Chinese Propolis Inhibits the Proliferation of Human Gastric Cancer Cells by Inducing Apoptosis and Cell Cycle Arrest

Propolis Stands out as a Multifaceted Natural Product: Meta-Analysis on Its Sources, Bioactivities, Applications, and Future Perspectives

Honeybee (Apis spp.) products have been used for centuries due to their nutritional value and diverse healing properties. Propolis, produced by honeybees, is a unique resin collected from tree buds, sap flows, and other plant exudates, which is then mixed with bee enzymes, beewax, and secretions. This comprehensive review starts with a meta-analysis following the PRISMA approach to explore recent advances in the chemical composition of propolis, its biological activities and pharmacological properties, its applications and products, and future perspectives. The composition of propolis varies depending on plant source, season of harvest, geography, type of bee flora, climate, and honeybee species at the site of collection, and some of these are related. Flavonoids, aromatic acids, phenolic acids, and their esters are key bioactive compounds in propolis, contributing to their diverse pharmacological properties, such as antioxidant, antibacterial, antiparasitic, antiviral, antileishmanial, antidiabetic, anti-inflammatory, immunomodulatory, and anticancer effects. In summary, propolis stands out as a multifaceted natural product with a broad spectrum of biological activities. This review aims to provide valuable insights for researchers, practitioners, and decision-makers involved in studying the sources, composition, and biological activities of propolis. The highlighted hotspots and emerging frontiers presented herein are poised to unlock the full potential of propolis, paving the way for innovative applications in health and wellness.

Effect of Propolis on PPP2R1A and Apoptosis in Cancer Cells

Recently, it has been shown that protein phosphatase 2A (PP2A) dysfunction was common in many cancer types and was mediated by various inactivation mechanisms. Although many research studies observed antitumor effect of propolis extracts in various types of cancer, the mechanism of effect are still obscure. In this study, we investigated the effect of propolis on PPP2R1A expression and its relationship with apoptosis in the SW-620 (colorectal cancer), DU-145 and PC-3 (prostate cancer), and MCF-7 (breast cancer) cell lines, with WI-38 (healthy fibroblast) cells serving as the control. Moreover, we aimed to investigate the impact of propolis on apoptosis by analyzing apoptosis markers such as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), APAF-1, and caspases-3, -8, and -9. Propolis samples were extracted, and their phenolic compounds were quantified using LC-MS/MS. The RealTime Cell Analysis System-xCELLigence (RTCA-SP) device and software were employed to assess cell viability and cytotoxicity of the propolis samples. The IC50 values for propolis were determined (298 μg/mL for SW-620, 185.6 μg/mL for DU-145, 250.7 μg/mL for PC - 3, 292.9 μg/mL for MCF-7, and 311.2 μg/mL for WI-38). Subsequently, the effects of propolis on PPP2R1A expression and apoptosis markers (TRAIL, Apaf-1, and caspases-3, -8, and -9) were analyzed. When we compared the healthy cell lines to cancer cell lines, a statistically significant increase in caspase-3 (3.62-fold) and in TRAIL (4.38-fold) was observed in the SW-620 cell line after the application of propolis. In addition, in the PC-3 cell line, a 1.4-fold increase in caspase-8 was observed compared with the healthy cell line, which is also statistically significant. Our findings indicated that propolis increased the PPP2R1A levels and apoptosis markers in cancer cell lines. It has been suggested that high PPP2R1A levels induced by propolis treatment might activate the apoptosis pathway. In this study, the inducible effect of propolis on PPP2R1A levels, identified as a new target for cancer treatment, was demonstrated for the first time. The findings suggest that propolis holds promise as a potential cancer therapy by increasing PPP2R1A levels, a key molecule in cancer treatment.

