Enhancing date seed phenolic bioaccessibility in soft cheese through a dehydrated liposome delivery system and its effect on testosterone-induced benign prostatic hyperplasia in rats

Introduction

The consumption of dairy products, including soft cheese, has been associated with numerous health benefits due to their high nutritional value. However, the phenolic compounds bioaccessibility present in soft cheese is limited due to their poor solubility and stability during digestion. So, this study aimed to develop an innovative soft cheese enriched with date seed phenolic compounds (DSP) extracted ultrasonically and incorporated into homogeneous liposomes and study its attenuation effect on testosterone-induced benign prostatic hyperplasia (BPH) in rats.

Methods

Date seed phenolic compounds were extracted using 98 and 50% ethanol along with water as solvents, employing ultrasonication at 10, 20, and 30-min intervals. The primary and secondary DSP-liposomes were prepared and dehydrated. The particle size, zeta potential, encapsulation efficiency, and morphology were measured. Incorporating dehydrated liposomes (1-3% w/w) into soft cheese and their impact on BPH using male Sprague-Dawley rats was assessed. After inducing BPH, rats were fed a cheese diet with dehydrated DSP-liposomes. Over 8 weeks, parameters including nutrition parameters, prostate enlargement analysis, biochemical parameters, hormones level, oxidative stress, and cytokines were analyzed.

Results and Discussion

The results showed that ultrasound-assisted extraction effectively reduced the extraction time and 30 min extraction EtOH 50% was enough to extract high yield of phenolic compounds (558 mg GA/g) and flavonoids (55 mg qu/g) with high antioxidant activity (74%). The biological results indicate that prostate weight and prostate index% were diminished in the treatment groups (1 and 2) compared to the BPH control group. The high antioxidant content present in the DSP-liposomes acted as the catalyst for suppressing the responses of the inflammatory cytokines, inhibiting the anti-inflammatory IL-10 production, and suppressing the elevated levels of lipid peroxidation products compared to the BPH group.

Conclusion

The treatment group (2) supplemented with dehydrated secondary DSP-liposomes exhibited the most significant variance (p < 0.05) as opposed to the BPH group. Liposomal encapsulation was proved to be a feasible approach for administering DSP in soft cheese, thereby establishing new functional food category possessing prophylactic properties against the advancement of BPH in rats.

Nutritional, medicinal and functional properties of different parts of the date palm and its fruit (Phoenix dactylifera L.) - A systematic review

Appraised for being one of the oldest staple nutritive foods mainly in the Arabian Peninsula, the date palm tree (Phoenix dactylifera L.), is a crop native to the subtropical and tropical regions of Southern Asia and Africa. Different parts of the date tree have been extensively studied for their nutritional and therapeutic properties. Despite an array of publications on the date tree, there has been no attempt to compile in a single study the traditional uses, nutritive value, phytochemical profile, the medicinal properties as well as the potential of the different plant parts as a functional food. Therefore, this review endeavors to systematically review the scientific literature to highlight the traditional uses of date fruit and parts around the world, the nutritional profile of several parts and the medicinal properties. A total of 215 studies was retrieved (traditional uses (n = 26), nutritional (n = 52), and medicinal (n = 84)). Scientific articles were further categorized as in vitro (n = 33), in vivo (n = 35), and clinical (n = 16) evidences. Date seeds were found to be effective against E. coli and Staphylococcus aureus. Aqueous date pollen was used to manage hormonal problems and boost fertility. Palm leaves showed anti-hyperglycemic effects via inhibition of α-amylase and α-glucosidase. Unlike previous studies, this study highlighted the functional roles of all the plant parts of the palm tree and provided insights into the various mechanism of action of their bioactive compounds. Although scientific shreds of evidence have been growing over the years, there is still a dearth of studies concerning the clinical validation of the date fruit and other plant parts to provide strong evidence on their medicinal uses. In conclusion, P. dactylifera can be regarded as a potent medicinal plant with prophylactic potential and should be further explored to alleviate the burden of both communicable and non-communicable diseases.

