Penta-O-galloyl-β-D-glucose attenuates cisplatin-induced nephrotoxicity via reactive oxygen species reduction in renal epithelial cells and enhances antitumor activity in Caki-2 renal cancer cells

Identification of ABC transporter Cdr1 inhibitors of Candida glabrata

Candida glabrata is one of the most common causes of invasive candidiasis. Rising treatment failures from resistance to current antifungal drugs highlight the need for new antifungals. Overexpression of efflux pump transporter genes is significantly associated with the development of multidrug resistance. In this study, we have identified novel and potential inhibitors of ABC transporter Cdr1 of Candida glabrata (CgCdr1) by employing high throughput virtual screening of large chemical datasets from five different chemical libraries (ZINC, DrugBank, ChemDiv antifungal, ChemDiv Kinases, and ChEMBL bioassay). As a result many molecules were predicted to have higher binding affinity toward the CgCdr1, in which a naturally occurring compound, pentagalloyl glucose, was identified to significantly reduce the growth of Candida glabrata with an IC50 value of 16.97 ± 2.1 μM. Molecular dynamics studies showed stable binding of pentagalloyl glucose with CgCdr1 protein. In summary, our research identifies pentagalloyl glucose as a novel antifungal compound that has the potential to be used for inhibiting the growth of Candida glabrata.

Pentagalloyl Glucose from Bouea macrophylla Suppresses the Epithelial-Mesenchymal Transition and Synergizes the Doxorubicin-Induced Anticancer and Anti-Migration Effects in Triple-Negative Breast Cancer

Background: Triple-negative breast cancer (TNBC) represents an aggressive form of breast cancer with few available therapeutic options. Chemotherapy, particularly with drugs like doxorubicin (DOX), remains the cornerstone of treatment for this challenging subtype. However, the clinical utility of DOX is hampered by adverse effects that escalate with higher doses and drug resistance, underscoring the need for alternative therapies. This study explored the efficacy of pentagalloyl glucose (PGG), a natural polyphenol derived from Bouea macrophylla, in enhancing DOX's anticancer effects and suppressing the epithelial-mesenchymal transition (EMT) in TNBC cells. Methods: This study employed diverse methodologies to assess the effects of PGG and DOX on TNBC cells. MDA-MB231 triple-negative breast cancer cells were used to evaluate cell viability, migration, invasion, apoptosis, mitochondrial membrane potential, and protein expression through techniques including MTT assays, wound healing assays, flow cytometry, Western blotting, and immunofluorescence. Results: Our findings demonstrate that PGG combined with DOX significantly inhibits TNBC cell proliferation, migration, and invasion. PGG enhances DOX-induced apoptosis by disrupting the mitochondrial membrane potential and activating caspase pathways; consequently, the activation of caspase-3 and the cleavage of PARP are increased. Additionally, the study shows that the combination treatment upregulates ERK signaling, further promoting apoptosis. Moreover, PGG reverses DOX-induced EMT by downregulating mesenchymal markers (vimentin and β-catenin) and upregulating epithelial markers (E-cadherin). Furthermore, it effectively inhibits STAT3 phosphorylation, associated with cell survival and migration. Conclusions: These results highlight the potential of PGG as an adjuvant therapy in TNBC treatment. PGG synergizes with DOX, which potentiates its anticancer effects while mitigating adverse reactions.

Pentagalloyl Glucose: A Review of Anticancer Properties, Molecular Targets, Mechanisms of Action, Pharmacokinetics, and Safety Profile

Pentagalloyl glucose (PGG) is a natural hydrolyzable gallotannin abundant in various plants and herbs. It has a broad range of biological activities, specifically anticancer activities, and numerous molecular targets. Despite multiple studies available on the pharmacological action of PGG, the molecular mechanisms underlying the anticancer effects of PGG are unclear. Here, we have critically reviewed the natural sources of PGG, its anticancer properties, and underlying mechanisms of action. We found that multiple natural sources of PGG are available, and the existing production technology is sufficient to produce large quantities of the required product. Three plants (or their parts) with maximum PGG content were Rhus chinensis Mill, Bouea macrophylla seed, and Mangifera indica kernel. PGG acts on multiple molecular targets and signaling pathways associated with the hallmarks of cancer to inhibit growth, angiogenesis, and metastasis of several cancers. Moreover, PGG can enhance the efficacy of chemotherapy and radiotherapy by modulating various cancer-associated pathways. Therefore, PGG can be used for treating different human cancers; nevertheless, the data on the pharmacokinetics and safety profile of PGG are limited, and further studies are essential to define the clinical use of PGG in cancer therapies.

