Theoretical Insights into Flavonol Solubilization by Deep Eutectic Solvents

The low solubility of flavonols in common solvents such as water hinders their extraction from natural sources, solubility, and bioavailability; thus, new solvents are required for the development of flavonols' related technologies and applications. The alternative of deep eutectic solvents for flavonols solubilization is considered in this work through the analysis of the properties and structure of archetypical flavonols (galangin, kaempferol, quercetin, myricetin) in a model deep eutectic solvent (choline chloride:glycerol 1:2) as a function of flavonol concentration through the use of a theoretical approach combining density functional theory and classical molecular dynamics simulations. The solvation and self-aggregation of flavonols in the considered solvent are analyzed through the study of extension and the nature of hydrogen bonding. The complexity of the considered fluids stands on the competing effect for hydrogen bonding development between the components of the solvent, those between the solvent and the flavonols, and the trend to self-aggregation between flavonol molecules, thus determining the solubility of flavonols and the mechanism of solubilization.