Azorubine and protein clumping in lab tests
What it found
In lab tests, the food colouring azorubine changed the shape of a human blood protein and caused it to form clumps under acidic conditions.
Those clumps harmed nerve cells grown in dishes.
What they found
Animal and lab studies
Protein shape changes
In lab tests, azorubine altered the shape of a human blood protein at both normal body acidity (pH 7.4) and a more acidic level (pH 3.5). The protein lost some of its coiled structure.
Clumps at low pH
At pH 3.5, azorubine caused the protein to form large, insoluble clumps. At normal body acidity (pH 7.4), the protein changed shape but did not form clumps.
Harm to nerve cells
When the protein clumps were added to human nerve cells grown in dishes, they harmed the cells. Higher amounts of clumps caused more harm.
Other findings
Stable binding shown by computers
Computer models showed that azorubine binds firmly to the human blood protein.
What the authors conclude
- They say their work shows how azorubine changes the shape of proteins in lab settings.
- The authors suggest future studies should look at other proteins, test different doses, check how this matters in living bodies, and explore ways to prevent these effects.
How it was done
Misfolded proteins can clump together and are linked to brain diseases like Alzheimer's and Parkinson's. The authors wanted to see if azorubine changes how proteins fold and whether it encourages clumping.
They mixed azorubine with a common human blood protein in lab dishes at normal body acidity and at a more acidic level. They also tested the resulting mixtures on human nerve cells grown in dishes and ran computer models of the interaction.
What it can’t tell you
- We summarised it from the abstract only.
- These are lab tests using isolated proteins and cells in dishes, so they cannot show what happens when people eat or drink azorubine.
- The acidic condition used (pH 3.5) may not match typical conditions inside the human body where this protein is found.
- Cell damage in a dish does not prove that eating azorubine causes disease in people.
Who paid
- Authors work at
- King Saud University, Saudi Arabia
The paper
- Title
- Aggregation and cytotoxicity of food additive dye (Azorubine)-albumin adducts: a multi-spectroscopic, microscopic and computational analysis
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Abstract only
- Cite
- Khan MS, Rehman MT, Shaik GM, et al (2025). Aggregation and cytotoxicity of food additive dye (Azorubine)-albumin adducts: a multi-spectroscopic, microscopic and computational analysis. Journal of biomolecular structure & dynamics. doi:10.1080/07391102.2023.2289046PubMed 38047623DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error