Exploring fruits from genus Prunus as a source of potential pharmaceutical agents - In vitro and in silico study

Exploring the Utility of Prunus mahaleb Extracts as a Source of Natural Bioactive Compounds for Functional Applications

Prunus mahaleb has garnered attention as a potent medicinal agent and functional component. We aimed to detect the chemical composition and biological activities of several parts (fruit, leaves, and twigs) of P. mahaleb. Biological activities were assessed for antioxidant properties, enzyme inhibition, mutagenic/antimutagenic effects, and antibacterial efficacy. Antioxidant capabilities were evaluated using various assays, including DPPH, ABTS, CUPRAC, FRAP, phosphomolybdenum, and metal chelating. The chemical constituents of the extracts were identified and quantified using the HPLC-ESI-MS/MS method. The effects of enzyme inhibition were examined on some enzymes, including AChE, BChE, tyrosinase, amylase, and glucosidase. The Ames test was used to evaluate the mutagenic and antimutagenic properties of the plant extracts. Furthermore, a broth microdilution assay was employed to evaluate the possible antibacterial effects of the extracts against microorganisms. The methanol extract of twigs showed superior antioxidant capabilities (DPPH: 388.39 mg TE/g; ABTS: 701.50 mg TE/g; CUPRAC: 459.05 mg TE/g; FRAP: 264.99 mg TE/g). The methanol extract of twigs demonstrated the highest tyrosinase inhibitory activity (61.91 mg KAE/g). A total of 40 metabolites, mainly flavonoids, were detected through HPLC-ESI-MS/MS analysis, revealing that ferulic acid, naringenin, and herniarin were the predominant compounds. In the Ames test, the tested extracts exhibited no mutagenic potential. The antimutagenicity assay demonstrated that methanol and ethyl acetate extracts from twigs and leaves were particularly efficient against frameshift and base pair substitution mutations induced by recognized mutagens. The metabolic activation system amplified these strong activities to inhibition rates ranging from 85% to 98%. The results from the antibacterial assay indicated antibacterial effectiveness at dosages between 6.25 and 0.195 mg/mL, particularly effective against Sarcina lutea, Bacillus cereus, Candida albicans, and Staphylococcus aureus. Our findings indicate that P. mahaleb can serve as a versatile raw material for the development of health-promoting applications, including medicines, cosmeceuticals, and nutraceuticals.

Fractionation of the antioxidant (poly)phenol-polysaccharide-protein complex extracted with ammonia from wild blackthorn (Prunus spinosa L.) fruits: structural features of the fractions obtained

Underutilized wild blackthorn fruits are an important source of mainly phenolic compounds, which makes them suitable as potential functional foods supporting human health. The crude polysaccharide complex (Am), isolated from wild blackthorn berries by ammonia, was subjected to ion-exchange chromatography to yield seven fractions differing in the content of carbohydrates, proteins, phenolics and constitutional saccharides. The non-retained fraction, eluted with water, was rich in α-D-glucan, while the fraction eluted with 0.1 M salts had a high xylose content, indicating the presence of a partly acetylated β-D-xylan-type polysaccharides (4-O-methyl-glucuronoxylan, etc.). However, the highest yields were obtained by elution with 0.5 and 0.25 M NaCl and 1.0 M NaOH solutions, while other fractions were low. The two dominant fractions eluted with 0.25 and 0.5 M saline solutions were found to have a high content of GalA and rhamnose, indicating the presence of rhamnogalacturonan (RGI) and 1,4-α-D-homogalacturonan (HG) regions with a low acetyl content and low degree of methyl esterification. The third fraction in terms of yield, eluted with 1.0 M alkali, was a dark brown material with the highest content of phenolic compounds among all fractions. Its carbohydrate portion was rich in glucose, galactose, rhamnose, xylose and arabinose residues, indicating the presence of polysaccharide complex such as α and β-D-glucans, rhamnogalacturonan, arabinan/arabinogalactan and β-D-xylan types of polymers.