Evaluation of the Antioxidant Properties and Biological Effects of a Novel Combined Barberry Root-Propolis Extract on HEK293T Cells

Background/Objectives: The health benefits of honeybee products and herbs are well known, and their appropriate combination may enhance their biological efficacy. This study investigated the biological properties of a combined barberry root and propolis extract (PBE) in comparison to a propolis extract (PE), a barberry root extract (BE), and pure berberine (BN). Methods: The antioxidant properties were evaluated using DPPH and FRAP methods and total phenolic contents (TPC) were assessed by the Folin-Ciocalteu method. HPTLC was used to quantify the BE in the tested samples. Their effect on HEK293T cells was monitored in real-time by using the xCELLigence system which recorded changes in the proliferative activity (PA). The metabolic activity (MA) was evaluated using an MTS test and cell migration was analyzed via a scratch assay. Results: The PE exhibited a higher TPC (198.67 mg/g) than the BE (119.3 mg/g). The PBE exhibited a comparable antioxidant effect to that of the PE. In the cell assays, the PE, the BE, and BN significantly reduced the proliferative activity at higher concentrations (p < 0.0001) while the PBE demonstrated a lower cytotoxicity and proved to be safer for the tested cells. The highest IC50 value was determined for the PBE (130 µg/mL), suggesting that this combination has a reduced cytotoxicity. However, the scratch test did not confirm a significant supportive effect of the PBE on cell migration. Conclusions: Although the PBE did not show enhanced antioxidant properties, it may mitigate cytotoxicity and support proliferation at lower concentrations. This suggests that extraction of raw propolis with a previously prepared barberry extract results in a safer preparation, but its therapeutic potential requires further studies using biological models.

Propolis: a natural compound with potential as an adjuvant in cancer therapy - a review of signaling pathways

Propolis is a natural product used in cancer treatment, which is produced by bees via different sources. The chemical composition of Propolis is determined based on the climatic and geographical conditions, as well as harvesting time and method. This compound has been the subject of numerous investigational endeavors due to its expansive therapeutic capacity which includes antibacterial, anti-fungal, anti-inflammatory, anti-oxidant, anti-viral, and anti-cancer effects. The growing incidence rate of different cancers necessitates the need for developing novel preventive and therapeutic strategies. Chemotherapy, radiotherapy, and stem cell therapy have proved effective in cancer treatment, regardless of the adverse events associated with these modalities. Clinical application of natural compounds such as Propolis may confer promise as an adjuvant therapeutic intervention, particularly in certain subpopulations of patients that develop adverse events associated with anticancer regimens. The diverse biologically active compounds of propolis are believed to confer anti-cancer potential by modulation of critical signaling cascades such as caffeic acid phenethyl ester, Galangin, Artepillin C, Chrysin, Quercetin, Caffeic acid, Nymphaeols A and C, Frondoside A, Genistein, p-coumaric acid, and Propolin C. This review article aims to deliver a mechanistic account of anti-cancer effects of propolis and its components. Propolis can prevent angiogenesis by downregulating pathways involving Jun-N terminal kinase, ERK1/2, Akt and NF-ƘB, while counteracting metastatic progression of cancer by inhibiting Wtn2 and FAK, and MAPK and PI3K/AKT signaling pathways. Moreover, propolis or its main components show regulatory effects on cyclin D, CDK2/4/6, and their inhibitors. Additionally, propolis-induced up-regulation of p21 and p27 may result in cell cycle arrest at G2/M or G0/G1. The broad anti-apoptotic effects of propolis are mediated through upregulation of TRAIL, Bax, p53, and downregulation of the ERK1/2 signaling pathway. Considering the growing body of evidence regarding different anti-cancers effects of propolis and its active components, this natural compound could be considered an effective adjuvant therapy aimed at reducing related side effects associated with chemotherapy and radiotherapy.

Antineoplastic Activity Evaluation of Brazilian Brown Propolis and Artepillin C in Colorectal Area of Wistar Rats

OBJECTIVE

The study's aim was to evaluate Brazilian Brown Propolis (BBP) and Artepillin C (ARC) chemopreventive action in Wistar rats' colons.

METHODS

Fifty male Wistar rats were divided into ten experimental groups, including control groups, groups with and without 1,2-dimethylhydrazine (DMH) induction, and BBP, ARC, and ARC enriched fraction (EFR) treatments, for sixteen weeks. Aberrant crypt foci (ACF) were classified as hyperplastic or dysplastic, and proliferating cell nuclear antigen (PCNA) expression was quantified.

