A New HPLC‐ELSD Method To Quantify Indican in Polygonum tinctorium L. and To Evaluate β‐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.

High yielding indigo sources in native Isatis (Brassicaceae) taxa from Turkey

“…In the same environmental conditions I. indigotica gave up to 11 kg/ha indigo with 4 harvests (Sales et al 2006). Our findings about indigo yields (8.13-87.13 kg/ha) were similar to Sales et al (2006) but lower than Angelini et al (2003) with the exception of I. constricta giving higher indigo yield.…”

“…The potential indigo yield was found as 82 kg/ha per season in four harvests from June to October in the temperate climate of Central Italy by Angelini et al (2003). Also Sales et al (2006) reported that indigo yield in I. tinctoria was up to 37 kg/ha per season (4 harvests) in Southern Spain.…”

Rapid determination of solanesol in tobacco by high-performance liquid chromatography with evaporative light scattering detection following microwave-assisted extraction

“…Evaporative light scattering detection (ELSD) is increasingly being used coupled with HPLC during the last decade. The principle of its operation involves nebulizations of the column effluent to form an aerosol, followed by solvent evaporation in a heated drift tube and then the detection of the remaining nonvolatile solute particles in the light scattering cell [6]. ELSD is a kind of mass and non-selective detector, it can analyse all samples which have low volatility than mobile phase, especially for non-UV-absorbing phytochemicals [7].…”

Determination of indican, isatin, indirubin and indigotin in Isatis indigotica by liquid chromatography/electrospray ionization tandem mass spectrometry

“…Various analytical methods have been applied to identify and quantitate the four indoxyl derivatives. Methods involving thin‐layer chromatography (TLC),15, 17 high‐performance thin‐layer chromatography (HPTLC),18 high‐performance liquid chromatography/ultraviolet (HPLC/UV)19 and HPLC coupled with evaporative light scattering detection (ELSD)20, 21 have been developed for the determination of indican in I. indigotica , I. tinctoria and other herbs. HPLC/UV was applied to determine isatin in human urine and plasma 22.…”