Pomegranate as a Potential Alternative of Pain Management: A Review

Treating chronic stress and chronic pain by manipulating gut microbiota with diet: can we kill two birds with one stone?

Background: Chronic stress and chronic pain are closely linked by the capacity to exacerbate each other, sharing common roots in the brain and in the gut. The strict intersection between these two neurological diseases makes important to have a therapeutic strategy aimed at preventing both to maintain mental health in patients. Diet is an modifiable lifestyle factor associated with gut-brain axis diseases and there is growing interest in its use as adjuvant to main therapies. Several evidence attest the impact of specific diets or nutrients on chronic stress-related disorders and pain with a good degree of certainty. A daily adequate intake of foods containing micronutrients such as amino acids, minerals and vitamins, as well as the reduction in the consumption of processed food products can have a positive impact on microbiota and gut health. Many nutrients are endowed of prebiotic, anti-inflammatory, immunomodulatory and neuroprotective potential which make them useful tools helping the management of chronic stress and pain in patients. Dietary regimes, as intermittent fasting or caloric restriction, are promising, although further studies are needed to optimize protocols according to patient's medical history, age and sex. Moreover, by supporting gut microbiota health with diet is possible to attenuate comorbidities such as obesity, gastrointestinal dysfunction and mood disorders, thus reducing healthcare costs related to chronic stress or pain.Objective: This review summarize the most recent evidence on the microbiota-mediated beneficial effects of macro- and micronutrients, dietary-related factors, specific nutritional regimens and dietary intervention on these pathological conditions.

Natural polyphenolic coffee extract administration relieves chronic nociplastic pain in a reserpine-induced fibromyalgia-like female mouse model

INTRODUCTION

Nociplastic pain involves reflexive and nonreflexive pain responses and it is a core symptom of fibromyalgia (FM). The increasing prevalence of this health condition and the low rates of patients' quality of life, combined with the lack of suitable pharmacologic treatments, evidence the demand to research new alternatives. Polyphenols may be potential therapeutic candidates as they have been reported to exert pathological pain modulation in preclinical models. In that context, this work was aimed to study the antinociceptive effects of a polyphenolic extract obtained from decaffeinated ground roasted coffee, in the RIM6 FM-like mouse model.

METHODS

To this end, RIM6 adult ICR-CD1 female mice were administered daily once a week with either 10 or 15 mg/kg of extract, and reflexive pain responses were evaluated for up to 3 weeks. At the end, the depressive-like behavior was assessed as a nonreflexive pain response, and spinal cord and serum samples were collected for immunohistochemical and toxicological analyses.

RESULTS

These findings showed that the repeated administration of the coffee polyphenolic extract (CE) modulated reflexive pain responses, depressive-like behavior, and spinal cord gliosis in a dose-dependent manner, without signs of systemic toxicity.

CONCLUSION

Thus, the CE may be a potential pharmacological treatment suitable to relieve nociplastic pain responses characteristic of FM.

Pomegranate: A Source of Multifunctional Bioactive Compounds Potentially Beneficial in Alzheimer's Disease

Pomegranate fruit (PF) is a fruit rich in nutraceuticals. Nonedible parts of the fruit, especially peels, contain high amounts of bioactive components that have been largely used in traditional medicine, such as the Chinese, Unani, and Ayurvedic ones, for treating several diseases. Polyphenols such as anthocyanins, tannins, flavonoids, phenolic acids, and lignans are the major bioactive molecules present in PF. Therefore, PF is considered a source of natural multifunctional agents that exert simultaneously antioxidant, anti-inflammatory, antitumor, antidiabetic, cardiovascular, and neuroprotective activities. Recently, several studies have reported that the nutraceuticals contained in PF (seed, peel, and juice) have a potential beneficial role in Alzheimer's disease (AD). Research suggests that the neuroprotective effect of PF is mostly due to its potent antioxidant and anti-inflammatory activities which contribute to attenuate the neuroinflammation associated with AD. Despite the numerous works conducted on PF, to date the mechanism by which PF acts in combatting AD is not completely known. Here, we summarize all the recent findings (in vitro and in vivo studies) related to the positive effects that PF and its bioactive components can have in the neurodegeneration processes occurring during AD. Moreover, considering the high biotransformation characteristics of the nutraceuticals present in PF, we propose to consider the chemical structure of its active metabolites as a source of inspiration to design new molecules with the same beneficial effects but less prone to be affected by the metabolic degradation process.

