Natural deep eutectic solvent extraction and evaluation of caffeine and chlorogenic acid from green coffee beans of coffea canephora

This study describes the optimization of a method that involves the use of the natural deep eutectic solvents, choline chloride-sorbitol for extracting caffeine and chlorogenic acid from green coffee beans of Coffea canephora. Extensive screening of conditions based on response surface methodology, Box-Behnken design allowed establishing optimal extraction conditions as 4:1 for the mole ratio of choline chloride-sorbitol, 60 min of extraction time, and 1:30 g/ml for the liquid-solid ratio, which yielded 5.87 mg/g of caffeine and 12.24 mg/g of chlorogenic acid. In case of the latter compound, this constitutes an increase of 297 % compared to the conventional maceration method. The evaluation of the extract obtained under optimal conditions for lipase inhibitory activity revealed that the extract inhibited porcine pancreatic lipase, with an IC₅₀ value of 32.46 μg/ml. The combination of a natural deep eutectic solvent with ultrasound-assisted extraction technology constituted the basis for the development of an environmentally friendly and easy-to-use extraction method.