E122 or Azorubine  is a sodium salt, a common food colour, an azo colour and an ingredient on the European food additives list as E122 and internationally known as CI 14270

What it is used for and where

Cosmetics

Restricted cosmetic ingredient as IV/19  a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported: Disodium 4-hydroxy-3-[(4-sulphonatonaphthyl)azo]naphthalenesulphonate

Safety

With regard to food safety, the EFSA (European Food Safety Authority) concluded that the component, while showing increased hyperactivity in 3-, 8- and 9-year-old children, did not reveal any signs of genotoxicity (1).

In May 2010, the FSA (Food Standard Agency) established guidelines for certain colours, including E122: "When using the colours listed below in food and drink there is a requirement (subject to a limited number of exemptions) to include the additional information that „name or E number of the colour(s)‟: may have an adverse effect on activity and attention in children" (2).

The problem with azo dyes (monoazo or diazo) is photocatalytic degradation leading to oxidation and the subsequent formation of impurities such as aromatic amines, some of which have carcinogenic activity (3).

Molecular Formula : C₂₀H₁₂N₂Na₂O₇S₂

Molecular Weight: 502.423 g/mol

CAS: 3567-69-9

EC number:  222-657-4

Synonyms : 

• E122
• CI 14270
• Carmoisine
• Acid red 14
• Acid Chrome Blue
• BA
• Acid Rubine
• Acid Brilliant
• Acid Fast Red FB
• Acetacid Red B

References________________________________________________________________________

(1) EFSA-Q-2008-226  24/9/2009  Published: 12/9/2009

(2) EFSA - Guidance on the labelling of certain food colours as set out in Regulation 1333/2008

(3) Chung KT, Stevens SE Jr, Cerniglia CE. The reduction of azo dyes by the intestinal microflora. Crit Rev Microbiol. 1992;18(3):175-90. doi: 10.3109/10408419209114557.

Abstract. Azo dyes are widely used in the textile, printing, paper manufacturing, pharmaceutical, and food industries and also in research laboratories. When these compounds either inadvertently or by design enter the body through ingestion, they are metabolized to aromatic amines by intestinal microorganisms. Reductive enzymes in the liver can also catalyze the reductive cleavage of the azo linkage to produce aromatic amines. However, evidence indicates that the intestinal microbial azoreductase may be more important than the liver enzymes in azo reduction. In this article, we examine the significance of the capacity of intestinal bacteria to reduce azo dyes and the conditions of azo reduction. Many azo dyes, such as Acid Yellow, Amaranth, Azodisalicylate, Chicago Sky Blue, Congo Red, Direct Black 38, Direct Blue 6, Direct Blue 15, Direct Brown 95, Fast Yellow, Lithol Red, Methyl Orange, Methyl Red, Methyl Yellow, Naphthalene Fast Orange 2G, Neoprontosil, New Coccine, Orange II, Phenylazo-2-naphthol, Ponceau 3R, Ponceau SX, Red 2G, Red 10B, Salicylazosulphapyridine, Sunset Yellow, Tartrazine, and Trypan Blue, are included in this article. A wide variety of anaerobic bacteria isolated from caecal or fecal contents from experimental animals and humans have the ability to cleave the azo linkage(s) to produce aromatic amines. Azoreductase(s) catalyze these reactions and have been found to be oxygen sensitive and to require flavins for optimal activity. The azoreductase activity in a variety of intestinal preparations was affected by various dietary factors such as cellulose, proteins, fibers, antibiotics, or supplementation with live cultures of lactobacilli.