Natural Deep Eutectic Solvents: Properties, Applications, and Perspectives

Abstract

As functional liquid media, natural deep eutectic solvent (NADES) species can dissolve natural or synthetic chemicals of low water solubility. Moreover, the special properties of NADES, such as biodegradability and biocompatibility, suggest that they are alternative candidates for concepts and applications involving some organic solvents and ionic liquids. Owing to the growing comprehension of the eutectic mechanisms and the advancing interest in the natural eutectic phenomenon, many NADES applications have been developed in the past several years. However, unlike organic solvents, the basic structural unit of NADES media primarily depends on the intermolecular interactions among their components. This makes NADES matrices readily influenced by various factors, such as water content, temperature, and component ratio and, thus, extends the metabolomic challenge of natural products (NPs). To enhance the understanding of the importance of NADES in biological systems, this review focuses on NADES properties and applications in NP research. The present thorough chronological and statistical analysis of existing report adds to the recognition of the distinctiveness of (NA)DES, involves a discussion of NADES-related observations in NP research, and reportes applications of these eutectic mixtures. The work identifies potential areas for future studies of (NA)DES by evaluating relevant applications, including their use as extraction and chromatographic media as well as their biomedical relevance. The chemical diversity of natural metabolites that generate or participate in NADES formation highlights the growing insight that biosynthetically primordial metabolites (PRIMs) are as essential to the biological function and bioactivity of unrefined natural products as the biosynthetically more highly evolutionary metabolites (HEVOs) that can be isolated from crude mixtures.

Saffron Processing Wastes as a Bioresource of High-Value Added Compounds: Development of a Green Extraction Process for Polyphenol Recovery Using a Natural Deep Eutectic Solvent

“…The predicted C DES levels implied the use of a significantly higher water amount compared with previous results from polyphenol extraction with DES, which indicated that 80% (w/w) to be the most appropriate C DES for high extraction yield [23][24][25][26]. Suitable DES mixing with water is indispensable for regulation of properties crucial to solid-liquid extraction, such as viscosity and polarity [27]. However, C DES cannot be below a certain level because excessive water amount would cause DES decomposition and therefore the intrinsic DES properties would be abolished [28].…”

Hydrophobic Deep Eutectic Solvents Incorporating Trioctylphosphine Oxide: Advanced Liquid Extractants

“…The term Deep Eutectic Solvent (DES) [1][2][3] is most commonly used to describe low melting liquids formed by combining organic salts such as choline chloride with urea or other hydrogen-bond donor components including carboxylic acids and alcohols. DES were initially popularised 4 as lower cost and more environmentally benign (greener) variants of non-volatile ionic liquids and have been used as non-aqueous electrolyte solutions, 5 and media for nanoparticle and materials synthesis, [6][7][8][9] solvents for catalysis 10 and as vehicles for delivery of active pharmaceutical ingredients 11,12 have been extensively investigated in recent years.…”

Self‐Assembled Gels Formed in Deep Eutectic Solvents: Supramolecular Eutectogels with High Ionic Conductivity

“…DESs are af ascinating example in which hydrogen-bondmediated anion binding,ak ey theme in supramolecular chemistry, [4] leads to significant changes in the properties of the bulk material. Like traditional ionic liquids,m any DESs have low vapour pressure,low flammability,and awide liquid range,b ut they also have additional advantages,i ncluding ease of preparation and the use of relatively inexpensive, nontoxic components.T hese solvents are being extensively explored for aw ide range of uses,i ncluding metal processing, [5] organic synthesis/catalysis, [6] nanomaterials synthesis, [7] analytical chemistry, [8] biotechnology, [9] and energy applications. [10] There has previously been considerable interest in structuring traditional ILs into soft materials,s uch as gels,t o generate "ionogels".…”