Mutagenicity and genotoxicity of sorbic acid-amine reaction products.

Sorbic acid as well as potassium and calcium sorbate (E202 and E203) are legally used as preservatives in numerous processed foods. Owing to its system of conjugated double bonds, sorbic acid is likely to undergo a nucleophilic attack, which may turn it into mutagenic products. The cyclic derivatives resulting from a double addition reaction between sorbic acid and various amines at two different temperatures (50 degrees C and 80 degrees C) have been analysed. A genotoxicity study has been performed with HeLa cells and plasmid DNA. A mutagenesis study has been carried out by using the Ames test. A SOS spot test and a cytotoxicity study have been realised as well. The results showed that the products involved exhibited neither mutagenic nor genotoxic activities.

Genotoxicity study of reaction products of sorbic acid.

Sorbic acid (E200) and its salts (potassium and calcium sorbate: E202 and E203) are allowed for use as preservatives in numerous processed foods. Sorbic acid has a conjugated system of double bonds which makes it susceptible to nucleophilic attack, sometimes giving mutagenic products. Under conditions typical of food processing (50-80 degrees C), we analyzed the cyclic derivatives resulting from a double addition reaction between sorbic acid and various amines. Mutagenesis studies, involving the Ames test and genotoxicity studies with HeLa cells and plasmid DNA, showed that none of the products studied presented either mutagenic or genotoxic activities.

Chemical and toxicological studies of products resulting from sorbic acid and methylamine interaction in food conditions.

Sorbic acid has a system of conjugated double bonds which makes it able to undergo nucleophilic addition reactions with certain functions. The interactions between sorbic acid and an amine present in the endogenous constituents of food were quantified. We demonstrated the formation of new products and studied the underlying mechanisms using ethyl sorbate and various amines. HPLC, GC, GC-SM and NMR analyses of the reaction mixes enabled the isolation and identification of the products. The addition reactions led, at 20 degrees C, to linear monoadducts and, at 50 degrees C, to cyclic derivatives resulting from double addition. Mutagenesis studies, involving Ames test and genotoxicity studies with HeLa cells and on plasmid DNA, in cyclic interaction products, showed that none of the products studied presented neither mutagenic nor genotoxic activities.

Mutagenicity and genotoxicity of sorbic acid-amine reaction products.

Sorbic acid (E200) and its salts (potassium and calcium sorbate: E202 and E203) are allowed for use as preservatives in numerous processed foods. Sorbic acid had a conjugated system of double bonds which makes it susceptible to nucleophilic attack, sometimes giving mutagenic products. Under conditions typical of food processing (50-80 degrees C), we analysed the cyclic derivatives resulting from a double addition reaction between sorbic acid and various amines. Mutagenesis studies, involving Ames' test and genotoxicity studies with HeLa cells and plasmid DNA, showed that none of the products studied presented either mutagenic or genotoxic activities.

Influence of various parameters on the browning of potassium sorbate in the presence of amines.

Potassium sorbate can undergo oxidation to form carbonyl moieties and cause browning. This investigation studied the fate of the compounds produced by auto-oxidation of potassium sorbate and measured the browning in the presence of amines. Experimental plans in which four factors were combined (temperature, oxygen, amine and light) led to the observation that the interaction between oxygen and high temperature (75 degrees C) favoured browning, independently of the presence of amine. At 4 degrees C, the amine seemed to cause a decrease in the proportion of carbonyl-containing compounds which would appear to participate in carbonyl-amine reactions. At 75 degrees C, the amine forms adducts with the potassium sorbate. In parallel, high temperature favours auto-oxidation reactions that produce carbonyls. GC/MS and NMR analysis of the reaction products of potassium sorbate/amine mixtures led to the identification of cyclic products.

Sorbic acid-amine function interactions.

Sorbic acid has a system of conjugated double bonds which makes it able to undergo nucleophilic addition reactions with certain functions. The interactions between sorbic acid and amine functions present in the endogenous constituents of food were quantified. The formation of new products was demonstrated and the underlying mechanisms studied using ethyl sorbate and various amines. HPLC, GC, GC-SM and NMR analyses of the reaction mixtures enabled the products to be isolated and identified. The addition reactions led, at 20 degrees C, to linear monoadducts and, at 50 degrees C and 80 degrees C, to cyclic derivatives resulting from double addition.

[Pesticides in human food]. / Les pesticides dans l'alimentation humaine.

Pesticides represent a good picture of the Risk-Profits equation. Owing to their pest-destroying properties they are required in the mondial food but they remain inevitably present as residues in foods from both animal and vegetal origins. Therefore due to their biological activity a problem arise in Public Health. Actually, the investigations carried out on food contamination show that--except in pinpoint cases--pesticides seem less worrying that other contaminant such as heavy metals or mycotoxins. However questions remain concerning the consequences of repeated ingestion at low levels, the extrapolation for human of experimental results from animals, the simultaneous presence of several active compounds, their consequences on the food-value and the relationship between toxicity and nutritional or pathological states.

