Hydrophobic Natural Deep Eutectic Solvents for Extraction of Bioactive Compounds: Multiscale Characterization, Quantum Simulations, and Molecular Interaction Studies with Cry j1 and Amb a1 Allergens

This study explores the synthesis, characterization, and extraction efficiency of hydrophobic natural deep eutectic solvents (NADES), along with the allergen-modulating potential of extracted bioactive compounds. Six NADES were synthesized using binary combinations of camphor, thymol, eugenol, and menthol (1:1 molar ratio) and characterized using FTIR, TGA, DFT, and MD simulations. Bioactive compounds were extracted from Thujopsis dolabrata wood biomass via ultrasonic-assisted extraction and analyzed using GC-MS. Molecular docking was performed to assess their allergen-modulating interactions with Amb a 1 and Cry j 1. All NADES exhibited single-stage decomposition (110–125°C) except camphor-menthol, which recrystallized. FTIR and simulations confirmed strong hydrogen bonding in eugenol-based NADES, particularly menthol-eugenol. Extraction identified 47 bioactive compounds, with 4,5α-Epoxy-3-methoxy-17-methyl-7α-(4-phenyl-1,3-butadienyl)-6β,7β-(oxymethylene) morphinan as the most abundant (9.31–11.16%). It exhibited the highest binding affinity (Cry j 1: -8.60 kcal/mol, Amb a 1: -7.40 kcal/mol) and lowest inhibition concentration (Cry j 1: 0.49 µM, Amb a 1: 3.74 µM), suggesting strong allergen-modulating potential. Hydrophobic interactions and hydrogen bonding drove protein-ligand binding. These findings highlight NADES as effective, sustainable solvents for extracting bioactive compounds with allergen-modulating potential.