New Class of Tunable Choline Bromide-Based Hydrophobic Deep Eutectic Solvents for the Extraction of Bioactive Compounds of Varying Polarity from a Plant Matrix

Giulia Mastellone; Nabeel Mujtaba Abbasi; Cecilia Cagliero; Jared L Anderson

doi:10.1021/acssuschemeng.3c00185

New Class of Tunable Choline Bromide-Based Hydrophobic Deep Eutectic Solvents for the Extraction of Bioactive Compounds of Varying Polarity from a Plant Matrix

ACS Sustain Chem Eng. 2023 Apr 20;11(17):6665-6675. doi: 10.1021/acssuschemeng.3c00185. eCollection 2023 May 1.

Authors

Giulia Mastellone¹, Nabeel Mujtaba Abbasi², Cecilia Cagliero¹, Jared L Anderson²

Affiliations

¹ Department of Drug Science and Technology, University of Turin, Via Pietro Giuria, 9, I-10125 Torino, Italy.
² Ames National Laboratory-USDOE and Department of Chemistry, Iowa State University, 1605 Gilman Hall, 50011 Ames, Iowa, United States.

Abstract

Deep eutectic solvents (DESs) are a class of sustainable solvents that have found numerous applications in different fields. One of their main attributes is the possibility of easily modifying their physicochemical properties by varying the type of hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA) that comprise them. Choline chloride ([Ch⁺][Cl^-])-based hydrophilic DESs were among the first studied and the most used because of their capacity to easily create a hydrogen bonding network that lies in its unique chemical structure, characterized by a hydroxyl substituent within the ammonium headgroup. In this study, a new class of hydrophobic [Ch⁺][Br^-]-modified salts were synthesized to produce HBAs with similar properties to choline for the preparation of hydrophobic DESs. Six different [Ch⁺][Br^-]-based HDESs were prepared and characterized in terms of hydrophobicity, viscosity, and solvation properties (hydrogen bonding, dispersion, dipolarity/polarizability, n-π, and π-π interactions). They were employed as solvents in a microextraction method for the determination of phytochemicals in Cannabis sativa L. plant. The extraction performance of the [Ch⁺][Br^-]-based HDESs was compared to eutectic mixtures based on conventional hydrophobic HBAs, and the results revealed that the unique properties of [Ch⁺][Br^-]-modified salts allowed for the extraction of both hydrophilic (i.e., flavonoids) and hydrophobic compounds (i.e., cannabinoids).