Influence of natural deep eutectic solvent pretreatment on the yield and composition of essential oil derived from Cyperi Rhizoma

This study systematically investigated the effect of hydrodistillation (HD) on the yield of essential oil derived from Cyperi Rhizoma following ultrasonic pretreatment using natural deep eutectic solvents (NADESS) as the medium. The parameters for ultrasonic pretreatment were analyzed using single-factor experiments and response surface methodology (RSM) to optimize the yield of essential oil. The findings indicated that the ideal settings for ultrasonic pretreatment were as follows: The water content of NADES-5, with a molar ratio of lactic acid to choline chloride of 3.25:1, was 38.6%. The ultrasonic treatment duration was 42.0 min, the ultrasonic power was 73.0 W, and the actual essential oil yield attained 1.341%. Scanning electron microscopy (SEM) analysis revealed that the application of NADES-5 as the extraction medium resulted in considerable degradation of the powder's composition, as evidenced by the presence of numerous tiny pores on the surface. This suggested that NADES-5 enhanced permeability and exerted an erosive impact, efficiently dismantling the plant cell wall. Gas chromatography-mass spectrometry (GC-MS) analysis identified 33 distinct components in the essential oil extracted via HD following ultrasonic pretreatment using NADES-5 as the solvent. This study illustrated that employing NADESs as the medium for ultrasonic pretreatment markedly improved the yield of essential oil derived from Cyperi Rhizoma, presenting a novel approach for effective essential oil extraction.