Quantitative analysis of indigo and indigo precursors in leaves of Isatis spp. and Polygonum tinctorium

• Published in: Biotechnology progress Vol. 20; no. 4; pp. 1289 - 1292
• Main Authors: Gilbert, K.G, Maule, H.G, Rudolph, B, Lewis, M, Vandenburg, H, Sales, E, Tozzi, S, Cooke, D.T
• Format: Journal Article
• Language: English
• Published: USA American Chemical Society 01-07-2004; American Institute of Chemical Engineers
• Subjects: Biological and medical sciences; Biotechnology; Chromatography, High Pressure Liquid; Fundamental and applied biological sciences. Psychology; High-performance liquid chromatography; Indigo; Indigo Carmine; Indoles - analysis; Isatis - chemistry; Isatis indigotica; Isatis tinctoria; Light; Mass Spectrometry; Plant Leaves - chemistry; Polygonum - chemistry; Polygonum tinctorium; Q1; Q2; Reference Standards; Scattering, Radiation; Spectrophotometry; Polygonum; Polygonaceae; Dicotyledones; Angiospermae; Spermatophyta; Plant leaf; Precursor; Quantitative analysis
• ISSN: 8756-7938; 1520-6033
• DOI: 10.1021/bp0300624

Analysis of extracts from two woad species (Isatis tinctoria and Isatis indigotica) and Polygonum tinctorium revealed that only one indigo precursor (indican) was present in Polygonum, but two precursors were found in Isatis spp. This was done using high performance liquid chromatography (HPLC), coupled to an evaporative light scattering detector (ELSD). In Isatis spp., the indigo precursors indican and a fraction representing isatan B were identified. The proportion of indican and isatan B was different between the two Isatis spp. tested. For the first time, it was possible to quantify the precursors in woad plant species, and the results were found to be in good agreement with those made from total indigo quantification using two different spectrophotometric methods or a derivatization technique.