Eco‐Innovative Approach for Biofungicide Formulations Based on Hydrophobic Deep Eutectic Solvents With Inhibitory Potential

Abstract

In contemporary agriculture, management strategies aimed at pre‐ and postharvest protection against phytopathogens relies on pesticides of diverse compositions. One of the main objectives of our approach is to identify a potent botanical‐based formulation as an alternative to synthetic fungicides that are harmful to the environment and human health. Natural deep eutectic solvents (NADES) were created in response to this demand, and a subclass called hydrophobic deep eutectic solvents (HDES) was developed to expand the range of applications of traditional hydrophilic NADES. In this work, we synthesised 24 HDES categorised into three groups, containing either menthol, thymol or camphor as one of the two components. HDES antifungal activity was evaluated by determining the minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), efficacy (E%) and half‐maximal inhibitory concentrations (IC 50 ). A phytotoxicity test was conducted using tuber potato slices. The results show that antifungal activity is influenced by the fungal strain and the HDES type. Menthol‐ and thymol‐based HDES demonstrated 18%–100%, 22%–100%, 3%–100% and 20%–100% antifungal efficacy (E%) against Alternaria alternata , Botrytis cinerea , Fusarium graminearum and Monilinia fructicola isolates, respectively. The IC 50 values of menthol‐ and thymol‐based HDES for all four isolates ranged from 0.1% to 29.8%. The HDES exhibited varying degrees of phytotoxicity, ranging from 0 to 5 (zero to 100% necrosis, respectively) within the 12.5%–100% concentration range. Camphor‐based HDES did not inhibit fungal growth. Considering the obtained data, HDES represent potentially effective botanical‐based formulations capable of suppressing phytopathogen growth.