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

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