Application of choline chloride deep eutectic solvents and high-speed counter-current chromatography to the extraction and purification of flavonoids from the thorns ofGleditsia sinensisLam

Introduction Flavonoids are the most important and effective constituents in the thorns ofGleditsia sinensisLam., which have been known to show antimicrobial, antiviral, anticancer, and anticoagulant activities. However, efficient extraction and separation methods for these flavonoids are not currently established. Objective To develop an efficient method for efficient extraction and rapid separation of flavonoids from the thorns ofG. sinensisusing choline chloride deep eutectic solvents (DESs) and high-speed counter-current chromatography (HSCCC). Methodology As for extraction, DES composed of choline chloride and 1,4-butanediol at 1:4 mole ratio, at an extraction temperature of 55 degrees C, 20% of water content, 1:30 mg/mL for solid-liquid ratio, and 45 min for extraction time were selected as the optimised extraction method for flavonoids from the thorns ofG. sinensis. As for separation, dichloromethane-methanol-n-butanol-water (4:3:0.5:2,v/v) was applied to develop a successful strategy for purification of the flavonoids by HSCCC. Results Totally, five flavonoids, including padmatin (1, 3.7 mg), isovitexin (2, 2.5 mg), 3 ',5,5 ',7-tetrahydroxyflavanonol (3, 11.2 mg), 7,4 '-dihydroxy-5,3 '-dimethoxyflavanonol (4, 4.1 mg), and quercetin (5, 3.8 mg), were successfully obtained from 250 mg of the extracted flavonoids by HSCCC. Conclusion Results demonstrated that the combination of DES and HSCCC is a powerful technique for the extraction, and isolation of flavonoids from the thorns ofG. sinensiscompared with conventional organic solvent extraction and column chromatography, which have been proven to provide higher extraction efficiency for flavonoids and rapidly obtain the quality control markers of flavonoids from the investigated plant.

Automated summary

This study aimed to develop an efficient method for the extraction and separation of flavonoids from Gleditsia sinensis thorns using choline chloride deep eutectic solvents (DES) and high-speed counter-current chromatography (HSCCC). Five flavonoids were successfully obtained using this method, demonstrating that the combination of DES and HSCCC is a powerful technique for extracting and isolating flavonoids compared to traditional methods.