From Nature to Innovation: The Uncharted Potential of Natural Deep Eutectic Solvents

Abstract

This review discusses the significance of natural deep eutectic solvents (NaDESs) as a promising green extraction technology. It employs the consolidated meta-analytic approach theory methodology, using the Web of Science and Scopus databases to analyze 2091 articles as the basis of the review. This review explores NaDESs by examining their properties, challenges, and limitations. It underscores the broad applications of NaDESs, some of which remain unexplored, with a focus on their roles as solvents and preservatives. NaDESs' connections with nanocarriers and their use in the food, cosmetics, and pharmaceutical sectors are highlighted. This article suggests that biomimicry could inspire researchers to develop technologies that are less harmful to the human body by emulating natural processes. This approach challenges the notion that green science is inferior. This review presents numerous successful studies and applications of NaDESs, concluding that they represent a viable and promising avenue for research in the field of green chemistry.

Keywords: NaDESs; biomimicry; green chemistry; green solvent; natural deep eutectic solvents.

Figure 1

NaDESs are formed by the complexation of a hydrogen bond acceptor (HBA) and hydrogen bond donors (HBDs), similarly to DESs. This charge delocalization leads to a decrease in the melting point compared to that of the raw materials. NaDESs are made of compounds found naturally in primary metabolites of living organisms, such as organic acids, amino acids, sugars, polyols, and tertiary amines. The NaDES concept was developed to explain the higher solubility of certain natural compounds, such as flavonoids, than in water, working as a third liquid phase in organisms.

Figure 2

(A) Dehydration. (B) Supercooling and intracellular ice formation. (C) Vitrification. (D) Cell lysis. (E) Apoptotic onset. The use of NaDESs in cryopreservation can prevent the formation of extracellular ice crystals, avoiding osmotic imbalance and consequent cellular dehydration. Rapid cooling rates and the addition of high concentrations of cryoprotectant agents (CPA) can achieve vitrification, an amorphous and ice-free state. However, high concentrations of CPA can be toxic to cells. NaDESs exhibit low toxicity when compared to conventional cryoprotectants. Finally, cryopreservation can induce apoptosis, leading to delayed cell death after thawing. Due to their low toxicity, NaDESs can decrease the death rate.