Ionic Liquids as Additives for Extraction of Saponins and Polyphenols from Mate (Ilex paraguariensis) and Tea (Camellia sinensis)

Extracts from plant tissue are a rich source of lead compounds for nutraceutical or pharmaceutical applications. Nevertheless, the concentration of added value compounds in the plants extracts is usually lower than 1-2%. As consequence, a search for new improved, more efficient technologies combined with solvent engineering has emerged in the last years. In this work, we evaluate the performance of ionic liquids (ILs) as additives in the extraction of saponins and polyphenols from tea and mate. Two families of ILs, imidazolium- and cholinium-based, combined with a wide variety of hydrophilic anions, have been tested. The influence of several parameters such as ionic liquid chemical structure, water content, solvent/raw material ratio, temperature, and contact time period was evaluated. The best performing IL in the extraction of saponins and polyphenols was chosen to pursue to the concentration step using ILs-based aqueous biphasic systems (ABS) were tested. Finally, the saponins and polyphenols existent in the ABS IL-rich phase were recovered through the addition of a second more hydrophobic IL.