Since prehistoric times, humans have used dye plants to colour fabrics, works of art and everyday objects. These include buckthorn berries (Rhamnus cathartica) are known for producing beautiful yellow to greenish hues thanks to their rich flavonoid content. These age-old practices are now attracting new scientific interest, particularly in terms of understanding the durability of natural dyes and preserving our textile heritage.

In this article, published in the journal Dyes and Pigments, Marine Chambaud, Lindsay Mas-Normand, Céline Joliot, Carole Mathe De Souza, Olivier Dangles and Gérald Culioli (EECAR-IMBE team) were interested in the evolution of the colours of cotton fabrics dyed with buckthorn berries and subjected to accelerated light ageing, simulating up to 300 years of exposure to museum light. The aim was to observe both the evolution of their colour and the chemical transformation of the natural dyes.

Observations show that the colour of dyed fabrics fades very quickly. After the equivalent of 300 years of exposure to light, dyed fabrics appear completely white, a sign of the complete degradation of the natural dyes.

However, thanks to a innovative approach to metabolomics by LC-MS, the researchers were able to detect and identify numerous molecules from the dye plant, even when the colour had visually disappeared. These results show that traces of natural dyes, such as flavonoids and anthraquinones, persist in the fibres and can still be revealed using advanced analytical techniques.

This study highlights the potential of metabolomics to help identify dyes in old textiles, thereby contributing to better heritage conservation and improving our knowledge of traditional skills.