Investigation of the inhibition effect of 1,2,3,4,6-pentagalloyl-β-D-glucose on gastric cancer cells based on a network pharmacology approach and experimental validation

Background

Gastric cancer (GC) is ranked as the third leading cause of cancer-related mortality worldwide. 1,2,3,4,6-Pentagalloyl-β-D-glucose (β-PGG) has various pharmacological activities and has been shown to suppress cancer development. However, the mechanism by which β-PGG inhibits gastric cancer has not been elucidated.

Objective

This study explored the potential targets and mechanism of β-PGG in GC using the network pharmacology approach combined with in-vitro experiments.

Methods

The PharmMapper software was used to predict the potential targets of β-PGG, and GC-related genes were identified on the GeneCards database. PPI analysis of common genes was performed using the STRING database. The potential regulatory mechanism of β-PGG in GC was explored through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. The binding ability of key genes and target proteins was verified by molecular docking. The effects of β-PGG on genes and proteins were evaluated using the CCK-8 assay, cell cycle analysis, apoptosis assay, real-time fluorescence quantification polymerase chain reaction (qRT-PCR), and Western blotting.

Results

Eight hub genes involved in cell cycle progression and apoptosis were identified. Cancer-related signaling pathways were identified using the Cytoscape tool. Some of those genes were significantly enriched in the p53 signaling pathway. The CCK-8 assay showed that β-PGG inhibited the proliferation of GC cells. Cell cycle and apoptosis experiments revealed that β-PGG induced cell cycle arrest and apoptosis of gastric cancer cells. qRT-PCR and Western blot analysis showed that β-PGG inhibited β-PGG cells by modulating the p53 signaling pathway.

Conclusion

In the present study, the targets and mechanism of β-PGG in gastric cancer were explored. The results indicate that β-PGG can be used to develop treatments for GC.

Pentagalloyl Glucose and Cisplatin Combination Treatment Exhibits a Synergistic Anticancer Effect in 2D and 3D Models of Head and Neck Carcinoma

Although cisplatin is a first-line chemotherapy drug for head and neck squamous cell carcinoma (HNSCC), its therapeutic efficacy is limited owing to serious side effects and acquired drug resistance. This study determined whether combining pentagalloyl glucose (PGG) and cisplatin enhanced their anti-tumor activities on HNSCC cell lines. We investigated the anticancer effect of PGG combined with cisplatin in 2D and 3D multicellular spheroid cell culture. The results revealed that PGG combined with cisplatin inhibited cell viability and produced synergistic effects. PGG potentiates the anticancer effect of cisplatin by promoting apoptosis and inhibiting cell migration. The western blot and molecular docking analysis revealed that the synergistic effect of the combination treatment may be related to the PGG-mediated reduced expression of phosphorylated STAT3 and phosphorylated Akt. Furthermore, we found that the combined treatment of PGG and cisplatin’s effect on 3D multicellular spheroid size was more potent than the monotherapies. Our findings indicated that the combination therapy of PGG and cisplatin synergistically inhibited HNSCC cancer cell viability and induced apoptosis in 2D and 3D models. The present results suggested that PGG may be a promising adjunct drug used with cisplatin for a practical therapeutic approach to head and neck cancer.