Chewable tablet with herbal extracts and propolis arrests Wuhan and Omicron variants of SARS-CoV-2 virus

Prevention of COVID-19 is of paramount importance for public health. Some natural extracts might have the potential to suppress COVID-19 infection. Therefore, this study aimed to design a standardised, efficient, and safe chewable tablet formulation (with propolis and three herbal extracts) for possible prevention against two variants (Wuhan B.1.36 and Omicron BA.1.1) of SARS-CoV-2 virus and other viral infections. Green tea, bilberry, dried pomegranate peel, and propolis extracts were selected for this purpose. Cytotoxicity and antiviral activity of each component, as well as the developed chewable tablet, were examined against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) virus using Vero E6 cells with the xCELLigence real-time cell analyser-multiple plates system. Anti-inflammatory and analgesic activities, as well as mutagenicity and anti-mutagenicity of the chewable tablet were also analysed. Compared to the control, it was observed that the chewable tablet at concentrations of 110 and 55 µg/mL had antiviral activity rates of 101% and 81%, respectively, for the Wuhan variant and 112% and 35%, respectively, for the Omicron variant. The combination of herbal extracts with propolis extract were synergically more effective (∼7-fold higher) than that of individual extract. The present work suggests that a combination of herbal extracts with propolis at suitable concentrations can effectively be used as a food supplement for the prevention of both variants of the SARS-CoV-2 virus in the oral cavity (the first entry point of the SARS-CoV-2 virus).

N-type calcium channel blockers: a new approach towards the treatment of chronic neuropathic pain

Neuropathic pain (NP) remains maltreated for a wide number of patients by the currently available treatments and little research has been done in finding new drugs for treating NP. Ziconotide (PrialtTM) had been developed as the new drug, which belongs to the class of ω-conotoxin MVIIA. It inhibits N-type calcium channels. Ziconotide is under the last phase of the clinical trial, a new non-narcotic drug for the management of NP. Synthetically it has shown the similarities with ω-conotoxin MVIIA, a constituent of poison found in fish hunting snails (Conus magus). Ziconotide acts by selectively blocking neural N-type voltage-sensitized Ca2+ channels (NVSCCs). Certain herbal drugs also have been studied but no clinical result is there and the study is only limited to preclinical data. This review emphasizes the N-type calcium channel inhibitors, and their mechanisms for blocking calcium channels with their remedial prospects for treating chronic NP.

Differential Antinociceptive Efficacy of Peel Extracts and Lyophilized Juices of Three Varieties of Mexican Pomegranate (Punica granatum L.) in the Formalin Test

Pharmacological treatment of pain often causes undesirable effects, so it is necessary to look for natural, safe, and effective alternatives to alleviate painful behavior. In this context, it is known that different parts of pomegranate have been widely consumed and used as preventive and therapeutic agents since ancient times. For example, it has been shown to have an antinociceptive effect, however, there are many varieties. Each part has been found to display unique and attractive pharmacological activities. The content of the active phytochemicals in pomegranate depends on the cultivar, geographical region, the maturity, and the processing method. In this context, the effects of various pomegranate varieties and other parts of the pomegranate (e.g., peel and juice) on pain behavior have not been examined. The aim was to evaluate and compare the antinociceptive effect of ethanolic extracts (PEx) and lyophilized juices (Lj) of three varieties of pomegranate in the formalin test. In addition, computer-aided analysis was performed for determining biological effects and toxicity. Peels were extracted with ethanol and evaporated by rotary evaporation, and juices were filtered and lyophilized. Wistar rats (N = 48) were randomly distributed into 8 groups (n = 6) (Vehicle, Acetylsalicylic Acid, PEx1, PEx2, PEx3, Lj1, Lj2, and Lj3). The formalin test (2%) was carried out, which consists of administering formalin in paw and counting the paw flinches for 1 h, with prior administration of treatments. All samples have an antinociceptive effect (phase 1: 2.8-10%; phase 2: 23.2-45.2%). PEx2 and Lj2 had the greatest antinociceptive effect (57.8-58.9%), and bioactive compounds such as tannins and flavonoids showed promising pharmacodynamic properties that may be involved in the antinociceptive effect, and can be considered as a natural alternative for the treatment of nociceptive and inflammatory pain.

