Revisiting Greek Propolis: Chromatographic Analysis and Antioxidant Activity Study

Active packaging coating based on Lepidium sativum seed mucilage and propolis extract: Preparation, characterization, application and modeling the preservation of buffalo meat

Buffalo meat is naturally perishable, making it susceptible to spoilage due to its high moisture content and vulnerability to microbial contamination. Edible coatings have attracted attention as a packaging method that can prolong the shelf life of meat. The study aimed to examine the impact of a combination of Lepidium sativum mucilage (LS) coating and propolis extract (PE) on prolonging the shelf life of buffalo meat. The chemical characteristics (chemical compounds, total phenol content (TPC), total flavonoid content (TFC), antioxidant activity, and cytotoxicity) and antimicrobial activity of the PE (disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration) were investigated. The effect of the PE on the cell wall of pathogenic bacteria was examined using a scanning electron microscope. Biological properties of LS (TPC, TFC, antioxidant activity and antimicrobial effect (pour plate method)) was investigated. Different concentrations of PE (0, 0.5, 1.5, and 2.5%) were added to the coating mixture containing LS, and their effects on extending the shelf life of buffalo meat samples stored at 4°C for 9 days were assessed. The PE included gallic acid, benzoic acid, syringic acid, 4-3 dimethoxy cinnamic acid, p-coumaric acid, myricetin, caffeic acid, luteolin, chlorogenic acid, and apigenin. The PE was determined to have a TPC of 36.67 ± 0.57 mg GAE/g and a TFC of 48.02 ± 0.65 mg QE/g. The extract's radical scavenging activity ranged from 0 to 76.22% for DPPH radicals and from 0 to 50.31% for ABTS radicals. The viability of C115 HeLa cell was observed to be 94.14 μg/mL. The PE and LS, exhibited strong antimicrobial properties against pathogenic bacteria. The LS was determined to have a TPC of 15.23 ± 0.43 mg GAE/g and a TFC of 11.51± 0.61 mg QE/g. The LS was determined to have a DPPH of 429.65 ± 1.28 μg/mL and a ABTS of 403.59 ± 1.46 μg/mL. The microbiological analysis revealed that the LS+2.5%PE treatment was the most effective in inhibiting the growth of total viable count (6.23 vs. 8.00 log CFU/g), psychrotrophic bacteria count (3.71 vs. 4.73 log CFU/g), coliforms count (2.78 vs. 3.70 log CFU/g), and fungi count (2.39 vs. 3.93 log CFU/g) compared to the control sample. The addition of PE to the edible coating also demonstrated a concentration-dependent effect on preserving the moisture, pH, color, and hardness of the buffalo meat. Sensory evaluation results suggested that incorporating PE into the edible coating extended the shelf life of buffalo meat by three days. In the second stage of this paper, this investigation employed two distinct forecasting methodologies: the Radial Basis Function (RBF) and the Support Vector Machine (SVM), to predict a range of quality indicators for coated meat products. Upon comparison, the RBF model exhibited a higher level of accuracy, showcasing its exceptional capacity to closely match the experimental outcomes. Therefore, this type of food coating, renowned for its strong antimicrobial properties, has the potential to effectively package and preserve perishable and delicate food items, such as meat.

Chemical Markers in Italian Propolis: Chrysin, Galangin and CAPE as Indicators of Geographic Origin

Knowledge of the chemical composition of propolis is crucial for understanding the characteristics of products of different origins, but also for quality control and regulatory purposes. To date, official monographs or official analyses that allow researchers to evaluate propolis in a proper way have not yet been released. This study focuses on the characterization of twenty-seven Italian propolis samples and the identification of chemical markers that define its geographical provenance. Total polyphenol (TP) and total flavonoid (TF) content, alongside the quantification of pinocembrin, chrysin, galangin, and caffeic acid phenethyl ester (CAPE), were identified as potential markers. Additionally, DPPH assays were conducted to evaluate the antiradical activity of propolis samples. Our findings demonstrated that TPs, TFs and pinocembrin differed in propolis of different origins, especially in samples from the islands. However, the quantification of the sum of chrysin and galangin and CAPE provided a clearer distinction of the geographical origin of the propolis samples. In contrast, the DPPH assay did not prove useful for this purpose, as most results were similar and, therefore, not significant. This study lays the groundwork for future research on propolis. These findings could contribute to the development of more refined methods for distinguishing propolis origins, enhancing the understanding, valuation and quality control of this natural product in various applications.

Efficacy of Propolis in the Prevention of Oral Mucositis in Patients Undergoing High-Dose Chemotherapy: A Randomized Controlled Trial

BACKGROUND

Oral mucositis is one of the most common symptoms in adults with a hematological cancer who are receiving high-dose chemotherapy. Propolis is a complementary and alternative method used to prevent oral mucositis in these patients.

OBJECTIVE

The aim of this study was to determine the efficacy of propolis in the prevention of oral mucositis in patients receiving high-dose chemotherapy and/or hematopoietic stem cell transplantation.

METHODS

A total of 64 patients, 32 in the propolis group and 32 in the control group, were enrolled in this prospective randomized controlled experimental study. Whereas the standard oral care treatment protocol was administered to the control group, aqueous propolis extract was applied to the propolis intervention group in addition to the standard oral care treatment protocol. Data collection forms included a Descriptive Information Form, the Karnofsky Performance Scale, the Cumulative Illness Rating Scale-Geriatric, Patient Follow-up Form, the World Health Organization Oral Toxicity Scale, and the National Cancer Institute Common Terminology Criteria for Adverse Events.

