Seasonal variation, chemical composition and antioxidant activity of Brazilian propolis samples

Biochemical Profile and Antioxidant Properties of Propolis from Northern Spain

The antioxidant, anti-inflammatory, and antimicrobial characteristics of propolis, a bioactive compound collected from hives, have prompted its use in the food sector in recent times. This study investigated the physicochemical characteristics, phenolic profile, and antioxidant capacity of 31 propolis extracts collected from Northern Spain. The physicochemical composition (resins, waxes, ashes mineral content, and heavy metals) was within the allowable regulatory limits. The analysis of bioactive compounds enabled the identification of 51 constituents: flavonoids (apigenin, catechin, chrysin, quercetin, and pinocembrin) and phenolic acids (caffeic, ferulic, and coumaric). The mean value of total polyphenols was 42.72 ± 13.19 Pinocembrin-Galangin Equivalents/100 g, whereas a range between 1.64 ± 0.04 and 4.95 ± 0.36 Quercetin Equivalents (QE) g/100 g was found for total flavonoids content. The determination of bioactivities revealed significant antioxidant capacity using DPPH (1114.28 ± 10.39 µM Trolox Equivalents and 3487.61 ± 318.66 µM Vitamin C Equivalents). Resin content in propolis samples was positively and significantly correlated with both polyphenols (rho = 0.365; p = 0.043) and flavonoid composition (rho = 0.615; p = 0.000) as well as the antioxidant capacity TEAC DPPH (rho = 0.415; p = 0.020). A multiple regression analysis modeled the correlation between resin composition, flavonoids, and TEAC DPPH values, yielding a significant regression equation (R2 = 0.618; F (2,28) = 22.629; p < 0.000; d = 2.299). Therefore, evaluating physicochemical parameters and biological activities provides a promising framework for predicting propolis' quality and antioxidant properties, thus suggesting its potential as a functional and bioactive compound for the food industry.

Antimicrobial Activity of Spanish Propolis against Listeria monocytogenes and Other Listeria Strains

The outbreaks of Listeria associated with food consumption are increasing worldwide concurrently with public concern about the need for natural growth inhibitors. In this context, propolis seems to be a promising bioactive product collected by honeybees, due to its antimicrobial activity against different food pathogens. This study aims to evaluate the efficacy of hydroalcoholic propolis extracts for controlling Listeria under several pH conditions. The physicochemical properties (wax, resins, ashes, impurities), the bioactive compounds (phenolic and flavonoid content), and the antimicrobial activity of 31 propolis samples collected from the half North of Spain were determined. Results showed similar trends in the physicochemical composition and bioactive properties, regardless of the harvesting area. Non-limiting pH conditions (7.04, 6.01, 5.01) in 11 Listeria strains (5 from collection and 6 wild strains from meat products) exhibited MICs (Minimum inhibition concentration) and MBCs (Minimum bactericidal concentration) ranging from 39.09 to 625 μg/mL. The antibacterial activity increased under acidic pH conditions, showing a synergistic effect at pH = 5.01 (p < 0.05). These findings suggest the potential of Spanish propolis as a natural antibacterial inhibitor to control Listeria growth in food products.

Investigation into Propolis Components Responsible for Inducing Skin Allergy: Air Oxidation of Caffeic Acid and Its Esters Contribute to Hapten Formation

Propolis is a resin-like material produced by bees from the buds of poplar and cone-bearing trees and is used in beehive construction. Propolis is a common additive in various biocosmetics and health-related products, despite the fact that it is a well-known cause of contact allergy. Caffeic acid and its esters have been the primary suspects behind the sensitization potency of propolis-induced contact allergy. However, the chemical structures of the protein adducts formed between these haptens and skin proteins during the process of skin sensitization remain unknown. In this study, the reactivity of three main contact allergens found in propolis, namely, caffeic acid (CA), caffeic acid 1,1-dimethylallyl ester (CAAE), and caffeic acid phenethyl ester (CAPE), was investigated. These compounds were initially subjected to the kinetic direct peptide reactivity assay to categorize the sensitization potency of CA, CAAE, and CAPE, but the data obtained was deemed too unreliable to confidently classify their skin sensitization potential based on this assay alone. To further investigate the chemistry involved in generating possible skin allergy-inducing protein adducts, model peptide reactions with CA, CAAE, and CAPE were conducted and analyzed via liquid chromatography-high-resolution mass spectrometry. Reactions between CA, CAAE, and CAPE and a cysteine-containing peptide in the presence of oxygen, both in closed and open systems, were monitored at specific time points. These studies revealed the formation of two different adducts, one corresponding to thiol addition to the α,β-unsaturated carbonyl region of the caffeic structure and the second corresponding to thiol addition to the catechol, after air oxidation to o-quinone. Observation of these peptide adducts classifies these compounds as prehaptens. Interestingly, no adduct formation was observed when the same reactions were performed under oxygen-free conditions, highlighting the importance of air oxidation processes in CA, CAAE, and CAPE adduct formation. Additionally, through NMR analysis, we found that thiol addition occurs at the C-2 position in the aromatic ring of the CA derivatives. Our results emphasize the importance of air oxidation in the sensitization potency of propolis and shed light on the chemical structures of the resultant haptens which could trigger allergic reactions in vivo.

