Punicalagin in Cancer Prevention-Via Signaling Pathways Targeting

Pomegranate polyphenol punicalagin as a nutraceutical for mitigating mild cognitive impairment: An overview of beneficial properties

Dementia treatment has become a global research priority, driven by the increase in the aging population. Punicalagin, the primary polyphenol found in pomegranate fruit, exhibits a variety of benefits. Today, a growing body of research is showing that punicalagin is a nutraceutical for the prevention of mild cognitive impairment (MCI). However, a comprehensive review is still lacking. The aim of this paper is to provide a comprehensive review of the physicochemical properties, origin and pharmacokinetics of punicalagin, while emphasizing the significance and mechanisms of its potential role in the prevention and treatment of MCI. Preclinical and clinical studies have demonstrated that Punicalagin possesses the potential to effectively target and enhance the treatment of MCI. Potential mechanisms by which punicalagin alleviates MCI include antioxidative damage, anti-neuroinflammation, promotion of neurogenesis, and modulation of neurotransmitter interactions. Overall, punicalagin is safer and shows potential as a therapeutic compound for the prevention and treatment of MCI, although more rigorous randomized controlled trials involving large populations are required.

An overview of Skp2: a promising new therapeutic target of psoriasis

INTRODUCTION

Psoriasis is a chronic immune-mediated disorder affecting over 2-3% of the population worldwide, significantly impacting quality of life. Despite the availability of various therapeutic interventions, concerns persist regarding lesion recurrence and potential alterations in immune surveillance promoting cancer progression. Recent advancements in understanding cellular and molecular pathways have unveiled key factors in psoriasis etiology, including IL-17, 22, 23, TNF-α, PDE-4, JAK-STAT inhibitors, and AhR agonists. This work explores the potential of S-phase kinase-associated protein 2 (Skp2) as a therapeutic target in psoriasis.

AREA COVERED

This review covers the current understanding of psoriasis pathophysiology, including immune dysregulation, and the role of keratinocytes and ubiquitin. It also delves into Skp2 role in cell cycle regulation, and its correlation with angiogenesis and ubiquitin in psoriasis. The evolving therapeutic approaches targeting Skp2, including small molecule inhibitors, are also discussed.

EXPERT OPINION

Targeting Skp2 holds promise for developing novel therapeutic approaches for psoriasis. By modulating Skp2 activity or expression, it may be possible to intervene in inflammatory and proliferative processes underlying the disease. Further research into Skp2 inhibitors and their efficacy in preclinical and clinical settings is warranted to harness the full potential of Skp2 as a therapeutic target in psoriasis management.

The polyphenolic compound punicalagin protects skin fibroblasts from UVA radiation oxidative damage

Polyphenols are a class of natural compounds that act as antioxidants, neutralising harmful free radicals that would damage cells and increase the risk of diseases such as cancer, diabetes and heart disease. They also reduce inflammation, which is thought to be at the root of many chronic diseases. We are investigating the photoprotective effects of punicalagin, a type of polyphenolic compound mainly found in pomegranates, against UVA-induced damage in human skin fibroblasts. Punicalagin increases cell viability and reduces the high levels of ROS generated by photooxidative stress through its ability to modulate the Nrf2 transcriptional pathway. Interestingly, activation of the Nrf2 pathway results in an increase in reduced glutathione, NADH, and subsequently protects mitochondrial respiratory capacity. Integrating molecular and imaging approaches, our results demonstrate a potential cytoprotective effect of punicalagin against UVA-induced skin damage through an anti-apoptotic mechanism.

Potential Mechanism of Tibetan Medicine Liuwei Muxiang Pills against Colorectal Cancer: Network Pharmacology and Bioinformatics Analyses

This study aimed to explore the mechanism through which Tibetan medicine Liuwei Muxiang (LWMX) pills acts against colorectal cancer (CRC). We firstly retrieved the active ingredients and the correlated targets of LWMX pills from public databases. The CRC-related targets were determined through bioinformatic analysis of a public CRC dataset. By computing the intersection of the drug-specific and disease-related targets, LWMX pill-CRC interaction networks were constructed using the protein-protein interaction (PPI) method and functional enrichment analysis. Subsequently, we determined the hub genes using machine learning tools and further verified their critical roles in CRC treatment via immune infiltration analysis and molecular docking studies. We identified 81 active ingredients in LWMX pills with 614 correlated targets, 1877 differentially expressed genes, and 9534 coexpression module genes related to CRC. A total of 5 target hub genes were identified among the 108 intersecting genes using machine learning algorithms. The immune infiltration analysis results suggested that LWMX pills could affect the CRC immune infiltration microenvironment by regulating the expression of the target hub genes. Finally, the molecular docking outcomes revealed stable binding affinity between all target hub proteins and the primary active ingredients of LWMX pills. Our findings illustrate the anti-CRC potential and the mechanism of action of LWMX pills and provide novel insights into multitarget medication for CRC treatment.

