A look on target-specificity of eutectic systems based on natural bioactive compounds

Natural occurring molecules often represent an interesting starting point for the development of novel greener solvents. Currently, as a result of centuries compiling information about these molecules, we have a vast library of promising raw materials. Natural deep eutectic systems (NADES) are mostly composed by natural primary metabolites such as sugars, sugar alcohols, organic acids, amino acids, and amines, but can also be formed with secondary metabolites such as terpenes and vanillin, or biopolymers. Moreover, NADES have been described as antibacterial and antibiofilm, antifungal, anticancer, antioxidant and wound healing agents. The tailor-made versatility and its compliance with the green chemistry metrics, have pushed forward the possible therapeutic role of these eutectic systems. In this chapter we aim to challenge the community to join the discussion on what we consider to be the next step in these systems comprehension—target-specificity. We already have evidences of its therapeutic role, so questions such as: does these systems work intra or extra cellularly? How do they interact with cellular membranes? Do they have an impact on gene expression? Are of most relevance to fulfill NADES potential as therapeutic agents. Furthermore, considering the current pursue for sustainability, the greenness and biosafety of NADES is briefly addressed coupling the major advances of eutectics as therapeutic agents with its promising contribution as an alternative to the industrial status quo.