Chemical composition, cytotoxicity, and antibacterial activity of propolis from Africanized honeybees and three different Meliponini species

A First Metabolite Analysis of Norfolk Island Pine Resin and Its Hepatoprotective Potential to Alleviate Methotrexate (MTX)-Induced Hepatic Injury

Drug-induced liver injury (DILI) represents a significant clinical challenge characterized by hepatic dysfunction following exposure to diverse medications. Methotrexate (MTX) is a cornerstone in treating various cancers and autoimmune disorders. However, the clinical utility of MTX is overshadowed by its ability to induce hepatotoxicity. The current study aims to elucidate the hepatoprotective effect of the alcoholic extract of Egyptian Araucaria heterophylla resin (AHR) on MTX-induced liver injury in rats. AHR (100 and 200 mg/kg) significantly decreased hepatic markers (AST, ALT, and ALP), accompanied by an elevation in the antioxidant's markers (SOD, HO-1, and NQO1). AHR extract also significantly inhibited the TGF-β/NF-κB signaling pathway as well as the downstream cascade (IL-6, JAK, STAT-3, and cyclin D). The extract significantly reduced the expression of VEGF and p38 with an elevation in the BCL2 levels, in addition to a significant decrease in the IL-1β and TNF-α levels, with a prominent effect at a high dose (200 mg/kg). Using LC-HRMS/MS analysis, a total of 43 metabolites were tentatively identified, and diterpenes were the major class. This study presents AHR as a promising hepatoprotective agent through inhibition of the TGF-β/NF-κB and JAK/STAT3 pathways, besides its antioxidant and anti-inflammatory effects.

Chemical characterization and antibacterial activities of Brazilian propolis extracts from Apis mellifera bees and stingless bees (Meliponini)

The aim of this study was to evaluate the physicochemical composition and antibacterial activity of Brazilian propolis extracts from different types, concentrations, and extraction solvents and from different regions in Brazil. A total of 21 samples were analyzed, comprising 14 samples from Apis mellifera (12 green, 1 brown, and 1 red) and 7 samples from stingless bees (3 mandaçaia, 2 jataí, 1 hebora, and 1 tubuna). The analyses performed were dry extract, total phenolic content (TPC) and antioxidant activity (DPPH and ABTS). The antibacterial activity was performed by Determination of Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC). The results showed that very low levels of phenolic compounds and antioxidant activity decreased the antimicrobial activity of the propolis extracts from tubuna and jataí. However, there was no correlation between the increase in propolis concentration in the extract, and the increase in antimicrobial activity. The highest TPC and antioxidant activity was obtained for green propolis extract made with 70% raw propolis that presented similar antibacterial activity to the samples formulated with 30% or less raw propolis. The aqueous propolis extract showed lower antimicrobial activity compared to the alcoholic extracts, indicating that ethanol is a better solvent for extracting the active compounds from propolis. It was observed that the MIC (0.06 to 0.2 mg/mL) and MBC (0.2 to 0.5 mg/mL) values for Gram-negative bacteria were higher compared to Gram-positive bacteria (MIC 0.001-0.2 mg/mL, and the MBC 0.02-0.5 mg/mL). The propolis extracts that exhibited the highest antimicrobial activities were from stingless bees hebora from the Distrito Federal (DF) and mandaçaia from Santa Catarina, showing comparable efficacy to samples 5, 6, and 7, which were the green propolis from the DF. Hence, these products can be considered an excellent source of bioactive compounds with the potential for utilization in both the pharmaceutical and food industries.

Chemical Profile and Biological Potential of Scaptotrigona Bee Products (Hymenoptera, Apidae, Meliponini): An Review

Stingless bees belong to the Meliponini tribe and are widely distributed in the tropics and subtropics, where they perform important ecological services. Among the best distributed groups of stingless bees is the genus Scaptotrigona, which includes 22 species distributed throughout the neotropical region, including the area from Mexico to Argentina. Bees of this genus are responsible for the production of products such as honey, propolis, geopropolis and fermented pollen ("saburá"). This review aimed to provide an overview of the chemical composition and biological activities associated with derived products from stingless bees of the genus Scaptotrigona. The bibliographic review was carried out through searches in the Scopus, Web of Science, ScienceDirect and PubMed databases, including publications from 2003 to January 2023. The study of the chemodiversity of products derived from Scaptotrigona demonstrated the mainly presence of flavonoids, phenolic acids, terpenoids and alkaloids. It was also demonstrated that products derived from bees of the genus Scaptotrigona exhibit a wide range of biological effects, such as antibacterial, antioxidant, anti-inflammatory and antifungal activities, among other bioactivities. This review provides an overview of phytochemical and pharmacological investigations of the genus Scaptotrigona. However, it is essential to clarify the toxicity and food safety of these products.