Improvement of the In Vitro Cytotoxic Effect on HT-29 Colon Cancer Cells by Combining 5-Fluorouacil and Fluphenazine with Green, Red or Brown Propolis

Cancer is regard as one of the key factors of mortality and morbidity in the world. Treatment is mainly based on chemotherapeutic drugs that, when used in targeted therapies, have serious side effects. 5-fluorouracil (5-FU) is a drug commonly used against colorectal cancer (CRC), despite its side effects. Combination of this compound with natural products is a promising source in cancer treatment research. In recent years, propolis has become the subject of intense pharmacological and chemical studies linked to its diverse biological properties. With a complex composition rich in phenolic compounds, propolis is described as showing positive or synergistic interactions with several chemotherapeutic drugs. The present work evaluated the in vitro cytotoxic activity of the most representative propolis types, such as green, red and brown propolis, in combination with chemotherapeutic or CNS drugs on HT-29 colon cancer cell lines. The phenolic composition of the propolis samples was evaluated by LC-DAD-ESI/MSⁿ analysis. According to the type of propolis, the composition varied; green propolis was rich in terpenic phenolic acids and red propolis in polyprenylated benzophenones and isoflavonoids, while brown propolis was composed mainly of flavonoids and phenylpropanoids. Generally, for all propolis types, the results demonstrated that combing propolis with 5-FU and fluphenazine successfully enhances the in vitro cytotoxic activity. For green propolis, the combination demonstrated an enhancement of the in vitro cytotoxic effect compared to green propolis alone, at all concentrations, while for brown propolis, the combination in the concentration of 100 μg/mL gave a lower number of viable cells, even when compared with 5-FU or fluphenazine alone. The same was observed for the red propolis combination, but with a higher reduction in cell viability. The combination index, calculated based on the Chou-Talalay method, suggested that the combination of 5-FU and propolis extracts had a synergic growth inhibitory effect in HT-29 cells, while with fluphenazine, only green and red propolis, at a concentration of 100 μg/mL, presented synergism.

Efficacy of Propolis Gel on Mature Biofilm Formed by Neocosmospora keratoplastica Isolated from Onychomycosis

This article describes Neocosmospora keratoplastica as an etiological onychomycosis agent. Ex vivo studies were initially performed to demonstrate the ability of this species to grow and form a well-organized characteristic biofilm on sterilized healthy nails. Based on the history of excellent results, both for antifungal and antibiofilm, of propolis resin gum, we evaluated its activity using artificially formed biofilm. In vitro, the minimal biofilm eradication concentration of the propolis extract (PE) was 375 µg of total polyphenol content (TPC) per mL, while for the propolis gel (PG) it was 450 µg of TPC per mL. In biofilm exposed to the propolis products, a decrease in hyphae and conidia was evident, accompanied by a disorganization of the extracellular matrix. Additionally, this low concentration of PE was able to significantly reduce the number of colony-forming units and the metabolic activity. Furthermore, the treatment of a 15-year nail infection due to N. keratoplastica was carried out exclusively using a topical treatment with a gel containing propolis (30%) with a daily dosage. This treatment achieved complete remission of the onychomycosis in 12 months. It is important to point out that some inconveniences previously reported by other patients treated with propolis extract were eliminated, increasing adherence to treatment.

Propolis: An update on its chemistry and pharmacological applications

Propolis, a resinous substance produced by honeybees from various plant sources, has been used for thousands of years in traditional medicine for several purposes all over the world. The precise composition of propolis varies according to plant source, seasons harvesting, geography, type of bee flora, climate changes, and honeybee species at the site of collection. This apiary product has broad clinical applications such as antioxidant, anti-inflammatory, antimicrobial, anticancer, analgesic, antidepressant, and anxiolytic as well asimmunomodulatory effects. It is also well known from traditional uses in treating purulent disorders, improving the wound healing, and alleviating many of the related discomforts. Even if its use was already widespread since ancient times, after the First and Second World War, it has grown even more as well as the studies to identify its chemical and pharmacological features, allowing to discriminate the qualities of propolis in terms of the chemical profile and relative biological activity based on the geographic place of origin. Recently, several in vitro and in vivo studies have been carried out and new insights into the pharmaceutical prospects of this bee product in the management of different disorders, have been highlighted. Specifically, the available literature confirms the efficacy of propolis and its bioactive compounds in the reduction of cancer progression, inhibition of bacterial and viral infections as well as mitigation of parasitic-related symptoms, paving the way to the use of propolis as an alternative approach to improve the human health. However, a more conscious use of propolis in terms of standardized extracts as well as new clinical studies are needed to substantiate these health claims.

Antibacterial Activity of Romanian Propolis against Staphylococcus aureus Isolated from Dogs with Superficial Pyoderma: In Vitro Test

Staphylococcal infection treatment in dogs is frequently associated with adverse side effects, high costs, prolonged treatment, and resistant strain selection. Staphylococcus aureus is the most frequently isolated staphylococci in cases of canine superficial pyoderma. The number of Staphylococcus strains to exhibit primary resistance to various drugs in vitro is increasing. Propolis has a diverse chemical composition and well-known therapeutic properties against bacterial infections. The current investigation evaluated in vitro the antimicrobial activity of the commercial allopathic antimicrobials, Romanian propolis ethanolic extracts, against clinical Staphylococcus aureus strains isolated from superficial dermatitis clinical samples in dogs and two reference strains: Staphylococcus aureus ATCC 25923 and Staphylococcus aureus ATCC 43300, as the MSSA and MRSA positive controls, respectively, in western Romania. We used the microdilution broth technique to evaluate the susceptibility profile of the bacteria. The minimum inhibitory concentration (MIC) of the Romanian propolis ethanolic extract ranged from 6 to 10 μg/mL for all isolates, determined by the broth microdilution method. The MICs of ethanolic Romanian propolis extracts had a pronounced antibacterial activity. These results indicate that propolis can potentially be used and recommended for in vivo experiments as a promising therapeutic agent against Staphylococcus aureus infections in superficial dermatitis of dogs.

