Ethylnitrolic Acid Research Articles

Microbial biotransformation of N-nitro-, C-nitro-, and C-nitrous-type mutagens by Lactobacillus delbrueckii subsp. bulgaricus in meat products

Processed meats are classified by the International Agency for Research on Cancer (IARC) as carcinogenic to humans. However, information on the responsible agents and the influence of industrial processing on the increased risk of cancer is still lacking. This study aimed to use cultures of Lactobacillus delbrueckii subsp. bulgaricus LB-UFSC 01 to biodegrade harmful C-nitrous, N-nitro, and C-nitro compounds in processed meat matrix. Firstly, positive results for ethylnitrolic acid (ENA) (>5.00 μg kg−1) and 2-methyl-1,4-dinitro-pyrrole (DNMP) (>12.0 μg kg−1) were obtained in mortadellas produced under different experimental conditions employing preservatives and antioxidants. Mortadellas containing nitrite and sorbate in the ratio of 8:1 (w/w) yielded the highest concentrations of mutagens. However, the treatment with the LB-UFSC 01 culture was able to modulate the harmful compounds in the mortadella samples. Several analytical methods employing liquid chromatography coupled to mass spectrometry and statistical models were employed to identify the metabolites and reaction routes during microbial biotransformation. For the first time, relevant information regarding the formation and degradation of ENA and DNMP in a processed meat model simulating real conditions was presented.

Assessing the mutagens ethylnitrolic acid and 2-methyl-1,4-dinitro-pyrrole in meat products: Sample preparation and simultaneous analysis by LC–MS/MS

The simultaneous use of nitrite and sorbate as preservatives in meat products may produce mutagenic compounds such as the ethylnitrolic acid and 2-methyl-1,4-dinitro-pyrrole. We developed a sensitive analytical method with high metrological reliability. After assessing several extraction approaches and chromatographic separation modes, a modified Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) approach was chosen for sample preparation, which were analyzed by reversed-phase liquid chromatography (with C18 as stationary phase) coupled to tandem mass spectrometry. After validation, we confirmed that this method is fit-for-purpose, since it was applied to the analysis of several meat products. Limits of detection were set from 5 to 20 µg kg−1. Satisfactory results were obtained for both compounds, such as precision (CV > 20%) and recoveries (77–92%). This method determine these carcinogenic compounds in processed meats, contributing to the preservation of public health and the improvement of food regulation and control.

Interactions of preservatives in meat processing: Formation of carcinogenic compounds, analytical methods, and inhibitory agents.

Meat products are important for balanced diets because of their nutritional richness. However, noxious compounds may be formed by interactions among reactants and specific conditions in processed meats. N-nitroso compounds, heterocyclic aromatic amines, polycyclic aromatic hydrocarbons, 1,4-dinitro-2-methyl pyrrole (DNMP), and ethyl nitrolic acid (ENA) are among the main compounds of toxicological concern. This review corroborates the International Agency for Research on Cancer (IARC)'s decision to classify those foodstuffs as carcinogenic to humans. Furthermore, this paper also aimed at clarifying how noxious compounds are formed in meat products, as well as their health effects for consumers. The preservatives abuse and the use of forbidden additives may increase the formation of carcinogens. Risks are not only due to preservatives, since some compounds are formed during processing or digestion, without clear link to any additive. Regulation should set specific residue limits for other noxious compounds in meat products, such as DNMP and ENA. The scope of control programs should be extended instead of assessing the proper use of additives only. Thus, reliable analytical methods for the quantitation of carcinogens should be available. Fermentative and enzymatic processes for bioconversion are among the main strategies to solve these problems in foodstuffs. The use of antioxidants is the most common approach, because of its low cost and effectiveness. In the future, the IARC classification should rather consider different categories of processing, as well as the chemical and microbiological composition of meat products. Further studies are still required to clarify the increase on cancer risk due to the consumption of meat products and to elucidate the main mechanisms of carcinogenicity. Notwithstanding, such carcinogens cannot be neglected, but continuously investigated, including their health implications in relation to other foods.

Theoretical studies of ethylnitrolic acid using Gaussian

The tautomerism of all possible forms of ethylnitrolic acid was investigated theoretically in various environment including gas phase, ethanol, dimethyl sulfoxide (DMSO) and water. The calculations were carried out at DFT/B3LYP and MP 2 of theory singly. It was found that, form of B eythynitrolic acid is the most stable isomer in the both gas phase and solvent. The activation energies for conversion of A to R and B to A in the gas phase and solvent using two methods DFT/B3LY and MP 2 were obtained. Geometrical parameters of three isomers, A, B and R, were calculated by (DFT/B3LYP and MP 2 ) in the gas phase and solvent. Vibrational analysis and acidity constants (PK a ) of two isomers (A and R) were calculated in the gas phase and water using DFT/B3LYP and MP 2 . After that, these quantities were evaluated with experimental values and it was determined that DFT/B3LYP is more accurate to obtain PK a .

Solvent effects in the decomposition reaction of some products formed by the reaction of sorbic acid with sodium nitrite: 1,4‐dinitro‐2‐methylpyrrole and ethylnitrolic acid

AbstractA kinetic study of the decomposition reaction of 1,4‐dinitro‐2‐methylpyrrole (NMP) and ethylnitrolic acid (ENA), both formed in the reaction between sorbic acid and sodium nitrite was performed in the 3.5–4.2 pH range in water/dioxane mixtures. Conclusions were drawn as follows: (i) The decomposition of NMP occurs through nucleophilic attack by OH− ions, the rate equation being: r = kdecNMP [OH− ][NMP]. (ii) The rate law for the decomposition of ENA is: r = $k_{dec}^{ENA}$ [ENA]Ka/(Ka + [H+]), Ka being the ENA dissociation constant. (iii) The value of Ka decreases when the water/dioxane ratio decreases, log Ka being proportional to the Onsager parameter (ϵ − 1)/(2ϵ + 1). This permits the equilibrium between non‐dissociated and the dissociated forms of ENA to be rationalized. (iv) No appreciable variation in the ΔH# and ΔS# values with composition of the medium was observed, either in the NMP decomposition reaction, or in the ENA decomposition reaction. Copyright © 2008 John Wiley & Sons, Ltd.

