Optimized green extraction of agarwood essential oil using custom natural deep eutectic solvents: Chemical analysis and bioactivity evaluation

This study explores an innovative and environmentally friendly method for extracting essential oils (EOs) from agarwood using custom natural deep eutectic solvents (DESs), and the optimal DES-solvent system was choline chloride and lactic acid. Compared with the traditional water distillation method, the extraction efficiency of essential oil of agarwood was increased 2.12 times by using the DESs system in this study. Gas chromatography-mass spectrometry (GC-MS) analysis revealed a richer profile of sesquiterpenes and alkane hydrocarbons in DES-extracted oils, and the results of the antioxidant activity experiments showed that the DES agarwood essential oil (IC 50 = 9.3602 mg/mL) had higher antioxidant activity than the essential oil extracted by traditional water distillation (IC 50 = 10.2261 mg/mL). Scanning electron microscopy (SEM) confirmed that DESs effectively disrupt agarwood cell walls, facilitating a more complete release of aromatic compounds while preserving volatile components. Additionally, DESs are biodegradable and exhibit reduced toxicity, offering a sustainable alternative in the essential oil extraction industry. This research underscores the potential of DES-based extraction techniques as a viable and superior method for producing high-quality agarwood EO, with significant implications for sustainable practices in the fragrance and pharmaceutical industries. • 1.Optimisation and establishment of the DESs for agarwood essential oils(EOs). • 2.DESs can significantly enhance the extraction rate of agarwood EOs. • 3.DESs extract higher quality agarwood EOs than traditional water distillation. • 4.The increased extraction rate owes to the disruption of the feedstock structure. • 5.This method reduces agarwood tree felling and aids environmental protection.