Formulation, Characterization and Optimization of β–Glucan and Pomegranate Juice Based Films for Its Potential in Diabetes

The aim of this study was to develop films based on β–glucans in association with pomegranate juice for its potential in metabolic disorders such as diabetes due to plenty of bioactive compounds from the film composition. Initially, a Box-Behnken design was generated by varying the level of β–glucan content (0.5, 1, 1.5 g), sodium alginate (0.2, 0.4, 0.6 g) and pomegranate juice (10, 20, 30 mL) for development of films. Subsequently, glycerin was added as 25% of the total dry matter. The optimization of the films prepared by the solvent casting method was conducted based on the different responses such as: water vapor transmission rate (WVTR), water vapor permeability (WVP), thickness, density, moisture content, solubility, film opacity and color. The water activity profile and FT–IR analysis were performed in all tests. The model was used to determine the optimal experimental values considering that the optimal film will make a sustained contribution to diabetes. The optimal values of the film sample made of β–glucans, sodium alginate, pomegranate juice and glycerin make it befitting for packaging dry powdered pharmaceuticals. Finally, antimicrobial activity against Gram-negative and Gram-positive bacteria, UV barrier properties and microcrack and pore detections through SEM were also investigated for the optimal film sample.

Exogenous Arginine Treatment Maintains the Appearance and Nutraceutical Properties of Hard- and Soft-Seed Pomegranates in Cold Storage

Arginine is a natural preservative; however, its effects on the storage of different cultivars of pomegranates have not been investigated extensively. Therefore, the fruit quality of soft-seed Tunisia and hard-seed Yudazi pomegranates was investigated after treatment with arginine at four concentrations during cold storage for 80 days. Pomegranates treated with 1.0 mM arginine exhibited a relatively lower loss of vitamin C, soluble solid, total phenol, and anthocyanin contents in arils, together with a better fruit appearance. Combined with principal component analysis (PCA), the storage life of fruits treated with 1.0 mM arginine showed a higher correlation with antioxidant enzyme activity (e.g., superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT)) during the first 40 days of cold storage, whereas after 40 days of cold storage, storage life was more dependent on the integrity of the cell membrane affected by malondialdehyde (MDA) content, electrolyte leakage (EL), and hydrogen peroxide (H2O2) accumulation. Arginine treatment contributed significantly to the appearance and inner quality of the hard-seed pomegranate cv. Yudazi fruit during cold storage compared to those of soft-seed Tunisia. Taken together, arginine application combined with cold storage enhanced the nutraceutical properties and marketability of pomegranate fruits.

Phytochemical Analysis, α-Glucosidase and α-Amylase Inhibitory Activities and Acute Toxicity Studies of Extracts from Pomegranate (Punica granatum) Bark, a Valuable Agro-Industrial By-Product

