Jovanović, Aleksandra A. Krgović, Nemanja Živković, Jelena Šavikin, Katarina info:eu-repo/semantics/article eng https://phaidrabg.bg.ac.rs/o:38650 doi:https://doi.org/10.1016/j.fbp.2026.04.008 http://creativecommons.org/licenses/by-nc-sa/4.0/legalcode Extraction, Natural deep eutectic solvent, Sustainable recovery, Polyphenols, Ultrasound probe, Wild thyme Elsevier application/pdf 3460758 bytes Eco-Friendly Valorization of Wild Thyme Processing Residue: Ultrasound Probe-Assisted Extraction Using Tailored Natural Deep Eutectic Solvents and Evaluation of Antioxidant Activity number: 157 startpage: 610 endpage: 628 The agro-industrial byproducts’ valorization represents an important strategy for sustainable bioresource utilization. Wild thyme residue remains an underexplored, valuable compound source, while conventional solvents pose environmental concerns. However, natural deep eutectic solvents-NADES have emerged as promising green alternatives due to low toxicity and high extraction efficiency. The presented study aims to investigate the recovery of these byproduct compounds using ultrasound probe-assisted NADES extraction. The NADESs and resulting extracts were comprehensively characterized through multiple physicochemical parameters, quantification of phenolics, and antioxidant activity. Citric acid- and lactic acid/salt-based NADESs, and malic acid or urea+glycerol (1:2 ratio) exhibited enhanced phenolic extraction (~31.9-57.4% and ~7.8-28.6% higher than in water and ethanol samples). Urea-based NADES provided the highest flavonoid content (16.38-24.42 mg CE/g) in comparison to other NADESs. Multivariate analysis revealed a significant impact of pH and electrical conductivity on flavonoid and protein extraction, while polyphenol recovery is additionally affected by viscosity. HPLC analysis revealed that solvent composition strongly influenced selective phenolic extraction: citric acid or malic acid+glycerol (1:2 ratio) yielded the highest concentrations of rosmarinic acid (~432-438 μg/mL) and luteolin-7-O-glucuronide (~115-119 μg/mL), respectively. Regarding HPLC data, pH, conductivity, and viscosity predominantly govern the selective extraction of individual polyphenols. Radical scavenging activity strongly depended on NADES composition, with the lactic acid+sodium acetate (3:1 ratio) exhibiting the highest activity in both DPPH and ABTS assays (IC₅₀ ~109.14 and ~40.23 µg/mL). These results highlight the critical role of NADES composition in optimizing the solubilization of bioactive compounds, suggesting their potential as sustainable alternatives for plant-based extract production. 2026 Eco-Friendly Valorization of Wild Thyme Processing Residue: Ultrasound Probe-Assisted Extraction Using Tailored Natural Deep Eutectic Solvents and Evaluation of Antioxidant Activity