RESULTS

The incidence and duration of oral mucositis were statistically significantly lower in the propolis intervention group than the control group, and the onset of oral mucositis and grade 2 to 3 oral mucositis occurred later ( P < .05).

CONCLUSION

Propolis mouthwash combined with standard oral care treatment delayed the onset of oral mucositis and decreased its incidence and the number of days it lasted.

IMPLICATIONS FOR PRACTICE

Mouthwash with propolis can be used as a nursing intervention to decrease oral mucositis and its symptoms in hematological cancer patients receiving high-dose chemotherapy.

Propolis in the management of cardiovascular disease

BACKGROUND

Propolis is a resinous compound that is obtained from honey bees. It consists of numerous chemical constituents that impart different therapeutic action. The heart is the core of the body and cardiovascular disease (CVD) is a burden for the human being. This article emphasizes how propolis is fruitful in the management of various CVDs.

SCOPE AND APPROACH

This review focuses on how various constituents of the propolis (such as terpenes, flavonoids, phenolics, etc.) impart cardio protective actions.

KEY FINDING AND CONCLUSION

With the support of various clinical trials and research outcomes, it was concluded that propolis owns niche cardio protective properties that can be a boon for various cardiac problems (both in preventive and therapeutic action) such as atherosclerosis, excessive angiogenesis, hypertension, and many more.

Algerian Propolis from Distinct Geographical Locations: Chemical Profiles, Antioxidant Capacity, Cytotoxicity and Inhibition of 5-Lipoxygenase Product Biosynthesis

Propolis was collected from honeybee hives in three geographically distinct Algerian climates and extracts were characterized for composition and bioactivity. Bees were identified as native subspecies using an in-silico DraI mtDNA COI-COII test. Over 20 compounds were identified in extracts by LC-MS. Extracts from the Medea region were more enriched in phenolic content (302±28 mg GAE/g of dry extract) than those from Annaba and Ghardaia regions. Annaba extracts had the highest flavonoid content (1870±385 mg QCE/g of dry extract). Medea extracts presented the highest free-radical scavenging activity (IC50=13.5 μg/mL) using the DPPH radical assay while Ghardaia extracts from the desert region were weak (IC50>100 μg/mL). Antioxidant activities measured using AAPH oxidation of linoleic acid were similar in all extracts with IC50 values ranging from 2.9 to 4.9 μg/mL. All extracts were cytotoxic (MTT assay) and proapoptotic (Annexin-V) against human leukemia cell lines in the low μg/mL range, although the Annaba extract was less active against the Reh cell line. Extracts inhibited cellular 5-lipoxygenase product biosynthesis with IC50 values ranging from 0.6 to 3.2 μg/mL. Overall, examined propolis extracts exhibited significant biological activity that warrant further characterization in cellular and in vivo models.

Propolis Protects GC-1spg Spermatogonial Cells against Tert-Butyl Hydroperoxide-Induced Oxidative Damage

Propolis is a natural resin produced by honeybees with plenty of pharmacologic properties, including antioxidant activity. Oxidative stress disrupts germ cell development and sperm function, with demonstrated harmful effects on male reproduction. Several natural antioxidants have been shown to reduce oxidative damage and increase sperm fertility potential; however, little is known about the effects of propolis. This work evaluated the role of propolis in protecting spermatogonial cells from oxidative damage. Propolis' phytochemical composition and antioxidant potential were determined, and mouse GC-1spg spermatogonial cells were treated with 0.1-500 µg/mL propolis (12-48 h) in the presence or absence of an oxidant stimulus (tert-butyl hydroperoxide, TBHP, 0.005-3.6 µg/mL, 12 h). Cytotoxicity was assessed by MTT assays and proliferation by Ki-67 immunocytochemistry. Apoptosis, reactive oxygen species (ROS), and antioxidant defenses were evaluated colorimetrically. Propolis presented high phenolic and flavonoid content and moderate antioxidant activity, increasing the viability of GC-1spg cells and counteracting TBHP's effects on viability and proliferation. Additionally, propolis reduced ROS levels in GC-1spg, regardless of the presence of TBHP. Propolis decreased caspase-3 and increased glutathione peroxidase activity in TBHP-treated GC-1spg cells. The present study shows the protective action of propolis against oxidative damage in spermatogonia, opening the possibility of exploiting its benefits to male fertility.

Anti-bacterial, anti-biofilm and anti-quorum sensing activities of honey: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Man has used honey to treat diseases since ancient times, perhaps even before the history of medicine itself. Several civilizations have utilized natural honey as a functional and therapeutic food to ward off infections. Recently, researchers worldwide have been focusing on the antibacterial effects of natural honey against antibiotic-resistant bacteria.

AIM OF THE STUDY

This review aims to summarize research on the use of honey properties and constituents with their anti-bacterial, anti-biofilm, and anti-quorum sensing mechanisms of action. Further, honey's bacterial products, including probiotic organisms and antibacterial agents which are produced to curb the growth of other competitor microorganisms is addressed.

MATERIALS AND METHODS

In this review, we have provided a comprehensive overview of the antibacterial, anti-biofilm, and anti-quorum sensing activities of honey and their mechanisms of action. Furthermore, the review addressed the effects of antibacterial agents of honey from bacterial origin. Relevant information on the antibacterial activity of honey was obtained from scientific online databases such as Web of Science, Google Scholar, ScienceDirect, and PubMed.

