Propolis: A Detailed Insight of Its Anticancer Molecular Mechanisms

Oral toxicity assessment and the mitigation of lung carcinogenesis by phytol and α-bisabolol combination treatment in swiss albino mice: insights into redox enzyme modulation and caspase-dependent cell death mechanisms

This study examined the safety and potential anti-lung cancer effects of combinations of phytol and α-bisabolol in Swiss albino mice. Both acute and subacute toxicity assessments showed that the combination of phytol and α-bisabolol is safe, with no adverse effects observed at higher concentrations. Hematological, biochemical, and histopathological tests showed no signs of toxicity in the heart, lungs, liver, spleen, and kidneys. The LD50 was greater than 2000 mg/kg, indicating a large safety margin. Histopathological analysis confirmed cancer induction in the B(a)P-induced group, which had significantly altered relative lung weights. Lung weight increased slightly pre and post-treatment, but histopathology showed normal alveolar epithelium. GSH and SOD levels increased significantly in B(a)P-exposed groups, indicating an adaptive antioxidant response. CAT levels increased significantly in the post-treatment group, demonstrating the role of combination of phytol and α-bisabolol in protecting against B(a)P-induced oxidative damage. Upregulation of Bax and downregulation of Bcl-2 caused a pro-apoptotic environment, suggesting a way to inhibit malignant cell survival. Modulation of caspase-3 and caspase-9 showed the complexity of carcinogen-induced apoptotic signaling. In conclusion, phytol and α-bisabolol were found to be safe and organ-protective, and demonstrated no acute or subacute toxicity. They modulate antioxidant defenses and apoptotic pathways, which may help prevent and treat lung cancer.

Preliminary Insights into the Cyto/Genoprotective Properties of Propolis and Its Constituent Galangin In Vitro

Propolis has been well known for centuries as a natural preventive and therapeutic agent. Its numerous health benefits are mainly attributed to its high content of phenolic compounds that have a remarkable antioxidant activity. Since phenolics may exert a dual nature (pro-oxidant and antioxidant) the aim of this study was to investigate the safety profile of the ethanolic extract of propolis and the related flavonoid galangin and their ability to protect lymphocytes from irinotecan-induced cyto/genotoxicity in vitro. Isolated human peripheral blood lymphocytes were exposed for 3 h to three concentrations of propolis extract and galangin corresponding to the average daily dose of 0.25 mL of extract [propolis in 70% ethanol (3:7, w/w)], as well as a five- and ten-fold higher concentration. Cyto- and genoprotective effects were tested using a cytokinesis-block micronucleus cytome assay. Treatment with propolis and galangin in the selected concentrations exerted high biocompatibility with lymphocytes and diminished the level of cytogenetic damage caused by irinotecan. Propolis at the same concentration offered a stronger protective effect than single galangin. Also, apoptosis was the prevailing mechanism of cell death in our experimental conditions. These preliminary results speak in favour of future investigations of propolis using other available cytogenetic methods and cell models.

Integrative computational and experimental study of propolis, polyvinyl alcohol, and alhagi maurorum complex as anticancer and antibacterial agents

The study examined the potential applications of propolis, polyvinyl alcohol (PVA), and Alhagi maurorum extracts in drug delivery systems, utilizing both computer and lab methods. The study uses molecular docking probes along with DFT (density functional theory) to investigate molecular interactions and examine the binding of drugs to carrier materials. The HOMO (Highest Occupied Molecular Orbital)-LUMO (Lowest Occupied Molecular Orbital) gap for the mix of PVA, galangin, and triterpene glycoside is -0.07621 eV, which matches the experiment results. This small gap enhances responsiveness in drug delivery applications, which is crucial for successful interactions with biological targets. It's possible that a delivery system that combines galangin and triterpene glycosides would work better and be more compatible with living things.The experimental results of the Methyl Thiazole Tetrazolium (MTT) show consistent findings: The viability of MCF7, a human breast cancer cell line, significantly decreased at all concentrations of propolis and polyvinyl alcohol compared to WRL68, a fetal liver cell line. Within-group comparisons showed less viability in both groups at 400 µg/ml. Mean ± SD: 42.05267 ± 1.951655; 67.12533 ± 7.401263.In the positive control group, the average number of malignant cells was 47.06, but the average number of cells in the fourth treatment (Propolis + PVA) and the third combination (Propolis + Alhagi maurorum + PVA) were 42.05267 and 42.97800, respectively. The Sustainable Development Goals in Industry and Innovation are focusing on developing a new combination of alhagi and propolis using PVA as a polymer carrier.

