A sustainable biphasic deep eutectic solvent system coupled with ultrasound-assisted emulsification for enhanced extraction of bioactive compounds from Rosmarinus officinalis

Current study developed and evaluated a biphasic system comprising hydrophobic and hydrophilic deep eutectic solvents (DES) for the extraction and fractionation of potent antioxidants from rosemary. Each DES was synthesised and systematically characterised based on its physicochemical and thermal properties. The optimal solvents with the highest extraction yields were used in combination with ultrasound emulsification technology to enhance extraction efficiency and selectivity. The immiscibility of the biphasic system, arising from the inherent differences in density and polarity, enabled effective phase separation and production of semi-purified extracts. Under the optimised extraction conditions, the developed system achieved a high fractionating efficiency of 80% and 70% for the amphiphilic carnosic acid and carnosol, respectively, into the hydrophobic phase, while rosmarinic acid was entirely retained in the hydrophilic phase. Overall, this study highlights the potential of developing a one-pot technology for the simultaneous extraction and fractionation of antioxidants with divergent polarities from rosemary.