Antimicrobial Triterpenoids and Ingol Diterpenes from Propolis of Semi-Arid Region of Morocco

The chemical composition and antimicrobial activity of propolis from a semi-arid region of Morocco were investigated. Fifteen compounds, including triterpenoids (1, 2, 7–12), macrocyclic diterpenes of ingol type (3–6) and aromatic derivatives (13–15), were isolated by various chromatographic methods. Their structures were elucidated by a combination of spectroscopic and chiroptical methods. Compounds 1 and 3 are new natural compounds, and 2, 4–6, and 9–11 are newly isolated from propolis. Moreover, the full nuclear magnetic resonance (NMR) assignments of three of the known compounds (2, 4 and 5) were reported for the first time. Most of the compounds tested, especially the diterpenes 3, 4, and 6, exhibited very good activity against different strains of bacteria and fungi. Compound 3 showed the strongest activity with minimum inhibitory concentrations (MICs) in the range of 4–64 µg/mL. The combination of isolated triterpenoids and ingol diterpenes was found to be characteristic for Euphorbia spp., and Euphorbia officinarum subsp. echinus could be suggested as a probable and new plant source of propolis.

From propolis to nanopropolis: An exemplary journey and a paradigm shift of a resinous substance produced by bees

Propolis, a natural resinous mixture produced by honey bees is poised with diverse biological activities. Owing to the presence of flavonoids, phenolic acids, terpenes, and sesquiterpenes, propolis has garnered versatile applications in pharmaceutical industry. The biopharmaceutical issues associated with propolis often beset its use as being too hydrophobic in nature; it is not absorbed in the body well. To combat the problem, various nanotechnological approaches for the development of novel drug delivery systems are generally applied to improve its bioavailability. This paradigm shift and transition of conventional propolis to nanopropolis are evident from the literature wherein a multitude of studies are available on nanopropolis with improved bioavailability profile. These approaches include preparation of gold nanoparticles, silver nanoparticles, magnetic nanoparticles, liposomes, liquid crystalline formulations, solid lipid nanoparticles, mesoporous silica nanoparticles, etc. Nanopropolis has further been explored to assess the potential benefits of propolis for the development of futuristic useful products such as sunscreens, creams, mouthwashes, toothpastes, and nutritional supplements with improved solubility, bioavailability, and penetration profiles. However, more high-quality clinical studies assessing the effects of propolis either alone or in combination with synthetic drugs as well as natural products are warranted and its safety needs to be firmly established.

Plasma-initiated graft polymerization of carbon nanoparticles as nano-based drug delivery systems

Plasma-initiated free radical polymerization was used to engineer carbon nanoparticles (CNPs) with tailored chemical and physical properties. Following surface modification, CNPs were loaded with a highly effective anti-infection agent called metal-free Russian propolis ethanol extract (MFRPEE), thus, creating nano-based drug delivery systems (NBDDSs). The loading of MFRPEE onto grafted CNPs occurred naturally through both electrostatic interactions and hydrogen bonding. When constructed under optimal experimental conditions, the NBDDSs were stable under physiologic conditions, and demonstrated enhanced anti-biofilm activity when compared with free MFRPEE. Mechanistic studies revealed that the enhanced anti-infectious activity of the NBDDSs was attributed to the modified surface chemistry of grafted CNPs. More specifically, the overall positive surface charge on grafted CNPs, which stems from quaternary ammonium polymer brushes covalently bound to the CNPs, provides NBDDSs with the ability to specifically target negatively charged components of biofilms. When studying the release profile of MFRPEE from the modified CNPs, acidic components produced by a biofilm triggered the release of MFRPEE bound to the NBDDS. Once in its free form, the anti-infectious properties of MFRPEE became activated and damaged the extracellular polymeric matrix (EPM) of the biofilm. Once the architecture of the biofilm became compromised, the EPM was no longer capable of protecting the bacteria encapsulated within the biofilm from the anti-infectious agent. Consequently, exposure of bacteria to MFRPEE led to bacterial cell death and biofilm inactivation. The results obtained from this study begin to examine the potential application of NBDDSs for the treatment of healthcare-associated infections (HCAIs).

Propolis: chemical diversity and challenges in quality control

Propolis is a resinous natural product produced by honeybees using beeswax and plant exudates. The chemical composition of propolis is highly complex, and varies with region and season. This inherent chemical variability presents several challenges to its standardisation and quality control. The present review was aimed at highlighting marker compounds for different types of propolis, produced by the species Apis mellifera, from different geographical origins and that display different biological activities, and to discuss strategies for quality control. Over 800 compounds have been reported in the different propolises such as temperate, tropical, birch, Mediterranean, and Pacific propolis; these mainly include alcohols, acids and their esters, benzofuranes, benzopyranes, chalcones, flavonoids and their esters, glycosides (flavonoid and diterpene), glycerol and its esters, lignans, phenylpropanoids, steroids, terpenes and terpenoids. Among these, flavonoids (> 140), terpenes and terpenoids (> 160) were major components. A broad range of biological activities, such as anti-oxidant, antimicrobial, anti-inflammatory, immunomodulatory, and anticancer activities, have been ascribed to propolis constituents, as well as the potential of these compounds to be biomarkers. Several analytical techniques, including non-separation and separation methods have been described in the literature for the quality control assessment of propolis. Mass spectrometry coupled with separation methods, followed by chemometric analysis of the data, was found to be a valuable tool for the profiling and classification of propolis samples, including (bio)marker identification. Due to the rampant chemotypic variability, a multiple-marker assessment strategy considering geographical and biological activity marker(s) with chemometric analysis may be a promising approach for propolis quality assessment.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11101-022-09816-1.