Antioxidant and Biological Activity of Mexican Madroño Fruit (Arbutus arizonica)

The fruit of the Mexican madroño (Arbutus arizonica) has been consumed since pre-Columbian times by North American tribes and native groups in Mexico. Despite this, reports on its chemical composition and biological activity are limited. This work aims to determine the antioxidant, antiproliferative, and digestive enzyme inhibition activities of the methanol amberlite-retained extract of Mexican madroño. Results showed that madroño fruit is rich in antioxidants: DPPH (EC50 = 0.89 ± 0.03 mg/mL), TEAC (1078 ± 4.9 μM/g), and hemolysis inhibition (IC50 = 358.07 μg/mL), with high phenolic and flavonoid content at 15.92 ± 3.2 mg GAE/g and 4.33 ± 0.3 mg CA/g, respectively. Using analytical chromatography, gallic acid, vanillic acid, chlorogenic acid, ferulic acid, quercetin, and rutin were quantified. The extract also showed α-glucosidase inhibition (IC50 = 3.1 ± 0.17 mg/mL), but no inhibition against α-amylase and lipase (>5 mg/mL), while showing antiproliferative activity against HeLa, HT-29, and MCF-7 cancer cell lines. These results point towards an interesting potential for the fruit of the A. arizonica as chemopreventive and hold potential for elaborating functional foods.

Antioxidant Active Polysaccharides Extracted with Oxalate from Wild Blackthorn Fruits (Prunus spinosa L.)

Although several therapeutic effects have been attributed to wild blackthorn fruits, their use is still negligible. Purification of the antioxidant-active fraction, obtained from wild blackthorn fruits by hot ammonium oxalate extraction (Ao), yielded seven fractions after successive elution with water, sodium chloride and sodium hydroxide solutions. The purified fractions differ in carbohydrates, proteins, and phenolics. About 60% of the applied Ao material was recovered from the column, with the highest yields eluted with 0.25 M NaCl solution, accounting for up to 70 wt% of all eluted material. Analyses have shown that two dominant fractions (3Fa and 3Fb) contain 72.8-81.1 wt% of galacturonic acids, indicating the prevalence of homogalacturonans (HG) with a low acetyl content and a high degree of esterification. The low content of rhamnose, arabinose and galactose residues in both fractions indicates the presence of RG-I associated with arabinogalactan. In terms of yield, the alkali-eluted fraction was also significant, as a dark brown-coloured material with a yield of ~15 wt% with the highest content of phenolic compounds of all fractions. However, it differs from other fractions in its powdery nature, which indicates a high content of salts that could not be removed by dialysis.

Re-discovering Prunus fruit varieties as antiangiogenic agents by metabolomic and bioinformatic approach

In this work, a comparative chemical-biological study of nine plum varieties (Prunus domestica L. and Prunus salicina Lindl.) with two commercial ones was carried out to improve their cultivation and use in the agri-food chain. The chemical quali-quantitative fingerprint by HR-Orbitrap/ESI-MS showed similar profiles, being 'Rossa Casa Velasco' the richest in phenols and anthocyanins. All the extracts were investigated for their in vitro antioxidant as well as antiangiogenic activity by two in vivo models, chick chorioallantoic membrane and zebrafish embryos. Among investigated varieties 'Scarrafona', 'Rusticano', 'Marisa', 'Rossa Casa Velasco', 'Verdone', and 'Sangue di Drago' showed the best antiangiogenic activities (30-50 % inhibition). Finally, the chemical/biological datasets processed with a bioinformatic approach revealed that a large group of flavonoids, procyanidins, and anthocyanins significantly correlated with all the three antioxidant tests (DPPH, FRAP, and ABTS), while quinic acid and icariside F2 resulted positively correlated with CAM at both 100 and 200 μg/egg.