Optimization of Extraction Parameters and Characterization of Tunisian Date Extract: A Scientific Approach Toward Their Utilization

The response surface methodology (RSM) was used in order to select the extraction conditions of extract from Kentichi date powder; a by-product of the date-processing process. Powder/solvent ratio, extraction temperature, and extraction time all had an impact on sugar yield, and these model factors have quadratic effects influencing sugar yield. Optimal extraction was obtained with 300 g/L powder/solvent ratio, 32.7 °C extraction temperature, and 2.1 h extraction time. Under these conditions, Kentichi date powder's (KDP) sugar yield was 77.1%, which was close to the predicted value of the model (80.50%). The results of Kentichi date powder extract (KDPE) showed that the total sugar content is 160.09 g/L. However, the protein content is 10.31 g/L with a majority of the essential amino acids (essentially glutamic acid (28.39 mg/L) and aspartic acid (9.65 mg/L)). The determination of antioxidant activity of KDPE showed a high activity (DPPH IC₅₀ = 4.8 mg/mL, ABTS IC₅₀ = 3 mg/mL, FRAP = 4.70 μmol AAE/mL and, TAA = 18.04 μmol Fe(II)/mL). The results show also that the freeze-drying technique has a lot of potential for producing powder from KDPE with many desirable properties. The findings indicate that KDPE with a high nutritional value could be used as a component for the formulation of functional foods.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12355-022-01223-2.

Extraction and characterization of phenolic compounds and their potential antioxidant activities

For thousands of years, plant has been widely applied in the medical area and is an important part of human diet. A high content of nutrients could be found in all kinds of plants, and the most outstanding group of nutrients that attracts scientists' attention is the high level of phenolic compounds. Due to the relationship between high phenolic compound content and high antioxidant capacity, plant extracts are expected to become a potential treatment for oxidation stress diseases including diabetes and cancer. However, according to the instability of phenolic compounds to light and oxygen, there are certain difficulties in the extraction of such compounds. But after many years of development, the extraction technology of phenolic compounds has been quite stable, and the only problem is how to obtain high-quality extracts with high efficiency. To further enhance the value of plant extracts, concentration and separation methods are often applied, and when detailed analysis is required, characterization methods including HPLC and LC/GC-MS will be applied to evaluate the number and type of phenolic compounds. A series of antioxidant assays are widely performed in numerous studies to test the antioxidant capacity of the plant extracts, which is also an important basis for evaluating value of extracts. This paper intends to provide a view of a variety of methods used in plants' phenolic compound extraction, separation, and characterization. Furthermore, this review presents the advantages and disadvantages of techniques involved in phenolic compound research and provides selected representative bibliographic examples.

Potential bioactivity of Phoenix dactylifera fruits, leaves, and seeds against prostate and pancreatic cancer cells

The use of functional foods' phytochemicals in the chemoprevention of different cancer diseases has become one of the hot scientific areas in the clinical nutrition field. For instance, the Khalas palm cultivar (KPC; Phoenix dactylifera) is one of the natural sustainable resources that have high bioactivity and functionality. This study aimed to investigate the antiproliferative activity and mode of action of KPC's different parts on prostate (Pc3) and pancreatic (panc1) cancer cells at a molecular level. In the methods, KPC's leaves, seeds, and fruits' chemical composition and phytochemical analysis were analyzed. Also, the cytotoxic effects of each extract were assessed against pc3 and panc1 cell lines. Besides, induction of apoptosis, cell cycle analysis, and gene expression of both Cap3 and Cap9 were studied. The obtained results indicated that KPC leaves extract exhibited the highest significant (P < 0.01) anti-proliferation activity against the utilized cancer cell lines compared to fruits and seeds extracts. Also, there were significant (P < 0.05) differences in the phenolic contents, flavonoid of compounds, and antioxidant power of the leaves when compared to the seeds and fruits. Additionally, the highest cytotoxic effect (lowest IC₅₀) was recorded with leave extract than seeds and fruits. Meanwhile, the seeds extract induced (P < 0.05) the apoptosis and arrested cells in the G2/M phase as well as up-regulated the gene expression of the apoptotic-related genes (Casp3 and Casp9) compared to the control group. In conclusion, this study showed that the presence of bioactive components in the KPC different parts extracts have the significant ability to induce the apoptotic pathway that could down-regulate the proliferation of prostate (pc3) and pancreatic (panc1) cancer cells. The pathway mechanism of action was induced by the phytol molecule presented in its leaves extract.