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.

Effect of Propolis Paste and Mouthwash Formulation on Healing after Teeth Extraction in Periodontal Disease

This study investigated the antimicrobial effects of a mouthwash containing propolis and the effect of a propolis paste formulation on dental healing after teeth extraction in patients with periodontal disease. In the mouthwash experience, the population comprised 40 patients, which were divided as follows: the control mouthwash, 0.2% chlorhexidine (v/v) mouthwash, 2% (w/v) propolis mouthwash, and propolis + chlorhexidine mouthwash. The study of the propolis paste comprised a population of 60 patients with periodontal disease, and a total of 120 symmetric tooth extractions were performed. Propolis showed antimicrobial activity by itself, and especially with the chlorhexidine association. Three days after surgery in the teeth treated with control paste, only 13.4% had completely healed; however, with propolis paste, in 90% of the periodontal sockets, healing was complete. In addition, a reduction in Streptococci mutans and Lactobacilli cfu was observed with propolis, and especially with the association of chlorhexidine + propolis. Propolis mouthwash reduced bacterial proliferation, especially in association with chlorhexidine. Propolis paste is a viable alternative for socket healing after dental extraction. The knowledge gained from these findings will provide a foundation for similar propolis therapies in order to improve the healing process after dental surgery.

Antiparasitic Properties of Propolis Extracts and Their Compounds

Propolis is a bee product that has been used in medicine since ancient times. Although its anti-inflammatory, antioxidant, antimicrobial, antitumor, and immunomodulatory activities have been investigated, its anti-parasitic properties remain poorly explored, especially regarding helminths. This review surveys the results obtained with propolis around the world against human parasites. Regarding protozoa, studies carried out with the protozoa Trypanosoma spp. and Leishmania spp. have demonstrated promising results in vitro and in vivo. However, there are fewer studies for Plasmodium spp., the etiological agent of malaria and less so for helminths, particularly for Fasciola spp. and Schistosoma spp. Despite the favorable in vitro results with propolis, helminth assays need to be further investigated. However, propolis has shown itself to be an excellent natural product for parasitology, thus opening new paths and approaches in its activity against protozoa and helminths.

Unraveling the Bioactive Profile, Antioxidant and DNA Damage Protection Potential of Rye (Secale cereale) Flour

Six different solvents were used as extraction medium (water, methanol, ethanol, acidified methanol, benzene and acetone) to check their phenolics extraction efficacy from flour of two rye cultivars. Rye extracts with different solvents were further analyzed for the estimation of phytochemicals and antioxidant properties. Different tests (TPC, TAC, DPPH, FRAP, ABTS, RPA and CTC) were performed to check the antioxidant properties and tannin contents in extracts. A bioactive profile of a rye cultivar indicated the presence of total phenolic compounds (0.08-2.62 mg GAE/g), total antioxidant capacity (0.9-6.8 mg AAE/g) and condensed tannin content (4.24-9.28 mg CE/100 g). HPLC was done to check phenolics in rye extract with the best solvent (water), which indicated the presence of Catechol (91.1-120.4 mg/100 g), resorcinol (52-70.3 mg/100 g), vanillin (1.3-5.5 mg/100 g), ferulic acid (1.4-1.5 mg/100 g), quercetin (4.6-4.67 mg/100 g) and benzoic acid (5.3 mg/100 g) in rye extracts. The presence of DNA damage protection potential in rye extracts indicates its medicinal importance. Rye flour could be utilized in the preparation of antioxidant-rich health-benefiting food products.

Immunity and physiological changes in adult honey bees (Apis mellifera) infected with Nosema ceranae: The natural colony environment

Nosema ceranae is a microsporidium that infects Apis mellifera, causing diverse physiological and behavioral alterations. Given the existence of individual and social mechanisms to reduce infection and fungal spread in the colony, bees may respond differently to infection depending on their rearing conditions. In this study, we investigated the effect of N. ceranae in honey bee foragers naturally infected with different fungal loads in a tropical region. In addition, we explored the effects of N. ceranae artificially infected young bees placed in a healthy colony under field conditions. Honey bees naturally infected with higher loads of N. ceranae showed downregulation of genes from Toll and IMD immune pathways and antimicrobial peptide (AMP) genes, but hemolymph total protein amount and Vitellogenin (Vg) titers were not affected. Artificially infected bees spread N. ceranae to the controls in the colony, but fungal loads were generally lower than those observed in cages, probably because of social immunity. Although no significant changes in mRNA levels of AMP-encoding were observed, N. ceranae artificially infected bees showed downregulation of miR-989 (an immune-related microRNA), lower vitellogenin gene expression, and decreased hemolymph Vg titers. Our results demonstrate for the first time that natural infection by N. ceranae suppresses the immune system of honey bee foragers in the field. This parasite is detrimental to the immune system of young and old bees, and disease spread, mitigation and containment will depend on the colony environment.

GC-MS Evaluation, Antioxidant Content, and Cytotoxic Activity of Propolis Extract from Peninsular Malaysian Stingless Bees, Tetrigona Apicalis

INTRODUCTION

Propolis has been used traditionally in several countries for treating various diseases as it possessed healing properties including antioxidant and anticancer qualities. In Peninsular Malaysia, Tetrigona apicalis is one of the species of stingless bees mainly found in virgin jungle reserves which largely contribute to propolis production. Therefore, this study is designed to evaluate the phytochemical contents, antioxidant properties, and the cytotoxic effect of ethanolic crude of propolis extract against MCF7 and MCF 10A cell lines.

