N-Nitrosamines are receiving special attention because they present high mutagenic and carcinogenic potential. They can be found in several areas. In rubber, for example, they can be found in Nipples ...and Pacifiers. Spiegelhalder and Pressumann, have observed that N-Nitrosamines present in nipples and pacifiers could easily migrate to artificial saliva. They have also observed that a considerable amount of N-Nitrosamines precursors, such as nitrosable amines, could migrate to saliva, increasing the possibility of N-Nitrosamines formation into the stomach of living beings. In 80's, Holland, Germany and FDA-U.S.A. have established volatile N-Nitrosamines limit levels. In 2002, in Brazil, limit levels came through Resolução RDC n° 221 of ANVISA. This resolution refers to NBR10334 and NBR 13793 standards where limits and analysis methods are specified. In this work SENAICETEPO presents the method adopted for determination of N-Nitrosamines and N-Nitrosables in nipples and pacifiers. The detection and determination limits of the analytical system as well the method uncertainty were evaluated, in order to demonstrate the adequacy of this technique to comply with the requirements of NBR10334/2003 and NBR 13793/2003 standard.
Ten lactic acid bacteria strains were isolated from a rippened ewes’ milk cheese and tested for stimulation or inhibition of the viability of Vero and myeloma cells. None of the strains significantly ...affected the viability of Vero cells. However, an isolate (CBL/J) showed a strong inhibition of the cellular viability (10
8
cfu
mL
−1, 10.1% of survival on myeloma cells). Isolate CBL/J was submitted to a characterisation scheme and identified as
Lactobacillus plantarum by DNA sequencing of 16S rRNA Polymerase Chain Reaction (PCR) products.
Lb. plantarum CBL/J showed a protective effect against three
N-nitrosamines
N-nitrosopyrrolidine (NPYR),
N-nitrosodibuthylamine (NDBA) and
N-nitrosopiperidine (NPIP) but not against
N-nitrosodimethylamine (NDMA). The highest protective effect was observed against NPIP at populations of 10
7
cfu
mL
−1 (110.9% of survival on Vero cells). To test the effect of
Lb. plantarum CBL/J on cytokine production, tumor necrosis factor alpha (TNF-
α), interleukin-1
β (IL-1
β) and interleukin-8 (IL-8), the human macrophage cell line (THP-1) was cultured in the presence and absence of lipopolysaccharide (LPS).
Lb. plantarum CBL/J induced IL-1
β release when cells were stimulating with and without LPS. However, IL-8 production was not observed in the presence of LPS and TNF-
α release was only produced in the presence of the LPS.
The aim of this study was to investigate the protective effect of isothiocyanates towards N-nitrosamine-induced DNA damage in the single-cell gel electrophoresis (SCGE)/HepG2 assay. None of the ...isothiocyanates (ITCs) concentrations tested in the presence or absence of formamidopyrimidine-DNA glycosylase (Fpg), caused DNA damage per se. Combined treatments of HepG2 cells with phenethyl isothiocyanate (PEITC), allyl isothiocyanate (AITC) or indol-3-carbinol (I3C) and N-nitrosopyrrolidine (NPYR) or N-nitrosodimethylamine (NDMA) reduced the genotoxic effects of the N-nitrosamines in a dose-dependent manner. The protective effect of the three ITCs tested was higher towards NPYR-induced oxidative DNA damage than against NDMA. The greatest protective effect towards NPYR-induced oxidative DNA damage was shown by I3C (1 microm, 79%) and by PEITC (1 microm, 67%) and I3C (1 microm, 61%) towards NDMA (in the presence of Fpg enzyme). However, in the absence of Fpg enzyme, AITC (1 microm, 72%) exerted the most drastic reduction towards NPYR-induced oxidative DNA damage, and PEITC (1 microm, 55%) towards NDMA. The results indicate that ITCs protect human-derived cells against the DNA damaging effect of NPYR and NDMA, two carcinogenic compounds which occur in the environment.
Some
N
-aminotriazines and -triazoles were treated with
Preyssler
’s anion as catalyst in acetic acid to afford the corresponding deaminated triazines and triazoles. The reaction is suggested to ...proceed
via
formation of
N
-nitrosamines with subsequent N–NO bond cleavage.
Background. Both N‐nitroso compounds and colonization with Helicobacter pylori represent known risk‐factors for the development of gastric cancer. Endogenous formation of N‐nitroso compounds is ...thought to occur predominantly in acidic environments such as the stomach. At neutral pH, bacteria can catalyze the formation of N‐nitroso compounds. Based on experiments with a noncarcinogenic N‐nitroso compound as end product, and using only a single H. pylori strain, it was recently reported that H. pylori only displays a low nitrosation capacity. As H. pylori is a highly diverse bacterial species, it is reasonable to question the generality of this finding. In this study, several genetically distinct H. pylori strains are tested for their capacity to form carcinogenic N‐nitrosamines.
Materials and Methods. Bacteria were grown in the presence of 0–1000 µM morpholine and nitrite (in a 1 : 1 molar ratio), at pH 7, 5 and 3.
Results. Incubation of Neisseria cinerea (positive control) with 500 µM morpholine and 500 µM nitrite, resulted in a significant increase in formation of N‐nitrosomorpholine, but there was no significant induction of N‐nitrosomorpholine formation by any of the H. pylori strains, at any of the three pH conditions.
