Allura Red AC

J Hazard Mater. 2015 Jun 15;290:34-42.

Decolorization and mineralization of Allura Red AC aqueous solutions by electrochemical advanced oxidation processes.[Pubmed: 25734532]

The decolorization and mineralization of solutions containing 230 mg L(-1) of the food azo dye Allura Red AC at pH 3.0 have been studied upon treatment by electrochemical oxidation with electrogenerated H2O2 (EO-H2O2), electro-Fenton (EF) and photoelectro-Fenton (PEF).
METHODS AND RESULTS:
Experiments were performed with a stirred tank reactor containing a boron-doped diamond (BDD) or Pt anode and an air-diffusion cathode to generate H2O2. The main oxidants were hydroxyl radicals formed at the anode surface from water oxidation and in the bulk from Fenton's reaction between H2O2 and added Fe(2+). The oxidation ability increased in the sequence EO-H2O2 < EF < PEF and faster degradation was always obtained using BDD. PEF process with BDD yielded almost total mineralization following similar trends in SO4(2-), ClO4(-) and NO3(-) media, whereas in Cl(-) medium, mineralization was inhibited by the formation of recalcitrant chloroderivatives.
CONCLUSIONS:
GC-MS analysis confirmed the cleavage of the −N=N− bond with formation of two main aromatics in SO4(2-) medium and three chloroaromatics in Cl(-) solutions. The effective oxidation of final oxalic and oxamic acids by BDD along with the photolysis of Fe(III)-oxalate species by UVA light accounted for the superiority of PEF with BDD. NH4(+), NO3(-) and SO4(2-) ions were released during the mineralization.

Bull Environ Contam Toxicol. 2013 Jan;90(1):22-6.

Genotoxicity assessment of amaranth and allura red using Saccharomyces cerevisiae.[Pubmed: 23132362]

Amaranth (E123) and Allura Red AC (E129), very important food azo dyes used in food, drug, paper, cosmetic and textile industries, were assessed for their genotoxic potential through comet assay in yeast cells. Comet assay was standardized by with different concentration of H(2)O(2).
METHODS AND RESULTS:
Concentrations of Amaranth and Allura red were maintained in sorbitol buffer starting from 9.76 to 5,000 μg/mL and 1 × 10(4) cells were incubated at two different incubation temperatures 28 and 37°C. Amaranth (E123) and Allura Red AC (E129) were found to exhibit their genotoxic effect directly in Saccharomyces cerevisiae. No significant genotoxic activity was observed for Amaranth and Allura Red AC at 28°C but at 37°C direct relation of Amaranth concentration with comet tail was significant and no positive relation was seen with time exposure factor. At 37°C the minimum concentration of Amaranth and Allura Red AC at which significant DNA damage observed through comet assay was 1,250 μg/mL in 2nd h post exposure time.
CONCLUSIONS:
The results indicated that food colors should be carefully used in baking products as heavy concentration of food colors could affect the fermentation process of baking.

Food Chem Toxicol. 2013 Sep;59:86-9.

The synthetic food colouring agent Allura Red AC (E129) is not genotoxic in a flow cytometry-based micronucleus assay in vivo.[Pubmed: 23748052]

The safety of several azo colouring agents, used as food additives, has during the years been questioned. Allura Red AC (E129) has in some publications been classified as genotoxic. In fact, in the European Union, Allura Red AC is permitted as a food additive in human food, but, surprisingly, it was not acceptable as an additive for use in animal feed.
METHODS AND RESULTS:
In this study we have evaluated whether Allura Red AC is genotoxic using a flow cytometer-based micronucleus assay in peripheral blood of mice. Male FVB mice were given a single intra-peritoneal injection of various doses of Allura Red AC and sacrificed at 46 h after treatment. The tested doses were 0, 100, 200, 400, 600, 800, 1000, 1500, and 2000 mg/kg body weight (b.w.). Each dose group constituted three mice, except for in the dose group of 1000 mg/kg b. w., which constituted four mice. Blood samples were collected and the frequency of micronucleated polychromatic erythrocytes (fMNPCE) and the cell proliferation (%PCE) was determined. The analyses did not show any significant difference in the %PCE or in the fMNPCE.
CONCLUSIONS:
Consequently, under the testing circumstances one can conclude that Allura Red AC is not genotoxic.

Food Chem. 2015 Mar 1;170:423-9.

Characterisation of interaction between food colourant allura red AC and human serum albumin: multispectroscopic analyses and docking simulations.[Pubmed: 25306366]

METHODS AND RESULTS:
Binding interaction of human serum albumin (HSA) with Allura Red AC, a food colourant, was investigated at the molecular level through fluorescence, ultraviolet-visible, circular dichroism (CD) and Raman spectroscopies, as well as protein-ligand docking studies to better understand the chemical absorption, distribution and transportation of colourants. Results show that Allura Red AC has the ability to quench the intrinsic fluorescence of HSA through static quenching. The negative values of the thermodynamic parameters ΔG, ΔH, and ΔS indicated that hydrogen bond and van der Waals forces are dominant in the binding between the food colourant and HSA.
CONCLUSIONS:
The CD and Raman spectra showed that the binding of Allura Red AC to HSA induces the rearrangement of the carbonyl hydrogen-bonding network of polypeptides, which changes the HSA secondary structure. This colourant is bound to HSA in site I, and the binding mode was further analysed with the use of the CDOCKER algorithm in Discovery Studio.