Chemical Characteristics and Antioxidant Activity of Arctostaphylos uva-ursi L. Spreng. at the Southern Border of the Geographical Range of the Species in Europe

The bearberry (Arctostaphylos uva-ursi L. Spreng.) is a source of herbal material—bearberry leaf (Uvae ursi folium), which is highly valued and sought by pharmaceutical and cosmetic industries. For many years, leaves of this plant have been used in traditional medicine as a diuretic, antimicrobial, and anti-inflammatory agent for various diseases of the urogenital tract. The bearberry has also been proposed as a natural antioxidant additive due to the high contents of phenolic compounds in its leaves. The study was focused on characterization of the basic phytochemical composition and antioxidant activity of extracts derived from bearberry leaves collected from plants located at the southern border of the geographical range of the species in Europe. The investigated herbal material is characterized by a different chemical profile compared to the chemical profiles of bearberry found in other parts of the continent. Bearberry extracts from plants growing in two different habitat types—heathlands and pine forests showed a wide range of variation, especially in the concentration of hyperoside, corilagin, and methylartutin and the total flavonoid contents. In addition to arbutin, bearberry can be a valuable source of phenolic compounds, which are mainly responsible for the antioxidant properties of extracts. The high content of phenols and high values of antioxidant parameters indicate a high potential of bearberry leaves to be used as a powerful natural source of antioxidants in herbal preparations. Therefore, the A. uva-ursi populations can be a source of plant material for pharmaceutical, cosmetic, and food industries.

Phytochemicals in Malignant Pleural Mesothelioma Treatment-Review on the Current Trends of Therapies

Malignant pleural mesothelioma (MPM) is a rare but highly aggressive tumor of pleura arising in response to asbestos fibers exposure. MPM is frequently diagnosed in the advanced stage of the disease and causes poor prognostic outcomes. From the clinical perspective, MPM is resistant to conventional treatment, thus challenging the therapeutic options. There is still demand for improvement and sensitization of MPM cells to therapy in light of intensive clinical studies on chemotherapeutic drugs, including immuno-modulatory and targeted therapies. One way is looking for natural sources, whole plants, and extracts whose ingredients, especially polyphenols, have potential anticancer properties. This comprehensive review summarizes the current studies on natural compounds and plant extracts in developing new treatment strategies for MPM.

Nephroprotective potential of Anogeissus latifolia Roxb. (Dhava) against gentamicin-induced nephrotoxicity in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Stem bark of Anogeissus latifolia Roxb. (Family: Combretaceae) is used traditionally and ethnomedicinally for correction of kidney disorders.

AIM OF THE STUDY

The present study demonstrates the nephroprotective potential of stem bark of A. latifolia Roxb.

MATERIALS AND METHODS

The HPTLC fingerprint and HPLC analysis were carried out to standardize the ethanolic extract of stem bark of A. latifolia (ALEE) using ellagic acid as a marker. Nephrotoxicity was induced in adult Wistar albino rats by gentamicin (100 mg/kg, intraperitoneally for 8 days) and they were treated with ALEE (100, 200 and 400 mg/kg, orally for 8 days), ellagic acid (10 mg/kg, orally for 8 days) and cystone syrup (5 ml/kg, orally), a standard reference a polyherbal formulation. Urine volume, serum and urine levels of creatinine, urea and uric acid, oxidative stress parameters (lipid peroxidation, catalase, superoxide dismutase and reduced glutathione), inflammatory markers (TNF-α and IL-6) and kidney weight along with its histological changes were studied in experimental animals.

RESULTS

HPTLC, HPLC and LC-MS analysis of ALEE revealed the presence of ellagic acid and other various phytoconstituents. Administration of gentamicin caused significant increase in urine output and kidney weight, elevated biochemical, inflammatory and oxidative stress parameters as well as caused histological damage in the kidney tissue. These parameters were attenuated by the concurrent treatment with ALEE and ellagic acid. The effects were comparable to cystone.

CONCLUSION

Present investigations concluded that ALEE exhibited nephroprotective potential and validated the traditional use of stem bark of A. latifolia in kidney disorders. The nephroprotective effect may be attributed to the antioxidant and anti-inflammatory phytoconstituents in ALEE.

