The doctoral dissertation in the field of Toxicology will be examined at the Faculty of Health Sciences at Kuopio campus. The public examination will be streamed online.
The safety of dyes obtained from bloodred webcap fungus can vary, M.Sc. (Pharm.) Johanna Yli-Öyrä discovered in her PhD dissertation. For example, red dye dermorubin appeared to be safe in cellular studies, whereas yellow emodin caused mutations and oxidative stress in human cells.
Bloodred webcap is a mushroom traditionally used for textile dyeing that produces up to fifteen different anthraquinone dyes. Yli-Öyrä has studied their toxicity in human cells.
“The synthetic dyes that are currently used, as well as their production, are a major environmental pollutant. There is a need for sustainably produced, biodegradable dyes for textiles and packaging, and bloodred webcap is a potential source for those.”
“However, natural origin is not a safety guarantee, and it is important to study the safety aspects before large scale production and use. Therefore, I studied the toxicity of the most common dyes of bloodred webcap – emodin, dermocybin and dermorubin – and a mixture extract of the mushroom. Additionally, I studied the metabolism of the dyes, or how they are chemically transformed in the body, as sometimes toxicity of a substance requires metabolic activation.”
It was found out that emodin, the most commonly present dye in bloodred webcap, causes mutations and oxidative stress in human cells. It can also cause skin sensitisation – in other words, allergies.
The orange dermocybin caused some oxidative stress in human cells but other harmful effects were not detected.
“However, it was found out that it is metabolised into several products whose activity is not known. Dermocybin seems to be a good dye option, but further studies are needed to be sure.”
“On the other hand, red dermorubin seems to be a safe and good dye – it did not cause cellular toxicity, and it does not get chemically transformed in the body.”
According to Yli-Öyrä, it can also be deduced from the results that, in terms of safety assessment, anthraquinones cannot be handled as a single group. “Even though their chemical structure is similar, their toxicity varies from compound to compound.”
The dissertation was a part of the BioColour research consortium that consists of a multidisciplinary group of researchers who examine new opportunities related to natural dyes. The results obtained give guidance to the further development of natural dye production.
Human immune and liver cell lines were used in the study. Skin sensitisation potential was assessed using the KeratinoSens assay which has been developed to replace sensitisation-related animal tests. Metabolism was studied using several metabolic enzymes from human and different animal species.
The doctoral dissertation of Johanna Yli-Öyrä, MSc (Pharm), entitled Toxicity and metabolism of Cortinarius sanguineus dyes will be examined at the Faculty of Health Sciences. The Opponent in the public examination will be Professor Nanna Fyhrquist of the University of Karlstadt and Karolinska Institutet, and the Custos will be Professor Jaana Rysä of the University of Eastern Finland.
Doctoral defence (in Finnish)
For further information, please contact:
Johanna Yli-Öyrä, MSc (Pharm), johanna.yli-oyra@uef.fi, https://uefconnect.uef.fi/en/johanna.yli-oyra/
