Phenolic compounds and polysaccharides in the date fruit (Phoenix dactylifera L.): Comparative study on five widely consumed Arabian varieties

Punica granatum L. polysaccharides: A review on extraction, structural characteristics and bioactivities

Punica granatum L., commonly known as pomegranate, is native to Afghanistan and Iran, and today widely cultivated all over the world. Pomegranate polysaccharides are one of the most important bioactive components of P. granatum, which have a wide range of beneficial biological activities, such as anticancer, immunostimulatory, hepatoprotection, anti-psoriasis and antioxidation. Hot water extraction is currently the most commonly used method to isolate pomegranate polysaccharides. The structural characteristics of pomegranate polysaccharides have been extensively investigated through various advanced modern analytical techniques. This review focuses on the extraction, purification, structural characteristics, biological activities and structure-activity relationships of polysaccharides from Punica granatum. The aim of this article is to comprehensively and systematically summarize recent information of polysaccharides from Punica granatum and to serve as a basis for further research and development as therapeutic agents and functional foods.

Valorization of Date Fruit (Phoenix dactylifera L.) as a Potential Functional Food and Ingredient: Characterization of Fiber, Oligosaccharides, and Antioxidant Polyphenols

The fruit of the date tree (Phoenix dactylifera L.) is increasingly recognized for its nutritional and functional value. This exotic fruit shows variable composition, influenced by factors such as variety, ripening stage, and climatic conditions. In this context, this study aimed to investigate the nutritional profile and the bioactive components, including phenolic compounds and oligosaccharides, in different varieties of dates from Saudi Arabia collected at the Tamr ripening stage. The HPLC-ESI-MS analysis identified a total of 15 phenolic compounds, principally phenolic acids and flavonoids. Among the varieties tested, Safawi exhibited the highest phenolic concentration (1132 µg/100 g dw). To the best of our knowledge, the oligosaccharide composition is described for the first time among different varieties, with Sukari showing the highest concentration (3.37 g/100 g dw). Moreover, the antioxidant capacity (DPPH, ABTS, and FRAP assays) was assessed following a solid-phase extraction (SPE) clean-up to remove interferents, especially sugars. These results provide valuable insights into the health-promoting properties of date fruit as a functional food and provide a foundation for further research into their industrial applications as functional ingredients.

Chemical Characterization of Phoenix dactylifera L. Seeds and their Beneficial Effects on the Vascular Response in Hypertensive Rats

Although Phoenix dactylifera dates are traditionally consumed for their health benefits, no research has been done on the vascular response in hypertensive animals. This study evaluated the vascular relaxation of hydroalcoholic extracts from seeds of three varieties of P. dactylifera; Sukkari seed (SS), Ajwa seed (AS), and Mabroom seed (MS) on L-NAME-induced hypertension and spontaneously hypertensive rats (SHR). Results showed that all extracts (10 µg/mL) caused relaxations higher than 60% in the aortic rings precontracted with 10- 6 M phenylephrine in normotensive rats, the SS extract was the most potent. Endothelial nitric oxide (NO) pathway is involved as significantly reduced vascular relaxation in denuded-endothelium rat aorta and with an inhibitor (10- 4 M L-Nω-Nitro arginine methyl ester; L-NAME) of endothelial nitric oxide synthase (eNOS). Confocal microscopy confirmed that 10 µg/mL SS extract increases NO generation as detected by DAF-FM fluorescence in intact aortic rings. Consistent with these findings, vascular relaxation in intact aortic rings at 10 µg/mL SS extract was significantly decreased in L-NAME-induced hypertensive rats (endothelial dysfunction model), but not in SHR. In both hypertensive models, the denuded endothelium blunted the vascular relaxation. In conclusion, the hydroalcoholic extract of the seed of P. dactylifera (Sukkari, Ajwa and Mabroom varieties) presents a potent endothelium-dependent vascular relaxation, via NO, in normotensive rats as well as in two different models of hypertension. This effect could be mediated by the presence of phenolic compounds identified by UHPLC-ESI-MS/MS, such as protocatechuic acid, and caftaric acid.

Comparison of phenolic composition in Australian-grown date fruit (Phoenix dactylifera L.) seeds from different varieties and ripening stages

In this research, different seeds of Australian-grown date palm (Phoenix dactylifera L.) were studied to evaluate the antioxidant potential and analyze their phenolic constituents. Phenolic compounds were extracted from seeds of various Australian-grown date varieties at different ripening stages. Eight varieties of date seeds (Zahidi, Medjool, Deglet nour, Thoory, Halawi, Barhee, Khadrawy, and Bau Strami) at three ripening stages (Kimri, Khalal, and Tamar) were investigated in this study. Date seeds at Khalal (9.87-16.93 mg GAE/g) and Tamar (9.20-27.87 mg GAE/g) stages showed higher total phenolic content than those at Kimri stage (1.81-5.99 mg GAE/g). For antioxidant assays like DPPH, FRAP, ABTS, RAP, FICA, and TAC, date seeds at Khalal and Tamar stages also showed higher antioxidant potential than Kimri stage. However, date seeds at Kimri stage (55.24-63.26 mg TE/g) expressed higher radical scavenging activity than Khalal (13.58-51.88 mg TE/g) and Tamar (11.06-50.92 mg TE/g) stages. Phenolic compounds were characterized using LC-ESI-QTOF-MS/MS, revealing the presence of 37 different phenolic compounds, including 8 phenolic acids, 18 flavonoids, and 11 other phenolic compounds. Further, phenolic compounds were quantified using LC-DAD, revealing that Zahidi variety of date seeds exhibited the highest content during the Kimri stage. In contrast, during the Khalal and Tamar stages, Deglet nour and Medjool date seeds displayed higher concentrations of phenolic compounds. The results indicated an increase in phenolic content in date seeds after the Kimri stage, with significant variations observed among different date varieties.

