title: A new HPLC-ELSD method to quantify indican in Polygonum tinctorium L. and to evaluate beta-glucosidase hydrolysis of indican for indigo production.
abstract: A method to quantify the indigo precursor indican (indoxyl-beta-D-glucoside) in Polygonum tinctorium L. has been developed. Plant material was extracted in deionized water, and indican was identified and quantified using high performance liquid chromatography (HPLC) coupled to an evaporative light scattering detector (ELSD). Results confirmed that with this method it is possible to measure indican content in a short time, obtaining reliable and reproducible data. Using this method, leaf indican content was quantified every 15 days during the growing season (from May to October) in P. tinctorium crops grown in a field experiment in Central Italy. Results showed that indican increased along the growing season until flowering and was positively affected by photosynthetic active radiation (PAR). Indican is naturally hydrolyzed by native beta-glucosidase to indoxyl and glucose, the indoxyl yielding indigo. The activity of two enzymes, sweet almond beta-glucosidase and Novarom G preparation, were compared with P. tinctorium native beta-glucosidase to evaluate indigo production. Results showed that the ability to promote indigo formation increased as follows: almond beta-glucosidase <or= Novarom G.
authors.affiliation: Dipartimento di Agronomia e Gestione dell'Agroecosistema, Università di Pisa, via S.Michele degli Scalzi 2, 56100 Pisa, Italy.
authors.forename: Luciana G
authors.initials: LG
authors.lastname: Angelini
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Campeol
authors.forename: Sabrina
authors.initials: S
authors.lastname: Tozzi
authors.forename: Kerry G
authors.initials: KG
authors.lastname: Gilbert
authors.forename: David T
authors.initials: DT
authors.lastname: Cooke
authors.forename: Philip
authors.initials: P
authors.lastname: John
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006868:Hydrolysis; D007200:Indican / Q000032:analysis / Q000378:metabolism*; D007203:Indigo Carmine; D007211:Indoles / Q000378:metabolism*; D010783:Photometry / Q000379:methods*; D010936:Plant Extracts / Q000032:analysis; D018515:Plant Leaves / Q000378:metabolism; D028502:Polygonum / Q000378:metabolism*; D015203:Reproducibility of Results; D012621:Seasons; D012680:Sensitivity and Specificity; D001617:beta-Glucosidase / Q000032:analysis / Q000378:metabolism*
chemical_list: D007211:Indoles; D010936:Plant Extracts; D007203:Indigo Carmine; D001617:beta-Glucosidase; D007200:Indican