METHOD

The ethanolic extract of propolis (EEP) was extracted using 80% ethanol. Identification of phytochemical contents and antioxidant properties of EEP was analysed by gas chromatography-mass spectrometry (GC-MS) and using 2, 2'-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) method, respectively. The EEP cytotoxic activity was evaluated on MCF7 and MCF 10A using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay.

RESULTS

Phytochemical contents of EEP demonstrated 28 compounds in which caryophyllene (99%), β-amyrin (96%), α-amyrin (93%), and caryophyllene oxide (93%) were the main compounds. The percentage of ABTS+ scavenging activity of EEP showed an inhibition of 9.5% with half-inhibitory concentration (IC50) value of 1.68 mg/mL. The EEP reduced MCF7 cells viability at IC50 value of 62.24 μg/mL, 44.15 μg/mL, and 32.70 μg/mL at 24, 48, and 72 hours, respectively. The IC50 value of MCF 10A was 49.55 μg/mL, 56.05 μg/mL, and 72.10 μg/mL at 24, 48, and 72 hours, respectively. The EEP cytotoxic effect of T. apicalis was more selective towards MCF7 at 72-hour incubation with a selectivity index (SI) of 2.20.

CONCLUSION

The EEP has been shown to have antioxidants and potential bioactive compounds and inhibited proliferation of the MCF7 cells. Further studies on the EEP role in the apoptosis pathway and its screening towards other cell lines will be evaluated.

Salt-dependent hypertension and inflammation: targeting the gut-brain axis and the immune system with Brazilian green propolis

Systemic arterial hypertension (SAH) is a major health problem around the world and its development has been associated with exceeding salt consumption by the modern society. The mechanisms by which salt consumption increase blood pressure (BP) involve several homeostatic systems but many details have not yet been fully elucidated. Evidences accumulated over the last 60 decades raised the involvement of the immune system in the hypertension development and opened a range of possibilities for new therapeutic targets. Green propolis is a promising natural product with potent anti-inflammatory properties acting on specific targets, most of them participating in the gut-brain axis of the sodium-dependent hypertension. New anti-hypertensive products reinforce the therapeutic arsenal improving the corollary of choices, especially in those cases where patients are resistant or refractory to conventional therapy. This review sought to bring the newest advances in the field articulating evidences that show a cross-talking between inflammation and the central mechanisms involved with the sodium-dependent hypertension as well as the stablished actions of green propolis and some of its biologically active compounds on the immune cells and cytokines that would be involved with its anti-hypertensive properties.

Acyclic Triterpenoid Isolated from Alpinia katsumadai Alleviates Formalin-Induced Chronic Mouse Paw Inflammation by Inhibiting the Phosphorylation of ERK and NF-κB

Chronic and excessive inflammation can destroy host organs and cause inflammatory diseases such as inflammatory bowel disease, asthma, and rheumatoid arthritis. In this study, we investigated the anti-inflammatory effects of Alpinia katsumadai seed-derived 2,3,5,22,23-pentahydroxy-2,6,10,15,19,23-hexamethyl-tetracosa-6,10,14,18-tetraene (PHT) using lipopolysaccharide (LPS)-stimulated J774 cells and a formalin-induced chronic paw inflammation mouse model. The in vitro results showed that PHT exhibited no cytotoxicity and decreased LPS-induced NO secretion. Additionally, PHT inhibited LPS-induced inducible NO synthase (iNOS) and cyclooxygenase 2 (COX2) protein expression. The quantitative real-time PCR results showed that PHT downregulated the gene expression of the proinflammatory cytokines interleukin-1β (IL-1β) and interleukin-6 (IL-6) but not tumor necrosis factor α (TNF-α). PHT inhibited the LPS-induced phosphorylation of extracellular signal-regulated kinase (ERK) and nuclear factor kappa light chain enhancer of activated B cells (NF-κB). In a mouse model, oral administration of 50 mg/kg PHT significantly alleviated both mouse paw thickness and volume. These results indicate that PHT has potential anti-inflammatory effects and should be considered a possible functional material.

Silver nanoparticles stabilized with propolis show reduced toxicity and potential activity against fungal infections

Aim: Elucidate the antifungal efficacy of biologically synthesized silver nanoparticles with ethanolic propolis extract (AgNPs PE) against the planktonic forms and biofilms of clinically important fungi. Materials & methods: AgNPs were synthesized, characterized and evaluated for cytotoxicity, mutagenicity and antimicrobial activity. Results: AgNPs PE displayed a colloidal appearance, good stability and size of 2.0–40.0 nm. AgNPs PE demonstrated lower cytotoxicity and nonmutagenic potential. In addition, AgNPs PE displayed antifungal properties against all tested isolates, inhibiting growth at concentrations lower than the cytotoxic effect. Mature biofilms treated for 48 h with AgNPs PE showed significant reduction of viable cells, metabolic activity and total biomass. Conclusion: This is the first time that AgNPs have been synthesized from an ethanolic extract of propolis only, proving antifungal, antibiofilm, atoxic and nonmutagenic properties.