RESULTS

Honey's antibacterial, anti-biofilm, and anti-quorum sensing activities are mostly attributed to four key components: hydrogen peroxide, methylglyoxal, bee defensin-1, and phenolic compounds. The performance of bacteria can be altered by honey components, which impact their cell cycle and cell morphology. To the best of our knowledge, this is the first review that specifically summarizes every phenolic compound identified in honey along with their potential antibacterial mechanisms of action. Furthermore, certain strains of beneficial lactic acid bacteria such as Bifidobacterium, Fructobacillus, and Lactobacillaceae, as well as Bacillus species can survive and even grow in honey, making it a potential delivery system for these agents.

CONCLUSION

Honey could be regarded as one of the best complementary and alternative medicines. The data presented in this review will enhance our knowledge of some of honey's therapeutic properties as well as its antibacterial activities.

Exploring the Functional Properties of Propolis, Geopropolis, and Cerumen, with a Special Emphasis on Their Antimicrobial Effects

Bee propolis has been touted as a natural antimicrobial agent with the potential to replace antibiotics. Numerous reports and reviews have highlighted the functionalities and applications of the natural compound. Despite much clamor for the downstream application of propolis, there remain many grounds to cover, especially in the upstream production, and factors affecting the quality of the propolis. Moreover, geopropolis and cerumen, akin to propolis, hold promise for diverse human applications, yet their benefits and intricate manufacturing processes remain subjects of intensive research. Specialized cement bees are pivotal in gathering and transporting plant resins from suitable sources to their nests. Contrary to common belief, these resins are directly applied within the hive, smoothed out by cement bees, and blended with beeswax and trace components to create raw propolis. Beekeepers subsequently harvest and perform the extraction of the raw propolis to form the final propolis extract that is sold on the market. As a result of the production process, intrinsic and extrinsic factors, such as botanical origins, bee species, and the extraction process, have a direct impact on the quality of the final propolis extract. Towards the end of this paper, a section is dedicated to highlighting the antimicrobial potency of propolis extract.

Fingerprinting Chemical Markers in the Mediterranean Orange Blossom Honey: UHPLC-HRMS Metabolomics Study Integrating Melissopalynological Analysis, GC-MS and HPLC-PDA-ESI/MS

(1) Background: Citrus honey constitutes a unique monofloral honey characterized by a distinctive aroma and unique taste. The non-targeted chemical analysis can provide pivotal information on chemical markers that differentiate honey based on its geographical and botanical origin. (2) Methods: Within the PRIMA project "PLANT-B", a metabolomics workflow was established to unveil potential chemical markers of orange blossom honey produced in case study areas of Egypt, Italy, and Greece. In some of these areas, aromatic medicinal plants were cultivated to enhance biodiversity and attract pollinators. The non-targeted chemical analysis and metabolomics were conducted using ultra-high-performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS). (3) Results: Forty compounds were disclosed as potential chemical markers, enabling the differentiation of the three orange blossom honeys according to geographical origin. Italian honey showed a preponderance of flavonoids, while in Greek honey, terpenoids and iridoids were more abundant than flavonoids, except for hesperidin. In Egyptian honey, suberic acid and a fatty acid ester derivative emerged as chemical markers. New, for honey, furan derivatives were identified using GC-MS in Greek samples. (4) Conclusions: The application of UHPLC-HRMS metabolomics combined with an elaborate melissopalynological analysis managed to unveil several potential markers of Mediterranean citrus honey potentially associated with citrus crop varieties and the local indigenous flora.

Ameliorative effects of propolis upon reproductive toxicity in males

Propolis is a sticky natural product produced by honeybees. Research studies have discussed the effectiveness of propolis, directly or indirectly, for ameliorating reproductive toxicity in males; however, this research has not yet been reviewed. The current paper presents an integrative summary of all research studies in Scopus and PubMed that investigated the effects of propolis on semen quality, and hence on male fertility, in conditions of reproductive toxicity. The consensus indicates that propolis ameliorates reproductive toxicity and enhances semen quality in vivo in test animals. These effects may be attributable to the ability of propolis to reduce testicular oxidative damage, enhance testicular antioxidant defense mechanisms, increase nitric oxide production, reduce testicular apoptotic injury, and boost testosterone production. However, to generalize these effects in humans would require further research.

Untargeted Metabolomics Analysis of the Orchid Species Oncidium sotoanum Reveals the Presence of Rare Bioactive C-Diglycosylated Chrysin Derivatives

Plants are valuable sources of secondary metabolites with pharmaceutical properties, but only a small proportion of plant life has been actively exploited for medicinal purposes to date. Underexplored plant species are therefore likely to contain novel bioactive compounds. In this study, we investigated the content of secondary metabolites in the flowers, leaves and pseudobulbs of the orchid Oncidium sotoanum using an untargeted metabolomics approach. We observed the strong accumulation of C-diglycosylated chrysin derivatives, which are rarely found in nature. Further characterization revealed evidence of antioxidant activity (FRAP and DPPH assays) and potential activity against neurodegenerative disorders (MAO-B inhibition assay) depending on the specific molecular structure of the metabolites. Natural product bioprospecting in underexplored plant species based on untargeted metabolomics can therefore help to identify novel chemical structures with diverse pharmaceutical properties.

Quality assessment and chemical diversity of Australian propolis from Apis mellifera bees

The propolis industry is well established in European, South American and East Asian countries. Within Australia, this industry is beginning to emerge with a few small-scale producers. To contribute to the development of the Australian propolis industry, the present study aimed to examine the quality and chemical diversity of propolis collected from various regions across Australia. The results of testing 158 samples indicated that Australian propolis had pure resin yielding from 2 to 81% by weight, total phenolic content and total flavonoid content in one gram of dry extract ranging from a few up to 181 mg of gallic acid equivalent and 145 mg of quercetin equivalent, respectively. Some Australian propolis showed more potent antioxidant activity than the well-known Brazilian green, Brazilian red, and Uruguayan and New Zealand poplar-type propolis in an in vitro DPPH assay. In addition, an HPLC–UV analysis resulted in the identification of 16 Australian propolis types which can be considered as high-grade propolis owing to their high total phenolic content. Chemometric analysis of their ¹H NMR spectra revealed that propolis originating from the eastern and western coasts of Australia could be significantly discriminated based on their chemical composition.