Targeted therapies for breast and lung cancers by using Propolis loaded albumin protein nanoparticles

BACKGROUND

Cancer is a popular disease among many others that can threaten human life. This is not only because of its invasiveness but also because of its resistance and the highly effective cost of its treatments. Propolis is rich in natural bioactive and polyphenolic compounds that have proven their strong effect on cancer cells such as MCF-7 and A549 cell lines.

METHODS

Propolis extract was immobilized into the bovine serum albumin (BSA) conjugated to folic acid (FA), to increase control of its delivery and to strengthen its cellular uptake.

RESULTS

The growth of MCF-7 was significantly decreased by propolis extract and BSA-propolis NPs after their incubation for 48 and 72 h by (54 ± 0.01 %, and 45 ± 0.005 %, P ≤ 0.001) and (20 ± 0.01 % and 10 ± 0.005 %, P ≤ 0.0001), respectively. Similarly, there is a significant inhibition in the growth of A549 obtained after their incubation with (propolis extract and albumin-propolis NPs) for 72 h (15 ± 0.03 % and 5 ± 0.01 %, P ≤ 0.00001). Propolis extract and BSA-propolis NPs exhibited a greater effect on protein expression of MCF-7 and A549, showing significant modulation of caspase-3, cyclin D1, and light chain 3 (LC3II). The result was supported by nuclear fragmentations and activation of acidic/neutral autophagosomes in acridine orange/ethidium bromide (AO/EB) and 4',6-diamidino-2-phenylindole (DAPI) nuclear stains. According to this study, the expression of phospho-GSK3β (Ser9) (p < 0.001) increased significantly in MCF-7 and A549 cells after their exposure to propolis extract and BSA-propolis NPs.

CONCLUSION

Results support the potency application of propolis and its encapsulation as an alternative therapeutic agent for cancer treatments instead of chemotherapies because of its action on multi-signaling pathways.

Potential application of bee products in food industry: An exploratory review

Over the past eight years, bee products such as wax, honey, propolis, and pollen have generated intense curiosity about their potential food uses; to explore these possibilities, this review examines the nutritional benefits and notable characteristics of each product related to the food industry. While all offer distinct advantages, there are challenges to overcome, including the risk of honey contamination. Indeed, honey has excellent potential as a healthier alternative to sugar, while propolis's remarkable antibacterial and antioxidant properties can be enhanced through microencapsulation. Pollen is a versatile food with multiple applications in various products. In addition, the addition of beeswax to oleogels and its use as a coating demonstrate significant improvements in the quality and preservation of environmentally sustainable foods over time. This study demonstrates that bee products and apitherapy are essential for sustainable future food and innovative medical treatments.

Cytotoxicity evaluation of phytochemicals from stingless bee (Tetragonula biroi) propolis

Three prenylated flavonoids (1-3) were isolated from Tetragonula biroi propolis. The structures of the isolated compounds were characterized by NMR, IR, and UV spectroscopic and mass spectrometric analyses. The cytotoxicity activity of the crude extracts, fractions and the isolated compounds were established against four cell lines such as Caco-2, HeLa, MCF-7, and OVK-18. Among the tested compounds, compound 1 showed cytotoxicity activity against MCF-7 cell lines, whereas compound 2 showed good activity against Caco-2 and OVK-18 cell lines with IC50 values of 14.73 and 14.44, respectively. Moreover, compound 3 exhibited strong activity against OVK-18 cell lines. These findings contribute to the phytochemical understanding of the T. biroi propolis, and their cytotoxicity effects for future pharmaceutical purposes.

