3,4-diphenyl-substituted furylthiazoles in comparison with the unsubstituted analogs of N-[4-(5-nitro-2-furyl)-2-thiazolyl]-formamide, N-[4-(5-nitro-2-furyl)-2-thiazolyl]-acetamide and 2-amino-4-(5-nitro-2-furyl)thiazole revealed that the phenyl groups drastically reduced their mutagenic activities. However, the relative order of activities formylamino greater than or equal to acetylamino greater than amino were the were the same between phenyl-substituted and unsubstituted analogs.

Biotransformation↗
PubMed1990

Effects of nitrofurans on adrenal cortical tissue in chickens.

In chicken adrenal glands, aspartate transaminase (AST) activity is concentrated in the adrenal cortical cells. Administration of a bolus dose of furazolidone (200 mg/kg) to the birds produced a decrease in AST activity in the adrenal glands and a general disorganization in the ultrastructure of the adrenal cortical cells. Many adrenal cortical mitochondria appeared to be moribund, being swollen, without cristae or apparently empty. These effects preceded atrophy of the adrenal cortical tissue, which was most marked in the central part of the adrenal glands. The atrophy was still present after 12 weeks, and it is therefore suggested that nitrofurans may be useful in the treatment of Cushing's disease in other animal species. When furazolidone or furaltadone was given in the diet at therapeutic levels, blebs of an electron-dense substance developed in adrenal cortical mitochondria and AST activity in the adrenal glands was reduced. These effects were found to be reversible, and the treatments did not produce atrophy of the adrenal cortical tissue.

Adrenal Cortex↗
PubMed1981

Nifurzide, a nitrofuran antiinfectious agent: interaction with Escherichia coli cells.

This paper presents a study of the interactions between Escherichia coli cells and nifurzide, a nitrofuran derivative which is used as an intestinal antiinfectious agent. At low concentrations of nifurzide, the growth rate of the cultures decreased, and elongated, nonseptate cells appeared. At high concentrations, complete growth inhibition occurred, accompanied by a rather strong bactericidal effect, but the appearance of the cells was normal; in particular, no bacteriolytic effect was observed. A very large number of antibiotic molecules were bound per bacterial cell. After cell disruption, similar amounts of nifurzide were found in the cytoplasm, cytoplasmic membranes, and cell wall, respectively. Most of the bound nifurzide was rapidly degraded or became protein bound. The structure of the outer membrane lipopolysaccharide appeared to have little influence on the activity of nifurzide.

Anti-Bacterial Agents↗
PubMed1991

Effect of nitrofurans on duodenal ulceration induced by cysteamine or indometacin.

The present experiments examined the protective effect of the nitrofuran drugs, furazolidone (FZ) and nitrofurazone (NF), on duodenal ulceration induced by cysteamine or indometacin in rats. FZ at oral doses of 25, 50 or 100 mg/kg for 2 consecutive days signficantly reduced, in a dose-dependent manner, the incidence and extent of cysteamine-induced ulceration. However, oral NF (100 mg/kg) given for 2 consecutive days had no significant effect on duodenal ulceration. The duodenal mucus content of rats was not significantly affected by either FZ or cysteamine treatments. FZ at an oral dose of 100 mg/kg for 2 consecutive days significantly reduced the incidence and extent of indometacin-induced ulceration. Smaller doses of 25 or 50 mg/kg had no significant effects.

Animals↗
PubMed1990

Studies on the antineoplasticity of Schiff bases containing 5-nitrofuran and pyrimidine.

Antineoplastic properties of different Schiff bases obtained by the interaction of 5-nitrofuran with substituted pyrimidines have been examined both in vitro and in vivo. In vitro studies on L 5178Y/asparaginase sensitive, HL 60 and P 388 cell lines and in vivo studies on the P 388 cell line indicate that all the compounds are potential antineoplastic agents. However, 2-(5-nitro-2-furfurylidene-amino)-pyrimidine (SBP1) is the most effective, and 2-(5-nitro-2-furfurylidene-amino)-6-hydroxypyrimidine (SBP3) is the least effective agent. Doubling time, rates of protein and DNA synthesis inhibition and LD50 values-1,000 mg/kg body weight for SBP1 and 1,275 mg/kg body weight for 2-(5-nitro-2-furfurylidene-amino)-4- methylpyrimidine (SBP2)- in the oral route support the activity and use of SBP1 and SBP2 as future anticancer agents.