Phenolic Content, Antioxidant Activity and In Vitro Anti-Inflammatory and Antitumor Potential of Selected Bulgarian Propolis Samples

BACKGROUND/OBJECTIVES

Propolis (bee glue) is a valuable bee product widely used as a natural remedy, a cosmetic ingredient, a nutritional value enhancer and a food biopreservative. The present research aims to investigate the phenolic content, antioxidant activity and in vitro anti-inflammatory and antitumor potential of six propolis samples from three regions of Bulgaria (Vidin, Gabrovo and Lovech).

METHODS

the analysis of propolis phenolic compounds was determined by high-performance liquid chromatography (HPLC); the antioxidant activity of ethanolic propolis extracts was assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and ferric-reducing antioxidant power (FRAP) assay; the in vitro anti-inflammatory activity was assessed by the inhibition of albumin denaturation method; the in vitro antitumor activity was determined in human metastatic breast cancer cell line MDA-MB-231 using 3-(4,5-Dimethyl -2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay.

RESULTS

The ethanolic propolis extracts exhibited the total phenolic content from 190.4 to 317.0 mg GAE/g, total flavonoid content from 53.4 to 79.3 mg QE/g and total caffeic acid derivatives content from 5.9 to 12.1 mg CAE/g. The studied propolis extracts showed significant antioxidant capacity (between 1000.3 and 1606.0 mM TE/g determined by the DPPH assay, and between 634.1 and 1134.5 mM TE/g determined by the FRAP assay). The chemical composition analysis indicated high concentrations of caffeic acid benzyl ester, chrysin, pinocembrin and pinobanksin-3-O-propionate, predominantly in three of the propolis samples originating from Gabrovo and Lovech regions. All propolis samples demonstrated promising in vitro anti-inflammatory activity, expressed as the inhibition of thermally induced albumin denaturation by 73.59% to 78.44%, which was higher than that of the conventional anti-inflammatory drugs Aspirin (58.44%) and Prednisolone Cortico (57.34%). The propolis samples exhibited high in vitro cytotoxicity against cancer cells MDA-MB-231 with IC50 values ranging between 9.24 and 13.62 µg/mL as determined by MTT assay.

CONCLUSIONS

Overall, we can suggest that the high phenolic content of Bulgarian propolis from respective areas contributes to its enhanced antioxidant, anti-inflammatory and antitumor activity. Taken together, our results support the beneficial properties of Bulgarian propolis, with potential application as a promising therapeutic agent.

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.

Network pharmacology and bioinformatic integrative analysis reveals candidate gene targets and potential therapeutic of East Kalimantan propolis against hepatocellular carcinoma

Introduction

Hepatocellular Carcinoma (HCC) is commonly treated with surgery, liver transplantation, and chemotherapy, but recurrence and metastasis remain challenges. Natural complementary therapies like propolis, known for its hepatoprotective properties, are gaining interest due to limited efficacy and toxicity of conventional chemotherapy. This study aims to identify core targets for HCC, assess the therapeutic potential of East Kalimantan propolis (EKP) from stingless bees, and analyze the molecular interactions.

Methods

EKP compounds were analyzed using target prediction tools related to HCC, alongside clinical data from the Gene Expression Omnibus (GEO) database, to identify overlapping genes with clinical relevance. The selected genes were then subjected to protein-protein interaction (PPI), GO and KEGG enrichment, immunohistochemical comparison and survival analysis to identify potential core targets and related pathways for HCC therapy. Furthermore, molecular docking and dynamics were conducted to verify the molecular interactions and stability of EKP compounds with targets.

Results

108 genes have been selected as HCC potential targets, which mostly associated with MicroRNAs in cancer, chemical carcinogenesis, and viral carcinogenesis pathways. These targets were obtained by overlapping genes from GEO clinical databases and target predictors. PPI network analysis revealed 4 main targets of propolis in HCC. Furthermore, differential expression genes, survival analysis, and Immunohistochemical analysis from databases suggested that AKR1C3 and MAPK1 promote HCC progression and shorten survival rate of HCC patients. Molecular docking and dynamic studies confirmed strong binding affinity and stability of Baicalein, Chrysin, Quercetin, and Myricetin with receptor targets within simulation time.