Punica granatum is a tree of the Punicaceae family which is widespread all over the world with several types of varieties. Its fruit juice is highly prized, whereas the bark, rich in in phytochemicals such as flavonoids, hydrolysable tannins, phenolic acids, and fatty acids, is regarded an agro-industrial waste. It is utilized in traditional medicine for its medicinal properties in the treatment and prevention of a variety of ailments. This study aims to extract and to separate the phytochemical compounds from the bark of P. granatum, to identify them and to study the inhibitory effect of its extracts against antidiabetic activity. First, we carried out successive hot extractions with solvents (chloroform, acetone, methanol, and water) of increasing polarity by the Soxhlet. Then, using both qualitative and quantitative phytochemical investigation, we were able to identify groups of chemicals that were present in all extracts. We identified the majority of the molecular structures of chemicals found in each extract using HPLC-DAD analysis. The inhibition against both intestinal α-glucosidase and pancreatic α-amylase enzymes by P. granatum extracts was used to evaluate their potential antidiabetic effect in vitro. Our results demonstrated the great potential of the acetone extract. Ellagic acid, (−)-catechin, vanillin and vanillic acid were proposed as the most active compounds by the correlation analysis, and their actions were confirmed through the calculation of their IC₅₀ and the determination of their inhibition mechanisms by molecular modelling. To summarize, these results showed that P. granatum bark, a natural agro-industrial by-product, may constitute a promising option for antidiabetic therapeutic therapy.

In vitro Antileishmanial, Antitrypanosomal, and Anti-inflammatory-like Activity of Terminalia mollis Root Bark

This study aims at determining the in vitro antitrypanosomal, antileishmanial, antioxidant, and anti-inflammatory-like activities of Terminalia mollis root crude extracts. The antitrypanosomal and antileishmanial activities on Trypanosoma brucei brucei (strain 427) and promastigotes of Leishmania mexicana mexicana (MHOM/BZ/84/BEL46) were evaluated in vitro. The methanolic root bark extract and standards were profiled by HPLC-PDA, and the majority of compounds identified using literature data. The in vitro antioxidant and anti-inflammatory-like activities were determined by evaluating the effect of crude extracts on reactive oxygen species produced by phorbol 12-myristate 13-acetate-stimulated equine neutrophils using lucigenin-enhanced chemiluminescence and on purified equine myeloperoxidase activity measured by specific immunological extraction followed by enzymatic detection. The methanolic, aqueous crude extract, and aqueous crude extract free of tannins exhibited good growth inhibition on Trypanosoma brucei brucei (IC₅₀ 3.72, 6.05, and 4.45 µg/mL respectively) but were inactive against Leishmania mexicana mexicana (IC₅₀ > 100 µg/mL). Suramin (IC₅₀ 0.11 µg/mL) and amphotericin (IC₅₀ 0.11 µg/mL) were used as standard respectively for the antitrypanosomal and antileishmanial activity. Very interesting antioxidant and anti-inflammatory-like activities were observed with 50% hydroethanolic, aqueous crude extracts, and aqueous crude extract free of tannins as well as with pure punicalagin, gallic, and ellagic acid (IC₅₀ 0.38 - 10.51 µg/mL for 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid), chemiluminescence, and specific immunological extraction followed by enzymatic detection assays. The study results support traditional medicinal use of the plant for the treatment of parasitical disorders and revealed for the first time the antitrypanosomal potential, anti-inflammatory-like, and antioxidant activity of Terminalia mollis root.

A Comprehensive Study of the Antibacterial Activity of Bioactive Juice and Extracts from Pomegranate (Punica granatum L.) Peels and Seeds

