Recovery of Natural Products from Deep Eutectic Solvents by Mimicking Denaturation

Abstract

A strategy was developed to recover natural products from deep eutectic solvents based on denaturation of the solvents. A method similar to nucleic acid denaturation was used to disrupt the intermolecular forces in the deep eutectic solvents to reduce their ability to solubilize and interact with the flavonoids at recovery. MIL-100 (Cr) was added to the system for sorptive separation and recovery of the target compounds from the denaturized deep eutectic solvents. The factors affecting denaturation of the deep eutectic solvents and adsorption of the target compounds were systematically investigated and optimized. The recovery method was further combined with mechanochemical extraction to establish a convenient and efficient protocol for obtaining natural products from plants. Moreover, due to the conjugated structure of MIL-100 (Cr), the adsorbed natural products could be directly analyzed by atmosphere matrix assisted laser desorption ionization-mass spectrometry (AP/MALDI-MS) without elution. This study provided a strategy for improving the efficiency of separation and recovery of natural products using deep eutectic solvents and also established a protocol for obtaining or analyzing natural products in a green, efficient, and convenient manner.

Innovative Extraction Techniques Using Deep Eutectic Solvents and Analytical Methods for the Isolation and Characterization of Natural Bioactive Compounds from Plant Material

“…In their study, several macroporous resins were tested (NKA-9, AB-8 and D101) for the recovery of flavonoids from the DES crude extract and the resin AB-8 was confirmed as the most promising with an excellent recovery power (more than 72% of the total extract content). In this study a 95% ethanol (v:v) was used as elution solvent, and certainly this stage of the method is more environmentally friendly than the methanol elution described above [165]. The authors also evaluated the possibility of DES recycling and found that the same solvent can be used four times, at least, with a promising result compared to the first extraction cycle (more than 75%).…”

“…For the recovery of the extracted bioactive compounds, in particular the flavonoids, there are several approaches such as solid phase extraction (SPE) [47,164], macroporous resin adsorption [79,103,111,143,144,148], anti-solvent precipitation [107,164,165], back-extraction [122], and adsorption chromatography [166] that have been evaluated to date.…”

“…In addition, the authors obtained higher recoveries by a simple SPE protocol using the stationary C18 phase, with recoveries for quercetin, kaempferol and isorhamnetin glycosides being 81%, 87% and 87%, respectively. In 2009, Tian et al improved a previously described anti-solvent method for the recovery of flavonoids from Flos Sophorae extracts and described a new recovery protocol in several subsequent steps [165]. In the first step, the intermolecular forces in the DES were also disrupted by using water as an anti-solvent to reduce the ability to solubilize and interact with extracted phenolic compounds [165].…”

“…In 2009, Tian et al improved a previously described anti-solvent method for the recovery of flavonoids from Flos Sophorae extracts and described a new recovery protocol in several subsequent steps [165]. In the first step, the intermolecular forces in the DES were also disrupted by using water as an anti-solvent to reduce the ability to solubilize and interact with extracted phenolic compounds [165]. Subsequently, organometallic framework material (MIL-100 (Cr)) was used as a sorbent for the separation of the target flavonoids from the denatured DES.…”

Deep Eutectic Solvents as Extraction Media for Valuable Flavonoids from Natural Sources

“…Finally, a novel method for extracting the flavonoids from the DES involves the mimicking of DNA denaturation in the DES, as described by Tian et al [56]. According to their research, the main goal in removing the flavonoids from the DES is the breakdown of the hydrogen mesh that holds the DES together, which is a process similar to denaturation.…”