RESULT

ACF amounts in experimental groups (induced or not) decreased in both colon portions, while the isolated Aberrant Crypt (AC) number increased. Experimental groups of animals showed higher hyperplasia and dysplasia amounts compared with control groups. The ACF dysplastic amount present in groups induced and treated, in both colon portions, had similar values to IDMH (DMH induction group without treatment). In addition, DMH was effective in ACF inducing and there was positive staining for PCNA in basal and upper dysplastic foci portions in all experimental groups, in the mitotic index (MI) evaluation. To conclude, considering all the experimental groups, the one treated with EFR (fraction enriched with ARC) had the lowest rates of cell proliferation.

CONCLUSION

BBP and its derivatives prevented crypt cell clonal expansion.

Caffeic Acid Phenethyl Ester: A Potential Therapeutic Cancer Agent?

BACKGROUND

Propolis and its major phenolic compound, caffeic acid phenethyl ester (CAPE), have garnered considerable scientific interest due to their anti- inflammatory properties and potential therapeutic applications.

OBJECTIVES

This narrative review explores the potential utility of CAPE in cancer treatment.

METHODS

We comprehensively reviewed relevant studies from scientific databases (PubMed and Web of Science) from 2000 to 2022. Our search focused on keywords such as cancer, natural drugs, caffeic acid phenethyl ester, CAPE, cancer cell lines, antitumor effects, and propolis.

RESULTS

CAPE exhibits diverse biological benefits, including antimicrobial, antioxidant, antiviral, anti-inflammatory, cytotoxic, and potentially anti-carcinogenic properties. Numerous studies have demonstrated its wide-ranging antitumor effects on various cancer cell lines, including growth inhibition, apoptosis induction, tumor invasiveness prevention, malignancy suppression, and anti-angiogenic activity.

CONCLUSION

Following comprehensive preclinical toxicity assessments, further evaluation of CAPE's efficacy and safety through clinical trials is highly recommended to elucidate its potential health benefits in diverse forms of human cancer.

Differential Apoptotic Effects of Bee Product Mixtures on Normal and Cancer Hepatic Cells

Most effective anticancer drugs normally generate considerable cytotoxicity in normal cells; therefore, the preferential activation of apoptosis in cancer cells and the reduction of toxicity in normal cells is a great challenge in cancer research. Natural products with selective anticancer properties used as complementary medicine can help to achieve this goal. The aim of the present study was to analyze the effect of the addition of bee products [propolis (PR) or royal jelly (RJ) or propolis and royal jelly (PR+RJ), 2-10%] to thyme (TH) and chestnut honeys (CH) on the differential anticancer properties, mainly the cytotoxic and pro-apoptotic effects, in normal and cancer hepatic cells. The cytotoxic effects of samples were analyzed using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay (0-250 mg/mL) and the effects on apoptosis were analyzed using cell cycle analysis, TdT-dUTP terminal nick-end labeling (TUNEL) assay, DR5 (Death Receptor 5) and BAX (BCL-2-Associated X) activation, and caspases 8, 9, and 3 activities. Both honey samples alone and honey mixtures had no or very little apoptotic effect on normal cells. Antioxidant honey mixtures enhanced the apoptotic capacity of the corresponding honey alone via both extrinsic and intrinsic pathways. Of all the samples, chestnut honey enriched with 10% royal jelly and 10% propolis (sample 14, CH+10RJ+10PR) showed the highest apoptotic effect on tumor liver cells. The enrichment of monofloral honey with bee products could be used together with conventional anticancer treatments as a dietary supplement without side effects. On the other hand, it could be included in the diet as a natural sweetener with high added value.

Ultrasound-assisted extraction of polyphenols from Chinese propolis

Introduction

Propolis is a beneficial bioactive food with rich polyphenols content. Nowadays, an increasing interest is attracted to the extraction of polyphenols from raw propolis. This study utilized the novel ultrasound-assisted approach for polyphenol extraction from Chinese propolis, aiming to improve its extraction yield and reveal the relevant mechanisms via extraction kinetic study as well as the compositional and structural analysis.

Methods

The optimum ultrasound-assisted extraction conditions were optimized according to the total phenolic content and total flavonoids content. Compositional and structural analysis were conducted using high performance liquid chromatography-quadrupole-time of flight tandem mass spectrometry, high-performance liquid chromatography, Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM).

