Ultrasound-assisted deep eutectic solvent–based extraction of phytochemicals from Mentha arvensis: optimization using Box-Behnken design

In the present study, choline chloride–based solvents (eutectics of choline chloride with ethylene glycol and malic acid) were prepared and used for the extraction of bioactive compounds from Mentha arvensis. The extraction of bioactive compounds was carried out by ultrasound-assisted extraction (UAE). The optimization of extraction parameters like time, temperature, and biomass to solvent ratio was done using Box-Behnken design (BBD). The highest quantities of total phenolic contents (TPC) 125 ± 4.0 mg GAE/g dry matter, total flavonoid contents (TFC) 95 ± 3.5 mg QE/g dry matter, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical inhibition 95% were assessed with choline chloride/ethylene glycol solvent. The choline chloride and ethylene glycol–based deep eutective solvents (DES) extracts showed significant antibacterial (S. aureus = 35.5 ± 1.4 mm, E. coli = 33.5 ± 1.4 mm) and antifungal activities (F. solani = 34.5 ± 1.44 mm, A. niger = 37.5 ± 1.4 mm) using Rifampicin and Terbinafine standards, respectively. The results indicate the ehanced extraction ability of these DESs over conventional aqueous methanol. The DESs are evidenced as one of the best substitutes for the extraction of bioactive ingredients from medicinal plants.