Date Seeds (Phoenix dactylifera): Antioxidant Potential and Profile of Free and Bound Polyphenols from Different Cultivars

Abstract

In this study, the antioxidant activities and detailed phenolic profiling of extracts from seven cultivars of date seeds were investigated. Significant differences were detected among cultivars. Total phenolic content (TP) ranged between 135.9±12.1 and 284.86±21.9 mg GAE/g DM. The total flavonoid value varied between 34.20±0.34 and 94.46±1.04 mg RE/g DM. The condensed tannin ranged from 24.17±1.13 to 201.60±9.95 mg CTE/g DM. Phloroglucinolysis was used to depolymerize the bound polyphenols. Results show the presence of phenolic acids: Hydroxybenzoic acid, hydroxycinnamic acid, and a high amount of flavan‐3ols (monomers, dimers, and trimers). Before depolymerization, the highest amount of total polyphenols was identified in Kenta (8.48 g/kg) and the lowest was detected in Hessa (4.74 g/kg). After depolymerization, the flavan‐3‐ols increased significantly, ranging between 46.91g/kg in Hessa and 72.38 g/kg in Deglet Nour, with a high degree of polymerization (DP) in all cultivars. It can be concluded that date seeds represent a good source of bioactive compounds.

Screening factors to affect ultrasound-assisted extraction of (poly)phenols from date palm seeds

“…These differences from previous works can be due to the different extraction methods and studied cultivars. For example, the catechin content in the present work was around 1.5- and 3.8-fold of that reported by other authors ( Bettaieb et al, 2023 ; Ranasinghe et al, 2023 ; Muñoz-Tebar et al, 2024 ). However, generally, authors reported (poly)phenols of free fraction and rarely in insoluble-bound fraction.…”

“…Although other authors have reported the main (poly)phenol to be catechin, benzoic acid, or p -coumaric ( Bouhlali et al, 2020 ; Ranasinghe et al, 2023 ; Muñoz-Tebar et al, 2024 ), the profile is in agreement with previous reports on date palm ( Ghnimi et al, 2017 ). Moreover, the abundance of flavan-3-ols has been previously reported by Djaoudene et al (2021) in different Algerian cultivars of date seeds ( P. dactylifera L.), who reported four procyanidins (trimeric and dimeric and B1, B2, and B2 3-O-gallate), and Bettaieb et al, 2023 , who detected two dimeric and three trimeric procyanidins. Hilary et al (2020) also detected five procyanidins, mainly dimers and trimers of type B, and different classes of caffeoyl shikimic acids and glycosylated quercetins in date seeds of the Khalas variety.…”

“…The antioxidant potential of date palm seed extracts obtained through conventional methods and UAE was studied using two different in vitro antioxidant assays, namely, DPPH and FRAP. As shown in Table 2 , the values reported were slightly higher than those reported by Muñoz-Tebar et al (2024) and lower than those reported by Bettaieb et al (2023) . Compared with other vegetable sources with similar particle sizes and whose antioxidant activity was measured following the same protocols, the antioxidant activity of date palm seed extracts was higher than that of persimmon flour and quinoa ( Lucas-González et al, 2018 ; Pellegrini et al, 2018 ) but lower than that of cacao shell, especially the antioxidant activity determined using the ABTS method ( Botella-Martínez et al, 2021 ; Delgado-Ospina et al, 2021 ).…”

Phenolic Profiling, Antioxidant, and Antibacterial Activities of Selected Medicinal Plants from Tunisia

“…The modified Folin‐Ciocalteu method as described by Bettaieb et al., [74] was assessed to evaluate the total polyphenol content. The reaction mixture consisted of 100 μl of each extract (5 %), 0.5 ml Folin‐Ciocalteu reagent (1/10 in water) and 4 ml sodium carbonate solution (Na 2 CO 3 , 1 M).…”