Characterization of Date (Deglet Nour) Seed Free and Bound Polyphenols by High-Performance Liquid Chromatography-Mass Spectrometry

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.

Arecaceae Seeds Constitute a Healthy Source of Fatty Acids and Phenolic Compounds

Seeds of most Arecaceae species are an underutilized raw material that can constitute a source of nutritionally relevant compounds. In this work, seeds of 24 Arecaceae taxa were analyzed for fatty acids (FAs) by GC-FID, for phenolics by HPLC-DAD and LC-MS, and for their antitumor activity against the HT-29 colorectal cancer cell line by the MTT assay. Lauric, oleic, and linoleic acids were the prominent FAs. Cocoseae species contained total FAs at 28.0-68.3 g/100 g seeds, and in other species total FAs were from 1.2 (Livistona saribus) to 9.9 g/100 g (Washingtonia robusta). Sabal domingensis, Chamaerops humilis, and Phoenix dactylifera var. Medjool had unsaturated/saturated FA ratios of 1.65, 1.33-1.78, and 1.31, respectively, and contained 7.4, 5.5-6.3, and 6.4 g FAs/100 g seeds, respectively. Thus, they could be used as raw materials for healthy oilseed production. Phenolics ranged between 39 (Livistona fulva) and 246 mg/100 g (Sabal palmetto), and of these, caffeic acid, catechin, dactylifric acid, and rutin had the highest values. (-)-Epicatechin was identified in most seed extracts by LC-MS. Hydroalcoholic extracts from five species showed a dose-dependent inhibitory effect on HT-20 cells growth at 72 h (GI₅₀ at 1533-1968 µg/mL). Overall, Arecaceae seeds could be considered as a cheap source of health-promoting compounds.

Utilization of natural deep eutectic solvents and ultrasound-assisted extraction as green extraction technique for the recovery of bioactive compounds from date palm (Phoenix dactylifera L.) seeds: An investigation into optimization of process parameters

The green extraction of bioactive compounds from date seeds was investigated using seven natural deep eutectic solvents (NADES) coupled with ultrasound-assisted extraction (UAE). The seven NADESs mainly consisted of choline chloride as hydrogen bond acceptors (HBA) and four sugars, two organic acids, and one polyalcohol as hydrogen bond donors (HBD) were utilized in this study. When the extraction efficiency of the NADESs was compared to that of the conventional solvents, all the NADESs showed superior bioactive compounds recovery efficacy. The lactic acid-based NADES had the highest extraction efficiency and was further optimized using the response surface method and Box-Behnken design. A four-factors including extraction time (10, 20, and 30 min), ultrasound amplitude (70, 80, and 90 %), % NADES content (30 %, 50 %, and 70 %) and solid-to-solvent ratio (1:30, 1.5:30, and 2:30 g/ml) each at three levels (-1, 0 and 1) using Box-Behnken design was applied. The % NADES content and the solid-to-solvent ratio were the major factors influencing the extraction efficiency of the total phenolic content (TPC) and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. The optimum extraction conditions included an extraction time of 15 min, ultrasound amplitude of 90 %, % NADES content of 70 % and solid-to-liquid ratio of 1:30 g/ml. The experimental values for TPC and DPPH at optimum extraction conditions were 145.54 ± 1.54 (mg GAE/g powder) and 719.19 ± 2.09 (mmol TE/g powder), respectively. The major phenolic compounds observed in the date seeds extracted using ChCl-LA were 3,4-dihydroxybenzoic acid, catechin and caffeic acid. This study reveals that the extraction of date seeds with NADES in combination with UAE technique was able to recover significantly higher amounts of phenolic compounds which could find useful applications in the food, pharmaceutical, and cosmetics industries.

Tackling the Future Pandemics: Broad-Spectrum Antiviral Agents (BSAAs) Based on A-Type Proanthocyanidins

A-type proanthocyanidins (PAC-As) are plant-derived natural polyphenols that occur as oligomers or polymers of flavan-3-ol monomers, such as (+)-catechin and (-)-epicatechin, connected through an unusual double A linkage. PAC-As are present in leaves, seeds, flowers, bark, and fruits of many plants, and are thought to exert protective natural roles against microbial pathogens, insects, and herbivores. Consequently, when tested in isolation, PAC-As have shown several biological effects, through antioxidant, antibacterial, immunomodulatory, and antiviral activities. PAC-As have been observed in fact to inhibit replication of many different human viruses, and both enveloped and non-enveloped DNA and RNA viruses proved sensible to their inhibitory effect. Mechanistic studies revealed that PAC-As cause reduction of infectivity of viral particles they come in contact with, as a result of their propensity to interact with virion surface capsid proteins or envelope glycoproteins essential for viral attachment and entry. As viral infections and new virus outbreaks are a major public health concern, development of effective Broad-Spectrum Antiviral Agents (BSAAs) that can be rapidly deployable even against future emerging viruses is an urgent priority. This review summarizes the antiviral activities and mechanism of action of PAC-As, and their potential to be deployed as BSAAs against present and future viral infections.