Antibacterial and Toxic Activity of Geopropolis Extracts from Melipona subnitida (Ducke, 1910) (Hymenoptera: Apidae) and Scaptotrigona depilis (Moure, 1942) (Hymenoptera: Apidae)

Bacteria are associated with many infections that affect humans and present antibiotic resistance mechanisms, causing problems in health organisations and increased mortality rates. Therefore, it is necessary to find new antibacterial agents that can be used in the treatment of these microorganisms. Geopropolis is a natural product from stingless bees, formed by a mixture of plant resins, salivary secretions, wax and soil particles, the chemical composition of this natural product is diverse. Thus, this study aimed to evaluate antibacterial activity, antibiotic modulation and the toxicity of geopropolis extracts from the stingless bees, Melipona subnitida (Ducke, 1910) and Scaptotrigona depilis (Moure, 1942) against standard and multi-resistant Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa bacteria. Geopropolis samples were collected in a meliponary located in Camaragibe, Pernambuco, Brazil. To determine the Minimum Inhibitory Concentration (MIC) and antibiotic modulation we performed broth microdilution tests. Mortality tests were used to verify extract toxicity in the model Drosophila melanogaster. The microbiological tests showing that the M. subnitida extracts had better inhibitory effects compared to S. depilis, presenting direct antibacterial activity against standard and multi-resistant strains. The extracts potentialized antibiotic effects, suggesting possible synergy and did not present toxicity in the model used. The information obtained in this study highlights extracts as promising antibacterial agents and is the first study to evaluate bacterial activity in these extracts, in addition to verifying their modulating effects and determining toxicity in the model used.

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.

Advances in the phytochemical screening and biological potential of propolis

Propolis is a natural resinous product collected from different parts of plants by bees and mixed with their salivary secretions. The occurrence of more than 180 different chemotypes has flavonoids, phenolic acids, esters, and phenolic aldehydes, as well as balsamic resins, beeswax, pollen, and essential and aromatic oils, among others. Its biological potential documented throughout the world justifies the need, from time to time, to organize reviews on the subject, with the intention of gathering and informing about the update on propolis. In this review (CRD42020212971), phytochemical advances, in vitro, in vivo, and clinical biological assays of pharmacological interest are showcased. The focus of this work is to present propolis clinical safety assays, antitumor, analgesic, antioxidant, anti-inflammatory, and antimicrobial activities. This literature review highlights propolis' promising biological activity, as it also suggests that studies associating propolis with nanotechnology should be further explored for enhanced bioprocessing applications.

Evaluation of the Chemical Profile and Antioxidant Capacity of Green, Brown, and Dark Propolis

The chemical composition of propolis varies between different types, due to the specific vegetation found near the hives and the climatic and soil conditions worldwide. Green propolis is exclusive to Brazil, produced by bees, with the resin of the plant Baccharis dracunculifolia. Brown propolis is a specific variety produced mainly in Northeast Brazil from the plant Hyptis divaricata, also known as "maria miraculosa". Dark propolis is a variety of propolis produced by bees from the resin of the plant known as Jurema Preta (Mimosa hostilis benth). In this study, the aqueous extracts of green, brown, and dark propolis were analyzed for their antioxidant capacity using ABTS, FRAP, and DPPH, and their chemical profiles were determined using paper spray mass spectrometry. Among the three extracts, green propolis had the highest content of total phenolic compounds (2741.71 ± 49.53 mg GAE. 100 g-1), followed by brown propolis (1191.55 ± 36.79 mg GAE. 100 g-1), and dark propolis had the lowest content (901.79 ± 27.80 mg GAE. 100 g-1). The three types of propolis showed high antioxidant capacity, with green showing the highest antioxidant capacity for the three methods used. Using paper spray mass spectrometry, it was possible to suggest the presence of 116 substances, including flavonoids (56), phenylpropanoids (30), terpenes (25), carboxylic acids (1), benzoic acid derivatives (1), fatty acids (1), amino acids (1) and alkaloids (1). The compounds in the green, brown, and dark propolis extracts reinforce the bioactive potential for application in these tree extracts' food and pharmaceutical products.