Due to the growing awareness of Punica granatum fruit’s health-promoting properties, the pomegranate is increasingly used for food purposes. This results in the formation of biological waste products such as peels. A biowaste circular bioeconomy strategy holds great prospective for a sustainable economy. Therefore, a sustainable and environmentally friendly way of disposing of waste (e.g., use of biowaste to obtain high-value components (e.g., punicalagins, enzymes)) is crucial for the protection of the environment and human health. In the presented study, the content of total phenols and proanthocyanidins in ten samples of Punica granatum fruit (juice, aqueous (H₂O) and ethanolic (EtOH) extracts of peels and seeds) was determined. Peel extracts were found to be the richest in the content of secondary metabolites and showed extremely high antioxidant potential (approximately 90% inhibition: DPPH radical scavenging activity). To the best of our knowledge, this is the first comparative study to determine the enzymatic activity of α-amylase, lipase, peroxidase, protease, and transglutaminase in different P. granatum samples. Furthermore, the antibacterial efficacy of all P. granatum samples was qualitatively determined against three strains of Gram-negative (Escherichia coli, Pseudomonas aeruginosa, and Pseudomonas fluorescens) and three strains of Gram-positive (Bacillus cereus, Staphylococcus aureus, and Streptococcus pyogenes) bacteria, susceptible to gaining antibiotic resistance. Moreover, the most promising peel extracts were quantified for antibacterial efficacy against tested bacteria at five different concentrations. All samples slowed down and inhibited the growth of all tested bacteria. MIC₉₀ values (2.7 or 0.3 mg/mL) were determined in 18 out of 24 experiments (four samples, six bacteria tested). There is no research in the reviewed literature that is current with such detailed and comprehensive determination of P. granatum peel extracts antibacterial activity. The results of the research showed great potential for the use of P. granatum in the field of antibacterial activity in biomedicine applications and in the cosmetic, food, and pharmaceutical industries.

Chitosan Nanoparticles as a Promising Nanomaterial for Encapsulation of Pomegranate (Punica granatum L.) Peel Extract as a Natural Source of Antioxidants

The encapsulation of pomegranate peel extract (PPE) in chitosan nanoparticles (CSNPs) is an advantageous strategy to protect sensitive constituents of the extract. This study was aimed to develop PPE-loaded CSNPs and characterize their physical, structural morphology, antioxidant and antimicrobial properties. Spherical NPs were successfully synthesized with a mean diameter of 174–898 nm, a zeta potential (ZP) of +3 – +36 mV, an encapsulation efficiency (EE) of 26–70%, and a loading capacity (LC) of 14–21% depending on their loaded extract concentrations. Based on these results, CSNPs with chitosan:PPE ratio of 1:0.50 (w/w) exhibited good physical stability (ZP = 27 mV), the highest loading (LC = 20%) and desirable encapsulation efficiency (EE = 51%), and thus, selected as optimally loaded NPs. The FTIR analysis of PPE-CSNPs demonstrated no spectral changes indicating no possible chemical interaction between the PPE and CSNPs, which confirms that the PPE was physically entrapped within NPs. Moreover, FTIR spectra of pure PPE showed specific absorption bands (at 3293–3450 cm⁻¹) attributed to the incidence of phenolic compounds, such as tannic acid, ellagic acid and gallic acid. Total phenolic content (TPC) and antioxidant analysis of selected CSNPs revealed that the encapsulated NPs had significantly lower TPC and antioxidant activity than those of pure PPE, indicating that CSNPs successfully preserved PPE from rapid release during the measurements. Antibacterial tests indicated that pure PPE and PPE-loaded CSNPs effectively retarded the growth of Gram-positive S. aureus with a minimum inhibitory concentration (MIC) of 0.27 and 1.1 mg/mL, respectively. Whereas Gram-negative E. coli, due to its protective cell membrane, was not retarded by pure PPE and PPE-CSNPs at the MIC values tested in this study. Gas chromatography-mass spectroscopy analysis confirmed the incidence of various phytochemicals, including phenolic compounds, fatty acids, and furfurals, with possible antioxidant or antimicrobial properties. Overall, CSNPs can be regarded as suitable nanomaterials for the protection and controlled delivery of natural antioxidants/antimicrobials, such as PPE in food packaging applications.

Interplay of Biochemical, Genetic, and Immunohistochemical Factors in the Etio-Pathogenesis of Gastric Ulcer in Rats: A Comparative Study of the Effect of Pomegranate Loaded Nanoparticles Versus Pomegranate Peel Extract

Background

Few data are available about the role of herbal extract loaded nanoparticles as an alternative safe medicine for the management of a gastric ulcer.

Aim

This work is targeted at exploring the physiological effects of pomegranate loaded nanoparticles (PLN) against an indomethacin IND-induced gastric ulcer and comparing the results with traditional pomegranate peel extract (PPE).