Results and discussion

The optimum ultrasound-assisted extraction conditions were as follows: ratio of liquid to solid, 60:1; ultrasound power, 135 W; ultrasound duration, 20 min. Under the optimum conditions, the antioxidant activities of the extract were increased by 95.55% and 64.46% by 2,2-diphenyl-1-picrylhydrazyl radical scavenging ability assay and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging ability assay, respectively, compared to those obtained by traditional maceration. The second-order kinetics model was employed to study the extraction process; it was found that ultrasound significantly accelerated the extraction of propolis and increased the maximum extraction volume of phenolic compounds. The qualitative and quantitative analysis of polyphenol compositions showed that ultrasound did not change the polyphenol types in the extract but it significantly improved the contents of various flavonoids and phenolic acids such as galangin, chrysin, pinocembrin, pinobanksin and isoferulic acid. Likewise, the FT-IR analysis indicated that the types of functional groups were similar in the two extracts. The SEM analysis revealed that the ultrasound-assisted extraction enhanced the contact areas between propolis and ethanol by breaking down the propolis particles and eroding the propolis surface.

Anticancer Effects of Propolis Extracts Obtained Using the Cold Separation Method on Breast Cancer Cell Lines

Propolis and its extracts show a wide spectrum of biological activity. Due to the necessity to use high temperatures and high polarity in the eluent, the obtained extracts are depleted of active compounds. The new, cold separation method allows obtaining a qualitatively better product containing a number of chemical compounds absent in extracts obtained using high-temperature methods. The purpose of our study was to evaluate the biological activity of propolis extracts produced with the cold separation method in four female breast cancer cell lines: MDA-MB-231, MDA-MB-468, MCF-7, and T-47D. The results of the breast cancer cell viability were obtained using the MTT test. Propolis extracts at 75 and 80% showed similar cytotoxicity against cancer cells, with the polyphenol fraction 75% being slightly more negative for cells. Propolis extracts at concentrations of 50, 75, and 100 µg/mL significantly reduced cell viability. With the exception of the MDA-MB-231 line, cell viability was also decreased after incubation with a concentration of 25 µg/mL. Our results suggest that propolis extracts obtained with the cold separation method may be considered as promising compounds for the production of health-promoting supplements.

The Role of Propolis as a Natural Product with Potential Gastric Cancer Treatment Properties: A Systematic Review

Gastric cancer is one of the most common, aggressive, and invasive types of malignant neoplasia. It ranks fifth for incidence and fourth for prevalence worldwide. Products of natural origin, such as propolis, have been assessed for use as new complementary therapies to combat cancer. Propolis is a bee product with antiproliferative and anticancer properties. The concentrations and types of secondary metabolites contained in propolis mainly vary according to the geographical region, the season of the year, and the species of bees that make it. The present study is a systematic review of the main articles related to the effects of propolis against gastric cancer published between 2011 and 2021 in the PubMed and Science Direct databases. Of 1305 articles published, only eight studies were selected; among their principal characteristics was the use of in vitro analysis with cell lines from gastric adenocarcinoma and in vivo murine models of the application of propolis treatments. These studies suggest that propolis arrests the cell cycle and inhibits proliferation, prevents the release of oxidizing agents, and promotes apoptosis. In vivo assays showed that propolis decreased the number of tumors by regulating the cell cycle and the expression of proteins related to apoptosis.

The Cytotoxicity and Anticancer Effects of Propolis against the Oral Squamous Cell Carcinoma: In Vitro Study

