Natural indigo typically comprises a variety of elements in variable amounts, along with mineral impurities and occasionally colourants of a different chemical origin, including flavonoids [47]. However, the existing methods of dye analysis, by high-performance liquid chromatography (HPLC), mostly detect indigotin and indirubin in fabrics colored with natural indigo but do not enable the accurate identification of the plant source(s) employed in each individual case [47].