Reduction Of Nitrofurazone Research Articles

Nitrofurazone Removal from Water Enhanced by Coupling Photocatalysis and Biodegradation.

(1) Background: Environmental contamination with antibiotics is particularly serious because the usual methods used in wastewater treatment plants turn out to be insufficient or ineffective. An interesting idea is to support natural biodegradation processes with physicochemical methods as well as with bioaugmentation with efficient microbial degraders. Hence, the aim of our study is evaluation of the effectiveness of different methods of nitrofurazone (NFZ) degradation: photolysis and photodegradation in the presence of two photocatalysts, the commercial TiO2-P25 and a self-obtained Fe3O4@SiO2/TiO2 magnetic photocatalyst. (2) Methods: The chemical nature of the photocatalysis products was investigated using a spectrometric method, and then, they were subjected to biodegradation using the strain Achromobacter xylosoxidans NFZ2. Additionally, the effects of the photodegradation products on bacterial cell surface properties and membranes were studied. (3) Results: Photocatalysis with TiO2-P25 allowed reduction of NFZ by over 90%, demonstrating that this method is twice as effective as photolysis alone. Moreover, the bacterial strain used proved to be effective in the removal of NFZ, as well as its intermediates. (4) Conclusions: The results indicated that photocatalysis alone or coupled with biodegradation with the strain A. xylosoxidans NFZ2 leads to efficient degradation and almost complete mineralization of NFZ.

DUT-67 and tubular polypyrrole formed a cross-linked network for electrochemical detection of nitrofurazone and ornidazole

The cross-linked network of DUT-67/tubular polypyrrole (T-PPY) composites was first synthesized by in-situ growth zirconium - based metal-organic frameworks (DUT-67) with T-PPY. The introduction of T-PPY effectively increases conductivity of DUT-67/T-PPY composites, weakens accumulation of the DUT-67, and exposes more active sites of DUT-67. DUT-67/T-PPY/GCE manifests increased electrocatalytic activity toward reduction of nitrofurazone and ornidazole compared with DTU-67. A novel electrochemical sensor based on DUT-67/T-PPY was established to effectively detect two anti-infective drugs, respectively. Under optimized experimental conditions, the proposed sensor shows a wider linear range for nitrofurazone that is composed by two line segments (9.08–354.08 μM and 354.08–1004.04 μM). Meanwhile, the sensor also displays a linear response to ornidazole in the range of (0.7–100.5 μM and 100.5–250.4 μM) as well as a low LOD as 0.25 μM (S/N = 3). The proposed sensor was used for the detection of nitrofurazone and ornidazole in actual samples, and the satisfactory results were acquired. This research provides an efficient strategy for fabricating novel electrochemical sensor based on cross-linked network structure of T-PPY and MOFs.

Voltammetric investigation of DNA damage induced by nitrofurazone and short-lived nitro-radicals with the use of an electrochemical DNA biosensor

Electrochemical behavior of nitrofurazone (NFZ) was investigated with the use of cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. The pH-dependence of NFZ was studied at a glassy carbon electrode (GCE) in ethanol/Britton–Robinson buffer (30:70), and short-lived nitro-radicals were generated by the reduction of NFZ at high pHs (>7.0). In the presence of DNA, the DPV peak current of NFZ decreased and the peak potential shifted negatively, which indicated that there was an electrostatic interaction between NFZ and DNA. An electrochemical dsDNA/GCE biosensor was prepared to study the DNA damage produced in the presence NFZ; this process was followed with the use of the Co(phen)32+ electroactive probe. Also, the oxidation peaks of guanosine (750mV) and adenosine (980mV) indicated that DNA damage was related directly to the nitro-radicals. Experiments demonstrated that DNA damage occurred via two different steps while NFZ was metabolized and nitro-radicals were produced. Novel work with AFM on the NFZ/DNA interaction supported the suggestion that in vivo, the nitro-radicals were more cytotoxic than the NFZ molecules. A linear DPV calibration plot was obtained for NFZ analysis at a modified dsDNA/GCE (concentration range: 2.50×10−6–3.75×10−5molL−1; limit of detection: 8.0×10−7molL−1), and NFZ was determined successfully in pharmaceutical samples.