The synergistic effect of oxaliplatin and punicalagin on colon cancer cells Caco-2 death

Objectives

The objectives of the study are to investigate the synergistic effect of oxaliplatin (oxa) and punicalagin (pun) on the death of colon cancer cells (Caco-2) by apoptosis and autophagy.

Methods

The effects of the combined treatments (5 μM oxa + 50 μM pun, 5 μM oxa + 75 μM pun, 20 μM oxa + 50 μM pun, and 5 μM oxa + 75 μM pun) were compared with untreated Caco2 cells (control) or cells treated with oxa alone. Apoptosis was detected using an Annex in V FITC flow cytometry assay and poly (ADP-ribose) polymerase cleavage by western blotting. Light chain 3 was detected by western blotting as an autophagy marker.

Results

The combined treatments significantly increased the number of apoptotic cells in comparison to untreated cells or cells treated with oxa alone. By contrast, the combined treatments had no significant effect on autophagy.

Conclusion

The combined treatment significantly promoted cell death through apoptosis while maintaining a basal level of autophagy.

Antiproliferative and cytotoxic effects of polyphenols from pomegranate peel and coffee pulp on cancer cells

Pomegranate peel (PP) and coffee pulp (CP) are by-products of the food industry that can cause environmental pollution if not handled adequately. These by-products contain a significant amount of polyphenolic compounds which have antioxidant and possibly anticancer properties. We investigated the antiproliferative and cytotoxic activities of polyphenols from PP, CP and a 50-50% mixture of both against HeLa, A549, MDA-MB and Hek-293 cells. The total phenolic content of the PP and CP extracts was determined by high performance liquid chromatography/electrospray ionisation/mass spectrometry, and the antiproliferative and cytotoxic potentials were evaluated by MTT (3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) and Lactate Dehydogenase assays, respectively. Results showed antiproliferative and cytotoxic effects of polyphenols from PP and CP when administered at different concentrations or mixtures on HeLa, A549 and MDA-MB cells. No significant antiproliferative effects were observed on Hek-293 cells treated under similar conditions. These results suggest the potential of PP and CP polyphenols, individually or in combination, to modulate biological mechanisms involved in cervical, breast and lung cancer.

Optimizing drug discovery for snakebite envenoming via a high-throughput phospholipase A2 screening platform

Snakebite envenoming is a neglected tropical disease that causes as many as 1.8 million envenomings and 140,000 deaths annually. To address treatment limitations that exist with current antivenoms, the search for small molecule drug-based inhibitors that can be administered as early interventions has recently gained traction. Snake venoms are complex mixtures of proteins, peptides and small molecules and their composition varies substantially between and within snake species. The phospholipases A2 (PLA2) are one of the main pathogenic toxin classes found in medically important viper and elapid snake venoms, yet varespladib, a drug originally developed for the treatment of acute coronary syndrome, remains the only PLA2 inhibitor shown to effectively neutralise venom toxicity in vitro and in vivo, resulting in an extremely limited drug portfolio. Here, we describe a high-throughput drug screen to identify novel PLA2 inhibitors for repurposing as snakebite treatments. We present method optimisation of a 384-well plate, colorimetric, high-throughput screening assay that allowed for a throughput of ∼2,800 drugs per day, and report on the screening of a ∼3,500 post-phase I repurposed drug library against the venom of the Russell's viper, Daboia russelii. We further explore the broad-spectrum inhibitory potential and efficacy of the resulting top hits against a range of medically important snake venoms and demonstrate the utility of our method in determining drug EC50s. Collectively, our findings support the future application of this method to fully explore the chemical space to discover novel PLA2-inhibiting drugs of value for preventing severe pathology caused by snakebite envenoming.

Antitumoral properties of the pomegranate peel and blueberry extracts against tongue carcinoma (in vitro study)

Background

Oral squamous cell carcinoma (OSCC) is one of the most common cancers globally. Considering the drawbacks of the traditional treatment phytochemicals have been introduced to the research field with consideration of their minimal, or no side effects and good efficacy against cancer cells. Pomegranate peel and blueberries are very well-known phytochemicals in this context.