Effect of Date Palm (Phoenix dactylifera) Phytochemicals on Aβ1-40 Amyloid Formation: An in-silico Analysis

Alzheimer's disease (AD) is a neurodegenerative disease and the most prevalent form of dementia. The generation of oxygen free radicals and oxidative damage is believed to be involved in the pathogenesis of AD. It has been suggested that date palm, a plant rich in phenolic compounds and flavonoids, can provide an alternative treatment to fight memory loss and cognitive dysfunction due to its potent antioxidant activity. Thus, we studied the effect of flavonoids present in date palm on Aβ1-40 amyloid formation using molecular docking and molecular dynamics simulation. AutoDock. Myricetin was used as a positive control drug. The flavonoids Diosmetin, Luteolin, and Rutin were found to be potent inhibitors of aggregation (docking energies ≤ -8.05 kcal mol-1) targeting Aβ1-40 fibrils (both 2LMO and 6TI5), simultaneously. Further screening by physicochemical properties and drug-likeness analysis suggested that all flavonoids except Rutin followed Lipinski's rule of five. Rutin was, thus, taken as a negative control (due to its violation of Lipinski's rule) to compare its dynamics with Diosmetin. Diosmetin exhibited the highest positive scores for drug likeness. Since Luteolin exhibited moderate drug-likeness and better absorption properties, it was also included in molecular dynamics simulation. Molecular dynamics of shortlisted compounds (Rutin, Diosmetin, and Luteolin) were performed for 200 ns, and the results were analyzed by monitoring root mean square deviations (RMSD), root mean square fluctuation (RMSF) analysis, the radius of gyration (Rg), and solvent accessible surface area (SASA). The results proved the formation of a stable protein-compound complex. Based on binding energies and non-bonded interactions, Rutin and Luteolin emerged as better lead molecules than Diosmetin. However, high MW (610.5), lowest absorption rate (16.04%), and more than one violation of Lipinski's rule make Rutin a less likely candidate as an anti-amyloidogenic agent. Moreover, among non-violators of Lipinski's rule, Diosmetin exhibited a greater absorption rate than Luteolin as well as the highest positive scores for drug-likeness. Thus, we can conclude that Diosmetin and Luteolin may serve as a scaffold for the design of better inhibitors with higher affinities toward the target proteins. However, these results warrant in-vitro and in-vivo validation before practical use.

Cytotoxic and Antioxidant Effects of Phoenix dactylifera L. (Ajwa Date Extract) on Oral Squamous Cell Carcinoma Cell Line

Aim

The aim of the current study is to investigate the antioxidant and apoptotic potential of Ajwa date flesh (ADF) and Ajwa date pit (ADP) extract on human squamous cell carcinoma cell line (HSC-2).

Method

ADF and ADP were extracted with a solvent extraction method using hexane, acetone, and ethanol, which were then subjected to antioxidant assay by 2,2-diphenyl-1-picrylhydrazyl (DPPH). HSC-2 cells were then treated with different concentrations of ADF and ADP extract for 24, 48, and 72 hours. MTT assay was performed to assess the antiproliferative effect, and Annexin V-FITC was used for the detection of cellular apoptosis.

