Natural deep eutectic solvents ultrasound-assisted extraction (NADES-UAE) of trans-cinnamaldehyde and coumarin from cinnamon bark [Cinnamomum burmannii (Nees & T. Nees) Blume]

Abstract

Natural deep eutectic solvents (NADES) have been shown to be more effective in extracting plant markercompounds than are organic solvents. In this study, mixtures of choline chloride or betaine with three combinations ofsugar molecules (glycerol, xylitol, and sorbitol) and three combinations of organic acids (lactic acid, citric acid, andmalic acid) were used as solvents in ultrasonic-assisted extraction (UAE) of trans-cinnamaldehyde and coumarin fromcinnamon bark [Cinnamomum burmannii (Nees & T. Nees) Blume]. Optimization of extraction conditions to obtain theoptimal trans-cinnamaldehyde content was performed by varying the percentage of water in NADES and extractiontime. Efficiency of extraction was determined by conventional extraction performed by maceration, reflux, and thesoxhlet method using 96% ethanol for comparison. Trans-cinnamaldehyde and coumarin contents were determined byhigh-performance liquid chromatography. The surfaces of samples before and after extraction were observed byscanning electron microscopy (SEM). The study results showed that choline chloride–citric acid (1:2) with 40% wateraddition for 30 minutes produced the highest trans-cinnamaldehyde content of 9.24 ± 0.01 mg/g dry weight. The highesttrans-cinnamaldehyde content from conventional extraction using the maceration method was 1.93 ± 0.01 mg/g dryweight. SEM analysis of sample surfaces showed that the ruptured cells in the NADES-UAE method gave a highertrans-cinnamaldehyde yield than that from the shrunken and damaged cells in the conventional extraction. NADESUAE provided higher extraction efficiency for trans-cinnamaldehyde and coumarin from C. burmannii than that of theconventional methods using 96% ethanol as solvent.