Characterization of the Bacterial Communities Inhabiting Tropical Propolis of Puerto Rico

Propolis is a resinous material produced by honeybees from different plant sources and used in the hive as a building material and to protect the colony from parasites and pathogens. Despite its antimicrobial properties, recent studies showed that propolis hosts diverse microbial strains, some with great antimicrobial potential. In this study, the first description of the bacterial community of propolis produced by the gentle Africanized honeybee was reported. Propolis was sampled from hives of two different geographic areas of Puerto Rico (PR, USA), and the associated microbiota investigated by both cultivation and metataxonomic approaches. Metabarcoding analysis showed appreciable bacterial diversity in both areas and statistically significant dissimilarity in the taxa composition of the two areas, probably due to the different climatic conditions. Both metabarcoding and cultivation data revealed the presence of taxa already detected in other hive components and compatible with the bee's foraging environment. Isolated bacteria and propolis extracts showed antimicrobial activity against Gram-positive and Gram-negative bacterial tester strains. These results support the hypothesis that the propolis microbiota could contribute to propolis' antimicrobial properties.

Comprehensive Metabolite Profiling of Berdav Propolis Using LC-MS/MS: Determination of Antioxidant, Anticholinergic, Antiglaucoma, and Antidiabetic Effects

Propolis is a complex natural compound that honeybees obtain from plants and contributes to hive safety. It is rich in phenolic and flavonoid compounds, which contain antioxidant, antimicrobial, and anticancer properties. In this study, the chemical composition and antioxidant activities of propolis were investigated; ABTS•+, DPPH• and DMPD•+ were prepared using radical scavenging antioxidant methods. The phenolic and flavonoid contents of propolis were 53 mg of gallic acid equivalent (GAE)/g and 170.164 mg of quercetin equivalent (QE)/g, respectively. The ferric ion (Fe3+) reduction, CUPRAC and FRAP reduction capacities were also studied. The antioxidant and reducing capacities of propolis were compared with those of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and Trolox reference standards. The half maximal inhibition concentration (IC50) values of propolis for ABTS•+, DPPH• and DMPD•+ scavenging activities were found to be 8.15, 20.55 and 86.64 μg/mL, respectively. Propolis extract demonstrated IC50 values of 3.7, 3.4 and 19.6 μg/mL against α-glycosidase, acetylcholinesterase (AChE) and carbonic anhydrase II (hCA II) enzyme, respectively. These enzymes' inhibition was associated with diabetes, Alzheimer's disease (AD) and glaucoma. The reducing power, antioxidant activity and enzyme inhibition capacity of propolis extract were comparable to those demonstrated by the standards. Twenty-eight phenolic compounds, including acacetin, caffeic acid, p-coumaric acid, naringenin, chrysin, quinic acid, quercetin, and ferulic acid, were determined by LC-MS/MS to be major organic compounds in propolis. The polyphenolic antioxidant-rich content of the ethanol extract of propolis appears to be a natural product that can be used in the treatment of diabetes, AD, glaucoma, epilepsy, and cancerous diseases.

Antimicrobial, Antibiofilm and Toxicological Assessment of Propolis

Antimicrobial resistance is a serious problem for the control of infections and infectious diseases. Propolis is a substance produced by honeybees with antimicrobial and antibiofilm properties. To consider propolis as an alternative to the use of antimicrobials for infection control, we assessed its antimicrobial and antibiofilm activities. To assess propolis for topical medical use, toxicological studies were also performed. A Portuguese 70% propolis ethanolic extract was chemically evaluated and studied for antimicrobial activity on staphylococcal field isolates (n = 137) and antibiofilm action (n = 45). Cell toxicological assessment was performed using keratinocytes and fibroblasts. Pinobanksin, chrysin, acacetin, apigenin, pinocembrin, and kaempferol-dimethyl-ether were detected. All 137 isolates were susceptible to 6.68 mg/mL or lower propolis concentration (80% isolates were susceptible to <1 mg/mL). The mean percentage of biofilm inhibition was 71%, and biofilm disruption was 88.5%. Propolis (<1 mg/mL) was well-tolerated by fibroblasts and moderately tolerated by keratinocytes. The combined antimicrobial and antibiofilm effect of propolis, together with its low toxicity to connective tissue and epithelial cells, suggests a good applicability for topical antibacterial treatment. Therefore, propolis seems to be a good alternative to antimicrobials for the treatment of infections with Staphylococcus spp. that deserves to be evaluated in vivo.

