Chemical characterization, antioxidant and anti-HIV activities of a Brazilian propolis from Ceará state

Antibiotic potential and metabolic modulation of Bacillus velezensis VTRNT 01 in response to bacterial elicitors

Bacterial elicitors are recognized for their ecological role in stimulating plant defenses and enhancing the production of beneficial metabolites. This study explores the antibiotic potential of endophytic Bacillus velezensis VTRNT 01, isolated from Adenosma bracteosum Bonati, under co-cultivation with bacterial elicitors (Staphylococcus aureus, Escherichia coli, and Aeromonas hydrophila). By leveraging these interactions, we aim to unlock the full potential of endophytic bacteria for sustainable applications in agriculture and pharmaceuticals. Using gas chromatography-mass spectrometry (GC-MS) analysis, we identified a total of 42 distinct chemical compounds produced under these conditions. Notably, 15 of these compounds were exclusively induced by the elicitor treatment, suggesting a strong interactive effect between Bacillus velezensis and the elicitors. Among the identified compounds, several have well-documented antimicrobial properties, including benzaldehyde, benzeneacetic acid, and tetradecanoic acid, which were shown to exhibit significant antibacterial activity against common pathogens. These findings demonstrate the potential of bio-elicitor strategies to enhance the biosynthesis of antimicrobial compounds, paving the way for innovative solutions in crop protection and the development of new therapeutic agents.

Investigating small molecules in propolis as Nipah virus glycoprotein (NiV-G) inhibitors through molecular interaction studies

Despite the significant fatality rates associated with Nipah virus (NiV) outbreaks in South Asia, including Bangladesh, and India, till today, there is no approved medications to treat it. In this context, small molecules in propolis were computationally screened through pharmacokinetic and toxicity studies followed by molecular docking and dynamics simulation with Nipah virus glycoprotein (NiV-G protein) to assess their anti-Nipah potential. A thorough literature analysis was performed to identify antiviral compounds in propolis from a pool of 84 experimental articles. Following ADMET analysis, 27 molecules out of 34 were docked against NiV-G and compared with a control ligand, ribavirin, which is an investigational drug against Nipah. The molecular docking revealed that bauer-7-en-3β-yl acetate (BA) and moronic acid (MA) bound more strongly to the active site of NiV-G than ribavirin and other ligands. Investigation of root-mean-square deviation (RMSD), root mean square fluctuations (RMSF), radius of gyration (Rg), solvent accessible surface area (SASA), molecular surface area (MolSA), binding free energy (MM-PBSA), the complexity of hydrogen bonds (HBs), and secondary structure of ligand-target interactions for 100 ns by molecular dynamics (MD) simulation study further supported the docked complex's stability and compactness. Therefore, the in silico molecular interaction analysis reports that both molecules may be the possible candidates against Nipah infection.

Chemical Characterization and Antimicrobial Activity of Green Propolis from the Brazilian Caatinga Biome

Green propolis, particularly from the unique flora of the Brazilian Caatinga biome, has gained significant interest due to its diverse chemical composition and biological activities. This study focuses on the chemical characterization and antimicrobial evaluation of Caatinga green propolis. Twelve compounds were isolated through different chromatographic techniques, including flavanones (naringenin, 7-O-methyleriodictyol, sakuranetin), flavones (hispidulin, cirsimaritin), flavonols (quercetin, quercetin-3-methyl ether, kaempferol, 6-methoxykaempferol, viscosine, penduletin), and one chalcone (kukulkanin B). Using liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (LC-QToF-MS), a total of 55 compounds excluding reference standards were tentatively identified, which include flavonoids, phenolic acids derivatives, and alkaloids, with flavonols, flavanones, and flavones being predominant. Antimicrobial testing against pathogens revealed that the crude extract exhibited low inhibitory activity, against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE) (IC50: 148.4 and 120.98 µg/mL, respectively). Although the isolated compounds showed limited individual activity, a fraction containing sakuranetin and penduletin (Fraction 8) exhibited moderated activity against Cryptococcus neoformans (IC50: 47.86 µg/mL), while a fraction containing quercetin and hispidulin showed moderated activity against VRE (IC50: 16.99 µg/mL). These findings highlight the potential application of Caatinga green propolis as an antimicrobial agent, particularly against resistant bacterial strains, and underscore the importance of synergistic interactions between compounds in enhancing biological effects.

