Monitoring the Antiradical Efficacy and Acoustic Behavior of Quercetin in Choline-Tryptophan Ionic Liquid Medium at Different Temperatures

Abstract

Quercetin is a naturally occurring flavonoid that has potent antioxidant properties, however, its practical application which is limited by poor aqueous solubility and low bioavailability. Amino acid based ionic liquids (AAILs) have emerged as promising biocompatible solvents capable of enhancing the solubility and stability of bioactive compounds, yet the molecular interactions governing quercetin behavior in such media remain poorly understood. This study analyses the acoustic behavior of quercetin in aqueous choline-tryptophan ionic liquid ([Ch][Trp] IL) medium over a temperature range of 293.15–313.15 K. It provides insights into solute–solvent interactions, solvation behavior and structural arrangement in aqueous AAILs. Concentration led to higher ultrasonic velocity, but reduced isentropic compressibility. The proposed molecular interactions are consistent with the observed acoustic behavior and previous spectroscopic and volumetric studies of same system. Antioxidant activity was evaluated separately under standard ethanolic DPPH assay conditions using EC₅₀, TEC₅₀ and the antiradical efficiency parameter (AE). These analyses show that IL induces favorable molecular arrangement while preserving quercetin’s radical scavenging activity. The combined acoustic and antioxidant investigations provide valuable insight into the molecular organization of flavonoids in AAILs and highlight the potential of [Ch][Trp] as a promising biocompatible medium for flavonoid formulation and delivery.