Erythrosine, a permitted food dye, is mutagenic in the Bacillus subtilis multigene sporulation assay

Assessment of synthetic food dye erythrosine induced cytotoxicity, genotoxicity, biochemical and molecular alterations in Allium cepa root meristematic cells: insights from in silico study

Background

Synthetic food dyes are being exponentially used in food products and scarce studies regarding their toxicities and safety raise concern. Erythrosine is one of the synthetic food dyes being used in jams, fig, pineapple marmalades, dairy products, soft drinks, pickles, relishes, smoked fish, cheese, ketchup, maraschino cherries and a variety of other foods.

Methodology

In this study the cyto-genotoxic effect of erythrosine was evaluated, using root meristematic cells of Allium cepa for the cellular and molecular alternations at concentrations 0.1, 0.25, 0.5 and 1 mg/mL.

Results

The results revealed a significant decrease of 57.81% in the mitotic index after 96 h at the 0.1 mg/mL concentration. In biochemical analysis, the malondialdehyde content increased significantly (5.47-fold), while proline content, catalase activity and superoxide dismutase activity decreased gradually in a concentration-dependent manner showing a maximum decrease of 78.11%, 64.68% and 61.73% respectively at the highest concentration after 96 h duration. The comet assay revealed increased DNA damage with increasing concentration and attenuated total reflectance- Fourier transform infrared spectroscopy (ATR-FTIR) analysis showed significant alterations in biomolecules as indicated by multivariate analysis, i.e. Principal Component Analysis (PCA). Furthermore, molecular docking demonstrated a strong binding energy (Gbest = -11.46 kcal/mol) and an inhibition constant (Ki) of 3.96 nM between erythrosine and the DNA minor groove.

Conclusion

The present study's findings revealed the cytotoxic and genotoxic potential of erythrosine on A. cepa root cells. Further, the study also proposed the usefulness of A. cepa as a model system for studying the toxicity of food additives.

Risk assessment of combined photogenotoxic effects of sunlight and food additives

The presence of flavored colorants (peach and raspberry), flavors (caramel, citric acid and vanilla) and food preservatives (sodium nitrite, sodium nitrate, sodium benzoate, benzoic acid, potassium sorbate and sodium chloride) in Escherichia coli suspension during exposure to sunlight did not change the extent of cell survival. No effect on viability and mutation induction (kanamycin resistant) was also seen when cells were kept in contact with any of the additives for 80 min in the dark. However, when the relevant additive was present in cell suspension during sunlight exposure the number of induced mutations was increased to varying extents over that seen with sunlight alone. Raspberry and peach increased the number of mutations in a dose dependent manner, while vanilla produced mutations in an additive fashion. Nitrite, nitrate, benzoate, sorbate and benzoic acid increased mutation somewhat additively over that of sunlight. Sodium chloride and citric acid were not effective. The impact of this investigation reflects the significance of combination of sunlight and chemical food additives as potential risk, which requires special attention and necessitates further investigations to evaluate the risk.

The use of surrogate endpoints to assess potential toxicity in humans

Data on toxic effects in humans may come from epidemiology studies, accidental poisonings, surveillance schemes or following intentional exposures. In many cases, a surrogate endpoint related to the adverse effect is investigated. Effects produced following intentional exposures are usually restricted to readily reversible, mild surrogate endpoints of the adverse effect of concern. Not all initial interactions within the target organ are related to the toxic effect, and many measurements are biomarkers of exposure not response. Biomarkers of response represent surrogate endpoints of response only if they are critical to the mode of action. The use of biomarkers and the possible problems with using surrogate endpoints are illustrated with data on aniline, cadmium, carbon monoxide, erythrosine, paracetamol (acetaminophen) and styrene. In vivo surrogate endpoints are normally used in risk assessment directly, whereas in vitro surrogate endpoints can be incorporated by the development of a biologically based dose-response model, or used to replace a default uncertainty factor by a chemical-specific adjustment factor.

The application of in vitro data in the derivation of the acceptable daily intake of food additives

The acceptable daily intake (ADI) for food additives is commonly derived from the NOAEL (no-observed-adverse-effect level) in long-term animal in vivo studies. To derive an ADI a safety or uncertainty factor (commonly 100) is applied to the NOAEL in the most sensitive test species. The 100-fold safety factor is considered to be the product of both species and inter-individual differences in toxicokinetics and toxicodynamics. Although in vitro data have previously been considered during the risk assessment of food additives, they have generally had no direct influence on the calculation of ADI values. In this review 18 food additives are evaluated for the availability of in vitro toxicity data which might be used for the derivation of a specific data-derived uncertainty factor. For the majority of the food additives reviewed, additional in vitro tests have been conducted which supplement and support the short- and long-term in vivo toxicity studies. However, it was recognized that these in vitro studies could not be used in isolation to derive an ADI; only when sufficient in vivo mechanistic data are available can such information be used in a regulatory context. Additional short-term studies are proposed for the food additives which, if conducted, would provide data that could then be used for the calculation of data-derived uncertainty factors.

Decontamination of aqueous solutions of biological stains

Aqueous solutions of a number of biological stains were completely decontaminated to the limit of detection using Amberlite resins. Amberlite XAD-16 was the most generally applicable resin but Amberlite XAD-2, Amberlite XAD-4, and Amberlite XAD-7 could be used to decontaminate some solutions. Solutions of acridine orange, alcian blue 8GX, alizarin red S, azure A, azure B, Congo red, cresyl violet acetate, crystal violet, eosin B, erythrosin B, ethidium bromide, Janus green B, methylene blue, neutral red, nigrosin, orcein, propidium iodide, rose Bengal, safranine O, toluidine blue O, and trypan blue could be completely decontaminated to the limit of detection and solutions of eosin Y and Giemsa stain were decontaminated to very low levels (less than 0.02 ppm) using Amberlite XAD-16. Reaction times varied from 10 min to 18 hr. Up to 500 ml of a 100 micrograms/ml solution could be decontaminated per gram of Amberlite XAD-16. Fourteen of the 23 stains tested were found to be mutagenic to Salmonella typhimurium. None of the completely decontaminated solutions were found to be mutagenic.

Multigeneration study of FD & C Red No. 3 (erythrosine) in Sprague-Dawley rats

Sprague-Dawley rats received dietary admixtures containing 0.0, 0.25, 1.0 or 4.0% FD & C Red No. 3 (25 rats/sex/group) in a three-generation reproduction study. Each generation was bred twice and breeders for subsequent generations were selected after weaning of the second mating from each generation. There were no compound-related adverse effects on reproductive indices and no gross anomalies were observed. The body weights of parents and pups were significantly reduced (P less than 0.05) in all generations at the 4.0% dietary concentration. Maternal body-weight gain during gestation was frequently reduced in the 1.0 and 4.0% groups. The conservative no-observed-adverse-effect level established in this study was 0.25% (approximately 149 and 255 mg/kg body weight/day for males and females, respectively).