Extraction of Parietin from Xanthoria Parietina
Xanthoria Parietina is a lichen that is gathering more and more scientific attention due to the presence of a dye similar to anthraquinone, called
parietin, which is showing interesting UV-blocking properties
This compound can easily be extracted from Xanthoria Parietina with hot ethanol.
This procedure can be easily done at home since not much starting
material is needed to obtain some of the final product.
For this extraction, 5,5g of Xanthoria Parietina were recovered from dry woods and put in a 250ml flask on an hot plate.
Enough ethanol (95%) was
added to cover all the material. About 70-80ml are needed.
The mixture was heated to boil for about 30 minutes and then filtered while still hot to remove all the residues.
 
The brown-yellow solution was left to cool at room temperature and then put in a refrigerator for a couple of hours.
After that time tiny yellow crystals had formed, that were filtered on a Buchner and washed with some very cold ethanol.
The yield was pretty low (<50mg) but enough to see some of the characteristic of this compound.
Parietin shows a pale orange fluorescence under
the UV light, and when it comes in contact with a strong alkaline solution, it becomes pink-red.
To test the product, it was dissolved in a concentrated NaOH solution, and immediately a very nice pink-red coloration appeared.
 
Resources:
[1] Parietin, the Vibrant Natural Dye in Xanthoria parietina https://www.researchgate.net/publication/376398083_Parietin_...
[2] https://en.wikipedia.org/wiki/Parietin
[Edited on 12-1-2024 by ItalianChemist]
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