Interaction between Chocolate Polyphenols and Encapsulated Probiotics during In Vitro Digestion and Colonic Fermentation

This study evaluated the interaction between probiotics and polyphenols in chocolates (45% and 70% cocoa) fortified with encapsulated probiotics. Cocoa powder was used as the main encapsulation component in a Na-alginate plus fructooligosaccharides formulation. Probiotic-chocolates (PCh) were produced by adding 1% encapsulated probiotics to the final mixture. The chocolate samples were subjected to in vitro gastrointestinal digestion and colonic fermentation. The data revealed that the most bioaccessible polyphenols in both formulations of PCh containing 45% and 70% cocoa were released in the gastric digested supernatant. The bioaccessible polyphenols from PCh with 70% cocoa reached 83.22–92.33% and 8.08–15.14% during gastrointestinal digestion and colonic fermentation, respectively. Furthermore, the polyphenols with higher bioaccessibility during colonic fermentation of both PChs developed with the CA1 formulation (cocoa powder 10%, Na-alginate 1% and fructooligosaccharides 2%) were detected in the presence of Streptococcus thermophilus and Lactobacillus sanfranciscensis. The results showed that PCh with specific probiotics favored the bioconversion of a specific polyphenol. For example, chocolate fortified with Lacticaseibacillus casei released larger quantities of epicatechin and procyanidin B1, while Lactiplantibacillus plantarum released more catechin and procyanidin B1 for Lacticaseibacillus rhamnosus LGG. Overall, the study findings concluded that chocolate polyphenols could be utilized by probiotics for their metabolism and modulating the gut, which improved the chocolates’ functionality.

In-vitro Investigation of Polyphenol-Rich Date (Phoenix dactylifera L.) Seed Extract Bioactivity

Date seeds are a by-product of the date fruit processing industry with minimal human use; however, they are a rich source of polyphenols with a range of potential biological properties. The current study investigates the cytotoxicity of date seed polyphenols against cancer cell lines, its ability to combat hyperglycemia, its antioxidant potential and its anti-adipogenic effect. The present work aimed to establish the usefulness of date seeds in the food industry as a functional ingredient. The anti-tumour activity of DSE was tested in a panel of cell lines such as MCF-7, MDA-MB-231, Hep-G2, Caco-2, and PC-3 by measuring cell viability and cleaved PARP. Lipid accumulation and effect on the differentiation of 3T3-L1 cells (adipocytes) were tested with date seed extract treatments. The influence of date seed polyphenols on glucose uptake was studied in 3T3-L1 cells and C2C12 cells (muscle cells). The antioxidant activity of the polyphenols from date seed products such as date seed extract (DSE), date seed powder (DSP), and date seeds fortified bread (DSB) was tested following in-vitro digestion to study their stability in the gastrointestinal milieu. DSE treatment resulted in significantly reduced viability in MCF-7 and Hep-G2 cells with 48-h treatments. Glucose uptake increased in the adipocytes with DSE treatments; moreover, it inhibited adipocyte differentiation and lipid accumulation. DSE decreased the expression levels of PPAR-γ, C/EBPα, adiponectin and upregulated GLUT-4, and phospho-AMPK. This study also found that date seed samples retained antioxidant activity in the digestive milieu and concludes that the date seed polyphenols remain active in the digestive milieu and exhibit potential anti-hyperglycemic and anti-adipogenic activity.

Date seeds alleviate behavioural and neuronal complications of metabolic syndrome in rats

Unhealthy dietary habits can play a crucial role in metabolic damages, promoting alteration of neural functions through the lifespan. Recently, dietary change has been perceived as the first line intervention in prevention and/or treatment of metabolic damages and related diseases. In this context, our study was designed to assess the eventual therapeutic effect of date seeds administration on memory and learning and on neuronal markers in a rat Metabolic Syndrome model. For this purpose, 32 adult male Wistar rats were fed with standard diet or high-fat high-sugar diet during ten weeks. After this, 16 rats were sacrified and the remaining rats received an oral administration of 300 mg of date seeds/kg of body weight during four supplementary weeks. Before sacrifice, we evaluate cognitive performances by the Barnes maze test. Afterwards, neuronal, astrocytic, microtubular and oxidative markers were investigated by immunoblotting methods. In Metabolic syndrome rats, results showed impairment of spatial memory and histological alterations. We identified neuronal damages in hippocampus, marked by a decrease of NeuN and an increase of GFAP and pTau396. Finally, we recorded an increase in protein oxidation and lipid peroxidation, respectively identified by an up-regulation of protein carbonyls and 4-HNe. Interestingly, date seeds administration improved these behavioural, histological, neuronal and oxidative damages highlighting the neuroprotective effect of this natural compound. Liquid Chromatography-Mass Spectrometry (LC-MS) identified, in date seeds, protocatechuic acid, caffeoylshikimic acid and vanillic acid, that could potentially prevent the progression of neurodegenerative diseases, acting through their antioxidant properties.