Results

Acetone extracts of ADF and ADP had the highest radical scavenging and antioxidant activities followed by the ethanolic extracts, whereas ADP appeared to have significantly higher antioxidant effects than ADF. MTT assay demonstrated that acetone extracts of ADF and ADP were significantly cytotoxic against HSC-2 cells in a dose- and time-dependent manner. The half inhibitory concentration (IC50) of ADF was found to be 8.69 mg/ml at 24 h, and the maximum cell growth inhibition was observed at 50 mg/ml. The IC50 for the ADP was found to be 0.97 mg/ml at 24 h, and the maximum cell growth inhibition was observed at 5 mg/ml. Statistical analysis of the flow cytometry assay showed that the treatment with ADF and ADP extracts had a significant apoptotic effect which occurred in a dose-dependent manner. HSC-2 cells were seen in the late apoptotic stage with higher doses of ADF and ADP extract. ADP extract demonstrated higher apoptotic activity than ADF extract. In addition, combined treatment of ADF and ADP was also performed on HSC-2 cells which demonstrated higher apoptotic activity when compared to the single extract.

Conclusion

Ajwa date fruit has a promising cytotoxic effect by inhibiting the growth and proliferation of OSCC cells and inducing cell death by apoptosis.

Evaluation of some nutritional quality criteria of seventeen Moroccan dates varieties and clones, fruits of date palm (Phoenix dactylifera L.)

Date fruit is known to be the staple food in the Arab countries. It provides a lot of potential health benefits and can be the essential source of nutrients. The majority of Moroccan varieties are not characterized for their chemical, biochemical and quality properties. The aim of this work was to assess the chemical composition of 17 varieties of Moroccan date fruits (Phoenix dactylifera L.) and to determine their nutritive components. The analysis showed that the dates are rich in sugars (51.80-87.98%), they contain low concentration of proteins (1.09-2.80%) and lipids (0.16-0.39%). The predominant mineral is potassium (1055.26-1604.10 mg/100 g DW). Moreover, they contain high concentrations of malic acid (69.48-495.58 mg/100 g (DW)), oxalic acid (18.47-233.35 mg/100 g DW) and tartaric acid (115.70-484.168 mg/100 g DW). These results suggest that the date fruit are nutritious and can be an excellent source for human nutrition and health benefits.

Alzheimer's Disease and Functional Foods: An Insight on Neuroprotective Effect of its Combination

Alzheimer's disease (AD) is a progressive neurodegenerative disease which impairs memory and cognitive function. Currently, AD has no cure and treatments are focused on relieving its symptoms. Several functional plants and foods, such as pomegranate, date fruits, honey, black seeds and figs, possess nutritious properties which alleviate AD. In vitro and in vivo studies reported that these functional foods exert neuroprotective effects through their antioxidant and anti-inflammatory properties. This review are going to discusses the bioactive components and neuroprotective activities of the functional foods such as pomegranate, dates, honey, black seeds and figs and the potential of functional foods combinations to alleviate AD. Functional food combinations have potential to be consumed for health benefit for the prevention and treatment of AD. This review summarises the functional foods which can be useful for the prevention, treatment and management of AD via oxidative and inflammatory mechanisms. Besides, it provides a new insight on the potential of functional food combinations for the prevention and treatment of AD.

Effect of Date Palm Pollen Supplementation on the Egg Production, Ovarian Follicles Development, Hematological Variables and Hormonal Profile of Laying Hens

This experiment studied the effect of DPP supplementation in the laying hens' diet on the ovarian follicle development, hematological variables and hormonal profile of laying hens. Eighty-four, 78-week-old, Lohman LSL hybrids layers were equally divided into four groups (4 groups × 7 replicates × 3 hens); hens in the 1st group were fed a basal diet (control), while those in the 2nd, 3rd and 4th groups, were fed on the same diet and supplemented with 1.25, 2.5 and 5.0 g DPP/kg diet. The results showed that the egg weight, egg mass and laying rate of laying hens treated with DPP levels were significantly increased compared to those of the hens in the control group. Egg weight, egg surface area, albumen quality and percentage of the yolk in treated hens significantly increased compared with controls. The increased DPP levels in laying hens' diet significantly (p < 0.05) increased WBC, Hb and TAC, while heterophil/lymphocyte (H/L ratio) significantly decreased. Additionally, the concentrations of FSH and LH and the weights of ovary and oviduct in the treated hens significantly (p < 0.05) increased compared with the control. In conclusion, the DPP supplementation in the hen diet significantly improved egg production, EW, H/L ratio, ovarian follicles, FSH and LH hormones concentrations.