Technologically Driven Approaches for the Integrative Use of Wild Blackthorn (Prunus spinosa L.) Fruits in Foods and Nutraceuticals

Different technological approaches were used in this study for the valorization of blackthorn (Prunus spinosa L.) fruits in marmalade, jam, jelly, and nutraceuticals. Marmalade showed the highest concentrations of polyphenols (7.61 ± 0.05 mg gallic acid equivalents/g dry weight (DW)) and flavonoids (4.93 ± 0.22 mg catechin equivalents/g DW), whereas jam retained the highest content of anthocyanins (66.87 ± 1.18 mg cyanidin-3-O-glucoside equivalents/g DW). A good correlation between polyphenol and flavonoid contents and antioxidant activity was found, the highest value being 21.29 ± 1.36 mmol Trolox/g DW for marmalade. Alternatively, the fresh pulp was enriched with inulin, followed by inoculation with Lactobacillus acidophilus, and freeze-dried, allowing a powder to be obtained with a viable cell content of 6.27 × 107 CFU/g DW. A chromatographic analysis of blackthorn skin revealed that myricetin (2.04 ± 0.04 mg/g DW) was the main flavonoid, followed by (+)-catechin (1.80 ± 0.08 mg/g DW), (-)-epicatechin (0.96 ± 0.02 mg/g DW), and vanillic acid (0.94 ± 0.09 mg/g DW). The representative anthocyanins were cyanidin 3-O-glucoside, cyanidin 3-O-rutinoside, and peonidin 3-O-glucoside, with an average concentration of 0.75 mg/g DW. The skin extract showed comparable IC50 values for tyrosinase (1.72 ± 0.12 mg/mL), α-amylase (1.17 ± 0.13 mg/mL), and α-glucosidase (1.25 ± 0.26 mg/mL). The possible use of kernels as calorific agents was demonstrated through the evaluation of calorific power of 4.9 kWh/kg.

Polysaccharides extracted with hot water from wild Prunus spinosa L. berries

Wild blackthorn berries represent an unexplored area in terms of the characterization of the natural biologically active polysaccharide complexes they contain. The antioxidant active fraction extracted from wild blackthorn fruits by hot water extraction (Hw) was subjected to ion-exchange chromatography and yielded six fractions by successive elution with salts. The purified fractions differed in the content of neutral sugars, uronic acids, proteins and phenolics. About 62% of the applied material was recovered from the column, with a higher yield of the fractions eluted with 0.25 M NaCl. Based on the sugar composition of the eluted fractions, several polysaccharide types were observed. The dominant components of Hw are the fractions eluted with 0.25 M NaCl (∼70%), which represent highly esterified homogalacturonan, containing up to 70-80% of galacturonic acids with a low content of rhamnogalacturonan associated with arabinan, galactan or arabinogalactan side chains, but no phenolics. Further, a dark brown polysaccharide material with a yield of ∼17% and with a high content of phenolic compounds, was eluted with alkali (1.0 M NaOH). It mainly represents an acidic arabinogalactan.

A New Bloody Pulp Selection of Myrobalan (Prunus cerasifera L.): Pomological Traits, Chemical Composition, and Nutraceutical Properties

A new accession of myrobalan (Prunus cerasifera L.) from Sicily (Italy) was studied for the first time for its chemical and nutraceutical properties. A description of the main morphological and pomological traits was created as a tool for characterization for consumers. For this purpose, three different extracts of fresh myrobalan fruits were subjected to different analyses, including the evaluation of total phenol (TPC), flavonoid (TFC), and anthocyanin (TAC) contents. The extracts exhibited a TPC in the range 34.52-97.63 mg gallic acid equivalent (GAE)/100 g fresh weight (FW), a TFC of 0.23-0.96 mg quercetin equivalent (QE)/100 g FW, and a TAC of 20.24-55.33 cyanidine-3-O-glucoside/100 g FW. LC-HRMS analysis evidenced that the compounds mainly belong to the flavonols, flavan-3-ols, proanthocyanidins, anthocyanins, hydroxycinnamic acid derivatives, and organic acids classes. A multitarget approach was used to assess the antioxidant properties by using FRAP, ABTS, DPPH, and β-carotene bleaching tests. Moreover, the myrobalan fruit extracts were tested as inhibitors of the key enzymes related to obesity and metabolic syndrome (α-glucosidase, α-amylase, and lipase). All extracts exhibited an ABTS radical scavenging activity that was higher than the positive control BHT (IC₅₀ value in the range 1.19-2.97 μg/mL). Moreover, all extracts showed iron-reducing activity, with a potency similar to that of BHT (53.01-64.90 vs 3.26 μM Fe(II)/g). The PF extract exhibited a promising lipase inhibitory effect (IC₅₀ value of 29.61 μg/mL).