Animals↗
PubMed1978

Comparative in vitro activity of five nitrofurans.

Five nitrofurans- nitrofurantoin, nifuratel, nitrofurazone, furazolidone and and SQ 18,506--have been tested against 201 microbial strains. Escherichia coli, Streptococcus faecalis, micrococci and Staphylococcus epidermidis were sensitive to all five compounds; furazolidone and SQ 18,506 were the most active against these species. Klebsiella aerogenes was less sensitive, and Proteus spp., Providencia stuartii and Pseudomonas aeruginosa strains were resistant. Nifuratel was inhibitory for some Candida albicans strains, and SQ 18,506 was highly active against this species. Nifuratel was judged overall to have superior in vitro antimicrobial properties to nitrofurantoin.

Bacteria↗
PubMed1992

Electronic properties and free radical production by nitrofuran compounds.

Substitution of nifurtimox tetrahydrothiazine moiety by triazol-4-yl, benzimidazol-l-yl, pyrazol-l-yl or related aromatic nitrogen heterocycles determines changes in the quantum chemistry descriptors of the molecule, namely, (a) greater negative LUMO energy; (b) lesser electron density on specific atoms, especially on the nitro group atoms, and (c) modification of individual net atomic charges at relevant atoms. These variations correlate with the greater capability of nifurtimox analogues for redox-cycling and oxygen radical production, after one-electron reduction by ascorbate or reduced flavoenzymes. Variation of the nitrofurans electronic structure can also explain the greater activity of nifurtimox analogues as inhibitors of glutathione reductase and Trypanosoma cruzi growth, although other factors, such as molecular hydrophobicity and connectivity may contribute to the latter inhibition.

Electrons↗
PubMed1975

Mutagenicity of nitrofurans, nitrothiophenes, nitropyrroles, nitroimidazole, aminothiophenes, and aminothiazoles in Salmonella typhimurium.

Thirty-two heterocyclic compounds, including 24 nitroheterocycles, 7 aminoheterocycles and derivatives, and 1 thiophene lacking a nitro group, were tested for mutagenic activity in Salmonella typhimurium TA 98 and TA 100. All the nitroheterocycles (11 new), including nitrofurans, nitrothiophenes, nitropyrroles, and 1 nitroimidazole, were mutagenic in TA 100; 13 were also mutagenic in TA 98. 5-Nitro-2-furoic acid, a noncarcinogen, was mutagenic in TA 100. Seven carcinogenic nitroheterocycles were mutagenic in both strains. Seven aminoheterocycles (4 new), aminothiophenes and aminothiazole derivatives, and 1 thiophene without a nitro group were not mutagenic. Both TA 98 and TA 100 were uvrB and lacked the ability of excision repair of DNA. Among the 24 mutagenic nitroheterocycles, only 13 compounds exhibited bacterial killing effects, suggesting that more than 1 mechanism may be involved in the interaction of nitroheterocycles with bacterial DNA.

Amines↗
PubMed1975

[Functional state of the testis after the use of certain antibiotics and nitrofuran preparations].

The functional state of the testis due to the effect of antibacterial therapy was studied in 50 patients suffering from chronic inflammatory diseases of the urinary-genital system and treated with neomycin, streptomycin, tetracycline, furadonin and furagin. It was shown that the above nitrofurans and neomycin had a negative effect on the testis function lowering the number of the spermatozoa in 1 ml and the whole ejaculate and their mobility. Contrary to it tetracycline therapy had no significant effect on the spermatozoa number, while the use of streptomycin was accompanied by a certain tendency to an increase in their number. The data were to some extent in certain accordance with the results of the experimental studies.

Adult↗
PubMedDate not supplied

Synthesis, characterization and antibacterial activities of some N-bridged heterocycles containing triazole, quinoline and nitrofuran moieties.

