Molecular and technical aspects on the interaction of serum albumin with multifunctional food preservatives.

Synthetic food preservatives like sodium acetate (SA), sodium benzoate (SB), potassium sorbate (PS) and Butyl paraben (BP) have been widely used in food and pharmacy industries. One of the toxicological aspects of food additives is evaluation of their interaction with serum proteins such as albumin. These additives interaction with human serum albumin (HSA) can exert considerable effect on the absorption, distribution, metabolism and toxicity of chemical compounds. It should be noticed that the aforementioned food preservatives intake increase mainly in the presence of glucose may lead to complex formation of SA, SB, PS and BP with HSA and accelerate the development of variety disease such as cancer, diabetes, multiple sclerosis, brain damage, nausea and cardiac disease. Therefore, to understand the mechanisms of aforementioned food additives interaction and conformational changes of proteins, we aim to review various studies that investigated albumin interaction with these additives using several procedures.

Sodium Acetate, Sodium Acid Pyrophosphate, and Citric Acid Impacts on Isolated Peripheral Lymphocyte Viability, Proliferation, and DNA Damage.

The present study examined the impacts of sodium acetate (SA), sodium acid pyrophosphate (SAPP), and citric acid (CA) on the viability, proliferation, and DNA damage of isolated lymphocytes in vitro. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) release assays were adopted to evaluate cell viability, while comet assay was employed to assess the genotoxic effects. The cells were incubated with different levels of SA (50, 100, and 200 mM), SAPP (25, 50, and 100 mM/L), or CA (100, 200, and 300 µg/mL). The lymphocytes treated with the tested food additives showed concentration-dependent decreases in both cell viability and proliferation. A concentration-dependent increase in LDH release was also observed. The comet assay results indicated that SA, SAPP, and CA increased DNA damage percentage, tail DNA percentage, tail length, and tail moment in a concentration-dependent manner. The current results showed that SA, SAPP, and CA are cytotoxic and genotoxic to isolated lymphocytes in vitro.

Effects of the food additives sodium acid pyrophosphate, sodium acetate, and citric acid on hemato-immunological pathological biomarkers in rats: Relation to PPAR-α, PPAR-γ and tnfα signaling pathway.

The food additives sodium acid pyrophosphate (SAPP), sodium acetate (SA), and citric acid (CA) were evaluated for their hemato-immunotoxic effects. Forty adult Sprague-Dawley rats were distributed into four groups and were orally administered water, SAPP (12.6 mg/kg), CA (180 mg/kg), or SA (13.5 mg /kg) daily for 90 days. Erythrogram and leukogram profiles were evaluated. The levels of lysozyme, nitric oxide, immunoglobulin, and phagocytic activity were measured. Histologic and immunohistochemical evaluations of splenic tissues were performed. Changes in the mRNA expression levels of peroxisome proliferator-activated receptor α and γ (PPAR-α and PPAR-γ), and tumor necrosis factor α (TNF-α) genes were assessed. A significant leukopenic condition was observed with SAPP, while CA induced marked leukocytosis, and SA showed a lymphocytosis condition. Both the innate and humoral parameters were significantly depressed. Various pathological lesions were observed, including diffuse hyperplasia of the red pulp, depletion of the white pulp, and capsular and parenchymal fibrosis. A marked decrease in CD3 T-lymphocyte and CD20 B-lymphocyte immunolabeling in rats treated with SAPP and SA was evident. Marked downregulation of PPAR-α and PPAR-γ together with upregulation of TNF-α was recorded. These results indicate that high doses of SAPP, SA and CA exert hematotoxic and immunotoxic effects with long-term exposure.

Safety assessment of sodium acetate, sodium diacetate and potassium sorbate food additives.

Cytotoxicity and genotoxicity of sodium acetate (SA), sodium diacetate (SDA), and potassium sorbate (PS) was tested on Human Umbilical Vein Endothelial Cells (HUVEC). Cytotoxicity was investigated by MTT assay and flow cytometry analysis, while genotoxicity was evaluated using DNA fragmentation and DAPI staining assays. The growth of treated HUVECs with various concentrations of SA, SDA and PS decreased in a dose-and time-dependent manner. The IC50 of 487.71, 485.82 and 659.96 µM after 24 h and IC50 of 232.05, 190.19 and 123.95 µM after 48 h of treatment were attained for SA, SDA and PS, respectively. Flow cytometry analysis showed that early and late apoptosis percentage in treated cells was not considerable. Also neither considerable DNA fragmentation nor DNA smear was observed using DAPI staining and DNA ladder assays. Overall, it can be concluded that the aforementioned food additives can be used as safe additives at low concentration in food industry.

Ecotoxicological response of marine organisms to inorganic and organic sediment amendments in laboratory exposures.

Experimental materials currently being investigated for use as amendments for the in situ remediation of contaminated sediments were assessed for their potential impacts on marine benthos. Laboratory toxicity tests involving lethal and sublethal endpoints were conducted on sediments amended with apatite, organoclay, chitin, or acetate, with the polychaete Neanthes arenaceodentata, the amphipod Eohaustorius estuarius, and the larval sheepshead minnow Cyprinodon variegatus. Amendments were mixed loosely into uncontaminated or metal-contaminated sediments, and also added inside experimental geotextile mats, at sediment dry weight (dw) concentrations ranging from 0.5% to 10%. The geotextile mats, containing apatite (5 or 10% dw), and/or organoclay (5%) did not result in adverse effects on any of the test organisms. Chitin and acetate, however, repetitively resulted in adverse effects on survival and/or adverse or positive effects on organism growth at concentrations of ≤ 2.5% dw. The adverse effects were attributed to water quality degradation in the exposure vessels (notably ammonia and dissolved oxygen concentration, for chitin and acetate, respectively) as a result of the microbial breakdown of the amendments. For N. arenaceodentata, growth was enhanced in the presence of chitin at concentrations as low as 0.5% sediment dw, which stimulated bacterial growth that may have provided an additional food source for the polychaete. Sediment chitin concentrations of 0.5% resulted in a statistically significant reduction in N. arenaceodentata body burdens of 61%, 29%, and 54%, relative to unamended contaminated sediment, for Cu, Zn, and Cd, respectively. The studies suggest a lack of inherent toxicity of these materials on the experimental organisms, as the adverse or positive responses observed are likely related to artifacts associated with laboratory exposure. Assessments in field settings are needed to verify this conclusion.

