Green analytical chemistry metrics: Towards a sustainable phenolics extraction from medicinal plants

Green metrics quantify the sustainability of chemical processes. Since their introduction many years ago, this topic has been an active area of research and discussion. However, the application of these tools as additional criteria for method selection is still unexploited. In the present work, a comparative study was carried out in order to assess the greenness of the most recent approaches for phenolics extraction from medicinal plants using the Green metrics. Considering the obtained results, a green and efficient Natural Deep Eutectic Solvent (NADES) mediated-ultrasound extraction for phenolic compounds was developed and applied to an Argentinian autochthonous plant (Larrea cuneifolia) commonly used in folk medicine. To this purpose, experimental conditions were chemometrically optimized to maximize efficiency and contribute to greening the approach. The results reveal that the proposed approach showed total penalty points similar to those obtained with water. Finally, the performance of NADES as extracting agent was compared with traditional solvents showing outstanding extractability for both polar and weak polar phenolics.