Polyphenol Extract from Evening Primrose (Oenothera paradoxa) Inhibits Invasion Properties of Human Malignant Pleural Mesothelioma Cells

Extracts from the defatted evening primrose (Oenothera paradoxa Hudziok) seeds are the source of a range of stable polyphenolic compounds, including ellagic acid, gallic acid, and catechin. Our studies evaluate, for the first time, the influence of evening primrose isopropanol extract (EPE) on malignant pleural mesothelioma (MPM) cells. MPM is rarely diagnosed, its high aggressiveness and frequently noted chemoresistance limit its treatment schemes and it is characterized by low prognostic features. Here, we demonstrate that EPE inhibited MPM growth in a dose-dependent manner in cells with increased invasion properties. Moreover, EPE treatment resulted in cell cycle arrest in the G2/M phase and increased apoptosis in invasive MPM cell lines. Additionally, EPE strongly limited invasion and MMP-7 secretion in MPM cancer cells. Our original data provide evidence about the potential anti-invasive effects of EPE in MPM therapy treatment.

Gallnuts: A Potential Treasure in Anticancer Drug Discovery

Introduction. In the discovery of more potent and selective anticancer drugs, the research continually expands and explores new bioactive metabolites coming from different natural sources. Gallnuts are a group of very special natural products formed through parasitic interaction between plants and insects. Though it has been traditionally used as a source of drugs for the treatment of cancerous diseases in traditional and folk medicinal systems through centuries, the anticancer properties of gallnuts are barely systematically reviewed. Objective. To evidence the traditional uses and phytochemicals and pharmacological mechanisms in anticancer aspects of gallnuts, a literature review was performed. Materials and Methods. The systematic review approach consisted of searching web-based scientific databases including PubMed, Web of Science, and Science Direct. The keywords for searching include gallnut, Galla Chinensis, Rhus chinensis, Rhus potaninii, Rhus punjabensis, nutgall, gall oak, Quercus infectoria, Quercus lusitanica, and galla turcica. Two reviewers extracted papers independently to remove the papers unrelated to the anticancer properties of gallnuts. Patents, abstracts, case reports, and abstracts in symposium and congress were excluded. Results and Conclusion. As a result, 14 articles were eligible to be evaluated. It is primarily evident that gallnuts contain a number of bioactive metabolites, which account for anticancer activities. The phytochemical and pharmacological studies reviewed strongly underpin a fundamental understanding of anticancer properties for gallnuts (Galla Chinensis and Galla Turcica) and support their ongoing clinical uses in China. The further bioactive compounds screening and evaluation, pharmacological investigation, and clinical trials are expected to progress gallnut-based development to finally transform the wild medicinal gallnuts to the valuable authorized anticancer drugs.

1,2,3,4,6-Penta-O-Galloyl-Beta-D-Glucopyranoside Inhibits Proliferation of Multiple Myeloma Cells Accompanied with Suppression of MYC Expression

Multiple myeloma (MM) still remains an incurable disease, therefore discovery of novel drugs boosts the therapeutics for MM. The natural compound 1,2,3,4,6-Penta-O-galloyl-beta-D-glucopyranoside (PGG) has been shown to exhibit antitumor activities against various cancer cells. Here, we aim to evaluate antitumor effects of PGG on MM cell lines. PGG inhibited the growth of three different MM cell lines in a dose- and time-dependent manner. Cell cycle analysis revealed that PGG treatment caused cell cycle arrest in G1 phase. It also induced apoptosis which was indicated by significant increases of Annexin V positive cells, caspase 3/7 activity, and cleaved caspase 3 expression in PGG treated MM cell. Since MYC is frequently hyperactivated in MM and inhibition of MYC leads to MM cell death. We further demonstrated that PGG decreased MYC expression in protein and mRNA levels and reversed the mRNA expression of MYC target genes such as p21, p27, and cyclin D2. In addition, PGG also reduced protein expression of DEPTOR which is commonly overexpressed in MM. Unexpectedly, PGG antagonized the cytotoxic effect of bortezomib in the combination treatment. However, PGG treatment sensitized MM cells to another proteasome inhibitor MG132 induced cytotoxicity. Moreover, MYC inhibitor JQ1 enhanced the cytotoxic effect of bortezomib on MM cells. Our findings raised concerns about the combinatory use of bortezomib with particular types of chemicals. The evidence also provide useful insights into the combination of MYC and proteasome-inhibitors for MM therapy. Finally, PGG has a therapeutic potential for treatment of MM and further development is mandatory.