Material and methods

Methanolic extracts are prepared from both pomegranate peel (PPE) and blueberry (BE) dried powders. The antioxidant content was determined by ORAC assay for both extracts. The cytotoxic levels of the extracts and IC50 on the HNO-97 cell line were defined using the colorimetric SRB assay. Then flow cytometric apoptosis analysis of the IC50 of both extracts was performed. Finally, an investigation of the metastasis through the wound healing assay was performed for both extracts.

Results

A significant difference in the antioxidant content was found between PPE and BE ethanolic extracts. The Ic50 for the PPE-treated cell line was 73.35 µg/ml while the BE showed it at 525.38 µg/ml with a significant difference between them. Both PPE and BE showed significant induction of cancer cell apoptosis with much better results with PPE treatment. The wound healing assay showed significant inhibition of cell migration when treated with PPE while there was not any significant effect on cell migration when treated with BE.

Conclusion

With the consideration that, the Phytochemicals used are well-known fruits with no harm on normal tissues. Low doses of PPE exert incredibly significant alteration in the HNO-97 tongue cancer cell proliferation, inducing apoptosis and inhibition of cancer cell migration. Meanwhile, treatment with BE needs much higher doses for showing anti-proliferative properties of cancer cells and induce cancer cell apoptosis. This gives promising results for further investigations about using them as a treatment or adjunctive treatment for oral cancer cases.

Modulatory effect of pomegranate peel extract on key regulators of ovarian cellular processes in vitro

In this study, response of ovarian cells (human granulosa cell line HGL5, and human adenocarcinoma cell line OVCAR-3) to short-term pomegranate peel extract (PPE) treatment (for 24 hours in cell culture) was evaluated in vitro. Quantitative and qualitative screening of polyphenols revealed punicalagins α and β as major polyphenolic components. Total phenolic content (TPC) was 93.76 mg GAE/g d.w. with a high antioxidant activity of 95.30 mg TEAC/g d.w. In OVCAR-3, PPE treatment inhibited the metabolic activity, and increased cyclin-dependent kinase 1 (CDKN1A, p21) level at the highest dose, but not in HGL5. Flow cytometry analysis could not detect any significant difference between proportions of live, dead, and apoptotic cells in both cell lines. Reactive oxygen species (ROS) revealed an antioxidant effect on HGL5, and a prooxidant effect by stimulating ROS generation in OVCAR-3 cells at the higher doses of PPE. However, in contrast to HGL5, PPE treatment decreased release of growth factors - TGF-β2 and EGF at the highest dose, as well as their receptors TGFBR2 and EGFR in OVCAR-3 cells. PPE also influenced steroidogenesis in granulosa cells HGL5 by stimulating 17β-estradiol secretion at higher doses. In conclusion, the present study highlighted the bioactive compounds in pomegranate peels and the possible mechanisms of action of PPE, shedding light on its promising role in ovarian cancer (chemo)prevention and/or management.

Antitumor Effects of Dietary Compounds

Cancer is reported to be a major cause of death worldwide, accounting for 10 million in 2020 based on 19 [...].

Natural products in attenuating renal inflammation via inhibiting the NLRP3 inflammasome in diabetic kidney disease

Diabetic kidney disease (DKD) is a prevalent and severe complications of diabetes and serves as the primary cause of end-stage kidney disease (ESKD) globally. Increasing evidence indicates that renal inflammation is critical in the pathogenesis of DKD. The nucleotide - binding oligomerization domain (NOD) - like receptor family pyrin domain containing 3 (NLRP3) inflammasome is the most extensively researched inflammasome complex and is considered a crucial regulator in the pathogenesis of DKD. The activation of NLRP3 inflammasome is regulated by various signaling pathways, including NF- κB, thioredoxin-interacting protein (TXNIP), and non-coding RNAs (ncRNA), among others. Natural products are chemicals extracted from living organisms in nature, and they typically possess pharmacological and biological activities. They are invaluable sources for drug design and development. Research has demonstrated that many natural products can alleviate DKD by targeting the NLRP3 inflammasome. In this review, we highlight the role of the NLRP3 inflammasome in DKD, and the pathways by which natural products fight against DKD via inhibiting the NLRP3 inflammasome activation, so as to provide novel insights for the treatment of DKD.

