Optimization of extraction process and estimation of flavonoids from fenugreek using green extracting deep eutectic solvents coupled with ultrasonication

Abstract

Abstract The extraction of flavonoids from fenugreek seeds was investigated using ultrasound-assisted deep eutectic solvents (DES). On the basis of bioactive profile, antioxidant potential and antimicrobial properties of fenugreek extracts, the most effective DES were selected after carefully analyzing the physicochemical properties of DES. The results suggested that all the six DES performed better than conventional solvent (methanol) and among DES, choline chloride-mallic acid (CCMA), choline chloride-citric acid (CCCA) and choline chloride-1,4-butanediol (CCBU) performed better under set conditions and further selected for optimization of processing conditions, including molar ratios, water required for dilution of DES, sonication power, sonication time and sonication temperature. Identification and quantification of the flavonoids present in optimized-DES extracts was carried out using HPLC-DAD. The results revealed that prominent individual flavonoid compounds were kaempferol (10.65 ± 0.49), rutin (18.33 ± 0.84) and quercetin (10.82 ± 0.59) mg/gm d.w. with recovery percentages of as 78.83%, 92.69% and 87.18% respectively. After analyzing the results of HPLC we can conclude that CCMA (DES) is a safer, greener and highly efficient extraction system for maximum and sustainable extraction of flavonoids compounds from fenugreek seeds.