Potentials and Safety of Date Palm Fruit against Diabetes: A Critical Review

Diabetes is a chronic metabolic disorder triggered by disturbances in carbohydrate, protein, and lipid metabolisms, where either reduced secretion or sensitivity of insulin is observed coupled with poor glucose control. Date palm fruits are one of the fruits reported to have good potential in diabetes treatment due to its presence of polyphenols exerting strong antioxidant activities. Other possible mechanisms of action include the polyphenolic compounds, which can inhibit enzymes like α-amylase and α-glucosidase. Flavonoids in dates can stimulate β-cells by increasing the number of islets and β-cells, recovering endocrine pancreatic tissues, reducing β-cell apoptosis, activating insulin receptors following the increase in insulin secretion, in addition to improving diabetes-induced complications. In this review, the in vitro, in vivo, and human study-based evidence of date palm as an anti-diabetic fruit is summarised.

Characterization of bioactive cranberry fractions by mass spectrometry

Increasing evidence indicates that fruits contain functional bio-active compounds that have several preventive and therapeutic health benefits. Our group has recently conducted studies to assess the potential effects of cranberry polyphenolic fractions on intestinal Caco-2/15 epithelial cells and a substantial reduction in oxidative stress and inflammation was observed. The aim of the present work was to determine the polyphenolic species most likely responsible for the observed biological activity. Low, medium, and high molecular weight cranberry fractions were generated with a Sephadex LH-20 column by elution with 60% MeOH, 100% MeOH, and 70% acetone, respectively. The total phenolic content in these fractions was determined by the Folin–Ciocalteu method. A combination of LC–MS and MALDI-TOF methods were used to characterize the nature of polyphenolic compounds in the cranberry extracts. High resolution mass spectrometry was used to generate empirical formulae for the detected species. The low molecular weight fraction was essentially constituted of small phenolic acids (hydroxycinnamic and hydroxybenzoic acids). The medium fraction was mostly composed of anthocyanin, flavonols (quercetin, myricetin, isorhamnetin, kaempferol), procyanidins monomers (epicatechin, catechin), dimers, and few small oligomers. The heavy fraction was devoid of phenolic acids and anthocyanins, and it contained for the most part oligomers and polymers of procyanidins. Proanthocyanidins oligomers up to n = 22 were detected, which is, to our knowledge, the largest individual polymers reported to date. With this approach, it was also possible to distinguish between the A-type and B-type linkages.

Inhibition of Digestive Enzyme and Stimulation of Human Liver Cells (HepG2) Glucose Uptake by Date Seeds Extract

Type 2 diabetes mellitus is increasing worldwide, and the United Arab Emirates is presenting one of the world's highest prevalence rates. Dietary polyphenols exert an antidiabetic effect by modulating carbohydrates digestion and cellular glucose uptake. Due to their particularly high content in polyphenols, date seeds represent a potential antidiabetic agent. This study aims to determine if date seed polyphenols inhibit the activity of the enzymes (α-amylase and α-glucosidase), responsible for the digestion of carbohydrates and modulating the glucose uptake by human liver cells. In vitro activity of the intestinal α-glucosidase, pancreatic α-amylase, the glucose uptake by HepG2 cells, and the expression of GLUT4 and AMPK analyzed by western blotting (with and without date seeds extract). Our result showed that the maximum enzymes inhibition was obtained with 400 μg/mL and 900 μg/mL DSE for α-amylase and α-glucosidase, respectively. The HepG2 cell viability significantly decreased up to 80% at 4000 μg/mL DSE. The expression of GLUT4 was higher at 100 μg/mL DSE (with insulin and without insulin). However, the expressions of P-AMPK and AMPK were increased by DSE, mainly in a non-insulin-dependent manner. Therefore, DSE, by inhibiting carbohydrate digestion and stimulating glucose uptake by HepG2, can potentially demonstrate the therapeutic potential for diabetes management.

