Assessing the Toxicity of Terpene- and Amino Acid-Based Natural Deep Eutectic Solvents

Over the past decade, there has been a significant increase in the discovery of greener solvents for industrial applications. In this context, deep eutectic solvents (DESs) have emerged as promising candidates across various sectors, including biomass conversion, paper and pulp, pharmaceuticals, and textiles. A new class of DESs, known as natural deep eutectic solvents (NADESs), is derived from natural chemicals and is expected to be more environmentally friendly. However, research into the environmental impact and toxicity of NADESs is still limited. Given the broad applications of DESs and the urgent need for sustainable alternatives, studying their toxicity is crucial. In our current study, we focused on NADESs formulated from menthol, thymol, and amino acid. We assessed their toxicity on different cell lines using standard biochemical assays. Remarkably, our findings also indicate that these NADESs exhibit low toxicity in the HaCaT cell line and a mice blood sample. We also found that all of the tested NADESs have shown better antimicrobial property values compared to the individual components of NADESs, indicating the importance of NADES formulation for applications. Among the tested NADESs, menthol:thymol (1:1) showed the best antibacterial properties. These results hold significant implications for the development of NADESs in industrial applications, suggesting a path forward for the adoption of greener and safer solvents.