Investigating Possible Synergism in the Antioxidant and Antibacterial Actions of Honey and Propolis from the Greek Island of Samothrace through Their Combined Application

Several honeybee products are known for their functional properties, including important antioxidant and antimicrobial actions. The present study examines the antioxidant activity (AA), total polyphenolic content (TPC), and antibacterial action of honey and propolis samples collected from the Greek island of Samothrace, which were applied in vitro either individually or in combination in selected concentrations. To accomplish this, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and the Folin-Ciocalteu assays were employed to determine the AA and TPC, respectively, while the antibacterial action was investigated against each one of four important pathogenic bacterial species causing foodborne diseases (i.e., Salmonella enterica, Yersinia enterocolitica, Staphylococcus aureus, and Listeria monocytogenes) using the agar well diffusion assay. Compared to honey, propolis presented significantly higher AA and TPC, while its combined application with honey (at ratios of 1:1, 3:1, and 1:3) did not increase these values. Concerning the antibacterial action, Y. enterocolitica was proven to be the most resistant of all the tested bacteria, with none of the samples being able to inhibit its growth. S. enterica was susceptible only to the honey samples, whereas L. monocytogenes only to the propolis samples. The growth of S. aureus was inhibited by both honey and propolis, with honey samples presenting significantly higher efficacy than those of propolis. Νo synergism in the antibacterial actions was observed against any of the tested pathogens. Results obtained increase our knowledge of some of the medicinal properties of honey and propolis and may contribute to their further exploitation for health promotion and/or food-related applications (e.g., as preservatives to delay the growth of pathogenic bacteria).

Evaluation of the Skin-Sensitizing Potential of Brazilian Green Propolis

Propolis is a resinous mixture produced by bees from their secretions and plant material, so its composition varies depending on its botanical origin. Propolis has several beneficial bioactivities, but its skin sensitization properties have long been suspected. Nevertheless, the skin sensitization potency of Brazilian green propolis (BGP) has not been scientifically evaluated. Here, we used scientifically reliable tests to evaluate it. In vitro antigenicity test based on the human cell line activation test (OECD TG 442E) was performed by measuring the expression of CD54 and CD86, which are indicators of the antigenicity of test substances, on THP-1 and DC2.4 cells. BGP did not affect the expression of either marker on THP-1 cells, but upregulated the expression of CD86 on DC2.4 cells, suggesting that BGP may be a skin sensitizer. Then, we performed local lymph node assay (LLNA, OECD TG 429) as a definitive in vivo test. LLNA showed that 1.70% BGP primed skin sensitization and is a "moderate sensitizer". Our results indicate scientific proof of the validity of arbitrary concentrations (1-2%), which have been used empirically, and provide the first scientific information on the safe use of BGP.

Antiviral, Antibacterial, Antifungal, and Antiparasitic Properties of Propolis: A Review

Propolis is a complex phytocompound made from resinous and balsamic material harvested by bees from flowers, branches, pollen, and tree exudates. Humans have used propolis therapeutically for centuries. The aim of this article is to provide comprehensive review of the antiviral, antibacterial, antifungal, and antiparasitic properties of propolis. The mechanisms of action of propolis are discussed. There are two distinct impacts with regards to antimicrobial and anti-parasitic properties of propolis, on the pathogens and on the host. With regards to the pathogens, propolis acts by disrupting the ability of the pathogens to invade the host cells by forming a physical barrier and inhibiting enzymes and proteins needed for invasion into the host cells. Propolis also inhibits the replication process of the pathogens. Moreover, propolis inhibits the metabolic processes of the pathogens by disrupting cellular organelles and components responsible for energy production. With regard to the host, propolis functions as an immunomodulator. It upregulates the innate immunity and modulates the inflammatory signaling pathways. Propolis also helps maintain the host's cellular antioxidant status. More importantly, a small number of human clinical trials have demonstrated the efficacy and the safety of propolis as an adjuvant therapy for pathogenic infections.

Untargeted Ultrahigh-Performance Liquid Chromatography-Hybrid Quadrupole-Orbitrap Mass Spectrometry (UHPLC-HRMS) Metabolomics Reveals Propolis Markers of Greek and Chinese Origin

Chemical composition of propolis depends on the plant source and thus on the geographic and climatic characteristics of the site of collection. The aim of this study was to investigate the chemical profile of Greek and Chinese propolis extracts from different regions and suggest similarities and differences between them. Untargeted ultrahigh-performance liquid chromatography coupled to hybrid quadrupole-Orbitrap mass spectrometry (UHPLC-HRMS) method was developed and 22 and 23 propolis samples from Greece and China, respectively, were analyzed. The experimental data led to the observation that there is considerable variability in terms of quality of the distinctive propolis samples. Partial least squares - discriminant analysis (PLS-DA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) models were constructed and allowed the identification of significant features for sample discrimination, adding relevant information for the identification of class-determining metabolites. Chinese samples overexpressed compounds that are characteristic of the poplar type propolis, whereas Greek samples overexpress the latter and the diterpenes characteristic of the Mediterranean propolis type.

