Author(s):
Pavlić, Branimir ; Mrkonjić, Živan ; Teslić, Nemanja ; Kljakić, Aleksandra Cvetanović ; Pojić, Milica ; Mandić, Anamarija ; Stupar, Alena ; Santos, Filipa ; Duarte, Ana Rita C. ; Mišan, Aleksandra
Date: 2022
Persistent ID: http://hdl.handle.net/10362/143805
Origin: Repositório Institucional da UNL
Subject(s): Antioxidant activity; NADES; Polyphenols; RSM optimization; Thymus serpyllum L; Analytical Chemistry; Chemistry (miscellaneous); Molecular Medicine; Pharmaceutical Science; Drug Discovery; Physical and Theoretical Chemistry; Organic Chemistry
Description
Funding Information: info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDB%2F50006%2F2020/PT Funding: This research was supported by the Science Fund of the Republic of Serbia, 6060592, Natural Deep Eutectic Solvents for Green Agri-Food Solutions—DEStiny and 7750168, Novel extracts and bioactive compounds from under-utilized resources for high-value applications—BioUtilize. This project received funding from the European Union’s Horizon 2020—European Research Council (ERC)—under grant agreement No ERC-2016-CoG 725034. T Funding Information: This research was supported by the Science Fund of the Republic of Serbia, 6060592, Natural Deep Eutectic Solvents for Green Agri-Food Solutions?DEStiny and 7750168, Novel extracts and bioactive compounds from under-utilized resources for high-value applications?BioUtilize. This project received funding from the European Union?s Horizon 2020?European Research Council (ERC)?under grant agreement No ERC-2016-CoG 725034. Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
Wild thyme (Thymus serpyllum L.) herbal dust has been recognized as a potential underutilized resource for the recovery of antioxidants. The aim of this paper was to optimize natural deep eutectic solvent (NADES) extraction of polyphenols to obtain improved antioxidant activity of extracts determined by selected in vitro assays (DPPH, FRAP, and ABTS). Twenty different NADES systems were investigated in the first step of the screening of the extraction solvent and L-proline (Pro)–glycerine (Gly) based solvents provided the best results. Preliminary experiments organized by 25−1 fractional factorial design narrowed down the number of extraction factors from five (temperature, extraction time, NADES type, water content and L/S ratio) to three and determined their experimental domain for the final step. A face-centered central composite design with temperature (40–55–70 °C), extraction time (60–120–180 min) and L/S ratio (10–20–30 g NADES/g sample) was applied for influence analysis and process optimization. Multi-response optimization suggested a temperature of 65 °C, time of extraction of 180 min and L/S ratio of 28 g NADES/g DW as optimal extraction parameters. Experimental validation confirmed good agreement between experimental and predicted results in the extract obtained at optimal conditions and the interactions in the most suitable NADES (N16; Pro–Gly–H2O; 1:2:1) were confirmed by the1H-NMR.