Plant-Derived Agents for Counteracting Cisplatin-Induced Nephrotoxicity

Cisplatin (CSP) is a chemotherapeutic agent commonly used to treat a variety of malignancies. The major setback with CSP treatment is that its clinical efficacy is compromised by its induction of organ toxicity, particular to the kidneys and ears. Despite the significant strides that have been made in understanding the mechanisms underlying CSP-induced renal toxicity, advances in developing renoprotective strategies are still lacking. In addition, the renoprotective approaches described in the literature reveal partial amelioration of CSP-induced renal toxicity, stressing the need to develop potent combinatorial/synergistic agents for the mitigation of renal toxicity. However, the ideal renoprotective adjuvant should not interfere with the anticancer efficacy of CSP. In this review, we have discussed the progress made in utilizing plant-derived agents (phytochemicals) to combat CSP-induced nephrotoxicity in preclinical studies. Furthermore, we have also presented strategies to utilize phytochemicals as prototypes for the development of novel renoprotective agents for counteracting chemotherapy-induced renal damage.

The synthesis and antitumor activity of twelve galloyl glucosides

Twelve galloyl glucosides 1-12, showing diverse substitution patterns with two or three galloyl groups, were synthesized using commercially available, low-cost D-glucose and gallic acid as starting materials. Among them, three compounds, methyl 3,6-di-O-galloyl-α-D-glucopyranoside (9), ethyl 2,3-di-O-galloyl-α-D-glucopyranoside (11) and ethyl 2,3-di-O-galloyl-β-D-glucopyranoside (12), are new compounds and other six, 1,6-di-O-galloyl-β-D-glucopyranose (1), 1,4,6-tri-O-galloyl-β-D-glucopyranose (2), 1,2-di-O-galloyl-β-D-glucopyranose (3), 1,3-di-O-galloyl-β-D-glucopyranose (4), 1,2,3-tri-O-galloyl-α-D-glucopyranose (6) and methyl 3,4,6-tri-O-galloyl-α-D-glucopyranoside (10), were synthesized for the first time in the present study. In in vitro MTT assay, 1-12 inhibited human cancer K562, HL-60 and HeLa cells with inhibition rates ranging from 64.2% to 92.9% at 100 μg/mL, and their IC50 values were determined to be varied in 17.2-124.7 μM on the tested three human cancer cell lines. In addition, compounds 1-12 inhibited murine sarcoma S180 cells with inhibition rates ranging from 38.7% to 52.8% at 100 μg/mL in the in vitro MTT assay, and in vivo antitumor activity of 1 and 2 was also detected in murine sarcoma S180 tumor-bearing Kunming mice using taxol as positive control.

P2X7 receptor blockade protects against cisplatin-induced nephrotoxicity in mice by decreasing the activities of inflammasome components, oxidative stress and caspase-3

Nephrotoxicity is a common complication of cisplatin chemotherapy and thus limits the use of cisplatin in clinic. The purinergic 2X7 receptor (P2X7R) plays important roles in inflammation and apoptosis in some inflammatory diseases; however, its roles in cisplatin-induced nephrotoxicity remain unclear. In this study, we first assessed the expression of P2X7R in cisplatin-induced nephrotoxicity in C57BL/6 mice, and then we investigated the changes of renal function, histological injury, inflammatory response, and apoptosis in renal tissues after P2X7R blockade in vivo using an antagonist A-438079. Moreover, we measured the changes of nod-like receptor family, pyrin domain containing proteins (NLRP3) inflammasome components, oxidative stress, and proapoptotic genes in renal tissues in cisplatin-induced nephrotoxicity after treatment with A-438079. We found that the expression of P2X7R was significantly upregulated in the renal tubular epithelial cells in cisplatin-induced nephrotoxicity compared with that of the normal control group. Furthermore, pretreatment with A-438079 markedly attenuated the cisplatin-induced renal injury while lightening the histological damage, inflammatory response and apoptosis in renal tissue, and improved the renal function. These effects were associated with the significantly reduced levels of NLRP3 inflammasome components, oxidative stress, p53 and caspase-3 in renal tissues in cisplatin-induced nephrotoxicity. In conclusions, our studies suggest that the upregulated activity of P2X7R might play important roles in the development of cisplatin-induced nephrotoxicity, and P2X7R blockade might become an effective therapeutic strategy for this disease.