[Package contaminations]. / Les contaminations par les emballages.

In this chapter, the authors consider the problems originating from packaging for foods and the possible risks of contamination. The methods available for evidencing the possible migrations from package to food are considered. Dealing with package safety, toxicological tests (animal, cells...) are described. Then, the different classes of materials, as well that are usual (wood, paper, cardboard, glass, ceramic, metal, ...) as the new materials (plastic, elastomer, ...) are described. The authors emphasis the importance of package and of its development in food industries. Safety control from toxicologist is critical.

Preventive measures for microflora and mycotoxin production in foodstuffs.

The conservation of foodstuffs by chemical or physical methods is now practiced on a wide scale. Certain procedures (drying, use of pesticides) are well proved and are used on an industrial scale, although in certain situations they are not without risk to human health. New techniques (controlled atmospheres, irradiation, fumigation) are in use and will undoubtedly see further development for conservation of seeds and cereals in both industrialized and non-industrialized countries. In the latter case, the use of cost-effective fumigants may be of particular value. Preventive measures for the control of molds in foodstuffs are discussed in this report.

Effect of quinpirole, a specific dopamine DA2 receptor agonist on the sympathoadrenal system in dogs.

The effects of quinpirole, a specific dopamine DA2 receptor agonist, were investigated on both cardiovascular responses in conscious dogs and catecholamine release from the adrenal medulla in anesthetized dogs. In conscious normal dogs, i.v. quinpirole (30 micrograms/kg) elicited a decrease in blood pressure and a marked increase in heart rate associated with a rise in plasma catecholamine levels. The increase in heart rate is due to both baroreflex and central mechanisms because a slight but significant positive chronotropic effect persists in sinoaortic denervated dogs (i.e., animals deprived of baroreflex pathways). The central origin of this excitatory effect was confirmed by two subsequent protocols: intracisterna magna injection of quinpirole (5 micrograms/kg) increased blood pressure, heart rate and plasma catecholamines; i.v. domperidone reversed the hypotensive effect of i.v. quinpirole into a pressor response. The rise in plasma catecholamines was associated with an increase in plasma vasopressin levels. In anesthetized dogs, i.v. quinpirole (10 micrograms/kg/min during 12 min), which also decreased blood pressure, failed to modify epinephrine (and norepinephrine) release from the adrenal medulla whatever the stimulation frequencies (1, 3 and 5 Hz) of the sectioned splanchnic nerve. Similar results were obtained with apomorphine (5 micrograms/kg/min during 12 min). These results show that two mechanisms are involved in the action of quinpirole: first, a peripheral depressor action (which elicits the decrease in blood pressure) and secondly, a central pressor component involving an increase in both sympathetic tone and vasopressin release. They also demonstrate clearly that peripheral DA2 receptors are not involved in the control of catecholamine release from the adrenal medulla under in vivo conditions.

Ethanol-inducible cytochrome P-450 activity and increase in acetaldehyde bound to microsomes after chronic administration of acetaldehyde or ethanol.

Chronic ethanol consumption results in acetaldehyde adduct formation with proteins such as haemoglobin and liver proteins in vivo. Our purpose was to study the binding of acetaldehyde to liver microsomal proteins, a site of ethanol oxidation via cytochrome P-450 (especially P-450 II E1), after chronic administration of ethanol or acetaldehyde for 21 days to rats. The liver microsomal oxidation of 1-butanol by the ethanol-inducible P-450 also was examined. Acetaldehyde bound to liver microsomal proteins was higher in ethanol-fed rats compared with acetaldehyde-treated rats (0.735 vs 0.413 nmol/mg of protein respectively). The biotransformation of n-butanol to butyraldehyde by liver microsomes was increased (by 136%) in ethanol-fed rats vs controls, whereas in acetaldehyde-treated rats this increase was much lower (only 27%). However, in this last group, a significant negative relationship between the quantity of acetaldehyde bound to microsomal proteins and the monooxygenase-catalyzed transformation of butanol by liver microsomes was demonstrated (r = -0.79, P less than 0.01). These results suggest that proteins of liver microsomes are a target for acetaldehyde binding during ethanol oxidation and such adduct formation could impair the oxidative properties of the alcohol-inducible cytochrome P-450.

In vitro kinetics of the oxidative reactivity of nitrate and nitrite in the rat erythrocyte.