Phenolic Composition, Antioxidant, Anti-Enzymatic, Antimicrobial and Prebiotic Properties of Prunus spinosa L. Fruits

Blackthorn (Prunus spinosa L.) fruit is bluish-black wild fruit traditionally used in nutrition and medicine. It is recently gaining attention as a functional food and an underutilized source of bioactive compounds for application in the food and pharmaceutical industry. This study aimed to assess the health-promoting potential of blackthorn fruits from Serbia by examining their chemical composition and in vitro biological activities. Phytochemical analysis of the blackthorn fruit extracts was performed using LC-DAD-ESI-MS. The total phenolic (TPC), total flavonoid (TFC), total anthocyanin (TAC) content, antioxidant capacity, and enzyme inhibitory activities were determined spectrophotometrically. The antimicrobial and prebiotic properties were tested using the broth microdilution method. Twenty-seven phenolics belonging to the classes of hydroxybenzoic and hydroxycinnamic acids derivatives, flavonoids, and anthocyanins were identified, with caffeoylquinic acid as the most abundant compound. Blackthorn extracts were characterized by notable TPCs, TFCs, and TACs, and free radical scavenging and reducing ability. The enzyme inhibitory effects (IC₅₀ = 0.43-2.16 mg/mL) were observed towards α-amylase, α-glucosidase, acetylcholinesterase, and tyrosinase. Blackthorn fruit extracts in a concentration-dependent manner (0.3-5 mg/mL) stimulated the growth of several probiotic microorganisms and their mixtures, especially the yeast Saccharomyces boulardii. Obtained results support further evaluation of the functional food potential of blackthorn fruit.

Targeting Natural Plant Metabolites for Hunting SARS-CoV-2 Omicron BA.1 Variant Inhibitors: Extraction, Molecular Docking, Molecular Dynamics, and Physicochemical Properties Study

(1) Background: SARS-CoV-2 Omicron BA.1 is the most common variation found in most countries and is responsible for 99% of cases in the United States. To overcome this challenge, there is an urgent need to discover effective inhibitors to prevent the emerging BA.1 variant. Natural products, particularly flavonoids, have had widespread success in reducing COVID-19 prevalence. (2) Methods: In the ongoing study, fifteen compounds were annotated from Echium angustifolium and peach (Prunus persica), which were computationally analyzed using various in silico techniques. Molecular docking calculations were performed for the identified phytochemicals to investigate their efficacy. Molecular dynamics (MD) simulations over 200 ns followed by molecular mechanics Poisson-Boltzmann surface area calculations (MM/PBSA) were performed to estimate the binding energy. Bioactivity was also calculated for the best components in terms of drug likeness and drug score. (3) Results: The data obtained from the molecular docking study demonstrated that five compounds exhibited remarkable potency, with docking scores greater than -9.0 kcal/mol. Among them, compounds 1, 2 and 4 showed higher stability within the active site of Omicron BA.1, with ΔGbinding values of -49.02, -48.07, and -67.47 KJ/mol, respectively. These findings imply that the discovered phytoconstituents are promising in the search for anti-Omicron BA.1 drugs and should be investigated in future in vitro and in vivo research.

Prunus lusitanica L. Fruits as a Novel Source of Bioactive Compounds with Antioxidant Potential: Exploring the Unknown

Prunus lusitanica L., also known as Portuguese laurel or locally known as ‘azereiro’, is a rare species with ornamental and ecological value. Only two studies regarding the bioactivity and chemical composition of its leaves were reported to date. Thus, the present study aims to qualitatively and quantitatively evaluate the phenolic profile, through HPLC-PAD-ESI-MS/MS (high-performance liquid chromatography–photodiode array detection–electrospray ionization tandem mass spectrometry), as well as the radical scavenging capacity, through ABTS (2,2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) and DPPH (2,2-diphenyl-1 picrylhydrazyl), and the reducing power (FRAP, ferric reducing antioxidant power) assays, of P. lusitanica fruits during a 4-year study. In total, 28 compounds were identified and quantified in the fruits, including 21 hydroxycinnamic acids (60.3%); 2 flavan-3-ols (27.9%), 2 anthocyanins (10.5%), 2 flavonols (1.0%), and 1 secoiridoid (0.3%). High antioxidant capacity was observed, with ABTS values ranging from 7.88 to 10.69 mmol TE (Trolox equivalents)/100 g fw (fresh weight), DPPH values from 5.18 to 8.17 mmol TE/100 g fw, and FRAP values from 8.76 to 11.76 mmol TE/100 g fw. According to these results, it can be concluded that these are rich sources of phenolic compounds with very promising antioxidant capacity and, therefore, with potential applications in the food and/or phytopharmaceutical sectors.