A comparative study between Chinese propolis and Brazilian green propolis: metabolite profile and bioactivity

Among different types, Chinese propolis (ChPs) and Brazilian green propolis (BrGPs) have been shown to contain multi-functional properties. Despite extensive research in the field, reports comparing propolis from different geographical areas are still limited, compromising our current understanding of the potential therapeutic effect associated with propolis and its derived compounds. Herein, a comparative study between ChPs and BrGPs including their metabolite profile and bioactivities was performed. Interestingly, even when ChPs and BrGPs showed similar anti-inflammatory potential, our results showed that they contained very different levels of ethanol extract, total flavonoids and total phenolic acids and in fact, LC-MS metabolic profiling and pattern recognition could effectively distinguish ChPs and BrGPs. Moreover, all the propolis samples tested showed good anti-oxidant activity and no significant difference of free radical scavenging capacity existed between ChPs and BrGPs. In conclusion, ChPs and BrGPs have a distinct chemome, but their antioxidant and anti-inflammatory activities are similar.

Biological control of yeast contamination of industrial foods by propolis

Bee glue (Propolis, PR), mixture of beeswax and resin is collected from honeybee (Apis mellifera) of different plant parts. The antimicrobial potential of PR against food borne yeast was reported. The experiment was designed to examine the way of antimicrobial impact of PR on food borne yeasts (Cryptococcus laurentii and Candida famata) and its usage use as biological strategy for the preservation of soft foods against microbial spoilage. The study also highlights, the ability of ethanol and water- PR extracts, discouraged growth of tested yeast. Antifungal properties were also determined using electron microscope while biochemical analysis was determined using free and proteinic amino acid technique and oxidative enzymes were determined using HPLC analysis. Antioxidant enzymes were determined using ELISA assay. The highest effect was recorded on C. laurentii however, the lowest effect shows on C. famata. The electron microscopic studies clearly disclosed the effect of water PR distillate on the external shape and internal organs of some tested yeast e.g. C. laurentii and C. famata. The result indicated some differences on concentrations of bio-chemical analyses for these tested yeasts treated with 70% water- PR extracts of different food materials. Moreover, biochemical analysis results also reported that the treated yeast indicated natural preservative to food products and considered as best alternative to the (chemical) preservatives currently employed.

Isolation, Identification, and Synthesis of a New Prenylated Cinnamic Acid Derivative from Brazilian Green Propolis and Simultaneous Quantification of Bioactive Components by LC-MS/MS

A new cinnamic acid derivative, (E)-3-[4-hydroxy-3-((E)-3-formyl-2-butenyl)phenyl]-2- propenoic acid (20) has been isolated from the ethanol extract of Brazilian green propolis along with three known cinnamic acid derivatives, 3,4-dihydroxy-5-prenyl-(E)-cinnamic acid (4), capillartemisin A (6), and 2,2-dimethylchromene-6-(E)-propenoic acid (8), and a flavonoid, dihydrokaempferide (16) by liquid-liquid participation, a series of column chromatography and preparative HPLC. Their structures have been determined by spectroscopic analyses and chemical synthesis of compound 20. The simultaneous quantification of 20 constituents, including 10 cinnamic acid derivatives, 7 flavonoids, and 3 caffeoylquinic acid derivatives, has also been developed and validated using LC-MS/MS. The new compound 20 was shown to activate PPAR α but not PPAR β or γ.

Potential therapeutic effect of Moroccan propolis in hyperglycemia, dyslipidemia, and hepatorenal dysfunction in diabetic rats

OBJECTIVES

The effect of propolis collected in Morocco on blood glucose, lipid profile, liver enzymes, and kidney function was investigated in control and diabetic rats.

MATERIALS AND METHODS

Antioxidant activity of propolis was evaluated with the use of DPPH, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS•+), ferric reducing power and total antioxidant activity assay. To study its effect in streptozotocin (STZ)-induced diabetes, the rats were divided into eight groups; four control and four diabetics. The animals received distilled water, glibenclamide, or propolis extract, 50 mg/kg/BW) or 100 mg/kg/b.wt, daily for 15 days. Blood glucose, triglyceride, lactic acid dehydrogenase, liver enzymes, creatinine, blood urea, lipid profile, and body weight were measured on day 15 after commencement of the treatment.

RESULTS

Propolis has a strong antioxidant activity and high total flavonoids and polyphenols content. Glibenclamide and propolis have no significant effect on lipid parameters, and renal and hepatic function in non-diabetic rats. However, propolis or glibenclamide caused a significant lowering of blood glucose after a single administration and at day 15 after daily administration in diabetic rats (P<0.05). Both interventions significantly lowered lactic acid dehydrogenase, increased body weight, and ameliorated dyslipidemia and abnormal liver and kidney function caused by diabetes. The effect of propolis was dose-dependent and in a high dose it was more potent than glibenclamide.

CONCLUSION

Propolis exhibited strong antihyperglycemic, antihyperlipidemic, and hepato-renal protective effects in diabetes, and significantly lowered the elevated lactic acid dehydrogenase. The study demonstrated for the first-time the effect of Moroccan propolis in diabetes and it will pave the way for clinical investigations.

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.

Propolis Induces AQP3 Expression: A Possible Way of Action in Wound Healing

Propolis is the generic name of a complex of resinous compound collected by honeybees and it has been utilized for many years in folk medicine. As other products generated by honeybees (such as royal jelly, pollen, honey), propolis has great therapeutic properties, but very little scientific information is available. Therefore, this study was aimed at exploring the potential wound healing properties of propolis. To that end, we utilized an in vitro scratch wound healing model consisting of human immortalized keratinocytes. Our scratch wound data clearly demonstrated that propolis induced a pronounced increase in the wound repair abilities of keratinocytes. A cell migration assay showed that propolis stimulated keratinocytes to close the wound. We revealed the role of H₂O₂ as the main mediator of propolis regenerative properties. We showed that this extracellularly released H₂O₂ could pass across the plasma membrane through a specific aquaporin (i.e., AQP3) modulating intracellular responses. The data offer a biological characterization of propolis positive effects suggesting that propolis could also be utilized in wound treatment within clinical settings.

