The quest for sustainable and eco-friendly solutions in various fields, including natural product and food chemistry, has led to growing interest in natural deep eutectic solvents (NADES). The green extraction of rutin and total flavonoids from Ipomoea pes-caprae leaves was explored using four different NADES combined with ultrasound-assisted extraction (UAE). The NADES preparations included choline chloride, arginine, and β-alanine as hydrogen bond acceptors, paired with organic acids such as citric acid, and one diamide (urea) as hydrogen bond donors. Phytometabolomics analysis using UHPLC-QToF-MS/MS revealed various secondary metabolites. The citric acid:β-alanine NADES demonstrated superior extraction efficiency for rutin for the first time compared to conventional solvents and other NADES. The extraction process was further optimized using response surface methodology, evaluating four factors: extraction time, power output, extraction temperature, and vessel distance from the corner. The optimal extraction conditions were found to have an extraction time of 44.57 min, high power output, an extraction temperature of 57.13 °C, and a vessel distance of 14.48 cm from the corner. Using NADES with UAE yielded better recovery of rutin and total flavonoids compared with extraction methods such as reflux and maceration. The combined investigation of solubility studies, surface morphology, and molecular dynamics simulations provided comprehensive insights into the extraction mechanism. High-performance liquid chromatography (HPLC) analysis confirmed the absence of residual phytochemical carryover in the recovered NADES. The reusability and efficiency of the recycled NADES were further validated by comparable total flavonoid content (TFC) in subsequent extraction cycles, demonstrating the sustainability and robustness of the NADES system for bioactive compound recovery.
Sharma et al. (Wed,) studied this question.