Quercetin, a Flavonoid with Great Pharmacological Capacity

Quercetin is a flavonoid with a low molecular weight that belongs to the human diet's phenolic phytochemicals and nonenergy constituents. Quercetin has a potent antioxidant capacity, being able to capture reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive chlorine species (ROC), which act as reducing agents by chelating transition-metal ions. Its structure has five functional hydroxyl groups, which work as electron donors and are responsible for capturing free radicals. In addition to its antioxidant capacity, different pharmacological properties of quercetin have been described, such as carcinostatic properties; antiviral, antihypertensive, and anti-inflammatory properties; the ability to protect low-density lipoprotein (LDL) oxidation, and the ability to inhibit angiogenesis; these are developed in this review.

Preparation and characterization of propolis reinforced eggshell membrane/ GelMA composite hydrogel for biomedical applications

Gelatin methacrylate-based hydrogels (GelMA) were widely used in tissue engineering and regenerative medicine. However, to manipulate their various chemical and physical properties and create high-efficiency hydrogels, different materials have been used in their structure. Eggshell membrane (ESM) and propolis are two nature-derived materials that could be used to improve the various characteristics of hydrogels, especially structural and biological properties. Hence, the main purpose of this study is the development of a new type of GelMA hydrogel containing ESM and propolis, for use in regenerative medicine. In this regard, in this study, after synthesizing GelMA, the fragmented ESM fibers were added to it and the GM/EMF hydrogel was made using a photoinitiator and visible light irradiation. Finally, GM/EMF/P hydrogels were prepared by incubating GM/EMF hydrogels in the propolis solution for 24 h. After various structural, chemical, and biological characterizations, it was found that the hydrogels obtained in this study offer improved morphological, hydrophilic, thermal, mechanical, and biological properties. The developed GM/EMF/P hydrogel presented more porosity with smaller and interconnected pores compared to the other hydrogels. GM/EMF hydrogels due to possessing EMF showed compressive strength up to 25.95 ± 1.69 KPa, which is more than the compressive strength provided by GM hydrogels (24.550 ± 4.3 KPa). Also, GM/EMF/P hydrogel offered the best compressive strength (44.65 ± 3.48) due to the presence of both EMF and propolis. GM scaffold with a contact angle of about 65.41 ± 2.199 θ showed more hydrophobicity compared to GM/EMF (28.67 ± 1.58 θ), and GM/EMF/P (26.24 ± 0.73 θ) hydrogels. Also, the higher swelling percentage of GM/EMF/P hydrogels (343.197 ± 42.79) indicated the high capacity of this hydrogel to retain more water than other scaffolds. Regarding the biocompatibility of the fabricated structures, MTT assay results showed that GM/EMF/P hydrogel significantly (p-value < 0.05) supported cell viability. Based on the results, it seems that GM/EMF/P hydrogel could be a promising biomaterial candidate for use in various fields of regenerative medicine.

Phenolic Compounds in Salicornia spp. and Their Potential Therapeutic Effects on H1N1, HBV, HCV, and HIV: A Review