Chemical Composition, Antioxidant and Anti-inflammatory Activity Evaluation of the Lebanese Propolis Extract

Background:

Propolis is a resinous substance produced by bees and known to possess antioxidant, antimicrobial, antiproliferative and anti-inflammatory activities.

Objective:

This study is aimed at evaluating the in vivo and in vitro anti-inflammatory potential of the Crude Ethanolic Extract (CE) of Lebanese propolis and its Ethyl Acetate Fraction (EAF).

Method:

Chemical content of propolis was characterized using high-performance liquid chromatography and LC-MS/MS. COX-2 and iNOS protein expression, nitric oxide (NO) and prostaglandin (PGE2) release in LPS-activated RAW monocytes were achieved respectively by western blot and spectrophotometry. Antioxidant activity was evaluated by DPPH free radical scavenging assay. Measurement of paw thickness in carrageenan-induced paw edema in mice and pathologic assessment of inflammation in paw sections were used to judge the anti-inflammatory properties of propolis.

Results:

Pathology analysis revealed in the treated group significant reduction of immune cell infiltration and edema. Both extract and ethyl acetate fraction showed significant anti-inflammatory and antioxidant effects in LPS-treated RAW cells characterized by the inhibition of COX-2 and iNOS protein expression, as well as PGE2 and NO release. Chemical analysis of the crude extract and its ethyl acetate fraction identified 28 different compounds of which two phenolic acids and nine other flavonoids were also quantified. Ferulic acid, caffeic acid, chrysin, galangin, quercetin, and pinocembrin were among the most representative compounds.

Conclusion:

Lebanese propolis is rich in a various amount of flavonoids which showed promising antiinflammatory and antioxidant properties. Additionally, chemical analysis showed unique chemical compositions with the potential of identifying ingredients with interesting anti-inflammatory activities.

Comparative analysis of volatile compound profiles of propolis from different provenances

BACKGROUND

Propolis is a complex mixture that honey bees produce from the exudates of various plants and presents many medicinal properties. Its chemical composition varies according to the phytogeography characteristics of each region, among others. The aim of this study was to identify and characterize the volatile organic compounds (VOCs) present in Venezuelan propolis and compare with reference samples such as Brazilian and Argentinian propolis.

RESULTS

A total of 90 VOCs were identified in a series of propolis samples using both solid-phase microextraction and dynamic headspace (DHS), both coupled to a gas chromatograph-electron ionization mass spectrometer. In the case of Venezuelan propolis, sesquiterpenes, esters, aromatic compounds, and aliphatic hydrocarbons were identified. Limonene was found only in Venezuelan samples, this being the first time it has been identified in samples from this country. In the case of green propolis, β-caryophyllene and nerolidol were the major compounds. As for the Argentinian samples, prenyl acetate, benzyl acetate, and 2-phenylethyl acetate were detected only in these samples.

CONCLUSIONS

Possible chemical markers of natural sources such as limonene were detected using DHS extraction. Several compounds have also been identified for the first time in Venezuelan propolis. Cluster analysis allowed the relating of the propolis VOCs profile to their provenance. © 2017 Society of Chemical Industry.

Plasma-initiated graft polymerization as an immobilization platform for metal free Russian propolis ethanol extracts designed specifically for biomaterials

The antibacterial and anti-biofilm activities of propolis have been intensively reported. However, the application of this folk remedy as a means to prevent biomedical implant contamination has yet to be completely evaluated. In response to the significant resistant and infectious attributes of biofilms, biomaterials engineered to possess specific chemical and physical properties were immobilized with metal free Russian propolis ethanol extracts (MFRPEE), a known antibacterial agent. The results obtained from this study begin to examine the application of MFRPEE as a novel alternative method for the prevention of medical and biomedical implant infections. When constructed under specific experimental conditions, immobilized biomaterials showed excellent stability when subjected to simulated body fluid and fetal bovine serum. The ability of immobilized biomaterials to specifically target pathogens (both Gram-positive and Gram-negative biofilm forming bacteria), while promoting tissue cell growth, renders these biomaterials as potential candidates for clinical applications.

Propolis Extract for Onychomycosis Topical Treatment: From Bench to Clinic

Onychomycosis is a chronic fungal infection of nails, commonly caused by dermatophyte fungi, primarily species of Trichophyton. Because of the limited drug arsenal available to treat general fungal infections and the frequent failure of onychomycosis treatment, the search for new therapeutic sources is essential, and topical treatment with natural products for onychomycosis has been encouraged. Propolis, an adhesive resinous compound produced by honeybees (Apis mellifera), has shown multiple biological properties including significant antifungal and anti-biofilm activities in vitro. In spite of promising in vitro results, in vivo results have not been reported so far. This study assessed an ethanol propolis extract (PE) as a topical therapeutic option for onychomycosis, including its characterization in vitro and its applicability as a treatment for onychomycosis (from bench to clinic). The in vitro evaluation included analysis of the cytotoxicity and the antifungal activity against the planktonic cells and biofilm formed by Trichophyton spp. We also evaluated the capacity of PE to penetrate human nails. Patients with onychomycosis received topical PE treatments, with a 6-month follow-up period. The results of the in vitro assays showed that PE was non-toxic to the cell lines tested, and efficient against both the planktonic cells and the biofilm formed by Trichophyton spp. The results also showed that PE is able to penetrate the human nail. The results for PE applied topically to treat onychomycosis were promising, with complete mycological and clinical cure of onychomycosis in 56.25% of the patients. PE is an inexpensive commercially available option, easy to obtain and monitor. Our results indicated that PE is a promising natural compound for onychomycosis treatment, due to its ability to penetrate the nail without cytotoxicity, and its good antifungal performance against species such as Trichophyton spp. that are resistant to conventional antifungals, both in vitro and in patients.

