Polyphenolic Profile and in vitro Antioxidant Activity of Three Algerian Date (Phoenix dactylifera) Varieties

Abstract

As known, dates are packed with antioxidants and bioactive compounds and provide various health benefits, as evidenced by their varying nitrite levels. Algerian dates, on the other hand, have not been thoroughly investigated for their bioactive compounds and overall antioxidant capacity. This research aims to tap into this potential by meticulously measuring total polyphenols, flavonoids, and condensed tannins in three popular Algerian varieties (Phoenix dactylifera L.) Ksiba, Hamraya, and Deglet Nour, and the determination of their antioxidant activity using (scavenging assays of 2,2-diphenyl-1-picryhydrazyl (DPPH) and 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, reducing power, and total antioxidant capacity. The analysis showed that the three varieties of date fruits are rich in total phenolics with an amount ranging between 71±51 and 7975±389 mg of gallic acid equivalent (GAE).100 g-1 of dry weight (DW), the flavonoid amount ranged from 31±3 to 767±4 mg of quercetin equivalent (QE) 100 g-1 DW and condensed tannins between 6± 2 and 653 ±64 mg of catechin equivalent (CE) 100 g-1 dry DW. The antiradical activity was quite promising and ranged between 0.5 and 24 µg AAE mg-1 extract for DPPH and between 2 and 113 µg AAE mg-1 extract for ABTS, while the reducing power and total antioxidant capacity values ranged from 16 to 154 μg ascorbic acid (AAE) mg-1 and 39 to 68 μg AAE mg-1 extract respectively. The results of this study show that Algerian date fruit can be regarded as a potential natural source of antioxidants, with ethyl acetate serving as the best extractant solvent, resulting in higher polyphenol content and antioxidant activities.