An ellagitannin-loaded CS-PEG decorated PLGA nano-prototype promotes cell cycle arrest in colorectal cancer cells

Colorectal cancer is associated with significant morbidity and mortality worldwide. Egypt, as a developing country, has a high-rise incidence of cancer. The current study objective was to investigate the antitumor influences of ellagitannin-loaded CS-PEG-decorated PLGA nano-prototypes against human colorectal cancer cell lines (HCT 116 as well as Caco-2) in vitro. Doxorubicin (DOX), punicalin (PN), and punicalagin (PNG)-encapsulated chitosan-polyethylene glycol-decorated PLGA (PLGA-CS-PEG) nanoparticles (NPs) were described. The cytotoxicity of each preparation was evaluated using MTT assays in HCT 116 as well as Caco-2 cells during G0, G1, S, and G2 cell cycle phases. Cell cycle-related gene expression and protein levels were measured after treatment. Reactive oxygen species (ROS) levels were also measured. Both PN and PNG PLGA-CS-PEG NPs induce colon cancer cell death with cell cycle arrest in the G1 phase in vitro. Caco-2 cells were more sensitive to the nano-therapy than HCT 116 cells. Upon treatment, the ratio of Bax to Bcl-2 expression was increased following nano-therapy, with increased levels of Cas-3 and decreased expression of Bcl-2, PI3k, and NF-ĸB compared to control. The nitric oxide level (NO), a marker of ROS, was increased following nano-therapy compared to control. In conclusion, ROS-mediated cell cycle arrest can be induced by PN as well as PNG nano-therapy in cell lines of colorectal cancer.

Ellagitannin Punicalagin Disrupts the Pathways Related to Bacterial Growth and Affects Multiple Pattern Recognition Receptor Signaling by Acting as a Selective Histone Deacetylase Inhibitor

Punicalagin (PA) is a key ellagitannin abundant in pomegranate with wide-ranging biological activities. In this study, we examined the biological processes by which PA regulates bacterial growth and inflammation in human cells using multiomics and molecular docking approaches. PA promoted macrophage-mediated bacterial killing and inhibited the growth of Citrobacter rodentium by inducing a distinct metabolome pattern. PA acted as a selective regulator of histone deacetylases (HDACs) and affected 37 pathways in macrophages, including signaling mediated by pattern recognition receptors, such as Toll-like and NOD-like receptors. In silico simulation showed that PA can bind with high affinity to HDAC7. PA downregulated HDAC7 at both mRNA and protein levels and resulted in a decrease in the level of histone 3 lysine 27 acetylation. Our findings provide evidence that PA exerts its biological effects via multiple pathways, which can be exploited in the development of this bioactive food ingredient for disease management.

Targeted tumor killing by pomegranate polyphenols: Pro-oxidant role of a classical antioxidant

One of the key biochemical features that distinguish a cancer cell from normal cells is its persistent pro-oxidative state that leads to intrinsic oxidative stress. Malignant cells have evolved sophisticated adaptation systems that involve high dependency on antioxidant functions and upregulation of pro-survival molecules to counteract the deleterious effects of reactive species and to maintain dynamic redox balance. This situation renders them vulnerable to further oxidative challenges by exogenous agents. In the present study, we advocated that pomegranate polyphenols act as pro-oxidants and trigger ROS-mediated apoptosis in cancer cells. With the help of both in vitro and in vivo models, we have established that pomegranate fruit extract (PFE) can cause a significant reduction in tumor proliferation while leaving normal tissues and cells unharmed. Administration of PFE (0.2% v/v) in Erhlich's ascites carcinoma-bearing mice for 3 weeks, inhibited the nuclear factor (erythroid-derived 2)-like 2-antioxidant response element signaling cascade, increased intracellular reactive oxygen species content, altered glutathione cycle thereby activating reactive oxygen species-induced apoptotic pathway in Erhlich's ascites carcinoma cells. Moreover, PFE mitigated epithelial to mesenchymal transition and migration in triple negative breast cancer cells (MDA-MB 231 cells) by down-regulating nuclear factor kappa light-chain-enhancer of activated B cells. Pre-treatment of tumor cells with N-acetyl cysteine protected these cells from undergoing PFE-induced apoptosis while siRNA-mediated silencing of Nuclear factor (erythroid-derived 2)-like 2 and nuclear factor kappa light-chain-enhancer of activated B cells in tumor cells increased the cytotoxic potential and pro-oxidative activity of PFE, indicating a clear role of these transcription factors in orchestrating the anticancer/pro-oxidative properties of PFE. The seminal findings provided may be exploited to develop potential therapeutic targets for selective killing of malignant cells.

