Azorubine, blood protein clumping and nerve cell harm in lab tests
What it found
In lab tests, Azorubine changed the shape of a blood protein and, under acidic conditions, made it clump into aggregates.
Clumps formed at pH 3.5 were toxic to nerve cells in a dose-dependent way.
What they found
Animal and lab studies
Protein shape changes
Azorubine destabilized the shape of human serum albumin at both pH 7.4 and pH 3.5. Loss of tryptophan fluorescence suggested major structural changes, especially around aromatic residues.
Secondary structure disrupted
Far UV-CD analysis showed disruptions in the protein's secondary structure, with a notable reduction in alpha-helical structures at pH 7.4. At pH 3.5, higher Azorubine concentrations led to a random coil conformation.
Clumping at acidic pH
At pH 3.5, larger insoluble aggregates formed. At pH 7.4, only shape changes occurred without aggregate formation.
Toxicity to nerve cells
In neuroblastoma (SH-SY5Y) cells, the albumin aggregates were toxic in a concentration-dependent way.
Stable binding confirmed
Molecular dynamics simulations reaffirmed a stable interaction between Azorubine and human serum albumin.
What the authors conclude
“At pH 3.5, larger insoluble aggregates formed, while at pH 7.4, only conformational changes occurred without aggregate formation.”
Also in their conclusions
- They say this research provides valuable insights into the mechanisms by which azorubine influences protein conformations.
- They suggest future directions such as exploring other proteins, studying dose-response relationship, gaining mechanistic insights, biological relevance, toxicity assessment, identifying alternative food colorants, and mitigation strategies to prevent adverse effects of azorubine on serum proteins.
How it was done
Protein misfolding is a central factor in the formation of harmful clumps and fibres linked to disorders like Alzheimer's and Parkinson's. The authors wanted to understand how food additives, particularly Azorubine, affect protein structures and their ability to clump.
They used human serum albumin as a model protein and tested how Azorubine bound to it and changed its shape at pH 7.4 and pH 3.5. They also measured clumping and tested the toxicity of the resulting albumin aggregates on neuroblastoma (SH-SY5Y) cells.
What it can’t tell you
- We summarised it from the abstract only.
- These are lab tests using a model protein and cells, not people. They can't show what happens in the human body after eating or drinking Azorubine.
- The study used a single protein and one cell type. It can't show whether similar effects occur with other proteins or in the whole body.
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 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error