Alizarin old and new: Extraction techniques for coloration, advances in detection methods for historical textiles and novel applications as a functional dye

The current study provides the first review of alizarin, a natural dye, in terms of its historical aspects and its potential for functional applications in textiles. The review begins with a brief overview of natural alizarin and its occurrence in Rubiaceae family plants, followed by a discussion of alizarin acquisition from its botanical sources through conventional and advanced extraction methods. A special emphasis of this study is on the identification of natural alizarin colourants in archaeological and cultural textiles by using analytical methods based on reflectance, Raman spectroscopy, mass spectrometry and chromatographic profiles. In addition, the functional properties of natural alizarin, including its antimicrobial activity, anti-oxidant activity, insect repellence and ultraviolet protection, are analysed. This paper summarises the methods for obtaining alizarin for coloration, as well as advanced techniques for detecting alizarin in historical textiles, and potential applications of natural alizarin as a functional textile dye.