Despite public health risk mitigation measures and regulation efforts by many countries, regions, and sectors, viral outbreaks remind the world of our vulnerability to biological hazards and the importance of mitigation actions. The saltwater-tolerant plants in the Salicornia genus belonging to the Amaranthaceae family are widely recognized and researched as producers of clinically applicable phytochemicals. The plants in the Salicornia genus contain flavonoids, flavonoid glycosides, and hydroxycinnamic acids, including caffeic acid, ferulic acid, chlorogenic acid, apigenin, kaempferol, quercetin, isorhamnetin, myricetin, isoquercitrin, and myricitrin, which have all been shown to support the antiviral, virucidal, and symptom-suppressing activities. Their potential pharmacological usefulness as therapeutic medicine against viral infections has been suggested in many studies, where recent studies suggest these phenolic compounds may have pharmacological potential as therapeutic medicine against viral infections. This study reviews the antiviral effects, the mechanisms of action, and the potential as antiviral agents of the aforementioned phenolic compounds found in Salicornia spp. against an influenza A strain (H1N1), hepatitis B and C (HBV/HCV), and human immunodeficiency virus 1 (HIV-1), as no other literature has described these effects from the Salicornia genus at the time of publication. This review has the potential to have a significant societal impact by proposing the development of new antiviral nutraceuticals and pharmaceuticals derived from phenolic-rich formulations found in the edible Salicornia spp. These formulations could be utilized as a novel strategy by which to combat viral pandemics caused by H1N1, HBV, HCV, and HIV-1. The findings of this review indicate that isoquercitrin, myricetin, and myricitrin from Salicornia spp. have the potential to exhibit high efficiency in inhibiting viral infections. Myricetin exhibits inhibition of H1N1 plaque formation and reverse transcriptase, as well as integrase integration and cleavage. Isoquercitrin shows excellent neuraminidase inhibition. Myricitrin inhibits HIV-1 in infected cells. Extracts of biomass in the Salicornia genus could contribute to the development of more effective and efficient measures against viral infections and, ultimately, improve public health.

Non-Lactic Probiotic Beverage Enriched with Microencapsulated Red Propolis: Microorganism Viability, Physicochemical Characteristics, and Sensory Perception

This work aimed to develop a non-dairy functional beverage fermented with probiotic strains and fortified with Brazilian red propolis (microencapsulated and extracted). The non-dairy matrix consisted of oats (75 g), sunflower seeds (175 g), and almonds (75 g). It was fermented by a starter co-culture composed of Lactiplantibacillus plantarum CCMA 0743 and Debaryomyces hansenii CCMA 176. Scanning electron microscopy analysis was initially performed to verify the integrity of the microcapsules. The viability of the microorganisms after fermentation and storage, chemical composition (high performance liquid chromatography (HPLC) and gas chromatography coupled to mass spectrometry (GC-MS) analyses), rheology, antioxidant activity, and sensory profile of the beverages were determined. After fermentation and storage, the starter cultures were well adapted to the substrate, reducing the pH (6.50 to 4) and cell count above 7.0 log CFU/mL. Lactic acid was the main organic acid produced during fermentation and storage. In addition, 39 volatile compounds were detected by gas chromatography coupled to mass spectrometry (GC-MS), including acids, alcohols, aldehydes, alkanes, alkenes, esters, ethers, phenols, terpenes, and others. The addition of propolis extract increased the antioxidant and phenolic activity and the presence of volatile esters but reduced the beverage’s acceptability. The addition of microencapsulated propolis was more associated with the presence of higher alcohols and had similar acceptance to the control beverage. The combination of a non-dairy substrate, a starter co-culture, and the addition of propolis led to the development of a probiotic beverage with great potential for health benefits.

Biological Activity and Chemical Composition of Propolis from Various Regions of Poland

Propolis is one of the bee products, with multiple biological properties used in numerous applications. The research objective was to determine the chemical composition and biological properties (antibacterial, antifungal, antiviral, antioxidant, and cytoprotective activity) of propolis extracts collected from various regions of Poland. The results indicated that the total content of phenols (116.16-219.41 mg GAE/g EEP) and flavonoids (29.63-106.07 mg QE/g EEP) in propolis extracts depended on their geographic origin. The high content of epicatechin, catechin, pinobanksin, myricetin, and acids: vanillic and syringic in propolis samples was confirmed by chromatographic analysis. Moreover, the presence of caffeic acid phenethyl ester was confirmed in all samples. The origin of propolis also influenced the biological properties of its extracts. The propolis extracts were characterized by moderate DPPH free radical scavenging activity (29.22-35.14%), and relatively low ferrous iron chelating activity (9.33-32.32%). The results indicated also that the propolis extracts showed high activity in the protection of human red blood cells against free radicals generated from 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH). The extracts exhibited diversified activity against the tested pathogenic bacteria and limited activity against fungal strains. The research of selected propolis extracts showed that only 2 of 5 examined samples showed moderate activity against HPV (human papillomaviruses) and the activity depended on its geographical distribution.