Determination of the elemental composition and antioxidant properties of dates (Phoenix dactyliferia) originated from different regions

Due to the growing interest in running a healthy life, including the diet a special interest has been put in searching for products that are rich in nutrients, macro and micronutrients and vitamins. Dates are the fruits that meet these requirements and show multidirectional pro-health effects. These fruits are a source of potassium and other macro- and micronutrients. They have antioxidant properties thanks to the content of flavonoids and polyphenols. The elemental composition (Al, Ca, Cu, Fe, K, Mg, Mn, P, Sr and Zn) and antioxidant properties (total equivalent antioxidant capacity, total polyphenol content, total flavonoid content) of various dates from different regions of the world was determined. The results have shown that the peel and flesh of dates differ significantly in chemical composition. The peel is significantly richer in chemical components of biological importance. Discriminant analysis of the results obtained for dates originated from various regions indicated that the main factor determining the tested chemical composition is the place of cultivation, not the variety.

Bioactive compounds from date fruit and seed as potential nutraceutical and functional food ingredients

Date palm is an important fruit bearing tree grown widely in the arid and semi-arid regions of the world. The date fruit and its by-products, such as seeds, have both nutritional and medicinal value. However, date fruit and seeds have not been fully considered as potential functional food ingredients to develop foods with promising health benefits. Based on the available information in the literature, fruit and seed of date palm are rich in phytochemicals, such as phenolics, anthocyanin, carotenoids, tocopherols, tocotrienols, phytosterols and dietary fiber. In addition, they were reported to possess several beneficial health properties explored under in-vitro and in-vivo conditions. Further research in this area would provide valuable information for the potential utilization of date fruit and seed as functional food ingredients. This review presents a comprehensive information about the bioactive compounds and nutraceutical properties of different varieties of date fruit and seed, as well as the potential for using them as functional food ingredients.

Antibacterial and Cytotoxic Potential of Biosynthesized Silver Nanoparticles by Some Plant Extracts

The provision of nanoparticles using biogenic material as a part of green chemistry is an attractive nanotechnology. The current research aimed to test the antimicrobial and cytotoxic efficacy of silver nanoparticles synthesized by extracts of Phoenix dactylifera, Ferula asafetida, and Acacia nilotica as reductant and stabilizing agents in silver nanoparticle formation. Synthesized nanoparticles were evaluated for their antimicrobial activity against Staphylococcus aureus (Gram-positive) and Pseudomonas aeruginosa and Escherichia coli (Gram-negative) using an agar well diffusion assay. Furthermore, cytotoxic ability was investigated against LoVo cells. The potential phyto-constituents of plant extracts were identified by Fourier-transform infrared spectroscopy (FT-IR) techniques. Field emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), and zeta potential analyzed the size and morphology of the biogenic nanoparticles. The current study revealed the ability of the tested plant extract to convert silver ions to silver nanoparticles with an average size that ranged between 67.8 ± 0.3 and 155.7 ± 1.5 nm in diameter. Biogenic AgNPs showed significant antibacterial ability (10 to 32 mm diameter) and anticancer ability against a LoVo cell with IC50 ranged between 35.15–56.73 μg/mL. The innovation of the present study is that the green synthesis of NPs, which is simple and cost effective, provides stable nano-materials and can be an alternative for the large-scale synthesis of silver nanoparticles.