Anticancer Effect of Pomegranate Peel Polyphenols against Cervical Cancer

Polyphenols are a broad group of bioactive phytochemicals with powerful antioxidant, anti-inflammatory, immunomodulatory, and antiviral activities. Numerous studies have demonstrated that polyphenol extracts obtained from natural sources can be used for the prevention and treatment of cancer. Pomegranate peel extract is an excellent source of polyphenols, such as punicalagin, punicalin, ellagic acid, and caffeic acid, among others. These phenolic compounds have antineoplastic activity in in vitro models of cervical cancer through the regulation of cellular redox balance, induction of apoptosis, cell cycle arrest, and modulation of different signaling pathways. The current review summarizes recent data from scientific reports that address the anticancer activity of the predominant polyphenol compounds present in PPE and their different mechanisms of action in cervical cancer models.

Antibiofilm effects of punicalagin against Staphylococcus aureus in vitro

Staphylococcus aureus is a common foodborne pathogen which can form biofilms to help them resist to antimicrobials. It brings great harm to human health. Punicalagin has good antimicrobial activities against S. aureus, but its effect on biofilm formation has not been clearly illustrated. The aim of this study was to explore the antibiofilm effects of punicalagin against S. aureus. Results showed that punicalagin did not significantly interfere with the growth of S. aureus at the concentrations of 1/64 MIC to 1/16 MIC. The biomass and metabolic activity of biofilms were significantly reduced when exposed to sub-inhibitory concentrations of punicalagin. The number of viable cells in the biofilms was also decreased after punicalagin treatment. Scanning electron microscopy and confocal laser scanning microscopy images confirmed that punicalagin damaged the structure of biofilms. The antibiofilm mechanism was partly due to the modification of the cell surface which led to the reduction of cell surface hydrophobicity. These findings suggest that punicalagin has the potential to be developed as an alternative to control S. aureus biofilms.

Chitosan-Based Gastric Dressing Materials Loaded with Pomegranate Peel as Bioactive Agents: Pharmacokinetics and Effects on Experimentally Induced Gastric Ulcers in Rabbits

This study reported the fabrication and characterization of gastric dressing, composed of gelatine (GEL), chitosan (CH), and pomegranate peel (PP) extract. The structural changes occurring after γ-irradiation of GEL−CH−PP dressing were reported. The results showed that the electron paramagnetic resonance (EPR) spectroscopy of un-irradiated GEL−CH−PP showed two paramagnetic centers, which corresponded to g = 2.19 and g = 2.002. After irradiation, a new active centre appeared at g = 2.0035 at 10 kGy. The Fourier transform infrared spectroscopy (FTIR) analyses revealed an increase in peak intensity at C−H chains, as well as the C=O carboxyl groups at 10 kGy, due to the cross-linking phenomenon. The X-ray diffraction analysis showed a low change of crystallinity between the range of 2θ (15−30°). Moreover, γ-rays enhanced scavenging DPPH radical activity (51±%) and chelating power activities 79.12%. A significant inhibition of antibacterial and anti-biofilm activities (p < 0.01) was noticed. The hemolysis rates showed 0.42%, suggesting a high hemocompatibility, and exhibited significant anti-inflammatory activity in vitro (48%). In vivo, the healing effects of GEL−CH−PP dressing showed that the incidence and severity of gastric histopathological lesions decreased, compared with the ulcerated group, which could explain the bioavailability and the pharmacokinetic findings. The results highlight the loading of bioactive agents into polymer-based gastric dressings, with promising pharmacokinetics properties and effects on the induced ulcera in rabbits.

Biological Characterization and Quantification of Rambutan (Nephelium lappaceum L.) Peel Extract as a Potential Source of Valuable Minerals and Ellagitannins for Industrial Applications

This study extracted ellagitannins from rambutan peel using the Soxhlet technique. The extract was further partitioned and fractionated to get extract rich in ellagitannin and geraniin, respectively. The partitioning of the extract significantly increased total phenolic content (TPC) by 36.3% and its biological properties. Mineral elements such as Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, and Zn were identified in both peel and extract. Ellagitannins such as geraniin and corilagin with metabolites (gallic acid and ellagic acid) were identified as the major compounds. Analysis of antioxidant activities shows that the ellagitannin rich extract is as powerful as vitamin C. Geraniin was the main contributor to the free radical scavenging activity. The study also revealed that extract with a fraction rich in geraniin has antioxidant activity equivalent to commercial geraniin (1.56 ± 0.11 Trolox equivalent g/g). It also showed low cytotoxicity on fibroblast L929 cells, moderate tyrosinase activity, and good efficacy against Staphylococcus aureus, Staphylococcus epidermidis, and Cutibacterium acnes strains. Successive fractionation of the extract is a promising technique to produce geraniin rich fractions with enhanced antioxidant property. Rambutan peel, as a natural product, is a good source of mineral elements and biologically active compounds for pharmaceutical, nutraceutical, and cosmetic formulations.