Lead exposure changes gastric motility in rats: role of nitric oxide (NO).

BACKGROUND: Abdominal colic, constipation and delay in gastric emptying are symptoms of lead poisoning, but there is scant information about the effect of lead on gastric motility. In the present study, we investigated the effect of lead acetate on gastric motility in rats. METHODS: Animals were divided into nine groups (n=8); four groups were exposed to lead acetate solution (1%) for 1, 2, 3, and 4 weeks (Pb1, Pb2, Pb3, and Pb4 groups, respectively). Sodium acetate solution was given to another four groups for 1, 2, 3, and 4 weeks (Na1, Na2, Na3, and Na4 groups, respectively) and the control group had free access to tap water. Gastric motility was measured in the basal and acetylcholine (Ach)-stimulated states using a physiograph instrument. Nitric oxide metabolite of gastric tissue was determined by Griess micro-assay. RESULTS: There were no significant differences between basal and Ach-stimulated gastric motility in Pb1, Pb2, Na1, and Na2 groups. However, it was significantly greater in Pb3 and Pb4 groups when compared with Na3 and Na4 groups in both basal and Ach-stimulated states (P<0.05). In addition, nitric oxide metabolite of gastric tissue was more in all Pb groups in comparison with their Na counterparts (P<0.05). CONCLUSION: We found that lead exposure could affect gastric motility via the nitric oxide pathway.

Effect of hypoxia on sodium and ammonium acetate toxicity for Daphnia.

Exposure of Daphnia in degassed (boiled) culturing water (hypoxia simulation) led to solitary lethal outcomes after more than 24 h. Before this term, hypoxia had no appreciable effect on the toxicity of sodium or ammonium acetate salts. The sensitivity of daphnias to the lethal effects of the tested chemicals did not change under conditions of normal oxygenation and increased sharply (by two orders of magnitude) under conditions of hypoxia, loosing the linear relationship with toxicant concentration. Ammonium acetate toxicity more markedly increased under conditions of hypoxia than sodium acetate toxicity. These data should be taken into consideration when predicting the results of combined effects of toxicants on water ecosystems and on human organism.

Effect of sodium acetate on cell proliferation and induction of proinflammatory cytokines: a preliminary evaluation.

We have studied the effect of sodium acetate exposure on the viability and proliferative activity of cultured human gastric adenocarcinoma epithelial (AGS) cells and changes in the release of proinflammatory cytokines. We evaluated the levels of IL-6, TNF-alpha, IL-8, and IL-1beta in cell culture supernatants using enzyme-linked immunosorbent assays, and cytokine mRNA levels were measured in whole cells using reverse transcriptase-polymerase chain reaction. We also measured cytokine levels in mice using immunohistochemistry. In vitro studies demonstrated that incubation with sodium acetate (up to 12.5 mM) for 72 h stimulated AGS cell viability and proliferation in a dose-dependent manner; however, incubation with >12.5 mM sodium acetate inhibited cell growth, also in a dose-dependent manner (the largest decrease in viability was >50%). Incubation with sodium acetate for 24 h increased the levels of IL-1beta, IL-8, and TNF-alpha protein and mRNAs (IL-6 was detected but its mRNA was not). The effect of sodium acetate on the expression of these cytokines in cell culture was verified in mice. Our data suggest that ingestion of high concentrations of sodium acetate in food has cytotoxic effects.

FETAX interlaboratory validation study: phase III--Part 1 testing.

The Frog Embryo Teratogenesis Assay-Xenopus (FETAX) is a 96-h whole embryo developmental toxicity screening assay that can be used in ecotoxicology and in detecting mammalian developmental toxicants when an in vitro metabolic activation system is employed. A standardized American Society for Testing and Materials (ASTM) guide for the conduct of FETAX has been published, along with a companion atlas that aids in embryo staging and identifying malformations. As part of the ASTM process, a three-phase interlaboratory validation study was undertaken to evaluate the repeatability and reliability of FETAX. Seven different participants collaborated in the study. In Phase I, FETAX proved to be more repeatable and reliable than many bioassays. However, some excessive variation was observed in a few laboratories. An initial lack of assay experience by some technicians caused variation. Phase II showed far less intra- and interlaboratory variability than Phase I. Non-teratogens showed the most consistent results, while more variability was observed for the two teratogens tested. Interlaboratory coefficient of variation values for all endpoints ranged from 7.3 to 54.7. Phase III--Part 1, using coded samples and test concentration ranges selected by each laboratory, showed results similar to Phase I. Analysis of the causes of variation suggested that some technicians judged some embryos to be malformed while others consistently judged similar embryos as normal. Concentration ranges tested by some of the laboratories varied greatly and a new protocol for selecting concentrations for initial testing was written to reduce variation from this source. Testing to date suggests that FETAX is as repeatable and reliable as other standard bioassays.