Chinese Propolis: Ultrasound-assisted enhanced ethanolic extraction, volatile components analysis, antioxidant and antibacterial activity comparison

This study was aimed to enhance the extraction yield of propolis samples using ultrasound technology, analyze the volatile compounds, and compare the antioxidant and antimicrobial effect of propolis extracts of different areas. Four propolis samples were collected from different regions of China, namely: Linqing, Shandong Province (LSP); Yingchun, Heilongjiang Province (YHP); Changge, Henan Province (CHP); and Raohe, Heilongjiang Province (RHP). The ultrasound extracts of CHP and RHP showed a higher total phenolic content (TPC) of 201.78 ± 4.60 mgGAE/g and 166.071 ± 1.53 mgGAE/g, total flavonoid content (TFC) of 519.77 ± 29.90 and 341.227 ± 10.82 mg quercetin/g respectively, as well as high antioxidant and antibacterial activity. Conventional extraction showed 15%-20% lower yield for TPC ranging from 72.02 ± 1.99 to 155.95 ± 3.69 mg GAE/g, TFC ranges from 129.675 ± 6.82 to 412.83 ± 12.14 mg quercetin/g, with lower antibacterial activity. The antioxidant activity of propolis extracts was determined by assays of reducing power, DPPH*, FRAP*, TEAC*, hydroxyl radical scavenging activity and superoxide anion scavenging activity. Collectively, the antioxidant activities of extracts from CHP and RHP were higher than those of the other two extracts(YHP and LSP). All the extracts showed high antimicrobial activity on Staphylococcus aureus, Listeria monocytogenes, and Bacillus subtilis, but no effect on Escherichia coli. A total of 150 compounds in propolis were detected by GC/MS. Terpenes (RHP 34%, YHP 5%, LSP 18%, and CHP 12%) and alcohols (RHP 12%, YHP 13%, LSP 12%, and CHP 10%) showed the highest relative content among all other extracts.

Biomedical Properties of Propolis on Diverse Chronic Diseases and Its Potential Applications and Health Benefits

The use of alternative medicine products has increased tremendously in recent decades and it is estimated that approximately 80% of patients globally depend on them for some part of their primary health care. Propolis is a beekeeping product widely used in alternative medicine. It is a natural resinous product that bees collect from various plants and mix with beeswax and salivary enzymes and comprises a complex mixture of compounds. Various biomedical properties of propolis have been studied and reported in infectious and non-infectious diseases. However, the pharmacological activity and chemical composition of propolis is highly variable depending on its geographical origin, so it is important to describe and study the biomedical properties of propolis from different geographic regions. A number of chronic diseases, such as diabetes, obesity, and cancer, are the leading causes of global mortality, generating significant economic losses in many countries. In this review, we focus on compiling relevant information about propolis research related to diabetes, obesity, and cancer. The study of propolis could generate both new and accessible alternatives for the treatment of various diseases and will help to effectively evaluate the safety of its use.

Plant Sources Responsible for the Chemical Composition and Main Bioactive Properties of Poplar-Type Propolis

Propolis is a resinous mixture, made by the honeybees from substances collected from tree or other plant buds, plant exudates, or resins found in the stem, branches, or leaves of different plants. The geographical origin of propolis is given by plant sources from respective areas. Different studies have classified this bee product according to the vegetal material from the same areas. Poplar-type propolis has the widest spread in the world, in the temperate zones from Europe, Asia, or North America. The name is given by the main plant source from where the bees are collecting the resins, although other vegetal sources are present in the mentioned areas. Different Pinus spp., Prunus spp., Acacia spp. and also Betula pendula, Aesculus hippocastanum, and Salix alba are important sources of resins for "poplar-type" propolis. The aim of this review is to identify the vegetal material's chemical composition and activities of plant resins and balms used by the bees to produce poplar-type propolis and to compare it with the final product from similar geographical regions. The relevance of this review is to find the similarities between the chemical composition and properties of plant sources and propolis. The latest determination methods of bioactive compounds from plants and propolis are also reviewed.

Effect of the Solvent on Propolis Phenolic Profile and its Antifungal, Antioxidant, and In Vitro Cytoprotective Activity in Human Erythrocytes Under Oxidative Stress

Propolis is a natural bee product with various beneficial biological effects. The health-promoting properties of propolis depend on its chemical composition, particularly the presence of phenolic compounds. The aim of this study was to evaluate the relationship between extraction solvent (acetone 100%, ethanol 70% and 96%) and the antifungal, antioxidant, and cytoprotective activity of the extracts obtained from propolis. Concentrations of flavonoids and phenolic acids in the propolis extracts were determined using ultrahigh-performance liquid chromatography. The antioxidant potential of different extracts was assessed on the basis of 2,2-diphenyl-1-picrylhydrazyl (DPPH·) free-radical-scavenging activity, Fe³⁺-reducing power, and ferrous ion (Fe²⁺)-chelating activity assays. The ability of the extracts to protect human red blood cell membranes against free-radical-induced damage and their antifungal activity was also determined. The results showed that the concentration of flavonoids in the propolis extracts was dependent on the solvent used in the extraction process and pinocembrin, chrysin, galangin, and coumaric acid were the most abundant phenols. All extracts exhibited high antioxidant potential and significantly protected human erythrocytes against oxidative damage. On the other hand, the antifungal activity of the propolis extracts depended on the solvent used in extraction and the fungal strains tested. It needs to be stressed that, to the best of our knowledge, there is no study relating the effect of solvent used for extraction of Polish propolis to its phenolic profile, and its antifungal, antioxidant, and cytoprotective activity.

