A sustainable approach to obtain polyphenols from Chilean wild murta, Ugni candollei B., and Ugni molinae T., using eutectic solvents and advanced extraction techniques

Murta, native to southern Chile, comprises red murta (Ugni molinae Turcz) and white murta (Ugni candollei Barm), traditionally utilized in ethnobotanical medicine for its anti-inflammatory and analgesic properties attributed to high flavonoid and phenolic acid content. Despite murta's potential, the combined effects of sustainable extraction techniques—eutectic solvents (ES), microwave-assisted extraction (MAE), and ultrasound-assisted extraction (UAE)—on its polyphenol profile remain unexplored. A comprehensive analysis should quantify extractable polyphenols (EPP) and non-extractable polyphenols (NEPP). This study evaluated eight ES mixtures for polyphenol extraction from red and white murta leaves and fruits, optimizing water percentage and feed:solvent ratio. Choline chloride:1,3-butanediol (ChCl:1,3BD) with 30 % water and a 1:10 ratio yielded the highest EPP content, as determined by HPLC-DAD. Among various MAE and UAE conditions tested, MAE at 353 K for 3 min achieved optimal phenolic compound yields, with catechin predominating in leaf extracts and gallic acid in fruit extracts. NEPP fractions, consisting primarily of non-extractable proanthocyanidins, represented 8–19 % of total polyphenols in fruits and leaves. These findings establish a sustainable methodology for obtaining polyphenol-rich extracts from murta and highlight the importance of both EPP and NEPP fractions in enhancing the potential of these antioxidant-enriched food extracts obtained through eco-friendly technologies.

This work was made possible thanks to funding from the Vice-Rectorate for Research of the P. Universidad Católica de Chile through the scholarship “Estadías en el Extranjero para Tesistas de Doctorado” awarded to N·F-J. Besides, M.V. was the recipient of a postdoctoral contract, “Margarita Salas” (Plan de Recuperación, Transformación y Resiliencia) from the Spanish Ministry of Universities/Madrid Autonomous University (CA1/RSUE/2021-00588). This work was also financially supported by the Comunidad Autónoma de Madrid (Spain) through the Multiannual Agreement with the Universidad Politécnica de Madrid in the Excellence Programme for University Professors line, in the context of the V PRICIT (Regional Plan of Research and Technological Innovation). Financial support was received from FONDECYT Regular project number 1230115. Authors also acknowledge grant PID2022-141965OB-C22 funded by MCIN/AEI/10.13039/501100011033 and by ‘ERDF A way of making Europe’, by the ‘European Union’.

Peer reviewed