Towards the identification of characteristic minor components from textiles dyed with weld (Reseda luteola L.) and those dyed with Mexican cochineal (Dactylopius coccus Costa)

The identity of a minor flavonoid component observed in extracts of textile samples dyed with weld (Reseda luteola L.) is confirmed as chrysoeriol (3'-O-methylluteolin) by HPLC-PDA analysis. HPLC-PDA, HPLC-MS and NMR techniques have been used to show that the unknown dcII component found in extracts of textiles dyed with Mexican cochineal (Dactylopius coccus Costa) is most probably the 7-C-glycoside of flavokermesic acid. In addition, the unknown dcIV and dcVII components have been shown to be isomeric with carminic acid, most probably differing only in the stereochemistry of the sugar moiety.