Natural Deep Eutectic Solvents and Ultrasound-Assisted Extraction for the Green Recovery of Bioactive Compounds from Gunnera tinctoria Mol.

Nalca (Gunnera tinctoria Mol.) is traditionally consumed for its edible petioles and valued for medicinal properties associated with its bioactive compounds. In this study, natural deep eutectic solvents (NADESs) were synthesized and applied for the ultrasound-assisted extraction of phenolic compounds and alkaloids from Nalca leaves. NADES synthesis was confirmed using 1H NMR, and their physicochemical properties were evaluated to assess their influence on extraction efficiency. The extracts showed total phenolic contents ranging from 6.8 to 142.6 mg GAE/g DW and total alkaloid contents ranging from 0.2 to 3.2 mg OXIE/g DW, depending on solvent composition. Antioxidant activity, evaluated using DPPH and FRAP assays, confirmed that most NADES extracts exhibited significant radical-scavenging and ferric-reducing capacities, generally correlating with phenolic content. The extraction yields obtained with specific NADES formulations were comparable or superior to those achieved with conventional solvents, demonstrating their efficiency. These results demonstrate that NADESs are effective and environmentally friendly alternatives to conventional solvents for extracting bioactive compounds from Nalca leaves. The physicochemical properties of NADESs enable the selective extraction of different metabolite classes, highlighting their potential for green extraction processes in food, nutraceutical, and pharmaceutical applications.