Background and aim: A wide range of therapeutic properties, including anti-cancer properties, are attributed to propolis, a resinous product obtained from several plants that possess a variety of medicinal properties. A study on honeybee-produced propolis showed that in mice, it showed a significant reduction in the progression of squamous cell carcinoma in the head and neck, but in humans, its role in HNSCC remains unclear. Method and materials: Propolis was sampled from two types of Iranian. Extraction was done using ethanolic extracts of propolis. The cll viability was evaluated by MTT assay. Cancer cell lines were assessed for gene expression, such as  mmp-2, mmp-9, bax, and bcl-2. Results: Increased sample concentrations reduced cell viability but did not cause significant cytotoxicity. A RT-PCR indicated that the Khalkhal sample produced more effects among the two samples, and the level of bax mRNA gene expression in the Khalkhal sample was increased. With an increasing concentration of Khalkhal samples, the expression increased. Increasing Khalkhal sample concentration also reduced mRNA levels of bcl-2, mmp-2, and mmp-9. Conclusion: Khalkhal’s propolis can be considered a suitable sample for the study of antiapoptotic and proapoptotic gene expression. Additionally, it can be used as a potential candidate for inhibiting the proliferation and spread of oral cancer cells.

Molecular and Cellular Mechanisms of Propolis and Its Polyphenolic Compounds against Cancer

In recent years, interest in natural products such as alternative sources of pharmaceuticals for numerous chronic diseases, including tumors, has been renewed. Propolis, a natural product collected by honeybees, and polyphenolic/flavonoid propolis-related components modulate all steps of the cancer progression process. Anticancer activity of propolis and its compounds relies on various mechanisms: cell-cycle arrest and attenuation of cancer cells proliferation, reduction in the number of cancer stem cells, induction of apoptosis, modulation of oncogene signaling pathways, inhibition of matrix metalloproteinases, prevention of metastasis, anti-angiogenesis, anti-inflammatory effects accompanied by the modulation of the tumor microenvironment (by modifying macrophage activation and polarization), epigenetic regulation, antiviral and bactericidal activities, modulation of gut microbiota, and attenuation of chemotherapy-induced deleterious side effects. Ingredients from propolis also "sensitize" cancer cells to chemotherapeutic agents, likely by blocking the activation of the transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). In this review, we summarize the current knowledge related to the the effects of flavonoids and other polyphenolic compounds from propolis on tumor growth and metastasizing ability, and discuss possible molecular and cellular mechanisms involved in the modulation of inflammatory pathways and cellular processes that affect survival, proliferation, invasion, angiogenesis, and metastasis of the tumor.

Polish and New Zealand Propolis as Sources of Antioxidant Compounds Inhibit Glioblastoma (T98G, LN-18) Cell Lines and Astrocytoma Cells Derived from Patient

Gliomas, including glioblastoma multiforme and astrocytoma, are common brain cancers in adults. Propolis is a natural product containing many active ingredients. The aim of this study was to compare the chemical composition, total phenolic content and concentration of toxic elements as well as the anticancer potential of Polish (PPE) and New Zealand (Manuka—MPE) propolis extracts on diffuse astrocytoma derived from patient (DASC) and glioblastoma (T98G, LN-18) cell lines. The antioxidants such as flavonoids and chalcones (pinocembrin, pinobanksin, pinobanksin 3-acetate and chrysin) were the main components in both types of propolis. The content of arsenic (As) and lead (Pb) in MPE was higher than PPE. The anti-proliferative study showed strong activity of PPE and MPE propolis on DASC, T98G, and LN-18 cells by apoptosis induction, cell cycle arrest and attenuated migration. These findings suggest that despite their different geographic origins, Polish and New Zealand propolis are sources of antioxidant compounds and show similar activity and a promising anti-glioma potential in in vitro study. However, further in vivo studies are required in order to assess therapeutic potential of propolis.

Anticancer Activity of Propolis and Its Compounds

Propolis is a natural material that honey bees (Apis mellifera) produce from various botanical sources. The therapeutic activity of propolis, including antibacterial, antifungal, and anti-inflammatory effects, have been known since antiquity. Cancer is one of the major burdens of disease worldwide, therefore, numerous studies are being conducted to develop new chemotherapeutic agents and treatments for cancer. Propolis is a rich source of biologically active compounds, which affect numerous signaling pathways regulating crucial cellular processes. The results of the latest research show that propolis can inhibit proliferation, angiogenesis, and metastasis of cancer cells and stimulate apoptosis. Moreover, it may influence the tumor microenvironment and multidrug resistance of cancers. This review briefly summarizes the molecular mechanisms of anticancer activity of propolis and its compounds and highlights the potential benefits of propolis to reduce the side effects of chemotherapy and radiotherapy.