Polyphenol characterisation of Phoenix dactylifera L. (date) seeds using HPLC-mass spectrometry and its bioaccessibility using simulated in-vitro digestion/Caco-2 culture model

The polyphenolic content in date seeds, a promising functional ingredient for food, was characterised in three forms viz., date seed powder (DSP), date seed pita bread (DSB) and date seed extract (DSE). Bioaccessibility of the polyphenols from the samples was assessed by in-vitro digestion coupled with transport using Caco-2 cells. HPLC-ESI-UV/MS/MS-(IT) analysis recorded the presence of phenolic acids, flavanols, flavonols and flavones. Flavan-3-ols was the most significant group with the highest concentration in DSP, 47.91 ± 0.13 g/kg, after depolymerisation. Phenolic acids such as protocatechuic acid, vanillic acid and caffeoylshikimic acid were recovered from DSP and DSE after in-vitro digestion. In comparison, the recovery was significantly lower in the bread sample. Similarly, transport of protocatechuic acid, p-hydroxybenzoic acid, caffeoylshikimic acid, p-coumaric acid, syringic acid hexoside and diosmin through Caco-2 monolayer was observed in DSP and DSE, while protocatechuic acid and p-hydroxybenzoic acid were the only polyphenols transported from digested DSB.

Fruit Seeds as Sources of Bioactive Compounds: Sustainable Production of High Value-Added Ingredients from By-Products within Circular Economy

The circular economy is an umbrella concept that applies different mechanisms aiming to minimize waste generation, thus decoupling economic growth from natural resources. Each year, an estimated one-third of all food produced is wasted; this is equivalent to 1.3 billion tons of food, which is worth around US$1 trillion or even $2.6 trillion when social and economic costs are included. In the fruit and vegetable sector, 45% of the total produced amount is lost in the production (post-harvest, processing, and distribution) and consumption chains. Therefore, it is necessary to find new technological and environmentally friendly solutions to utilize fruit wastes as new raw materials to develop and scale up the production of high value-added products and ingredients. Considering that the production and consumption of fruits has increased in the last years and following the need to find the sustainable use of different fruit side streams, this work aimed to describe the chemical composition and bioactivity of different fruit seeds consumed worldwide. A comprehensive focus is given on the extraction techniques of water-soluble and lipophilic compounds and in vitro/in vivo functionalities, and the link between chemical composition and observed activity is holistically explained.

Urine Metabolites and Antioxidant Effect after Oral Intake of Date (Phoenix dactylifera L.) Seeds-Based Products (Powder, Bread and Extract) by Human

A cross-over study was conducted in 16 healthy adult volunteers to describe the urinary excretion of polyphenols from date seeds and investigate the antioxidant effect after consumption of different doses of date seeds powder (DSP), bread (DSB) and extract (DSE). After 12 h of fasting, one of the six treatments (0.25 g and 0.5 g/kg bodyweight DSP, 360 g of 10% and 15% DSB, 30 mg and 60 mg/kg bodyweight DSE) was provided along with breakfast, with a two weeks wash-out period between 2 consecutive treatments. Blood was drawn at baseline, 1, 2, 8 and 24 h post intake. Urine was collected at baseline, 3, 8, and 24 h post intake. An abundant release of polyphenols was detected in urine within the 0-3 h post intake, reached a peak at 8 h, then decreased with polyphenols still being detected up to 24 h post intake. The antioxidant defence system, as measured by reduced glutathione (GSH), was strengthened as soon as 1 h and up to 8 h post intake. Markers of protein and lipid oxidative damages were reduced from 1 h and up to 8 and 24 h post intake, respectively. This supports an antioxidant effect of date seeds products in humans, most probably due to their polyphenols.

Phoenix dactylifera L. seeds: a by-product as a source of bioactive compounds with antioxidant and enzyme inhibitory properties

Date (Phoenix dactylifera L.) seeds are a valuable and abundant by-product with various potential food applications and a source of functional and bioactive ingredients.

Extraction and Analysis of Phenolic Compounds in Rice: A Review

Rice represents the main source of calorie intake in many world countries and about 60% of the world population include rice in their staple diet. Whole grain rice, also called brown rice, represent the unpolished version of the more common white rice including bran, germ, and endosperm. Many health-promoting properties have been associated to the consumption of whole grain rice and, for this reason, great attention has been paid by the scientific community towards the identification and the quantification of bioactive compounds in this food item. In this contribution, the last five years progresses in the quali-quantitative determination of phenolic compounds in rice have been highlighted. Special attention has been devoted to the most recent strategies for the extraction of the target compounds from rice along with the analytical approaches adopted for the separation, identification and quantification of phenolic acids, flavonoids, anthocyanins, and proanthocyanidins. More specifically, the main features of the “traditional” extraction methods (i.e., maceration, ultrasound-assisted extraction) have been described, as well as the more innovative protocols involving advanced extraction techniques, such as MAE (microwave-assisted extraction). The predominant role of HPLC in the definition of the phenolic profile has been examined also presenting the most recent results obtained by using mass spectrometry-based detection systems. In addition, the most common procedures aimed to the quantification of the total amount of the cited classes of phenolic compounds have been described together with the spectrophotometric protocols aimed to the evaluation of the antioxidant properties of rice phenolic extracts (i.e., FRAP, DPPH, ABTS and ORAC).