Extraction optimization and in vitro and in vivo anti-postprandial hyperglycemia effects of inhibitor from Phoenix dactylifera L. parthenocarpic fruit

Phoenix dactylifera L. plays an important role in social, economic, and ecological Tunisian sectors. Some date palms produce parthenocarpic fruit named Sish. The aqueous ethanolic extract from P. dactylifera parthenocarpic dates demonstrated a potent inhibition of the enzymes related to type II diabetes. In this work, extraction optimization of amylase inhibitors was carried out using Box-Behnken Design. Bioactivity-guided fractionation of the 70% aqueous ethanol extract was performed to identify the active compounds. The physicochemical results by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis showed the presence of 13 phenolic compounds. The in vitro study showed that the extract exhibited a more specific inhibitor of α-glucosidase than α-amylase with an IC₅₀ value of 0.6 and 2.5mg/mL, respectively. The in vivo study of this extract effect on the postprandial hyperglycemia activity showed a decrease in plasma glucose levels after 30min stronger than the Acarbose effect. These results confirmed the anti-postprandial hyperglycemia activity of the aqueous ethanolic extract from P. dactylifera parthenocarpic dates, which could lend support for its pharmaceutical use.

Date Palm Tree (Phoenix dactylifera L.): Natural Products and Therapeutic Options

Many plants, including some of the commonly consumed herbs and spices in our daily food, can be safely and effectively used to prevent and/or treat some health concerns. For example, caffeine the active ingredient found in coffee beans (Coffea), shows biological activity in the treatment of the central nervous system (CNS) disorders, indole-3-carbinol, and 3,3'-diindolylmethane are both broccoli (Brassica oleracea) derived phytochemicals with potential anti-cancer activity, and resveratrol, isolated from grape (Vitis vinifera), is reported to extend lifespan and provide cardio-neuro-protective, anti-diabetic, and anti-cancer effects. Date palm fruits possess high nutritional and therapeutic value with significant antioxidant, antibacterial, antifungal, and anti-proliferative properties. This review focuses on the date fruit extracts and their benefits in individual health promoting conditions and highlights their applications as useful to the pharmaceutical and nutraceutical industries in the development of natural compound-based industrial products.

Ajwa Date (Phoenix dactylifera L.) Extract Inhibits Human Breast Adenocarcinoma (MCF7) Cells In Vitro by Inducing Apoptosis and Cell Cycle Arrest

Introduction

Phoenix dactylifera L (Date palm) is a native plant of the Kingdom of Saudi Arabia (KSA) and other Middle Eastern countries. Ajwa date has been described in the traditional and alternative medicine to provide several health benefits including anticholesteremic, antioxidant, hepatoprotective and anticancer effects, but most remains to be scientifically validated. Herein, we evaluated the anticancer effects of the Methanolic Extract of Ajwa Date (MEAD) on human breast adenocarcinoma (MCF7) cells in vitro.

Methods

MCF7 cells were treated with various concentrations (5, 10, 15, 20 and 25 mg/ml) of MEAD for 24, 48 and 72 h and changes in cell morphology, cell cycle, apoptosis related protein and gene expression were studied.

Results

Phase contrast microscopy showed various morphological changes such as cell shrinkage, vacuolation, blebbing and fragmentation. MTT (2-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay demonstrated statistically significant dose-dependent inhibitions of MCF7 cell proliferation from 35% to 95%. Annexin V-FITC and TUNEL assays showed positive staining for apoptosis of MCF7 cells treated with MEAD (15 mg and 25 mg for 48 h). Flow cytometric analyses of MCF7 cells with MEAD (15 mg/ml and 20 mg/ml) for 24 h demonstrated cell cycle arrest at 'S' phase; increased p53, Bax protein expression; caspase 3activation and decreased the mitochondrial membrane potential (MMP). Quantitative real time PCR (qRT-PCR) analysis showed up-regulation of p53, Bax, Fas, and FasL and down-regulation of Bcl-2.

Conclusions

MEAD inhibited MCF7 cells in vitro by the inducing cell cycle arrest and apoptosis. Our results indicate the anticancer effects of Ajwa dates, which therefore may be used as an adjunct therapy with conventional chemotherapeutics to achieve a synergistic effect against breast cancer.