Antiviral effects of Brazilian green and red propolis extracts on Enterovirus surrogates

Propolis is a natural product of bees with biological activities that are mainly associated with bee type and geographic origin. Propolis extract has been proposed with several applications in environmental health. The ethanol extracts have shown good antimicrobial activity. The association of this technique with ultrasound-assisted extraction has been studied to improve the characteristics of the obtained extracts. Thus, the objective of this work is to verify the antiviral action against two strains of bacteriophages of two extracts of Brazilian propolis (green and red) obtained by conventional extraction and ultrasonic extraction. The activities of the propolis red and green extracts were confirmed by the significant ~3 and ~4.5 Log 10 PFU/mL reduction in the concentrations of the MS2 and Av-08 bacteriophages, respectively. It was found that ultrasound-assisted extraction is comparable to the maceration process and demonstrated the best antiviral activities. Brazilian red propolis was more effective than green propolis in viral reduction in all treatments.

Chemical Profile and Antibacterial Activity of a Novel Spanish Propolis with New Polyphenols also Found in Olive Oil and High Amounts of Flavonoids

Propolis is a natural product obtained from hives. Its chemical composition varies depending on the flora of its surroundings, but nevertheless, common for all types of propolis, they all exhibit remarkable biological activities. The aim of this study was to investigate the chemical composition and antimicrobial activity of a novel Spanish Ethanolic Extract of Propolis (SEEP). It was found that this new SEEP contains high amounts of polyphenols (205 ± 34 mg GAE/g), with unusually more than half of this of the flavonoid class (127 ± 19 mg QE/g). Moreover, a detailed analysis of its chemical composition revealed the presence of olive oil compounds (Vanillic acid, 1-Acetoxypinoresinol, p-HPEA-EA and 3,4-DHPEA-EDA) never detected before in propolis samples. Additionally, relatively high amounts of ferulic acid and quercetin were distinguished, both known for their important therapeutic benefits. Regarding the antimicrobial properties of SEEP, the minimal inhibitory and bactericidal concentrations (MIC and MBC) against Staphylococcus epidermidis strains were found at the concentrations of 240 and 480 µg/mL, respectively. Importantly, subinhibitory concentrations were also found to significantly decrease bacterial growth. Therefore, the results presented here uncover a new type of propolis rich in flavonoids with promising potential uses in different areas of human health.

Phytochemical analysis and in vitro anti-proliferative activity of Viscum album ethanolic extracts

Background

Viscum album L. (Santalaceae), commonly known as mistletoe, is a hemiparasitic plant traditionally used in complementary cancer treatment. Its antitumor potential is mostly attributed to the presence of aqueous soluble metabolites; however, the use of ethanol as solvent also permits the extraction of pharmacological compounds with antitumor potential. The clinical efficacy of mistletoe therapy inspired the present work, which focuses on ethanolic extracts (V. album “mother tinctures”, MT) prepared from different host trees.

Methods

Samples from three European subspecies (album, austriacum, and abietis) were harvested, and five different V. album-MT strains were prepared. The following phytochemical analyses were performed: thin layer chromatography (TLC), high-performance liquid chromatography (HPLC) and liquid chromatography-high resolution mass spectrometry (LC-HRMS). The proliferation assay was performed with WST-1 after incubation of tumor (Yoshida and Molt-4) and fibroblast cell lines (NIH/3 T3) with different MT concentrations (0.5 to 0.05% v/v). The cell death mechanism was investigated by flow cytometry (FACS) using Annexin V-7AAD.

Results

Chemical analyses of MT showed the presence of phenolic acids, flavonoids and lignans. The MT flavonoid and viscotoxin contents (mg/g fresh weight) were highest in Quercus robur (9.67 ± 0.85 mg/g) and Malus domestica (3.95 ± 0.58 mg/mg), respectively. The viscotoxin isoform proportions (% total) were also different among the VA subspecies with a higher content of A3 in V. album growing on Abies alba (60.57 ± 2.13). The phytochemical compounds as well as the viscotoxin contents are probably related to the antitumor effects of MT. The cell death mechanisms evaluated by colorimetric and FACS methodologies involved necrotic damage, which was host tree-, time- and dose- dependent, with different selectivity to tumor cells. Mother tincture from V. album ssp. abietis was the most effective at inducing in vitro cellular effects, even when incubated at the smallest concentration tested, probably because of the higher content of VT A3.

Conclusion

Our results indicate the promising antitumor potential of Viscum album ethanolic extracts and the importance of botanical and phytochemical characterization for in vitro anti-proliferative effects.

Synergistic, bacteriostatic effect of propolis and glycerol against Listeria monocytogenes in chocolate milk under refrigerated storage

Propolis ethanolic extracts, with or without glycerol, were added into pasteurized, non-fat chocolate milk, which was artificially contaminated with Listeria monocytogenes. The addition of propolis ethanolic extracts dissolved into glycerol led to a definite anti-listerial effect in milk stored at 4 ℃, with both propolis concentrations tested (2 or 4 mg of dry propolis ethanolic extract per milliliter of chocolate milk) leading to inhibition of L. monocytogenes growth throughout 20 days of storage. The combined addition of propolis ethanolic extracts with glycerol was also effective in significantly reducing the rate of growth of L. monocytogenes in chocolate milk stored under improper (10 ℃) refrigeration storage conditions (more than five-fold increase in the generation time of L. monocytogenes compared to control trials). Finally, the combined addition of a deodorized propolis ethanolic extract with glycerol resulted in a significant anti-listerial effect upon storage of contaminated milk at 4 ℃ (more than three-fold increase in the generation time of L. monocytogenes compared to controls) and in a smaller anti-listerial effect upon milk storage at 10 ℃ (two-fold increase in the generation time of the pathogen compared to controls). Of note, chocolate milk containing deodorized propolis ethanolic extract and glycerol received a positive consumer acceptability score on the nine-point hedonic scale (median acceptability score of "7"). Hence, propolis may possess a promising role as a natural anti-listerial preservative in dairy drinks.