Conclusions

This study provides insight into the mechanism of action of EKP on HCC and identifies AKR1C3 and MAPK1 as candidate target treatments for future drug development.

Antimicrobial Activity of Honey and Propolis from Alba County, Romania

Investigating the quality of bee products obtained across different geographical regions and analyzing their antimicrobial activity is of significant interest to various scientific disciplines. This study focuses on comparing the antimicrobial activity of honey and propolis samples from different areas of Alba County, Romania. The quality parameters of five samples of two types of bee products (honey and propolis) were assessed. Then, the samples were tested to comparatively determine their antimicrobial properties against 12 species of bacteria (Escherichia coli, Salmonella typhimurium, Salmonella enteritidis, Salmonella anatum, Salmonella choleraesuis, Pseudomonas aeruginosa, Pseudomonas fluorescens, Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Bacillus subtilis, and Listeria monocytogenes) and 7 fungal strains (Candida albicans, Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum, Rhizopus stolonifer, Fusarium oxysporum, and Alternaria alternata). Of the bacterial strains, the most sensitive to the action of honey samples were the two strains of Staphylococcus followed by P. fluorescens. The two strains of Pseudomonas and L. monocytogenes were the most sensitive to the activity of propolis. Of the fungal strains, F. oxysporum was the most sensitive to the actions of both honey and propolis, followed by P. chrysogenum in the case of honey samples and the two Aspergillus strains in the case of propolis. These findings indicate that bee products are rich sources of bioactive compounds exhibiting strong antimicrobial properties and significant potential for the development of new phytopharmaceutical products.

miRNA, phytometabolites and disease: Connecting the dots

miRNAs are tiny noncoding ribonucleotides that function as critical regulators of gene-expression in eukaryotes. A single miRNA may be involved in the regulation of several target mRNAs forming complex cellular networks to regulate diverse aspects of development in an organism. The deregulation of miRNAs has been associated with several human diseases. Therefore, miRNA-based therapeutics is gaining interest in the pharmaceutical industry as the next-generation drugs for the cure of many diseases. Medicinal plants have also been used for the treatment of several human diseases and their curative potential is attributed to their reserve in bioactive metabolites. A role for miRNAs as regulators of the phytometabolic pathways in plants has emerged in the recent past. Experimental studies have also indicated the potential of plant encoded secondary phytometabolites to act as cross-regulators of mammalian miRNAs and transcripts to regulate human diseases (like cancer). The evidence for this cross-kingdom gene regulation through miRNA has gathered considerable enthusiasm in the scientific field, even though there are on-going debates regarding the reproducibility and the effectiveness of these findings. In this review, we provide information to connect the medicinal and gene regulatory properties of secondary phytometabolites, their regulation by miRNAs in plants and their effects on human miRNAs for regulating downstream metabolic or pathological processes. While further extensive research initiatives and good clinical evidence are required to prove or disapprove these findings, understanding of these regulations will have important implications in the potential use of synthetic or artificial miRNAs as effective alternatives for providing health benefits.

A novel black poplar propolis extract with promising health-promoting properties: focus on its chemical composition, antioxidant, anti-inflammatory, and anti-genotoxic activities

Propolis is a resinous mixture produced by honeybees which has been used since ancient times for its useful properties. However, its chemical composition and bioactivity may vary, depending on the geographical area of origin and the type of tree bees use for collecting pollen. In this context, this research aimed to investigate the total phenolic content (using the Folin-Ciocalteu assay) and the total antioxidant capacity (using the FRAP, DPPH, and ABTS assays) of three black poplar (Populus nigra L.) propolis (BPP) solutions (S1, S2, and S3), as well as the chemical composition (HPLC-ESI-MSn) and biological activities (effect on cell viability, genotoxic/antigenotoxic properties, and anti-inflammatory activity, and effect on ROS production) of the one which showed the highest antioxidant activity (S1). The hydroalcoholic BPP solution S1 was a prototype of an innovative, research-type product by an Italian nutraceutical manufacturer. In contrast, hydroalcoholic BPP solutions S2 and S3 were conventional products purchased from local pharmacy stores. For the three extracts, 50 phenolic compounds, encompassing phenolic acids and flavonoids, were identified. In summary, the results showed an interesting chemical profile and the remarkable antioxidant, antigenotoxic, anti-inflammatory and ROS-modulating activities of the innovative BPP extract S1, paving the way for future research. In vivo investigations will be a possible line to take, which may help corroborate the hypothesis of the potential health benefits of this product, and even stimulate further ameliorations of the new prototype.