Variations in Hormones and Antioxidant Status in Relation to Flowering in Early, Mid, and Late Varieties of Date Palm (Phoenix dactylifera) of United Arab Emirates

The present study was carried out to assess the status of various hormones responsible for the flower induction of Nagal, Lulu, and Khalas date palm varieties in UAE. The nonenzymatic antioxidant compounds and the antioxidant enzymatic activities at preflowering, flowering, and postflowering stages of the date palm varieties were quantified. The ABA and zeatin concentrations were found to be significantly higher during the preflowering stage but gradually decreased during the flowering period and then increased after the flowering stage. Gibberellic acid (GA) concentrations were significantly higher in the early flowering varieties and higher levels of ABA may contribute to the delayed flowering in mid and late varieties. The results on hormone profiling displayed a significant variation between seasons (preflowering, flowering, and postflowering) and also between the three date palms (early, mid, and late flowering varieties). Ascorbic acid (AA) concentration was low at the preflowering stage in the early flowering Nagal (0.694 mg/g dw), which is similar with the late flowering Lulu variety (0.862 mg/g dw). However, Khalas variety showed significantly higher amount of AA content (7.494 mg/g dw) at the preflowering stage when compared to other varieties. In flowering stage, Nagal (0.814 mg/g dw) and Lulu (0.963 mg/g dw) were similar with respect to the production of AA, while the mid flowering variety showed significantly higher amount of AA (9.358 mg/g dw). The Khalas variety produced the highest tocopherol at 4.78 mg/g dw compared to Nagal and Lulu, at 1.997 and 1.908 mg/g dw, respectively, during the preflowering stage. In Nagal variety, the content of reduced glutathione (GSH) at the preflowering stage was 0.507 mg/g dw, which was not significantly different from the flowering and postflowering stages at 0.4 and 0.45 mg/g dw, respectively. The GSH was significantly higher in Khalas compared to Nagal and Lulu varieties, at 1.321 mg/g dw in the preflowering phase followed by 3.347 mg/g dw and 2.349 mg/g dw at the flowering and postflowering phases, respectively. Catalase activity increased with different stages of growth. The lowest catalase activity was observed at the preflowering stage in Khalas (0.116), with similar observations noted during flowering (0.110) and postflowering stage. This study provides an insight into the possible roles of endogenous hormones and antioxidants and in the activities of antioxidant enzymes in the regulation of flower development in date palm varieties.

Antioxidant activity of various Mauritanian date palm (Phoenix dactylifera L.) fruits at two edible ripening stages

The increasing interest in plant phenolics and flavonoids outlined the necessity of determining their contents and biological activity in Mauritanian date palm fruits. Methanolic extracts of fruit of six date palm cultivars commonly grown in Mauritania were screened for their antioxidant activity, total phenolics, and flavonoid content at two edible ripening stages. Polyphenols and flavonoids were higher in theBlah stage, corresponding toKhalal in the standard Iraqi Arabic nomenclature, compared to the fully matureTamr stage regardless the cultivar. The average of total phenolics atBlah andTamr stages were 728.5 and 558.9 mg gallic acid equivalents (GAE) per 100 g dry matter (DM), whereas the average flavonoid content was 119.6 and 67.3 mg quercetin equivalents (QE) per 100 g DM, respectively. TheBlah stage also exhibited the highest total antioxidant activity with a Trolox equivalents antioxidant capacity (TEAC) value of 129.3 μmol/100 g DM founded in Bou seker's Blah date, followed by Tijib cultivar with TEAC value of 114.3 μmol/100 g DM and an average TEAC value of 107.5 μmol/100 g DM. Furthermore, a high positive correlation was found between total phenolics inTamr (r = 0.92) andBlah (r = 0.87) stages and TEAC of fruit methanolic extracts compared to the flavonoids, suggesting that phenolics were the major contributor to the antioxidant activity.