Survey of Dipeptidyl Peptidase III Inhibitors: From Small Molecules of Microbial or Synthetic Origin to Aprotinin

Dipeptidyl peptidase III (DPP III) was originally thought to be a housekeeping enzyme that contributes to intracellular peptide catabolism. More specific roles for this cytosolic metallopeptidase, in the renin-angiotensin system and oxidative stress regulation, were confirmed, or recognized, only recently. To prove indicated (patho)physiological functions of DPP III in cancer progression, cataract formation and endogenous pain modulation, or to reveal new ones, selective and potent inhibitors are needed. This review encompasses natural and synthetic compounds with experimentally proven inhibitory activity toward mammalian DPP III. Except for the polypeptide aprotinin, all others are small molecules and include flavonoids, coumarin and benzimidazole derivatives. Presented are current strategies for the discovery or development of DPP III inhibitors, and mechanisms of inhibitory actions. The most potent inhibitors yet reported (propioxatin A and B, Tyr-Phe- and Phe-Phe-NHOH, and JMV-390) are active in low nanomolar range and contain hydroxamic acid moiety. High inhibitory potential possesses oligopeptides from the hemorphin group, valorphin and tynorphin, which are poor substrates of DPP III. The crystal structure of human DPP III-tynorphin complex enabled the design of the transition-state peptidomimetics inhibitors, effective in low micromolar concentrations. A new direction in the field is the development of fluorescent inhibitor for monitoring DPP III activity.

A comparison study between ultrasound-assisted and enzyme-assisted extraction of anthocyanins from blackcurrant (Ribes nigrum L.)

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2 anthocyanin extraction methods have been developed in blackcurrant by EAE and UAE.

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The 7 major anthocyanins have been separated in less than 7 min.

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The composition of the extraction solvent has been the most influential variable.

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Optimal extraction times have been 5 min for UAE and 10 min for EAE.

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No differences have been observed in anthocyanin extraction with both methods.

Blackcurrant (Ribes nigrum L.) is a fruit rich in vitamins, fatty acids, minerals, essential oils and phenolic compounds, including anthocyanins. In the present work, two anthocyanin extraction methods from blackcurrant samples based on Ultrasound-Assisted Extraction (UAE) and Enzyme-Assisted Extraction (EAE) have been developed. A Plackett–Burman design with seven variables has been preliminary used for both UAE and EAE in order to determine the most influential variables in each methodology. After that, a Box-Behnken design was employed to optimize the extraction methods. The composition of the extraction solvent (% EtOH in water) has been the most influential variable for both UAE and EAE. The optimal extraction times have been 5 min for UAE and 10 min for EAE. No differences have been observed in anthocyanin extraction with both methodologies. Both methods have been applied to blackcurrant-derived products and proven their suitability for quality control analysis.

Valorization of by-products from Prunus genus fruit processing: Opportunities and applications

Food processing, especially the juice industry, is an important sector that generate million tons of residues every. Due to the increasing concern about waste generation and the interest in its valorization, the reutilization of by-products generated from the processing of popular fruits of the Prunus genus (rich in high-added value compounds) has gained the spotlight in the food area. This review aims to provide an overview of the high added-value compounds found in the residues of Prunus fruits (peach, nectarine, donut peach, plum, cherry, and apricot) processing and applications in the food science area. Collective (pomace) and individual (kernels, peels, and leaves) residues from Prunus fruits processing contains polyphenols (especially flavonoids and anthocyanins), lipophilic compounds (such as unsaturated fatty acids, carotenes, tocopherols, sterols, and squalene), proteins (bioactive peptides and essential amino acids) that are wasted. Applications are increasingly expanding from the flour from the kernels to encapsulated bioactive compounds, active films, and ingredients with technological relevance for the quality of bread, cookies, ice cream, clean label meat products and extruded foods. Advances to increasing safety has also been reported against anti-nutritional (amygdalin) and toxic compounds (aflatoxin and pesticides) due to advances in emerging processing technologies and strategic use of resources.