Conclusion. H. pylori does not induce formation of the carcinogenic N‐nitrosomorpholine in vitro. The previously reported weak nitrosation capacity of H. pylori is not sufficient to nitrosate the more difficultly nitrosatable morpholine. This probably also holds true for other secondary amines. These results imply that the increased incidence of gastric cancer formation that is associated with gastric colonization by H. pylori is unlikely to result from the direct induced formation of carcinogenic nitrosamines by H. pylori. However, this has to be further confirmed in in vivo studies.
The ability of 20 compounds, all but one tobacco constituents, to inhibit the formation of tobacco-specific N-nitrosamines (TSNA) was investigated in buffer and detergent solution and in tobacco ...midrib and lamina systems. In solution at pH 5.5, ascorbic acid and the phenolic acids caffeic and ferulic acid were the most potent inhibitors of the reaction between nornicotine and nitrite, with nearly complete inhibition at molar ratios test compound/nitrite > 1:1. Also, cysteine > dihydrocaffeic acid > protocatechuic acid ≈ catechin acted as strong inhibitors with >90% inhibition at a ratio of 3:1. Lower inhibitions were observed with chlorogenic acid > p-coumaric acid > sclareol > serine. Rutin showed an inhibition of 34% at a ratio of 0.1:1. Sclareol, alanine, proline, and serine did not significantly affect the N-nitrosonornicotine (NNN) formation. α-Tocopherol and glutathione enhanced NNN formation at pH 5.5 but were inhibitors at pH 3. Cinnamic acid, vanillic acid, eugenol, and esculin enhanced NNN formation. Increased NNN formation was also observed for dihydrocaffeic acid, chlorogenic acid, protocatechuic acid, and catechin at a less-than-equimolar ratio of test compound to nitrite. The tobacco matrix experiments were performed with air-cured, ground tobacco midrib and lamina. Caffeic acid, ferulic acid, dihydrocaffeic acid and catechin were potent inhibitors of the formation of TSNA in the midrib as well as in the lamina. Also protocatechuic acid, glutathione, ascorbic acid, p-coumaric acid, chlorogenic acid and cysteine were inhibitors, while α-tocopherol and rutin inhibited the reaction in the midrib but not in the lamina. Cinnamic acid, vanillic acid, eugenol, alanine, proline and serine showed small effects only. The molar ratio of secondary alkaloid(s)/nitrite in the test systems were 0.1:1 (solution), ∼0.25:1 (midrib), and ∼1:1 (lamina) and is most likely the major contributor to the observed order of inhibition potency (solution > midrib > lamina) of the test compounds. The vicinal phenolic hydroxyl groups of polyphenols and the simultaneous presence of a phenol group and an olefinic bond in hydroxycinnamic acids were the most characteristic structural elements of the potent inhibitors. Keywords: Tobacco-specific N-nitrosamines; nitrosation; nornicotine; secondary alkaloids; nitrite scavengers; ascorbic acid; α-tocopherol; phenolic acids; flavonoids; coumarins, amino acids; tobacco matrix; midrib; lamina
An HPLC method has been developed for the determination of nitrosamines. Five nitrosamines were separated simultaneously on a 250 mm×4.6 mm i.d. Phenomenex Luna CN (particle size 5 µm) column with ...methanol-1.0 m M K
2
HPO
4
(pH 4.0) solvent, programmed as mobile phase and with a photodiode array detector. The limits of detection were 0.02, 0.02, 0.02, 0.03, and 0.03 mg L
−1
for N-nitrosodiethanolamine, N-nitroso-bis-(2-hydroxypropyl)amine, N-nitrosodimethyamine, N-nitrosodi-n-propylamine and N-nitrosodiphenylamine, respectively. The method is applied for the simultaneous quantitative determination of nitrosamine in cosmetics and biological fluids.
N-nitrozamini pripadaju grupi organskih spojeva opće kemijske strukture
R1
N(-R2
)-N=O, a nastaju reakcijama oksidacije sekundarnih ili tercijarnih
amina uz pomoć nitrozacijskog sredstva. Pronađeni ...su u duhanskim
proizvodima, sušenom mesu, alkoholnim pićima, siru, konzerviranom
voću, te se smatraju nepoželjnim tvarima za konzumiranje. Redovito su
prisutni u otpadnim vodama u procesima prerade kože, ribe, u proizvodnji
pesticida, boja i gume.
Iako prisutni u tragovima, predstavljaju ozbiljnu prijetnju za vodni okoliš
i ljudsko zdravlje. Posljednjih godina N-nitrozamini predmet su brojnih
analitičkih istraživanja, privlače pozornost različitih regulatornih tijela te
se svrstavaju u tvari koje su „vjerojatno kancerogene za ljude”. Poznavanje
puteva nastajanja N-nitrozamina u vodenim sustavima, mehanizama
razgradnje i transformacije te njihovog učinka na okoliš i zdravlje čovjeka,
ključno je za sprječavanje njihovog nastanka i odabir fizikalno-kemijskih
i drugih postupaka za njihovo uklanjanje iz voda. U ovom preglednom
radu, detaljno su opisani mehanizmi nastanka i učinkovitost uklanjanja
N-nitrozamina iz voda pojedinim metodama.
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