Reactivity of Some Products Formed by the Reaction of Sorbic Acid with Sodium Nitrite: Decomposition of 1,4-Dinitro-2-methylpyrrole and Ethylnitrolic Acid

Sorbic acid reacts with nitrite to yield mutagenic products such as 1,4-dinitro-2-methylpyrrole (NMP) and ethylnitrolic acid (ENA). In order to know the stability of these compounds, a kinetic study of their decomposition reactions was performed in the 6.0-9.5 pH range. The conclusions drawn are as follows: (i) The decomposition of NMP occurs through a nucleophilic attack by OH- ions, with the rate equation as follows: r = k(dec)NMP[OH-][NMP] with k(dec)NMP (37.5 degrees C) = 42 +/- 1 M(-1) s(-1). (ii) The rate law for the decomposition of ENA is as follows: r = k(dec)ENA[ENA]K(a)/(K(a) + [H+]), with K(a) being the ENA dissociation constant and k(dec)ENA (37.5 degrees C) = (7.11 +/- 0.04) x 10(-5) s(-1). (iii) The activation energies for NMP and ENA decomposition reactions are, respectively, E(a) = 94 +/- 3 and 94 +/- 1 kJ mol(-1). (iv) The observed values for the decomposition rate constants of NMP and ENA in the pH range of the stomach lining cells, into which these species can diffuse, are so slow that they could be the slow determining step of the alkylation mechanisms by some of the products resulting from NMP and ENA decomposition. Thus, the current kinetic results are consistent with the low mutagenicity of these species.

Sorbate–nitrite reactions in meat products

The effects of system composition and processing conditions on the formation of mutagenic reaction products (ethylnitrolic acid and 1,4-dinitro-2-methylpyrrole) from the reaction of potassium sorbate and sodium nitrite were investigated in model systems resembling meat products, using gas chromatography–mass spectrometry and high perfomance liquid chromatography. It was observed that 1,4-dinitro-2-methylpyrrole formation was precluded when ascorbic acid or cysteine were present. Ethylnitrolic acid was detected in all systems studied after heating at 35 or 60°C. Results highlight the need for minimizing the combined use of nitrites and sorbates in food products.

New NO-donors with antithrombotic and vasodilating activities, part 15 nitrolic acids.

Five 1-oximino-1-nitro compounds (nitrolic acids) were prepared and tested for antithrombotic and blood pressure lowering activities. 1-Nitro-ethanone 1-oxime (1, ethylnitrolic acid) 2 h after oral administration to rats inhibited thrombus formation by a laser beam in mesenteric arterioles of rats by 69% and by 46% in venules (60 mg/kg). The blood pressure of SHR rats even at this high dose only was decreased by 10% suggesting that antithrombotic and blood pressure effects can be dissociated. The in vitro decomposition of 1 at 37 degrees C nearly exclusively gave N2O and acetic acid indicating that HNO primarily had been formed.

Reactions of nitrile oxides with nitrogen oxides. 1. Reactions with nitrogen tetroxide

We have studied the reaction of nitrile oxides with nitrogen tetroxide. It was shown that the reaction is selective: acetonitrile oxide yields ethylnitrolic acid, α-oximinophenylacetonitrile oxide gives a mixture of isomers of phenylnitrofuroxan, and aromatic nitrile oxides give aryltrinitromethanes.

Review: putative mutagens and carcinogens in foods. II: sorbate and sorbate-nitrite interactions.

Sorbic acid and potassium sorbate are widely used Generally Recognized as Safe (GRAS) food additives with an extremely high (25 mg/kg) acceptable daily intake level. Some children between the ages of 6-24 months may actually ingest this amount. While presently not permitted to be added directly to meat and poultry products in the US, potassium sorbate has been proposed as a preservative for bacon, as an additive in conjunction with nitrite and ascorbate or erythorbate. Sorbate and nitrite form several species of direct-acting mutagens and genotoxic agents when present together at pH's mimicking gastric conditions. Two of the mutagens have been identified as ethylnitrolic acid and 1,4-dinitro-2-methylpyrrole. Mutagen formation is blocked by ascorbate at low pH. Ascorbate at eightfold molar excess leads to inactivation of 1,4-dinitro-2-methylpyrrole near neutral pH but does not destroy the mutagenic nitro compound at low pHs. The combination of sorbate with nitrite represents a potential health risk in the absence of adequate inactivating levels of ascorbate (vitamin C).

Formation of ethylnitrolic acid by the reaction of sorbic acid with sodium nitrite.

Formation of ethylnitrolic acid by the reaction of sorbic acid with sodium nitrite.

Chromoisomerism of potassium salt of 1,1-dinitroethane

A change in the color of the K salt of 1,1-dinitroethane when it is irradiated is caused by the formation of the colored K salt of ethylnitrolic acid as one of the photolysis products, and this refutes the viewpoint postulated in the literature that chromoisomerism exists in 1,1-dinitroethane salts.

The unit cell and space group of ethyl nitrolic acid

The unit cell and space group of ethyl nitrolic acid