Comparative Study of Antiviral, Cytotoxic, Antioxidant Activities, Total Phenolic Profile and Chemical Content of Propolis Samples in Different Colors from Turkiye

Propolis is a valuable natural substance obtained by honey bees after being collected from the bark, resin of trees, plant leaves and mixed with their saliva, and has been widely used for various biological activities. The properties of propolis can vary widely by botanical origin, location of the hives and colony population. It is thought that the color of propolis is one of the main factors determining its acceptability and originates from the flower markers, pollen and nectar of some plants and is directly related to its chemical content. It is important to compare and standardize the colors, chemical content and biological activities of propolis in our country, which has a rich endemic plant diversity. Thus, in this study, the color indexes of 39 propolis samples from different locations in Turkiye were determined by Lovibond Tintometer, for the first time. The color index, total phenolic content, cytotoxic and antioxidant activities relationship of propolis and two commercial propolis samples were also investigated by HCA and PCA. Turkish propolis, which is defined by its color indices, chemical contents and many different activity potentials, such as antioxidant, antiviral and cytotoxic activity, will find use in many fields from medicine to cosmetics with this study.

Plant genetic diversity by DNA barcoding to investigate propolis origin

Identify the botanical origins of a certain type of propolis may be challenging and time demanding, since it involves bee's behavior observation, plant resins collection and chemical analysis. Thus, this study aimed to determine the plant genetic materials in propolis from southern Brazil using the DNA barcoding to investigate their botanical origins, as well as to compare it with the phytochemical composition determined by ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-HRMS) and with the pollinic profile. As principal results, non-native Populus carolinensis Moench (Salicaceae) was almost the only DNA source in some propolis samples, which coincided with the presence of flavonoids typical from poplar exudates. Conversely, other propolis samples had DNA material coming mainly from native plant species, most of them characterized to the species level, although no specific chemical markers from those plants could be identified by UHPLC-HRMS. However, pollen from several plants identified by the DNA barcoding were extracted from some propolis samples. Despite the identification of typical diterpenes, DNA material from Araucaria angustifolia (Bertol.) Kuntze (Araucariaceae), which have been indicated as a major resin source for propolis from preservation areas in southern Brazil, was found in very small abundancies, likely because bees do not drag tissue material containing DNA when collecting resin from this native species. In conclusion, DNA barcoding analysis successfully provided information about the provenance of propolis, although, depending on the plant resin sources, this information is likely to come from pollen.

Deer Velvet Antler Extracts Exert Anti-Inflammatory and Anti-Arthritic Effects on Human Rheumatoid Arthritis Fibroblast-Like Synoviocytes and Distinct Mouse Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes joint deformity and disability. Deer velvet antler (DA), a traditional Chinese medicine, has been used to treat various types of arthritis for several thousands of years, but the underlying mechanisms are unknown. Herein, we investigated the anti-arthritic and anti-inflammatory effects of DA in vitro and in vivo. The ethyl acetate layer of DA ethanol extract (DA-EE-EA) was used to treat tumor necrosis factor (TNF)-[Formula: see text]-stimulated fibroblast-like synoviocyte MH7A cells, collagen-induced arthritis DBA/1 mice, and SKG mice with zymosan-induced arthritis. DA-EE-EA reduced nitric oxide production, prostaglandin E2 levels, and levels of pro-inflammatory cytokines including interleukin (IL)-1[Formula: see text], IL-6, and IL-8 in MH7A cells. DA-EE-EA also downregulated the phosphorylation of mitogen-activated protein kinase p38 and c-Jun N-terminal kinase and the translocation of nuclear factor kappa B p65. Intraperitoneal injection of DA-EE-EA for 3 weeks substantially reduced clinical arthritis scores in vivo models. Pathohistological images of the hind paws showed that DA-EE-EA reduced immune cell infiltration, synovial hyperplasia, and cartilage damage. The levels of pro-inflammatory cytokines, such as tumor necrosis factor alpha, IL-1[Formula: see text], IL-6, IL-8, IL-17A, and interferon-gamma, decreased in the hind paw homogenates of DA-EE-EA-treated mice. We also identified several potential components, such as hexadecanamide, oleamide, erucamide, and lysophosphatidylcholines, that might contribute to the anti-inflammatory effects of DA-EE-EA. In conclusion, DA-EE-EA has the potential to treat RA by regulating inflammatory responses. However, the individual components of DA-EE-EA and the underlying anti-inflammatory mechanisms need further investigation in future studies.