The antiviral and immunomodulatory activities of propolis: An update and future perspectives for respiratory diseases

Propolis is a complex natural product that possesses antioxidant, anti-inflammatory, immunomodulatory, antibacterial, and antiviral properties mainly attributed to the high content in flavonoids, phenolic acids, and their derivatives. The chemical composition of propolis is multifarious, as it depends on the botanical sources from which honeybees collect resins and exudates. Nevertheless, despite this variability propolis may have a general pharmacological value, and this review systematically compiles, for the first time, the existing preclinical and clinical evidence of propolis activities as an antiviral and immunomodulatory agent, focusing on the possible application in respiratory diseases. In vitro and in vivo assays have demonstrated propolis broad-spectrum effects on viral infectivity and replication, as well as the modulatory actions on cytokine production and immune cell activation as part of both innate and adaptive immune responses. Clinical trials confirmed propolis undeniable potential as an effective therapeutic agent; however, the lack of rigorous randomized clinical trials in the context of respiratory diseases is tangible. Since propolis is available as a dietary supplement, possible use for the prevention of respiratory diseases and their deleterious inflammatory drawbacks on the respiratory tract in humans is considered and discussed. This review opens up new perspectives on the clinical investigation of neglected propolis biological properties which, now more than ever, are particularly relevant with respect to the recent outbreaks of pandemic respiratory infections.

Focus on the high therapeutic potentials of quercetin and its derivatives

BACKGROUND

Polyphenols and particularly flavonoids are of constant interest to the scientific community. Flavonoids are investigated for their biological and pharmacological purposes, notably as antioxidant, anticancer, antiviral and for their anti-inflammatory activities. Certainly, one of the best-known flavonols recognized for its therapeutic and preventive properties, is quercetin. Despite its biological interest, quercetin suffer from some drawbacks, mainly related to its bioavailability. Hence, its synthetic or biosynthetic derivatives have been the subject of intensive research. The health-promoting biological activities of flavonols and derivatives mainly arise from their capacity to disrupt the host-pathogen interactions and/or to regulate host cellular functions including oxidative processes and immunological responses. In the age of coronavirus pandemic, the anti-inflammatory and antiviral potential of flavonols should be put forward to explore these substances for decreasing the viral load and inflammatory storm caused by the infection.

PURPOSE OF STUDY

The present review will decipher and discuss the antioxidant, anti-inflammatory and antiviral capacities of major flavonol with a focus on the molecular basis and structure-activity relationships.

STUDY DESIGN

Current study used a combination of quercetin derivatives, pathway, antioxidant, anti-inflammatory, antiviral activities as keywords to retrieve the literature. This study critically reviewed the current literature and presented the ability of natural analogs of quercetin having superior antioxidant, anti-inflammatory and antiviral effects than the original molecule.

RESULTS

This review allowed the identification of relevant key structure-activity relationship elements and highlight approaches on the mechanisms governing the antioxidant, antiviral and anti-inflammatory activities.

CONCLUSION

Through a critical analysis of the literature, flavonols and more precisely quercetin derivatives reviewed and found to act simultaneously on inflammation, virus and oxidative stress, three key factors that may lead to life threatening diseases.

Naringenin as a Possible Candidate Against SARS-CoV-2 Infection and in the Pathogenesis of COVID-19

Naringenin, widely distributed in fruits and vegetables, is endowed with antiviral and other health beneficial activities, such as immune-stimulating and anti-inflammatory actions that could play a role in contributing, to some extent, to either preventing or alleviating coronavirus infection. Several computational studies have identified naringenin as one of the prominent flavonoids that can possibly inhibit internalization of the virus, virus-host interactions that trigger the cytokine storm, and replication of the virus. This review highlights the antiviral potential of naringenin in COVID-19 associated risk factors and its predicted therapeutic targets against SARS-CoV-2 infection.

How diverse is the chemistry and plant origin of Brazilian propolis?

