title: A multivariate study of the performance of an ultrasound-assisted madder dyes extraction and characterization by liquid chromatography-photodiode array detection.
abstract: An extraction method of madder (Rubia tinctorum) roots dyes is established and optimized to obtain the original chemical composition. A central composite design (CCD) was developed to specify the importance of the three major factors studied (time, temperature and solvent composition) affecting the ultrasound-assisted extraction of this matrix. A preliminary granulometric study of madder roots is realized in the aim to determine the optimal particles size corresponding to the best ultrasound effects. A comparison with the classical extraction method of madder dyes by reflux is described. The identification of the constituents of R. tinctorum is carried out by liquid chromatography coupled with a photodiode array detector (LC-PDA). Anthraquinonic aglycone and heterosidic dyes compounds are characterized by retention time and UV spectrum: alizarin (1,2-dihydroxyanthraquinone), purpurin (1,2,4-trihydroxyanthraquinone), lucidin (1,3-dihydroxy-2-hydroxymethylanthraquinone), rubiadin (1,3-dihydroxy-2-methylanthraquinone), xanthopurpurin (1,3-dihydroxyanthraquinone), pseudopurpurin (1,2,4-trihydroxy-3-carboxyanthraquinone), lucidin primeveroside, ruberythric acid (alizarin primeveroside), galiosin (pseudopurpurin primeveroside) and rubiadin primeveroside. The optimal experimental conditions are 18min, 36 degrees C and 37/63 MeOH/H(2)O (v/v).
authors.affiliation: Université d'Avignon et des Pays de Vaucluse, Laboratoire de Chimie Bioorganique et des Systèmes Moléculaires Vectoriels, Faculté des Sciences, 33 rue Louis Pasteur, 84000 Avignon, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Cuoco
authors.forename: Carole
authors.initials: C
authors.lastname: Mathe
authors.forename: Paul
authors.initials: P
authors.lastname: Archier
authors.forename: Farid
authors.initials: F
authors.lastname: Chemat
authors.forename: Cathy
authors.initials: C
authors.lastname: Vieillescazes
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004396:Coloring Agents / Q000302:isolation & purification*; D003365:Costs and Cost Analysis; D015999:Multivariate Analysis; D018517:Plant Roots / Q000737:chemistry*; D045470:Rubia / Q000737:chemistry*; D013696:Temperature; D014465:Ultrasonics
chemical_list: D004396:Coloring Agents