A Sustainable Extraction Approach of Phytochemicals from Date (Phoenix dactylifera L.) Fruit Cultivars Using Ultrasound-Assisted Deep Eutectic Solvent: A Comprehensive Study on Bioactivity and Phenolic Variability

Ouarda Djaoudene; Mostapha Bachir-Bey; Connie Schisano; Sabrina Djebari; Gian Carlo Tenore; Anabela Romano

doi:10.3390/antiox13020181

A Sustainable Extraction Approach of Phytochemicals from Date (Phoenix dactylifera L.) Fruit Cultivars Using Ultrasound-Assisted Deep Eutectic Solvent: A Comprehensive Study on Bioactivity and Phenolic Variability

Antioxidants (Basel). 2024 Jan 31;13(2):181. doi: 10.3390/antiox13020181.

Authors

Ouarda Djaoudene¹, Mostapha Bachir-Bey², Connie Schisano³, Sabrina Djebari⁴, Gian Carlo Tenore³, Anabela Romano⁵

Affiliations

¹ Centre de Recherche en Technologies Agroalimentaires, Route de Targa Ouzemmour, Campus Universitaire, Bejaia 06000, Algeria.
² Laboratory of Applied Biochemistry, Department of Food Sciences, Faculty of Natural and Life Sciences, University of Bejaia, Bejaia 06000, Algeria.
³ Department of Pharmacy, University of Naples Federico II, 80131 Napoli, Italy.
⁴ Laboratory of Biomathematic, Biophysic, Biochemistry and Scientometry, Faculty of Natural and Life Sciences, University of Bejaia, Bejaia 06000, Algeria.
⁵ MED-Mediterranean Institute for Agriculture, Environment and Development, CHANGE-Global Change and Sustainability Institute, Faculdade de Ciências e Tecnologia, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.

Abstract

The present study aimed to evaluate the efficacy of natural deep eutectic solvents (NADESs) on the extraction of phytochemicals from eight Algerian date fruit cultivars (Phoenix dactylifera L.). In this study, lactic acid/sucrose-based NADESs were used as an alternative to conventional chemical solvents using the ultrasound-assisted extraction (UAE) method. The obtained extracts were assessed for the determination of bioactive compound contents, phenolic composition, antioxidant activity, and enzyme inhibitory potential. The results showed a considerable variation in phytochemical compositions and related activities between cultivars, where the greatest contents of total phenolics (1288.7 mg GAE/100 g), total flavonoids (53.8 mg QE/100 g), proanthocyanidins (179.5 mg CE/g), and total triterpenoids (12.88 mg OAE/100 g) were detected in the fruits of the Ourous cultivar. The same cultivar displayed the highest antioxidant capacity against DPPH^• free radical (595 mg AAE/100 g), ABTS^•+ cation radical (839 mg TE/100 g), and ferric reducing antioxidant potential (704 mg AAE/100 g). All extracts manifested moderate antioxidant activities tested by phosphomolybdenum, NO^•, and linoleic acid lipid peroxidation assays. These extracts also exhibited interesting levels of in vitro enzyme inhibition; the Ourous cultivar gave the best inhibitory activity against α-amylase and acetylcholinesterase with 45 and 37%, respectively. HPLC-DAD-MS detected a total of five compounds, with phenolic acids and flavonoids being the main phenolics identified in the extract. The phenolic composition exhibited significant variability among cultivars. Notably, the highest amounts were revealed in the Tazizaout cultivar, with the predominance of gallic acid. The results confirmed that the combination of UAE and NADESs provides a novel and important alternative to chemical solvents for sustainable and environmentally friendly extraction and can represent a good alternative in food and pharmaceutical industry applications.

Keywords: Phoenix dactylifera fruits; antioxidant activity; enzyme inhibition; green extraction; natural deep eutectic solvents; phytochemicals; ultrasound-assisted extraction.

Grants and funding

This research received no external funding.