Isolated rat erythrocytes were incubated in the presence of nitrate and nitrite. Glucose, lactate, reduced glutathione, methaemoglobin, malondialdehyde and Na+/K+ membrane exchange were investigated. Nitrite induced a strong methaemoglobinaemia and a net depletion of reduced glutathione in the intracellular medium associated with membrane lipid peroxidation. This oxidative reactivity induced by nitrate and nitrite altered the cell's ionic flux.

Action of phosphine (PH3) on production of sterigmatocystin by various fungal strains isolated from foodstuffs.

Phosphine is a food fumigant, used until now as an insecticide and rodenticide. The present work researches the action of phosphine treatment on growth and sterigmatocystin production of several fungal strains. Production of sterigmatocystin decreased by a ratio of 100 to 500 or was abolished.

Rilmenidine (S 3341) and the sympathoadrenal system: adrenoreceptors, plasma and adrenal catecholamines in dogs.

1. The effects of rilmenidine, a new alpha 2-adrenoreceptor agonist with antihypertensive properties, were investigated on plasma catecholamines, blood cell adrenoreceptors and adrenal medullary function. 2. In conscious sino-aortic denervated (SAD) dogs, rilmenidine (1 mg kg-1 orally for 2 weeks) significantly reduced both blood pressure and heart rate when compared with placebo treatment. The drug decreased plasma noradrenaline and adrenaline levels and corrected the decrease in leucocyte beta-adrenoreceptors observed in placebo-treated SAD dogs. There was no change in platelet alpha 2-adrenoreceptors. 3. In anaesthetized normotensive dogs, rilmenidine (0.1 and 0.3 mg kg-1 i.v.) induced a dose-dependent decrease in both cardiovascular parameters (blood pressure and heart rate) and catecholamine release from the adrenal medulla. 4. The present study shows that rilmenidine decreases sympathetic tone mainly by an action on the adrenal medulla. In addition, its ability to lower blood pressure in SAD dogs, i.e. a model of hypertension in which high sympathetic tone is present, indicates that rilmenidine may also depress other parts of the sympathetic nervous system.

Is adrenal medulla involved in the antihypertensive effect of nicardipine?

The effects of nicardipine, a dihydropyridine calcium channel blocker, on adrenal medulla were investigated in chloralose-anesthetized dogs. For analysis of the adrenal medullary function, adrenal venous catecholamine rates were determined. Intravenous administration of nicardipine (50 micrograms/kg) induced a marked increase in both adrenal catecholamine rates and heart rate and a simultaneous decrease in blood pressure. This effect on epinephrine and norepinephrine release is probably explained by the involvement of baroreflex mechanisms. After acute splanchnicectomy, nicardipine (50 and 100 micrograms/kg i.v.) failed to modify catecholamine secretion rates from the denervated adrenal medulla during electrical stimulation of the splanchnic nerve at low (2 Hz) and high (5 Hz) frequencies. In conclusion, these results suggest that in vivo a functional dihydropyridine-sensitive calcium channel is not required for calcium entry mechanisms into dog chromaffin cells. Moreover, adrenal medulla is not involved in the antihypertensive action of nicardipine.

Action of phosphine on production of aflatoxins by various Aspergillus strains isolated from foodstuffs.

Phosphine is a food fumigant, used until now as an insecticide and rodenticide. The present work researches the action of phosphine treatment on growth and aflatoxin production of 23 Aspergillus strains. Production of aflatoxins B1, B2, G1, and G2 decreased in almost all cases by a ratio of 10 to 100. Phosphine treatment therefore seems favorable to prevent growth of various Aspergillus strains, in the context of keeping food safe.

Effect of chronic acetaldehyde intoxication on ethanol tolerance and membrane fatty acids.

Recent studies have suggested that acetaldehyde participates directly in the pathogenesis of alcoholism. Its action has been attributed mainly to its physico-chemical properties. Results of direct intoxication of laboratory animals with acetaldehyde have been reported, but only for short periods of exposure and at high doses. These are probably not representative of the conditions found during alcohol intoxication. The pulmonary route of administration described here enables long term intoxication with acetaldehyde, at levels corresponding to values measured during chronic ethanol intoxication. Chronic administration of acetaldehyde during 3 weeks induced a metabolic tolerance to ethanol as tested by the sleeping time after a challenge dose of ethanol; behavioural tolerance (measured by blood alcohol levels on waking) was not observed. At the end of the intoxication, phospholipid fatty acids of erythrocyte and synaptosome membranes were also analysed. Small changes in levels of the shorter fatty acids were observed in the phosphatidyl-choline fraction. By comparison with the effects of ethanol on the same membrane preparations, only a small part of this effect can be attributed to acetaldehyde. The first metabolite of ethanol has, however, a sure effect on the pattern of fatty acid phospholipids.