Propolis is a honey bee product containing chiefly beeswax and resins originated from plant buds or exudates. Propolis resin exerts a diversity of biological activities, such as antitumoral, anti-inflammatory, antimicrobial, and defense of the hive against pathogens. Chemical standardization and identification of botanical sources is crucial for characterization of propolis. Types of Brazilian propolis are characteristic of geographical regions and respective biomes, such as savannas (Cerrado), mangroves, dry forest (Caatinga), rain forests (Amazon, Atlantic, and Interior forests), altitudinal fields ("Campos Rupestres"), Pantanal, and Araucaria forests. Despite the wide diversity of Brazilian biomes and flora, relatively few types of Brazilian propolis and corresponding resin plant sources have been reported. Factors accounting for the restricted number of known types of Brazilian propolis and plant sources are tentatively pointed out. Among them, the paper discusses constraints that honey bees must overcome to collect plant exudates, including the characteristics of the lapping-chewing mouthpart of honey bee, which limit their possibilities to cut and chew plant tissues, as well as chemical requirements that plant resins must fulfil, involving antimicrobial activity of its constituents and innocuity to the insects. Although much still needs to be done toward a more comprehensive picture of Brazilian propolis types and corresponding plant origins, the prospects indicate that the actual diversity of plant sources of honey bee propolis will remain relatively low.

Propolis increases Foxp3 expression and lymphocyte proliferation in HIV-infected people: A randomized, double blind, parallel-group and placebo-controlled study

HIV infection and the prolonged use of antiretroviral therapy (ART) contribute to persistent inflammation and immune deregulation in people living with HIV/AIDS (PLWHA). Propolis is a bee product with plenty of biological properties, including immunomodulatory and anti-inflammatory action. This work aimed to evaluate possible changes in the immune/inflammatory response in PLWHA under ART after propolis intake. Asymptomatic PLWHA were double-blindly randomized into parallel groups receiving propolis (500 mg/day, n = 20) for 3 months or placebo (n = 20). Plasma cytokines (TNF-α, IL-2, IL-4, IL-6, IL-10 and IL17) were evaluated by cytometric bead array; cytokine production by PBMC (IFN-γ, IL-5, IL-17, IL-10, IL-1β, IL-18, and IL-33) was assessed by ELISA; gene expression (T-bet, GATA-3, RORγt and Foxp3) was determined by RT-qPCR, and cell proliferation was analysed by flow cytometry using CFSE staining. The average of gender, age, CD4⁺/CD8⁺ T cell count, time of diagnosis and treatment were similar in both groups. No differences were observed in cytokine levels nor in inflammasome activation. However, Pearson's correlation showed that IL-10 was directly correlated to CD4⁺ T cell count and inversely to IFN-γ after treatment with propolis. Foxp3 expression and lymphocyte proliferation increased in the propolis group. Data suggested that daily propolis consumption may improve the immune response and decrease the inflammatory status in asymptomatic PLWHA under ART.

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.

Antioxidant Activity in Bee Products: A Review

Bee products have been used since ancient times both for their nutritional value and for a broad spectrum of therapeutic purposes. They are deemed to be a potential source of natural antioxidants that can counteract the effects of oxidative stress underlying the pathogenesis of many diseases. In view of the growing interest in using bioactive substances from natural sources to promote health and reduce the risk of developing certain illnesses, this review aims to update the current state of knowledge on the antioxidant capacity of bee products such as honey, pollen, propolis, beeswax, royal jelly and bee venom, and on the analytical methods used. The complex, variable composition of these products and the multitude of analytical methods used to study their antioxidant activities are responsible for the wide range of results reported by a plethora of available studies. This suggests the need to establish standardized methods to more efficiently evaluate the intrinsic antioxidant characteristics of these products and make the data obtained more comparable.

