Exploring the potential of deep eutectic solvents for extracting bioactive compounds from tea: Insights from molecular dynamics simulations

Deep eutectic solvents (DESs) are sustainable alternatives to traditional solvents used for natural compound extraction. In this study, the possibility of extracting alkaloids, flavonoids, and catechin compounds from tea plants is investigated using four different binary eutectic solvents through molecular dynamics (MD) simulations and Density functional theory (DFT) calculations. The structural and thermodynamic characteristics of the solvents, as well as their interactions with the tea's bioactive components, are explored. In this study, choline chloride (CHO) is combined with 1,2-butanediol (1,2BUT), 1,3-butanediol (1,3BUT), 1,4-butanediol (1,4BUT), and 2,3-butanediol (2,3BUT) to produce four different types of solvents. According to the obtained results from the MD simulation, the interaction of the target compounds with the different DESs varied significantly, some of the solvents are more soluble and show a good selectivity for certain compounds. The average total interaction energy of target molecules with the solvents follows the order Epigallocatechin (EGC) > Epicatechin gallate (ECG) > Epigallocatechin gallate (EGCg) > Kaempferol (KAM) > Theobromine (TBM) > Caffeine (CAF) > Catchin (CAT). Therefore, among the target molecules, EGC interacts more effectively with solvents. The interaction energy of this molecule with the solvent is changed from −24 kJ/mol to −95 kJ/mol. Overall; this study highlights the importance of considering the specific target compounds when selecting a binary eutectic solvent for extraction and provides a theoretical basis for further experimental investigations.