A series of 2-(2-furyl)4-quinolinecarboxylic acids (3), 2-(5-nitro-2-furyl)4-quinolinecarboxylic acids (6), 4-(3-aryloxymethyl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazolo-6-yl)-2-(furyl)quinolines (5) and 4-(3-aryloxymethyl-1.2,4-triazolo[3,4-b]-1,3,4-thiadiazolo-6-yl)-2-(5-nitro-2-furyl)quinolines (7) were synthesized. The structures of the newly synthesized compounds are confirmed on the basis of elemental analysis, IR, 1H-NMR and mass spectral data. The newly synthesized compounds are evaluated for their antibacterial activities. Compounds containing nitrofuran moiety showed excellent antibacterial activity. Results of such studies are disscussed in this paper.

4-Quinolones↗
PubMed2003

ESR spin trapping studies of free radicals generated from nitrofuran derivative analogues of nifurtimox by electrochemical and Trypanosoma cruzi reduction.

Electron spin resonance (ESR) spectra of radicals obtained from two analogues of the antiprotozoal drug nifurtimox by electrolytic and Trypanosoma cruzi reduction were analyzed. The electrochemistry of these compounds was studied using cyclic voltammetry. STO 3-21G ab initio and INDO molecular orbital calculations were performed to obtain the optimized geometries and spin distribution, respectively. The antioxidant effect of glutathione on the nitroheterocycle radical was evaluated. DMPO spin trapping was used to investigate the possible formation of free radicals in the trypanosome microsomal system. Nitro1 and Nitro2 nitrofuran analogues showed better antiparasitic activity than nifurtimox. Nitro2 produced oxygen redox cycling in T. cruzi epimastigotes. The ESR signal intensities were consistent with the trapping of either the hydroxyl radical or the Nitro2 analogue radicals. These results are in agreement with the biological observation that Nitro2 showed anti-Chagas activity by an oxidative stress mechanism.

Animals↗
PubMed1992

Mechanism of the polarographic reduction of a new 5-nitrofuran derivative with antibacterial activity.

The reduction at mercury electrodes of a new 5-nitrofuran derivative with antibacterial activity, N2-(5-nitrofurfurylidene)formohydrazide-4-(3,5-dicyanophenyl)-6-ethoxy-2- pyridyl)imide, was studied by conventional, normal pulse, reverse normal pulse and differential pulse polarography in water-dimethylformamide (30%) buffered media. The waves observed, whose number depended on pH, are attributed to the reduction of the nitro group (6 electrons) and the azomethinic unit (4 electrons). The basic mechanisms of the electrode reactions have been deduced from the characteristics of the waves. Conditions for determining the formal potential of the nitroderivative/radical-anion system, a parameter related to pharmacological activity, are also reported.

Anti-Infective Agents↗
PubMed1990

[The effect of nitrofuran and asymmetrically substituted urea on Trichomonas vaginalis and Tritrichomonas foetus in vitro and in vivo].

Antitrichomonal activity of selected nitrofuran derivatives and asymmetrically substituted ureas was investigated in vitro and in vivo and compared with the activity of the effective therapeutic agent tinidazole. In experimental infection with Trichomonas vaginalis and Tritrichomonas foetus in mice, some substituted urea derivatives exhibited an antiparasitic effect slightly lower than that of tinidazole. The substance N1-(3-nitrophenyl)-N3-(2-pyrimidinyl)urea proved to be the most effective of the substances tested. On the basis of preliminary toxicity tests the chemotherapeutic value of this substance appears to be promising.

Animals↗
PubMed1987

Generation of nitro radical anions of some 5-nitrofurans, 2- and 5-nitroimidazoles by norepinephrine, dopamine, and serotonin. A possible mechanism for neurotoxicity caused by nitroheterocyclic drugs.