Effect of propolis phenolic compounds on free fatty acid receptor 4 activation

Propolis is known to have multiple biological and pharmacological properties including the regulation of energy homeostasis. Although phenolic compounds are considered to be the major active components in propolis, there is little information available about their mechanisms underlying the regulation of energy homeostasis. In this study, the effects of five phenolic compounds in propolis, chrysin, pinocembrin, galangin, pinobanksin, and caffeic acid phenethyl ester (CAPE) were evaluated on the activation of free fatty acid receptor 4 (FFA4), which are involved in the control of energy homeostasis by enhancing insulin signaling, increasing glucose uptake, and regulating adipogenesis. The results showed that three phenolic compounds exhibited the activation of FFA4, which were ranked in the order of pinocembrin, CAPE and pinobanksin in FFA4-expressing cells. These results suggest that some phenolic compounds in propolis, particularly pinocembrin, may affect the control of energy homeostasis via the activation of FFA4.

Composition and functional properties of propolis (bee glue): A review

Propolis is a natural substance collected by honey bees from various plants such as, poplar, palm, pine, conifer secretions, gums, resins, mucilage and leaf buds. It is collected and brought very painstakingly by honey bees to be used for sealing cracks and crevices occurring in their hives. Originally, it as an antiseptic meant for preventing bee-hive from microbial infections along with preventing decomposition of intruders. Additionally, propolis has been used in folk medicine for centuries. The biological characteristics of propolis depend upon its chemical composition, plant sources, geographical zone and seasons. More than 300 compounds have been identified in propolis such as, phenolic compounds, aromatic acids, essential oils, waxes and amino acids. Many scientific articles are published every year in different international journals, and several groups of researchers have focused their attention on the chemical compounds and biological activity of propolis.

Photometric Analysis of Propolis from the Island of Samothraki, Greece. The Discovery of Red Propolis

Propolis presents notable and variable antioxidant activity depending on the territory and the local flora. As a result, propolis collected from areas presenting botanical diversity can become an intriguing research field. In the present study, we examined propolis from different areas of Samothraki, a small Greek island in the north-eastern Aegean Sea, considered a hot-spot of plant biodiversity. The analysis of propolis samples presented huge variability in the antioxidant activity, the total polyphenol content and the total flavonoids content. Propolis from two areas presented high antioxidant activity with a maximum at 1741.48 μmol of Trolox equivalents per gram of dry propolis weight, very high polyphenol content, 378.73 mg of gallic acid equivalents per gram of dry propolis weight, and high flavonoid content with a maximum concentration of 70.31 mg of quercetin equivalents per gram of dry propolis weight. The samples that presented the best qualitative characteristics were all red propolis which is a type that has never been reported in any part of Europe.

High temperature treatment allows the detection of episesamin in paulownia wood extractives

The composition and the relative variation of secondary metabolites of Paulownia tomentosa S. wood under thermal effect is a little explored area. Wood material was previously thermo-treated at 210 °C for 3 hours using a press vacuum technology. Extractives of untreated and thermo-treated wood material achieved with Soxhlet extraction techniques were obtained. Then the extracts were chromatographed by using thin layer chromatography. Component groups in extracts were determined by gas chromatography in combination with mass spectrometry. In terms of wood change the thermo-treatment of wood induces a darkening of wood color surface (ΔL* = 28.3), an increase of mass loss (3.5%) and an increase of the amount of extractives and lignin content as well as an increase of the chloroform soluble fraction. This work mainly describes the chemical exploration of the extract from paulownia wood, leading to the isolation and identification of episesamin.

Chemical characterization and biological activity of six different extracts of propolis through conventional methods and supercritical extraction

Propolis is a natural product with many demonstrated biological activities and propolis extract has been used in the food, pharmaceutical and cosmetics industries. Different works have showed the variations in the chemical composition, and consequently, on the biological activity of the propolis that are associated with its type and geographic origin. Due to this study evaluated propolis extracts obtained through supercritical extraction and ethanolic extraction (conventional) in three samples of different types of propolis (red, green and brown), collected from different regions in Brazil (state of Bahia). Analyses were performed to determine the humidity, water activity, the content of total ash, proteins, lipids and fiber in raw propolis samples. The content of phenolic compounds, flavonoids, in vitro antioxidant activity (DPPH), catechin, ferulic acid and luteolin and antimicrobial activity against two bacteria (Staphylococcus aureus and Escherichia coli) were determined for all extracts. For the green and red ethanolic extracts the anti-leishmanicidal potential was also evaluated. The physicochemical profiles showed agreement in relation to the literature. The results identified significant differences among the extracts (p>0.05), which are in conformity with their extraction method, as well as with type and botanical origin of the samples. The extraction with supercritical fluid was not efficient to obtain extracts with the highest contents of antioxidants compounds, when compared with the ethanolic extracts. The best results were shown for the extracts obtained through the conventional extraction method (ethanolic) indicating a higher selectivity for the extraction of antioxidants compounds. The red variety showed the largest biological potential, which included the content of antioxidants compounds. The results found in this study confirm the influence of the type of the raw material on the composition and characteristics of the extracts. The parameters analysis were important to characterize and evaluate the quality of the different Brazilian propolis extracts based on the increased use of propolis by the natural products industry.

