Green extraction of Glycyrrhizic acid from Glycyrrhiza glabra using choline chloride based natural deep eutectic solvents (NADESs)

Natural Deep Eutectic Solvents (NADESs) have attracted growing interest in the scientific community as an alternative to conventional organic solvents and are exclusively made up of naturally occurring non-toxic, environment friendly compounds. In the present study, NADESs based on choline chloride and carboxylic acids are presented as new and green extraction media for glycyrrhizic acid (GA) extraction from Glycyrrhiza glabra. Initial solvent screening indicated that the highest extraction yield was achieved using choline chloride-lactic acid mixture at mole ratio 1:1. Various extraction conditions were optimized, such as 30 % water in choline chloride:lactic acid NADES, liquid/solid ratio 40:1 (v/w, mL/g), temperature 40℃, agitation speed 400 rpm, and extraction time 30 min yielding 53.72 ± 0.57 mg/g GA. The NADES extraction method successfully provided enhanced yield and improved in-vitro anti-inflammatory activity, which was assessed using human red blood cell membrane stabilization method. In addition, it was found to be energy efficient and economical compared to conventional extraction techniques. SEM was performed to study the surface morphology of Glycyrrhiza glabra powder before and after extraction. Also, FTIR was used to provide information about hydrogen bonding in NADES. The results presented valuable information towards NADES implementation for designing of extraction process for bioactive compounds.