Natural hydrophobic deep eutectic solvents for the extraction of bioactive compounds from complex samples

The valorization of plants and their products is fundamental in terms of sustainable development. In recent years, public attention to environmental sustainability has increased dramatically, and regulatory agencies are developing strategies and designing roadmaps to promote the efficient use of resources, the restoration of biodiversity, and the reduction of waste. In this sense, natural products can be used as a valuable source of phytochemicals for the production of more environmentally friendly solvents for various applications, including more sustainable extraction methods, according to the principle of Green (Analytical) Chemistry. In particular, deep eutectic solvents (DESs) represent a more environmentally friendly alternative to conventional solvents, thanks to their easy preparation and low costs of raw material. They consist of two or more components that form a hydrogen bonding network, which is the key to the formation of DESs. Natural compounds, such as those isolated from essential oils, can be used as hydrogen bond donors or acceptors to form hydrophobic (H)DESs. In this communication, the potential of natural HDESs for the extraction of bioactive compounds from complex samples is presented. The possibility of isolating non-volatile compounds from natural resources and volatile potential allergens from cosmetic products using the described HDESs is reported, as well as the possibility of combining (micro)extraction with analytical characterization by various chromatographic techniques.