Catecholamine neurotransmitters such as norepinephrine, dopamine, and related catecholamine derivatives reduce nitroheterocyclic drugs such as nitrofurantoin, nifurtimox, nifuroxime, nitrofurazone, misonidazole, and metronidazole in slightly alkaline solutions. Drugs which contain 5-nitrofurans are reduced at lower pH than drugs which contain 2- and 5-nitroimidazoles. 5-Nitroimidazole derivatives such as metronidazole and ronidazole are known to be more difficult to reduce than 2-nitroimidazole derivatives, due to their lower redox potential. Catecholamines, when reducing nitro drugs, undergo concomitant oxidation to form semiquinone radicals. Both semiquinone radicals and nitro anion radicals formed in a reaction of nitro drug and catecholamine derivative were detected by electron spin resonance spectroscopy. Oxygen consumption studies in solutions containing nitro drug and catecholamine derivative showed that nitro anion radicals formed under aerobic conditions reduce oxygen to form the superoxide radical and hydrogen peroxide. Quinones formed in the reaction of catecholamine and nitro drug were detected by optical spectroscopy. Biosynthetic precursors and some metabolic products of catecholamines were also used in these studies, and they all exhibited reactions similar to catecholamines. Bovine chromaffin granules which synthesize and store catecholamines produced the nitrofurantoin anion radical when intact granules were treated with nitrofurantoin. These radicals formed inside the granules were observed by ESR spectroscopy. The formation of nitrofurantoin radical, semiquinone radicals of catecholamines, and oxygen-derived radicals by chromaffin granules is proposed to cause damage to adrenal medulla, and this process may lead to neurotoxicity.

Animals↗
PubMedDate not supplied

[Effect of quinones and nitrofurans on Trypanosoma mega and Crithidia fasciculata].

Demonstration of trypanocidal effects in vitro is a first step for the development of new antichagasic drugs. In order to obtain an experimental model allowing the pre-screening of potential trypanocides for Trypanosoma cruzi in a short time and under safe conditions, the trypanosomatids T. mega and C. fasciculata were assayed for their response to a) compounds known for their action on T. cruzi, and b) compounds not tested before on the latter. The drugs were assayed on the organisms growth in a liquid culture medium, cell multiplication being measured by the medium turbidity increase, using a photoelectric colorimeter previously calibrated with cell suspensions of known concentration. A series of quinones (Lapachones and related compounds), naftoquinone-imines, benzoquinones (perezone and dihydroperezone), a quinol (miconidine) and several nitrofurans, including nifurtimox and (5-nitro-2-furfurylidene)-amino (NF-group) derivatives, inhibited the flagellates growth, specially T. mega, with half-maximal inhibitory concentrations lesser than 5.0 microM, for the most active compounds. T. mega response to nifurtimox, NF-derivatives and beta-lapachone was in close agreement with that of T. cruzi. Cultures of T. mega in the presence of NF-pyrazole, NF-indazoles and NF-imidazole but not nifurtimox, showed irreversible damage since, after re-incubation in fresh medium without inhibitor, these cells grew significantly less than their corresponding controls. Similar effects were observed in C. fasciculata, with beta-lapachone and one naftoquinone-imine. Our results qualify T. mega as an adequate experimental model for the assay of antichagasic agents, as C. fasciculata and T. brucei brucei do for the african trypanosomes.

Animals↗
PubMed1987

Enhancement of toxicity from N-(2-chloroethyl)-N'-cyclohexyl-N-nitrosourea in V79 spheroids by a nitrofuran.

Hypoxic cell radiosensitizers enhance the cytotoxicity of several common chemotherapeutic agents in vitro and in vivo. Although this process has generally been called sensitization, few studies have documented true potentiation. We have used Chinese hamster V79 spheroids to study chemosensitization and fluorescence-activated cell sorting to specifically evaluate the roles of sensitizer binding and hypoxia in the effect. By using the median effect analysis to quantify the interactions of the agents, we conclude that marked potentiation can indeed be achieved. Somewhat greater potentiation was observed at increased depths within the spheroids, but the relative change was less than predicted on the basis of the decreasing oxygen tension. Further, increased toxicity did not necessarily lead to increased chemopotentiation, nor was potentiation directly related to the metabolism/binding of the nitrofuran. Thus, chemopotentiation is clearly a complicated process, highly dependent upon the sensitizer to antitumor drug ratio and the exposure conditions.

Animals↗
PubMed1985

[Toxicologic evaluation of nitrofuran derivatives].

The most important side effects of numerous nitrofuran derivatives are their mutagenicity and carcinogenicity. They are due to metabolites of this group of substances in the microbial and animal metabolism. The mutagenic or carcinogenic metabolites are either excreted or covalently bound in the animal organism and may then form persistent residues in the slaughtered animal. If active at all, such residues are toxicologically less active than free metabolites. To determine their bioavailability and to exclude any risk to the consumer, their relay-toxicity should be tested using suitable experimental animals.

Animals↗