Insight into the influence of natural deep eutectic solvents on the extraction of phenolic compounds from poplar type propolis: Composition and in vitro biological activity

Natural deep eutectic solvents (NADESs) have been considered promising to replace traditional volatile and toxic organic solvents for the extraction of biologically active substances from natural sources. This work applied an efficient and ethanol-exclusion strategy for extraction of phenolic compounds from poplar type propolis using five known NADESs (lactic acid:1,2-propanediol 1:1, lactic acid:fructose 5:1, choline chloride:1,2-propanediol 1:3, choline chloride:1,2-propanediol:water 1:1:1 and betaine:malic acid:water 1:1:6). The selected NADESs' extractability was evaluated by measuring the concentrations of total phenolics and total flavones and flavonols in the propolis extracts obtained, which qualitative chemical composition was further determined in detail by gas chromatography-mass spectrometry (GC-MS) analysis. It demonstrated that the chemical profiles of NADES and 70% ethanolic propolis extracts are similar. To expand the knowledge about the role of the applied solvents in the poplar propolis extraction process, the in vitro antimicrobial, cytotoxic and genotoxic activity of both NADESs and liquid NADES extracts were evaluated. The results revealed that the use of the selected NADESs as an extraction media for phenolic compounds from poplar propolis not only delivered a good extraction yield in some cases, but generally led to the preservation of propolis extracts' biological activity and even to the enhancement of their antimicrobial effect in comparison with the hydroethanolic one. Besides, the tested NADESs except for lactic acid:fructose and betaine:malic acid:water exerted low to negligible toxicity against normal cells treated and apart from lactic acid:fructose the remaining solvents demonstrated concentration-dependent moderate to subtle genotoxicity. There is a probability that not the supramolecular structure of the NADESs, but their components, played a key role for the observed biological effects. The present study has demonstrated an alternative approach for extracting the biologically active complex from poplar type propolis using NADESs, which could be useful for further pharmaceutical and cosmeceutical applications.

3,3'-O-dimethylquercetin: A bi-functional vasodilator isolated from green propolis of the Caatinga Mimosa tenuiflora

In the search for novel, bi-functional compounds acting as CaV1.2 channel blockers and K+ channel stimulators, which represent an effective therapy for hypertension, 3,3'-O-dimethylquercetin was isolated for the first time from Brazilian Caatinga green propolis. Its effects were investigated through electrophysiological, functional, and computational approaches. In rat tail artery myocytes, 3,3'-O-dimethylquercetin blocked Ba2+ currents through CaV1.2 channels (IBa1.2) in a concentration-dependent manner, with the inhibition being reversed upon washout. The compound also shifted the voltage dependence of the steady-state inactivation curve to more negative potentials without affecting the slope of the inactivation and activation curves. Furthermore, the flavonoid stimulated KCa1.1 channel currents (IKCa1.1). In silico simulations provided additional evidence for the binding of 3,3'-O-dimethylquercetin to KCa1.1 and CaV1.2 channels and elucidated its mechanism of action. In depolarized rat tail artery rings, the flavonoid induced a concentration-dependent relaxation. Moreover, in rat aorta rings its antispasmodic effect was inversely related to the transmembrane K+ gradient. In conclusion, 3,3'-O-dimethylquercetin demonstrates effective in vitro vasodilatory properties, encouraging the exploration of its scaffold to develop novel derivatives for potential use in the treatment of hypertension.

Molecular Mechanism of Natural Food Antioxidants to Regulate ROS in Treating Cancer: A Review

Cancer is the second-highest mortality rate disease worldwide, and it has been estimated that cancer will increase by up to 20 million cases yearly by 2030. There are various options of treatment for cancer, including surgery, radiotherapy, and chemotherapy. All of these options have damaging adverse effects that can reduce the patient's quality of life. Cancer itself arises from a series of mutations in normal cells that generate the ability to divide uncontrollably. This cell mutation can happen as a result of DNA damage induced by the high concentration of ROS in normal cells. High levels of reactive oxygen species (ROS) can cause oxidative stress, which can initiate cancer cell proliferation. On the other hand, the cytotoxic effect from elevated ROS levels can be utilized as anticancer therapy. Some bioactive compounds from natural foods such as fruit, vegetables, herbs, honey, and many more have been identified as a promising source of natural antioxidants that can prevent oxidative stress by regulating the level of ROS in the body. In this review, we have highlighted and discussed the benefits of various natural antioxidant compounds from natural foods that can regulate reactive oxygen species through various pathways.