Nitrofurazone: Kinetics and oxidative stress in the singlepass isolated perfused rat liver

The disposition of the antibiotic nitrofurazone was studied in the singlepass isolated perfused rat liver. Both the effects of the steady-state level of drug and the composition of the perfusate were evaluated. The higher level (120 μg/ml) of nitrofurazone in a perfusion medium lacking the glutathione (GSH) precursors, glycine, glutamic acid and cysteine, caused a marked increase in bile flow (from 1.01 ±0.07 to 2.33 ± 1.07 μl/min/g), massive biliary efflux of glutathione disulfide (GSSG) (from 0.55 ± 0.07 to 60.6 ± 25.4 nmol/min/g) and a sharp decline in the caval efflux of GSH (to undetectable levels) and the tissue level of GSH (from 5.74 ± 0.20 to 2.68 ± 0.13 μmol/g). Even after the drug was discontinued, these parameters were not restored to control levels. The lower level (30 μg/ml) of nitrofurazone with or without amino acid supplementation and the higher level with supplementation induced less dramatic effects. Using [ 35S]methionine, a new conjugated metabolite of nitrofurazone and glutathione was detected. The data suggest that the toxicity of the reactive oxygen species generated by the redox cycling of the nitro group and the reactive metabolites generated by further reduction of nitrofurazone can be mitigated by adequate glutathione levels, but that livers lacking sufficient glutathione to scavenge these reactive species may be damaged.

Evidence for the involvement of a nitrenium ion in the covalent binding of nitrofurazone to DNA.

We have shown that the xanthine oxidase-catalyzed anaerobic reduction of nitrofurazone in the presence of added DNA leads to the formation of covalently bound adducts. Further, by systematically decreasing the pH of the reaction mixture, we have demonstrated that generation of the reactive species is facilitated under mildly acidic conditions. From these observations, we conclude that it is the nitrenium ion formed from nitrofurazone which binds to DNA.

Nitrofurazone-reducing enzymes in E. coli and their role in drug activation in vivo.

Earlier work showed that Escherichia coli contains at least two enzymes which reduce nitrofurazone and other nitrofuran derivatives. One of these enzymes is lacking in some nitrofurazone-resistant mutant strains. We now report that there are three separable nitrofuran reductases in this organism: reductase I (mol. wt. approximately 50 000, insensitive to O2), reductase IIa (mol. wt. approximately 120 000, inhibited by oxygen), reductase IIb (mol. wt. approximately 700 000, inhibited by O2). Unstable metabolites formed during the reduction of nitrofurazone by preparations containing reductases IIa and IIb produce breaks in DNA in vitro. In vivo experiments with nitrofurazone-resistant strains, which lack reductase II but contain reductases IIa and IIb, demonstrated that lethality, mutation, and DNA breakage are all greatly increased when cultures are incubated under anaerobic conditions, i.e., conditions such that reductase II is active. These results provide further evidence for the importance of reductive activation of nitrofurazone.

ニトロフラン系防腐剤の不活性化現象

Nitrofurazone which has been applied for preservation of fish sausages in Japan was shown o decrease its activity when heated with mammalian meat such as whale, mutton and horse meat. Evidence obtained might suggest that the decrease in bacteriostatic activity is caused by the reduction of nitrofurazone during the heating process by reducing substances in meat and in the presence of Fe++ ion from hemoglobin and myoglobin. Nitrofurylacrylamide, showed rapid reduction in its activity when heated with the cysteine without any cations, and this appeares to elucidate the unsuccessful application of the preserv-atives for Kamaboko or other meat products. The dependency of the heating reduction of the nitrofurans on hydrogen ion concentration and metalic ions was determined with simplified systems containing the nitrofurans, cysteine and cations. From the results of the above experiments, several methods to eluminate the heat reduction of nitrofurans were devised and some of them were shown to be successful when they were applied to Kamaboko.

Site of reduction of nitrofurazone by bacteria.

ANTIBACTERIAL, nitrofurans are reduced to the corresponding amino-compounds by Aerobacter aerogenes 1. The site of the reaction (in a different organism) is now shown to be the cytoplasmic membrane rather than the cell wall or cytoplasm. Lack of an enzyme system capable of effecting this reaction in the bacterial cell walls was not unexpected2.