Ionic liquid‐modified countercurrent chromatographic isolation of high‐purity delphinidin‐3‐rutinoside from eggplant peel

Abstract

Delphinidin-3-rutinoside, a high-value of anthocyanin, was isolated and purified by ionic liquid (IL)-modified countercurrent chromatography (CCC) from waste peel of eggplant (Solanum melongena), one of the most common vegetables consumed all around the world. Different conventional CCC and IL-CCC solvent systems were evaluated in respect of partition coefficient (K), separation factor (α), and stationary phase retention factor (S f ) to separate polar target and other components. Basic solvent system, kind of ILs, and amount of ILs were systematically optimized by totally Ktargeted strategy, which drastically reduced the experimental effort. Finally, a novel CCC two-phase solvent system (methyl tert-butyl ether-butanol-acetonitrile-1% trifluoroacetic acid water-1-butyl-3-methylimidazolium hexafluorophosphate ([C 4 MIM][PF 6 ]) [2:4:1:5:0.2; v/v/v/v/v]) was successfully established and applied. The baseline separation of target fraction was obtained in one cycle process. The purity of delphinidin-3-rutinoside was over 99%. Moreover, the distribution behavior of different kinds of ILs in biphasic solvent system and the removal method of ILs were explored. The results showed that hydrophobic IL significantly improved the partition of polar anthocyanin in organic solvent system, thereby the separation resolution and stationary phase retention through introducing intermolecular forces. This IL-modified CCC strategy may be applied for the separation of other anthocyanins from variety of natural food resources and waste.

Plant Secondary Metabolites: An Opportunity for Circular Economy

“…These solvents have already been used for the extraction of waste from natural products. For instance, solutions of surface-active ILs in water were used to efficiently extract triterpenic acids from apple peels [203], oleanolic acid from O. europaea [138], anthocyanins from grape pomace and peel of eggplant [204,205].…”

Screening and Isolation of Potential Anti-Inflammatory Compounds from Saxifraga atrata via Affinity Ultrafiltration-HPLC and Multi-Target Molecular Docking Analyses

“…Controlling these separation effects during the instrument's operation necessitates a range of approaches, leading to drawbacks including poor separation resolution, the need to determine the partition coefficient, and complex operating procedures. High resolution and repeatability are essential for the separation and preparation of high-purity compounds [16][17][18]. To overcome these issues, additional separation techniques are needed to facilitate the large-scale purification of high-purity bioactive compounds derived from S. atrata.…”

Liquid–liquid chromatography as a promising technology in the separation of food compounds

“…LLC has been applied in isolating a wide range of polyphenolic compounds, such as anthocyanins and flavonoids. A broad variety of anthocyanins have been isolated with LLC from red wine, elderberry and blood orange juice, blackberries, purple corn, black rice, grape seeds, pine bark, cinnamon bark, cocoa seeds, and eggplant (Degenhardt et al, 2001; Fan, Li, et al, 2020; Hillebrand et al, 2004; Jeon et al, 2015; Phansalkar et al, 2018; Schwarz et al, 2003). The polyphenolic profile (together with other classes of compounds) in tea or coffee extracts has also been explored with the use of LLC (Fan et al, 2022; Si et al, 2006; Stodt et al, 2015; Yanagida et al, 2006; Yuan et al, 2004).…”