Therapeutic potential of propolis in alleviating inflammatory response and promoting wound healing in skin burn

Burns can cause inflammation and delayed healing, necessitating alternative therapies due to the limitations of conventional treatments. Propolis, a natural bee-produced substance, has shown promise in facilitating burn healing. This literature review provides a comprehensive overview of propolis' mechanisms of action, wound-healing properties, and its application in treating skin burns. Propolis contains bioactive compounds with antimicrobial, antioxidant, and anti-inflammatory properties, making it a promising candidate for managing skin burn injuries. It helps prevent infections, neutralize harmful free radicals, and promote a well-balanced inflammatory response. Moreover, propolis aids in wound closure, tissue regeneration, collagen synthesis, cellular proliferation, and angiogenesis, contributing to tissue regeneration and remodeling. The article discusses various propolis extracts, extraction methods, chemical composition, and optimized formulations like ointments and creams for burn wound treatment. Considerations regarding dosage and safety are addressed. Further research is needed to fully understand propolis' mechanisms, determine optimal formulations, and establish suitable clinical dosages. Nevertheless, propolis' natural origin and demonstrated benefits make it a compelling avenue for burn care exploration, potentially complementing existing therapies and improving burn management outcomes.

Antitumor Effect of Poplar Propolis on Human Cutaneous Squamous Cell Carcinoma A431 Cells

Propolis is a gelatinous substance processed by western worker bees from the resin of plant buds and mixed with the secretions of the maxillary glands and beeswax. Propolis has extensive biological activities and antitumor effects. There have been few reports about the antitumor effect of propolis against human cutaneous squamous cell carcinoma (CSCC) A431 cells and its potential mechanism. CCK-8 assays, label-free proteomics, RT-PCR, and a xenograft tumor model were employed to explore this possibility. The results showed that the inhibition rate of A431 cell proliferation by the ethanol extract of propolis (EEP) was dose-dependent, with an IC50 of 39.17 μg/mL. There were 193 differentially expressed proteins in the EEP group compared with the control group (p < 0.05), of which 103 proteins (53.37%) were upregulated, and 90 proteins (46.63%) were downregulated. The main three activated and suppressed Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were extracellular matrix (ECM)-receptor interaction, amoebiasis, cell adhesion molecules (CAMs), nonalcoholic fatty liver disease (NAFLD), retrograde endocannabinoid signaling, and Alzheimer's disease. The tumor volume of the 100 mg/kg EEP group was significantly different from that of the control group (p < 0.05). These results provide a theoretical basis for the potential treatment of human CSCC A431 cell tumors using propolis.

Targeting HIF-1 for prostate cancer: a synthesis of preclinical evidence

INTRODUCTION

Hypoxia-inducible factor (HIF) mediates multiple intracellular processes that drive cellular metabolism and induce proliferation. Dysregulated HIF expression is associated with oncogenic cellular transformation. Moreover, high HIF levels correlate with tumor aggressiveness and chemoresistance, indicating the vital effect of HIF-1α on tumorigenicity. Currently, widespread in-vitro and in-vivo research is focusing on targeting HIF with drugs that have already been approved for use by the FDA, such as belzutifan, in renal cell carcinoma. HIF inhibition is mostly associated with tumor size reduction; however, drug toxicity remains a challenge.

AREA COVERED

In this review, we focus on the potential of targeting HIF in prostate cancer (PC) and summarize the scientific background of HIF activity in PC. This finding emphasizes the rationale for using HIF as a therapeutic target in this malignancy. We have listed known HIF inhibitors that are being investigated in preclinical studies and their potential as anticancer drugs for PC.

EXPERT OPINION

Although HIF-targeting agents have been investigated for over a decade, their use in therapy-resistant cancers remains relevant and should be explored further. In addition, the use of naturally occurring HIF inhibitors should be considered as an add-on therapy for the currently used regimens.