Methods

Twenty-four rats were equally distributed into four groups: control, IND-treated, PLN-treated, and PPE-treated groups. Gross examination of gastric mucosa, and the calculation of ulcer and inhibition indices were done. Serum malondialdehyde (MDA), total antioxidant capacity (TAC), interleukin 2 (IL-2), IL-6, IL-10, gastric homogenate prostaglandin E₂ (PGE₂), and nitric oxide (NO) were estimated. Mucosal endothelial nitric oxide synthase (eNOS mRNA) expression was identified by qPCR. Histological and immuno-histochemical staining of Tumor necrosis factor-α (TNF-α) and eNOS of stomach mucosa were performed.

Results

In comparison with the control group, IND-treated rats showed visible multiple ulcers with ulcer index, serum MDA, IL-2 and IL-6 were elevated while IL-10, PGE₂, NO, and eNOS mRNA expression were significantly reduced. Damaged surface epithelium with disrupted glandular architecture and heavy leucocyte infiltration of lamina propria was noticed. Immunohistochemical staining of stomach mucosa revealed marked increased TNF-α and reduced eNOS. Oral administration of PLN and PPE succeeded in improving the gross mucosal picture, and all biochemical, histological, and immunohistochemical alterations.

Conclusion

Both PLN and PPE potently alleviated IND-induced gastric ulceration via increasing TAC, PGE₂, NO, eNOS mRNA, and protein expression. However, the healing effect of PLN was obviously greater than PPE-treated rats.

Subacute and subchronic toxicity of microencapsulated pomegranate juice in rats and mice

Pomegranate (Punica granatum L.) is a fruit used extensively in traditional medicine by ancient and modern cultures. Different parts of the tree and fruit, such as leaf, peel, pericarp, aril, seed, and juice contain considerable amounts of phenolic compounds with high antioxidant activities. To improve its storability, pomegranate juice was microencapsulated by spray drying. The present study evaluated microencapsulated pomegranate juice (MPJ) for toxic effects in Wistar rats and CD-1 mice to determine if MPJ can be considered safe for human consumption and used as a nutraceutical. No deaths or deleterious effects occurred when high doses of 5000 mg/kg were orally administered in rats for 14 days, indicating an absence of subacute toxicity. Similarly, 3000 mg/kg MPJ administered to CD-1 mice for 90 days did not show subchronic toxicity. In fact, MPJ resulted in lowered weight gain in both rats and mice. Cytotoxic and microbiological analyses of MPJ were also performed. MPJ did not cause any cytotoxicity in epithelial cell culture as tested using the Alamar blue assay. Additionally, histopathological analysis of kidney and liver corroborated the absence of toxicity in CD-1 mice. The microbial load of the MPJ was low, and no pathogenic bacteria were present. In conclusion, the results reported here show that high doses of MPJ are apparently innocuous in rats and mice for the 14 and 90 days investigated, respectively. Although preliminary, our results suggest that MPJ may be safe to ingest and may even have beneficial effects in reducing weight gain.

In silico analysis of polyphenols and flavonoids for design of human Nav1.7 inhibitors

Neuropathic pain is commonly associated with lesion or disease of the somatosensory system and often reflected as indicator of impaired life. Although the central nervous system is main regulator of pain but for initiation and maintenance of the neuropathic pain is regulated by peripheral nervous system. Sodium channels particularly Nav1.7, Nav1.8, Nav 1.9 are key stake holders in the peripheral neuropathy, activation of these sodium channels might lead to genesis and propagation. Flavonoids and polyphenols showed promising effects in neuropathic pain. Here we are reporting In silico analysis of some selected flavonoids and polyphenols on sodium activated voltage channel 1.7 to explore the structural fragments required for binding. Results indicated Baicalin, Butrin, Dihydromonospermoside, Icariin, Isocoreopsin and Isosaponarin are showing promising docking score with sodium activated voltage channel 1.7 than other compounds. Structural modification of these promising leads keeping pharamcophoric requirement intact may yield potent Nav1.7 inhibitors for peripheral pain management.Communicated by Ramaswamy H. Sarma.