Polyphenols are biologically active compounds present in a large number of plants and their purpose is to protect the plant from negative external influences. Due to the anti-age properties of polyphenols, their application in the cosmetics industry has been investigated in recent years. Therefore, this work aimed to prepare DES and select an appropriate method for the extraction of polyphenolic compounds from plantain leaves. 19 solvents were prepared, 12 of which showed good physicochemical properties for further use in the extraction process. Physicochemical properties (density, viscosity, pH, and polarity) were determined for the selected solvents, FTIR spectra were recorded and the concentration of total phenols was determined after the extraction. In addition, the influence of water addition on the extraction efficiency and physicochemical properties of DESs was monitored. The best extraction efficiency was shown by DES La: Fru: Gly (2: 1: 2) with 30 and 50 wt% water and for La: Fru: Gly - 50 wt% process optimization was performed. The best extraction method and the time for achieving equilibrium polyphenol concentration were determined. Furthermore, the equilibrium concentration of polyphenols at the phase boundary was determined for the selected solvent, and the diffusion coefficient and the transfer coefficient of the substance were determined.