Comparison of Deep Eutectic Solvent-based Ultrasoundand Heat-assisted Extraction of Bioactive Compounds from Withania somnifera and Process Optimization Using Response Surface Methodology

Abstract

Extraction of bioactive compounds from Withania somnifera roots was studied using sodium acetate-glycerol deep eutectic solvent (DES) and two techniques of extraction: ultrasound-assisted extraction (UAE) and heat-assisted extraction (HAE) under response surface methodology (RSM). For UAE and HAE, total phenolic content (TPC, mg gallic acid equivalents per g dry weight (mg GAE g–1 DW)), total flavonoid content (TFC, mg rutin equivalents g–1 DW (mg RE g–1 DW)), radical scavenging activity (RSA, mg AAE (ascorbic acid equivalents) g–1 DW), and iron chelating activity (ICA, mg EDTAE (ethylenediaminetetraacetate equivalents) g–1 DW) were 6.51, 6.08, 12.56, and 3.57, respectively, and 3.33, 3.98, 6.57, and 2.48, respectively. For UAE, the optimal conditions were a DES concentration of 50%, temperature of 60 °C, and time of 20 min, and for HAE, a DES concentration of 60%, temperature of 60 °C, and time of 75 min. The discovered models were strongly supported by the validation experiments. UAE was more efficient and less time-consuming for extracting phytoconstituents of the W. somnifera than HAE.