Biological and biomedical functions of Penta-O-galloyl-D-glucose and its derivatives

Penta-O-galloyl-D-glucose (PGG) is a simple hydrolysable tannin in plants. PGG exists in two anomeric forms, α-PGG and β-PGG. While β-PGG can be found in a wide variety of plants, α-PGG is rather rare in nature. Numerous studies with β-PGG revealed a wide variety of biological activities, such as anti-microbial and anti-cancer functions. Until recently, studies with α-PGG were limited by the lack of its availability. Since the development of an efficient chemical synthesis of the compound, several investigations have revealed its anti-diabetic, anti-cancer, and anti-platelet-coagulation functions. Based on structure-activity-relationship (SAR) studies with α-PGG, a variety of α-PGG-related novel compounds were synthesized and some of them have been shown to possess promising therapeutic activities. In this review, the authors will survey and evaluate the biological functions of PGG with a focus on α-PGG and its derivatives.

Triggering of suicidal erythrocyte death by penta-O-galloyl-β-D-glucose

The polyphenolic 1,2,3,4,6-penta-O-galloyl-beta-d-glucose from several medicinal herbs triggers apoptosis and has, thus, been proposed for treatment of malignancy. The substance is at least partially effective through caspase activation. In analogy to apoptosis of nucleated cells, erythrocytes may enter suicidal death or eryptosis, which is characterized by cell shrinkage and by phosphatidylserine translocation to the erythrocyte surface. Eryptosis is triggered by increase of cytosolic Ca²⁺-activity ([Ca²⁺]i). The sensitivity to [Ca²⁺]i is enhanced by ceramide. The present study explored whether penta-O-galloyl-β-d-glucose stimulates eryptosis. Cell volume was estimated from forward scatter, phosphatidylserine exposure from annexin V binding, hemolysis from hemoglobin-release, [Ca²⁺]i from Fluo3-fluorescence and ceramide abundance from fluorescent antibodies. A 48-h exposure of human erythrocytes to penta-O-galloyl-β-d-glucose significantly decreased forward scatter (50 µM) and significantly increased annexin V binding (10 µM). Up to 50 µM penta-O-galloyl-β-d-glucose did not significantly modify [Ca²⁺]i. However, the effect of penta-O-galloyl-β-d-glucose (25 µM) induced annexin V binding was slightly, but significantly, blunted by removal of extracellular Ca²⁺, pointing to sensitization of erythrocytes to the scrambling effect of Ca²⁺. Penta-O-galloyl-β-d-glucose (25 µM) further increased ceramide formation. In conclusion, penta-O-galloyl-β-d-glucose stimulates suicidal erythrocyte death or eryptosis, an effect partially due to stimulation of ceramide formation with subsequent sensitization of erythrocytes to Ca²⁺.

Co-treatment with quercetin and 1,2,3,4,6-penta-O-galloyl-β-D-glucose causes cell cycle arrest and apoptosis in human breast cancer MDA-MB-231 and AU565 cells

Breast cancer is the most universal cancer in women, but the medications for breast cancer usually cause serious side effects and offer no effective treatment for triple-negative breast cancer. Here, we investigated the growth inhibitory effects of gallic acid (GA), (-)-epigallocatechin gallate (EGCG), or 1,2,3,4,6-penta-O-galloyl-β-D-glucose (5GG) combined with quercetin (Que) on breast cancer cells. In this study, we tested the combined effects of these compounds on estrogen receptor (ER)/human epidermal growth factor 2 (Her2)-negative (MDA-MB-231), ER-positive/Her2-negative (BT483), and ER-negative/Her2-positive (AU565) breast cancer cells. After treatment of each cell line with these compounds, we found that Que combined with 5GG induced S-phase arrest and apoptosis in MDA-BM-231 cells through downregulation of S-phase kinase protein 2 expression, but induced G2/M-phase arrest and apoptosis in AU565 cells through downregulation of Her2 expression. Additionally, Que combined with 5GG was more effective in inhibiting MDA-MB-231 cell growth than Que combined with EGCG (5GG analogue) or GA. The combination of 5GG and Que can offer great potential for the chemoprevention of ER-negative breast cancer.