Supercritical Extraction of Red Propolis: Operational Conditions and Chemical Characterization

The objective of this study was to determine the best operational conditions for obtaining red propolis extract with high antioxidant potential through supercritical fluid extraction (SFE) technology, using carbon dioxide (CO₂) as the supercritical fluid and ethanol as the cosolvent. The following parameters were studied: overall extraction curve, S/F (mass of CO₂/mass of sample), cosolvent percentage (0, 1, 2 and 4%) and global yield isotherms as a function of different pressures (250, 350 and 450 bar) and temperatures (31.7, 40 and 50 °C). Within the investigated parameters, the best conditions found were an S/F of 131 and the use of ethanol at the highest concentration (4% w/w), which resulted in higher extract yields and higher content of antioxidant compounds. Formononetin, the main biomarker of red propolis, was the compound found at the highest amounts in the extracts. As expected, the temperature and pressure conditions also influenced the process yield, with 350 bar and 40 °C being the best conditions for obtaining bioactive compounds from a sample of red propolis. The novel results for red propolis found in this study show that it is possible to obtain extracts with high antioxidant potential using a clean technology under the defined conditions.

Perspective: The Potential Effects of Naringenin in COVID-19

Coronavirus disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), was declared a pandemic by the World Health Organization in March 2020. Severe COVID-19 cases develop severe acute respiratory syndrome, which can result in multiple organ failure, sepsis, and death. The higher risk group includes the elderly and subjects with pre-existing chronic illnesses such as obesity, hypertension, and diabetes. To date, no specific treatment or vaccine is available for COVID-19. Among many compounds, naringenin (NAR) a flavonoid present in citrus fruits has been investigated for antiviral and anti-inflammatory properties like reducing viral replication and cytokine production. In this perspective, we summarize NAR potential anti-inflammatory role in COVID-19 associated risk factors and SARS-CoV-2 infection.

Discovery, synthesis, and optimization of an N-alkoxy indolylacetamide against HIV-1 carrying NNRTI-resistant mutations from the Isatis indigotica root

From an aqueous decoction of the traditional Chinese medicine "ban lan gen" (the Isatis indigotica root), an antiviral natural product CI - 39 was isolated as an NNRTI (non-nucleoside reverse transcriptase inhibitor) (EC50 = 3.40 μM). Its novel structure was determined as methyl (1-methoxy-1H-indol-3-yl)acetamidobenzoate by spectroscopic data and confirmed by single crystal X-ray diffraction. Through synthesis and structure-activity relationship (SAR) investigation of CI - 39 and 57 new derivatives (24 with EC50 values of 0.06-8.55 μM), two optimized derivatives 10f and 10i (EC50: 0.06 μM and 0.06 μM) having activity comparable to that of NVP (EC50 = 0.03 μM) were obtained. Further evaluation verified that 10f and 10i were RT DNA polymerase inhibitors and exhibited better activities and drug resistance folds compared to NVP against seven NNRTI-resistant strains carrying different mutations. Especially, 10i (EC50 = 0.43 μM) was more active to the L100I/K103N double-mutant strain as compared to both NVP (EC50 = 0.76 μM) and EFV (EC50 = 1.08 μM). The molecular docking demonstrated a possible binding pattern between 10i and RT and revealed activity mechanism of 10i against the NNRTI-resistant strains.

Methacrylate: An alternative fixing agent for identifying the botanical origin of propolis

PREMISE

A new technique was developed to identify the botanical origin of propolis, a resin-like material made by bees by mixing saliva and beeswax with plant buds and exudates, using methacrylate for permanent slide preparation.

METHODS AND RESULTS

Propolis samples were fixed in methacrylate to produce permanent slides. The anatomical structures of the plant fragments in the methacrylated propolis were compared with propolis slides prepared using conventional techniques that consist of propolis sediment obtained during a series of solvent reactions, filtration, and centrifugations, which cost a similar amount to produce. The techniques resulted in qualitative differences between the slides obtained. The methacrylated propolis sections allowed the detailed observation and identification of plant anatomical structures that were obscured in samples prepared using the conventional procedure. This clarity enabled the detailed evaluation of valuable taxon-diagnostic characters in a permanent slide, which can also be used for histochemical tests.

CONCLUSIONS

The methacrylated embedding of propolis is an affordable technique that could be implemented as a routine laboratory procedure. This new technique enables the efficient determination of the botanical origin of propolis.