Profile of Polyphenolic and Essential Oil Composition of Polish Propolis, Black Poplar and Aspens Buds

In this work, we studied similarities and differences between 70% ethanol in water extract (70EE) and essential oils (EOs) obtained from propolis, black poplars (Populus nigra L.) and aspens (P. tremula L.) to ascertain which of these is a better indicator of the plant species used by bees to collect propolis precursors. Composition of 70EE was analyzed by UPLC-PDA-MS, while GC-MS was used to research the EOs. Principal component analyses (PCA) and calculations of Spearman's coefficient rank were used for statistical analysis. Statistical analysis exhibited correlation between chemical compositions of propolis and Populus buds' 70EE. In the case of EOs, results were less clear. Compositions of black poplars, aspens EOs and propolises have shown more variability than 70EE. Different factors such as higher instability of EOs compared to 70EE, different degradation pattern of benzyl esters to benzoic acid, differences in plant metabolism and bees' preferences may be responsible for these phenomena. Our research has therefore shown that 70EE of propolis reflected the composition of P. nigra or complex aspen⁻black poplar origin.

Inhibitory Effect of Propolis on Platelet Aggregation In Vitro

Platelet hyperactivity plays an important role in arterial thrombosis and atherosclerosis. The present study was aimed to investigate the effects of different extracts of propolis and components of flavonoids on platelet aggregation. Platelet-rich plasma was prepared and incubated in vitro with different concentrations of the tested extracts and components of flavonoids. Platelets aggregation was induced by different agonists including adenosine diphosphate (ADP, 10 μM), thrombin receptor activator peptide (TRAP, 50 μM), and collagen (5 μg/mL). At 25 mg/L to 300 mg/mL, the water extract propolis (WEP) inhibited three agonists-induced platelet aggregations in a dose-dependent manner. The flavonoids isolated from the propolis also showed markedly inhibited platelet aggregation induced by collagen, ADP, and TRAP, respectively. The components including caffeic acid phenethyl ester (CAPE), galangin, apigenin, quercetin, kaempferol, ferulic acid, rutin, chrysin, pinostrobin, and pinocembrin and their abilities of inhibiting platelet aggregation were studied. It was concluded that propolis had an antiplatelet action in which flavonoids were mainly implicated.

Chemical characterization and cytotoxic activity evaluation of Lebanese propolis

Chemical composition, anti-proliferative and proapoptotic activity as well as the effect of various fractions of Lebanese propolis on the cell cycle distribution were evaluated on Jurkat leukemic T-cells, glioblastoma U251 cells, and breast adenocarcinoma MDA-MB-231 cells using cytotoxic assays, flow cytometry as well as western blot analysis. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis revealed that ferulic acid, chrysin, pinocembrin, galangin are major constituents of the ethanolic crude extract of the Lebanese propolis, while the hexane fraction mostly contains chrysin, pinocembrin, galangin but at similar levels. Furthermore chemical analysis was performed using gas chromatography-mass spectrometry (GC-MS) to identify major compounds in the hexane fraction. Reduction of cell viability was observed in Jurkat cells exposed to the ethanolic crude extract and the hexane fraction, while viability of U251 and MDA-MB-231 cells was only affected upon exposure to the hexane fraction; the other fractions (aqueous phase, methylene chloride, and ethyl acetate) were without effect. Maximum toxic effect was obtained when Jurkat cells were cultivated with 90μg/ml of both the crude extract and hexane faction. Toxicity started early after 24h of incubation and remained till 72h. Interestingly, the decrease in cell viability was accompanied by a significant increase in p53 protein expression levels and PARP cleavage. Cell cycle distribution showed an increase in the SubG0 fraction in Jurkat, U251 and MDA-MB-231 cells after 24h incubation with the hexane fraction. This increase in SubG0 was further investigated in Jurkat cells by annexinV/PI and showed an increase in the percentage of cells in early and late apoptosis as well as necrosis. In conclusion, Lebanese propolis exhibited significant cytotoxicity and anti-proliferative activity promising enough that warrant further investigations on the molecular targets and mechanisms of action of Lebanese propolis.

A density functional theory study on the hydrogen bonding interactions between luteolin and ethanol

Ethanol is one of the most commonly used solvents to extract flavonoids from propolis. Hydrogen bonding interactions play an important role in the properties of liquid system. The main objective of the work is to study the hydrogen bonding interactions between flavonoid and ethanol. Luteolin is a very common flavonoid that has been found in different geographical and botanical propolis. In this work, it was selected as the representative flavonoid to do detailed research. The study was performed from a theoretical perspective using density functional theory (DFT) method. After careful optimization, there exist nine optimized geometries for the luteolin - CH₃CH₂OH complex. The binding distance of X - H···O, and the bond length, vibrational frequency, and electron density changes of X - H all indicate the formation of the hydrogen bond in the optimized geometries. In the optimized geometries, it is found that: (1) except for the H2', H5', and H6', CH₃CH₂OH has formed hydrogen bonds with all the hydrogen and oxygen atoms in luteolin. The hydrogen atoms in the hydroxyl groups of luteolin form the strongest hydrogen bonds with CH₃CH₂OH; (2) all of the hydrogen bonds are closed-shell interactions; (3) the strongest hydrogen bond is the O3' - H3'···O in structure A, while the weakest one is the C3 - H3···O in structure E; (4) the hydrogen bonds of O3' - H3'···O, O - H···O4, O - H···O3' and O - H···O7 are medium strength and covalent dominant in nature. While the other hydrogen bonds are weak strength and possess a dominant character of the electrostatic interactions in nature.