A Comprehensive Review of Stingless Bee Products: Phytochemical Composition and Beneficial Properties of Honey, Propolis, and Pollen

The stingless bee has been gaining more attention in recent years due to the uniqueness and benefits of its products. Similar to the common honeybee, stingless bees also produce honey, propolis, and pollen, which offer superior benefits for direct or indirect consumption. However, reports on the benefits of stingless bee products are scarce. This article summarises recent reports on stingless bee products. The function and application of the properties of the products such as phenolic compounds, antioxidant properties, and chemical content are elucidated. The antimicrobial properties and anticancer potential of the products are also highlighted. Future trends, potential, and uniqueness of stingless bee products are discussed. Stingless bee honey is highlighted as a superfood that exceptionally has the potential to be an active ingredient in treating cancer. Stingless bee propolis has been extensively studied for its rich beneficial chemical compounds that contribute to its antioxidant properties. Though studies on stingless bee pollen are scarce, it has been reported that it also has the potential of being a functional food.

Chemical Characterization and Cytotoxic/Antibacterial Effects of Nine Iranian Propolis Extracts on Human Fibroblast Cells and Oral Bacteria

Multimicrobial infections caused by pathobionts are called dysbiotic multimicrobial illnesses. Commercial mouthwashes, such as chlorhexidine, have negative side effects that can prevent tooth decay and infection. The present study aimed to determine the antifungal, antibacterial, and cytotoxicity characteristics of the propolis extracts from different areas (Iran). The ethanolic extract of propolis was prepared. GC/MS carried out the characterization to determine the thymol, carvacrol, and menthol extracts, and also, total phenol and flavonoid were assed for all samples. The antimicrobial and antibiofilm effects were evaluated against S. mutans, S. mitis, S. salivarius, L. acidophilus, E. coli, S. aureus, and C. albicans. The cytotoxic effect of extracts was measured on human fibroblast cells by MTT test. The MIC values in mg mL⁻¹ were ranged as follows: S. salivarius (0.003 to 0.048), S. mutans (0.003 to 0.029), S. mitis (0.007 to 0.058), L. acidophilus (0.007 to 0.117), C. albicans (0.014 to 0.234), E. coli (0.007 to 0.058), and S. aureus (0.007 to 0.058), while MBC were, respectively, S. mutans (0.007 to 0.058), S. salivarius (0.007 to 0.117), S. mitis (0.007 to 0.117), L. acidophilus (0.014 to 0.234), C. albicans (0.029 to 0.468), E. coli (0.014 to 0.234), and S. aureus (0.007 to 0.117). Cariogenic bacteria and Candida albicans were demonstrated to be resistant to propolis extracts. Therefore, propolis extracts may make good mouthwashes.

Evaluation of Total Phenolic and Flavonoid Contents, Antibacterial and Antibiofilm Activities of Hungarian Propolis Ethanolic Extract against Staphylococcus aureus

Propolis is a natural bee product that is widely used in folk medicine. This study aimed to evaluate the antimicrobial and antibiofilm activities of ethanolic extract of propolis (EEP) on methicillin-resistant and sensitive Staphylococcus aureus (MRSA and MSSA). Propolis samples were collected from six regions in Hungary. The minimum inhibitory concentrations (MIC) values and the interaction of EEP-antibiotics were evaluated by the broth microdilution and the chequerboard broth microdilution methods, respectively. The effect of EEP on biofilm formation and eradication was estimated by crystal violet assay. Resazurin/propidium iodide dyes were applied for simultaneous quantification of cellular metabolic activities and dead cells in mature biofilms. The EEP1 sample showed the highest phenolic and flavonoid contents. The EEP1 successfully prevented the growth of planktonic cells of S. aureus (MIC value = 50 µg/mL). Synergistic interactions were shown after the co-exposition to EEP1 and vancomycin at 108 CFU/mL. The EEP1 effectively inhibited the biofilm formation and caused significant degradation of mature biofilms (50-200 µg/mL), as a consequence of the considerable decrement of metabolic activity. The EEP acts effectively as an antimicrobial and antibiofilm agent on S. aureus. Moreover, the simultaneous application of EEP and vancomycin could enhance their effect against MRSA infection.