Hydroethanolic Extract of Prunus domestica L.: Metabolite Profiling and In Vitro Modulation of Molecular Mechanisms Associated to Cardiometabolic Diseases

High consumption of fruit and vegetables has an inverse association with cardiometabolic risk factors. This study aimed to chemically characterize the hydroethanolic extract of P. domestica subsp. syriaca fruit pulp and evaluate its inhibitory activity against metabolic enzymes and production of proinflammatory mediators. Ultra-high-performance liquid chromatography high-resolution mass spectrometry(UHPLC-HRMS) analysis showed the presence of hydroxycinnamic acids, flavanols, and glycoside flavonols, while nuclear magnetic resonance(NMR) analysis showed, among saccharides, an abundant presence of glucose. P. domestica fruit extract inhibited α-amylase, α-glucosidase, pancreatic lipase, and HMG CoA reductase enzyme activities, with IC50 values of 7.01 mg/mL, 6.4 mg/mL, 6.0 mg/mL, and 2.5 mg/mL, respectively. P. domestica fruit extract inhibited lipopolysaccharide-induced production of nitrite, interleukin-1 β and PGE2 in activated J774 macrophages. The findings of the present study indicate that P. domestica fruit extracts positively modulate in vitro a series of molecular mechanisms involved in the pathophysiology of cardiometabolic diseases. Further research is necessary to better characterize these properties and their potential application for human health.

Cancer protective effects of plums: A systematic review

Plums is one of the most cultivated stone fruits due to its fast growing popularity. It has various traditionally recognized health benefits. There are two main commercial types of plums: the European plum (Prunus domestica) and the Japanese plum (Prunus salicina), each having many varieties. Researchers are gathering further evidence of pharmacological effects for plums by scientifically studying its anti-inflammatory, antioxidant properties. A systematic review analysing the literature related to the effects of plums on prevention and treatment of cancer is warranted. This is the first review examining the cancer-related effects of plums. Antioxidation properties of the active constituents of plum were also compared. Scopus, Google Scholar, PubMed, Medxriv and Cochrane Library databases, from their date of inception until July 2021 were utilized. The risk of bias was assessed using CONSORT checklist. A total of 6639 studies were screened and eventually only 54 studies were included. Full-text review of included studies revealed that plum extracts were rich in antioxidants. Overall, most of the studies that fulfilled the eligibility criteria were in vitro and a few clinical studies involving in vivo work. Therefore, it would be beneficial to perform more studies on animals or humans, to confirm that the result obtained from these in vitro studies are able to be extrapolated in a wider range of applications. Further clinical and in vivo studies are warranted to validate plums as a functional food for treatment and prevention of cancer.

Novel extraction of polyphenols from sour cherry pomace using natural deep eutectic solvents - Ultrafast microwave-assisted NADES preparation and extraction

In this work, new approaches for the green extraction of polyphenols from sour cherry pomace were explored. Three Natural Deep Eutectic Solvents (NADES) systems based on choline chloride (ChCl) as a hydrogen bond acceptor (HBA) and malic acid, urea, and fructose (MalA, Ur, and Fru) as hydrogen bond donors (HBD) were used. NADES systems were prepared by heating and stirring (H&S), ultrasound (US), and microwave (MW) methods. It was found that MW-assisted preparation was the fastest requiring less than 30 s. Polyphenol extraction from cherry pomace was performed also by three mentioned methods, and compared with conventional methods. MW extraction was the most rapid with less than 5 min necessary for the extract preparation. All three NADES systems were highly efficient for anthocyanin extraction, but the most efficient was ChCl:MalA system. Extract based on ChCl:MalA system was for 62.33% more efficient for anthocyanin extraction comparing with the conventional solvent.