Deep eutectic solvent-assisted extraction of cinnamaldehyde-rich cinnamon (Cinnamomum cassia) essential oil: enabled by molecular simulation and microwave-ultrasound pretreatment.

Cinnamomum essential oil (CEO), particularly its major component cinnamaldehyde (CA), shows strong antibacterial and antioxidant activities but is inefficiently extracted by conventional hydrodistillation. Here, a molecular mechanism guided strategy is used to screen deep eutectic solvents (DESs), and choline chloride-glycerol is identified as the optimal one through binding energy and frontier orbital analyses. Microwave-ultrasound pretreatment combined with DESs is applied, and subsequent by the hydrodistillation. Under optimal conditions optimized using response surface methodology, the CEO yield reaches 1.97% (76% higher than hydrodistillation), and the CA content is about 74%. The resulting CEO strongly inhibited Candida albicans, Staphylococcus aureus, and Escherichia coli with inhibition zone diameters of 72.3, 26.4, and 23.9 mm (MIC/MBC: 0.04-0.62 mg/mL), and showed notable antioxidant activity with ABTS and DPPH IC50 values of 8.81 and 69.1 mg/mL. This study provides an efficient and mechanism-driven approach for efficient essential oil extraction.