Use of a choline chloride-urea based deep eutectic solvent for the improvement of HPLC resolution in complex botanical extracts

Abstract

Turnera diffusa is a plant with hepatoprotective activity. Hepatodamianol - a biomarker of this plant - is identified as the main compound responsible for this activity. There are no chromatographic methods with adequate peak resolution for quantifying this analyte in T. diffusa extracts. Deep Eutectic Solvents (DESs) have emerged as an option to improve the performance of chromatographic systems. Therefore, the present study aimed to develop and validate a chromatographic method for hepatodamianol analysis in the presence of a Choline chloride-Urea (ChCl-Ur) based DES and its application in standardized extracts of T. diffusa. The developed method used a Hypersil GOLD RP C18 column with methanol-0.1% formic acid aqueous solution as the mobile phase. The use of DES for sample dissolution increased the resolution from 0.76 to 2.59. The method was linear (5-100μgmL-1); it exhibited high precision and accuracy with relative standard deviations below 2 and 8% for intra- and inter-day precision, respectively, and recoveries between 97.46 and 105.65%. The detection and quantification limits were 0.87μgml-1 and 4.45μgml-1, respectively. The proposed method efficiently analyzed the standardized extracts of T. diffusa, thus representing a quality control tool for herbal products based on this species.