Eco-friendly extraction of six different rosemary (Rosmarinus officinalis L.) genotypes-using natural deep eutectic solvents: Optimization and modeling via response surface methodology (RSM)

New environmentally friendly extraction methods and solvents such as ultrasound assisted extraction (UAE) and natural deep eutectic solvents (NADES) are replacing the traditional extraction methods with organic solvents. In the present study, NADES prepared with choline chloride 1,2-propylene glycol (ChCl-PG) were characterized and running parameters for the UAE process of phenolics were optimized and modeled with response surface methodology (RSM) using ChCl-PG. The optimum conditions obtained from running parameters were used to compare efficiency of NADES with four traditional solvents and NADES was found to be for phenolics extraction from rosemary. Experimental data was used to maximize extraction yields of phenolics and antioxidant activities, rosmaranic acid, chlorophyll and carotene content using six rosemary genotypes under optimal conditions with NADES and a traditional solvent (ethanol:water, 80:20 v/v) with UAE. Rosemary genotypes showed significant differences for bioactive compound yields except chlorophyll and carotene content. NADES and traditional solvents did not affect rosmarinic acid and carotenoid yield, but extraction yield of other compounds and their antioxidant capacities were significantly affected by the solvent. While rosmarinic acid content was not affected, chlorophyll and carotenoid contents were affected by the solvent type. Out of 21 Pearson correlation coefficients, 5 and 7 had significant positive correlations between traditional and NADES solvents, respectively. Results showed that NADES with UAE is an effective method could be used for extraction of secondary compounds.