Use of Stingless Bee Propolis and Geopropolis against Cancer-A Literature Review of Preclinical Studies

Cancer is one of the major maladies affecting humankind and remains one of the leading causes of death worldwide. The investigation of the biological activities of stingless bee products, especially propolis and geopropolis, has revealed promising therapeutic properties, especially in the research on new antineoplastic agents. This literature review of preclinical trials, involving biological assays of antitumor activity and identification of the chemical composition of propolis and geopropolis of stingless bee species, describes the cytotoxicity in tumor lineages (breast, lung, ovarian, liver, mouth, pharynx, larynx, colon, stomach, colorectal, cervix, kidney, prostate, melanoma, human glioblastoma, canine osteosarcoma, erythroleukemia, human chronic myelocytic leukemia, and human promyelocytic leukemia) of propolis and geopropolis of 33 species of stingless bees. The chemical composition of propolis and geopropolis was identified, indicating that these belong to the chemical classes of phenolic acids, flavonoids, coumarins, benzophenones, anthraquinones, alkaloids, terpenes, steroids, saponins, fatty acids, and carbohydrates and are possibly responsible for the cytotoxicity in tumor cells. Apoptosis was one of the main mechanisms of cytotoxicity of extracts and substances isolated from stingless bee products. Although the results found are encouraging, other preclinical studies and clinical trials are essential for the discovery of new anticancer agents.

Experimental Evidence for Therapeutic Potentials of Propolis

Propolis is produced by honeybees from materials collected from plants they visit. It is a resinous material having mixtures of wax and bee enzymes. Propolis is also known as bee glue and used by bees as a building material in their hives, for blocking holes and cracks, repairing the combs and strengthening their thin borders. It has been extensively used since ancient times for different purposes in traditional human healthcare practices. The quality and composition of propolis depend on its geographic location, climatic zone and local flora. The New Zealand and Brazilian green propolis are the two main kinds that have been extensively studied in recent years. Their bioactive components have been found to possess a variety of therapeutic potentials. It was found that Brazilian green propolis improves the cognitive functions of mild cognitive impairments in patients living at high altitude and protects them from neurodegenerative damage through its antioxidant properties. It possesses artepillin C (ARC) as the key component, also known to possess anticancer potential. The New Zealand propolis contains caffeic acid phenethyl ester (CAPE) as the main bioactive with multiple therapeutic potentials. Our lab performed in vitro and in vivo assays on the extracts prepared from New Zealand and Brazilian propolis and their active ingredients. We provided experimental evidence that these extracts possess anticancer, antistress and hypoxia-modulating activities. Furthermore, their conjugation with γCD proved to be more effective. In the present review, we portray the experimental evidence showing that propolis has the potential to be a candidate drug for different ailments and improve the quality of life.

Antibacterial Activity of Propolis-Embedded Zeolite Nanocomposites for Implant Application

This study investigates the potential of propolis-embedded zeolite nanocomposites for dental implant application. Propolis-embedded zeolite nanocomposites were fabricated by complexation of propolis and zeolites. Then, they were pelleted with Poly(L-lactide) (PLA)/poly(ε-caprolactone) (PCL) polymer for the fabrication of a dental implant. The chemical properties of propolis were not changed during the fabrication of propolis-embedded zeolite nanocomposites in attenuated total reflection-fourier transform infra-red (ATR FT-IR) spectroscopy measurements. Propolis was continuously released from propolis-embedded zeolite nanocomposites over one month. PLA/PCL pellets containing propolis-embedded zeolite nanocomposites showed longer sustained release behavior compared to propolis-embedded zeolite nanocomposites. Propolis-embedded zeolite nanocomposite powder showed similar antibacterial activity against C. albicans in an agar plate and formed an inhibition zone as well as chlorohexidine (CHX) powder. Eluted propolis solution from PLA/PCL pellets also maintained antibacterial activity as well as CHX solution. Furthermore, eluted propolis solution from PLA/PCL pellets showed significant antibacterial efficacy against C. albicans, S. mutans and S. sobrinus. Dental implants fabricated from PLA/PCl polymer and propolis-embedded zeolite nanocomposites also have antibacterial efficacy and negligible cytotoxicity against normal cells. We suggest that PLA/PCl pellets containing propolis-embedded zeolite nanocomposites are promising candidates for dental implants.