Structural characterization, chain conformation and immunomodulatory activity of a heteropolysaccharide from Inonotus hispidus

A new polysaccharide (IHP-1aa) was isolated from the fruiting body of Inonotus hispidus by hot water extraction, ethanol precipitation and column chromatography. The molecular weight of IHP-1aa was 26.9 kDa. Structural analysis showed that IHP-1aa consisted of glucose (Glc), galactose (Gal), fucose (Fuc), mannose (Man) and contained a certain amount of 3-O-methylgalactose (3-O-Me-Gal). The structure was mainly composed of →6)-α/β-D-Glcp-(1→, →6)-α-D-Galp-(1→, →6)-(3-O-Me)-α-D-Galp-(1→, →6)-α-D-Manp-(1 → and →2, 6)-α-D-Galp-(1 → as the main chain. Branched at O-2 with single β-L-Fucp-(1 → 6)-α-D-Galp-(1 → 6)-α-D-Glcp-(1 → as major the side chain. The results of SEM, XRD and AFM combined with Congo red indicated that IHP-1aa may be amorphous granular chain conformation. In addition, IHP-1aa stimulated macrophage function and improved phagocytic ability of RAW264.7, as well as promoted the secretion of NO, TNF-α and IL-6. IHP-1aa, a 3-O-methylgalactose-containing heteropolysaccharide, was isolated for the first time from the I. hispidus, which may be used as a potential immunomodulator in functional foods.

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

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.

Polysaccharides and Phenolic Compounds Recovered from Red Bell Pepper, Tomato and Basil By-Products Using a Green Extraction by Extractor Timatic®

Fruits and vegetables processing produces significant amounts of by-products rich in valuable bioactive compounds such as polyphenols and dietary fiber. Food by-product re-use promotes the eco-sustainability of several crops. This study aimed to apply green extractions of bioactive compounds from by-products of basil, tomato, and red bell pepper production. Tests were performed by applying extraction procedures both at laboratory scale and using the Timatic® extractor. Water and ethanol 10% and 20% were used for extraction of red bell pepper and tomato, testing different temperatures (30, 50, and 90 °C; water at 90 °C and ethanol 20% were applied for basil. The obtained phenolic extracts were analyzed by HPLC-DAD-MS. Polysaccharides of tomato and red bell pepper were extracted at laboratory scale and chemically characterized using 1H-NMR to define the methylation and acylation degree, and DLS to estimate the hydrodynamic volume. Laboratory extraction tests allowed efficient scaling-up of the process on the Timatic® extractor. Phenolic content in the dried extracts (DE) ranged 8.0-11.2 mg/g for tomato and red bell pepper and reached 240 mg/g for basil extracts. Polysaccharide yields (w/w on DM) reached 6.0 and 10.4% for dried tomato and red bell pepper, respectively. Dry extracts obtained using the Timatic® extractor and water can be useful sources of bioactive phenols. The study provided new data on tomato and red bell pepper polysaccharides that may be useful for future applications.

Extraction, Characterization, and Antioxidant Activity of Polysaccharides from Ajwa Seed and Flesh

The date palm has been cultivated in dry and hot areas of the planet for much of human history. In the Kingdom of Saudi Arabia, dates are the main crop used as a source of food. Among several species of date fruits, the Ajwa AL-Madinah date is unique, growing only in Al-Madinah geographical region. The Ajwa date is used in traditional medicine due to its abundant active components and therapeutic properties. This study investigates the structural properties and the antioxidant effects of water-soluble polysaccharides extracted from Ajwa flesh and seed. The polysaccharides were isolated by two techniques including hot water and ultrasonic extraction. After isolation and partial purification, the physicochemical properties of four samples of polysaccharides extracted from flesh and seed were studied by several techniques including FTIR, solid-state NMR, elemental analysis, and mass spectrometry. Several radical scavenging experiments were combined to study the antioxidant activity of the polysaccharide compounds. FTIR and NMR results showed a structure typical of heterogeneous polysaccharides. Mass spectrometry revealed that the polysaccharide samples were composed mainly of mannose, glucose, galactose, xylose, arabinose, galacturonic acid, and fucose. In addition, the physicochemical properties and composition of polysaccharides extracted from flesh and seed were compared. The extracted polysaccharides showed antioxidant activity, with 2, 2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, Fe chelating ability, hydroxyl free radical scavenging ability, and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging. These results highlight their potential to be a useful nutritional element or supplemental medication.