Antitrypanosomal, antileishmanial and cytotoxic activities of Brazilian red propolis and plant resin of Dalbergia ecastaphyllum (L) Taub

The treatment for leishmaniasis and Chagas disease can be hard and painful, such that many patients give up on the treatment. In order to find an alternative path for the treatment of these diseases, researchers are using natural products to fight these parasites. The aim of this study was to evaluate the antiprotozoan and cytotoxic activities of red propolis samples collected from different Brazilian states and seasons whilst searching for possible activity differences. We also compared the red propolis results with the ones obtained for the plant resin extract collected from Dalbergia ecastaphyllum trees. The hydroethanolic red propolis extracts from Pernambuco and Alagoas, and the D. ecastaphyllum resin were evaluated regarding their antileishmanial, antitrypanosomal and cytotoxic activity. All extracts showed antiprotozoan and cytotoxic activity. RP-PER showed to be more cytotoxic against protozoan parasites and fibroblast cells. All propolis extracts showed a higher cytotoxic activity when compared to resin extracts. The propolis sample collected in Pernambuco during the rainy season killed the parasites with lower concentrations than the sample collected in the dry season. The IC₅₀ observed against the parasites could be used without high fibroblast cell damage.

Propolis increases neutrophils response against Candida albicans through the increase of reactive oxygen species

AIM

To investigate whether Brazilian green propolis improves the immune response against recurrent form isolate recurrent vulvovaginal candidiasis (RVVC) caused by Candida albicans by increasing neutrophil oxidative burst.

MATERIALS & METHODS

We evaluated oxidant species production, oxygen consumption, microbicidal activity and myeloperoxidase activity in neutrophils previously treated with propolis and activated with different isolates of C. albicans (RVVC), vulvovaginal candidiasis, asymptomatic isolates and the reference strain.

RESULTS

Propolis significantly increased oxidant species production, oxygen consumption, microbicidal activity and myeloperoxidase activity of neutrophils against different isolates of C. albicans including RVVC isolate that are considered resistant to the microbicidal activity of neutrophils.

CONCLUSION

Brazilian green propolis may increase neutrophil burst oxidative response to RVVC leading to an efficient removal of C. albicans.

Evaluation of Antioxidant Activities and Phenolic Compounds of Scorzonera latifolia (Fisch. & Mey.) DC. Collected from Different Geographic Origins in Turkey

Objectives

The chemical composition of plants is considered to be affected by many parameters. Therefore, the region where the samples are collected is likely to have an influence on the composition of phenolic compounds, so that their biological activities. In the present study, evaluation of antioxidant activity potentials of Scorzonera latifolia (Fisch. & Mey.) DC. aerial parts and roots, which were collected from different regions of Turkey, was aimed.

Materials and Methods

1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method and measurement of malondialdehyde (MDA) levels were used for determining antioxidant capacities of the tested extracts. In order to observe variations in the chemical composition of the investigated samples qualitatively as well as quantitatively, high performance liquid chromatography analyses were performed.

Results

Quantitative analysis showed that the amounts of chlorogenic acid and hyperoside in plants vary according to the regions where the samples were collected. As a result aerial parts of the S. latifolia collected from the Kars region have found to contain higher amount of chlorogenic acid (1246.78±3.20 µg/g) as well as hyperoside (652.32±2.48 µg/g) than other samples. The highest DPPH radical scavenging activity was determined with the IC₅₀ value of 1.036 mg/mL for S. latifolia aerial parts of Kayseri sample. MDA level was detected as the lowest with treatment of S. latifolia Bayburt root sample (4.41 nmol/mL).

Conclusion

According to the antioxidant activity results, no significant difference was observed in the antioxidant potential between the samples collected from different locations except for S. latifolia collected from the Kars region.

New propolis type from north-east Brazil: chemical composition, antioxidant activity and botanical origin

BACKGROUND

Propolis is a bee product with wide diversity of biological activity. It has a complex composition, which is dependent on its botanical source. The present study aimed to determine the chemical profile, antioxidant activity and botanical origin of two samples of a propolis type from two locations of the state of Rio Grande do Norte (RN, north-east Brazil).

RESULTS

The standard chemical characteristics of the RN propolis are similar or superior to the internationally marketed Brazilian green propolis. RN propolis from two locations have high antioxidant activity, corresponding to 10% (municipality of Afonso Bezerra) and 13% (municipality of Alto do Rodrigues) of quercetin activity by the 2,2-diphenyl-1-picrylhydrazyl method and to 15% (both locations) by the β-carotene discoloration method. High-performance liquid chromatography with diode array detection (HPLC-DAD)-electrospray ionization-tandem mass spectrometry analyses revealed that most constituents of the RN propolis are flavonoids, mainly flavonols and chalcones. HPLC-DAD analysis of ethanol extracts revealed a great similarity between the chemical profile of RN propolis and shoot apices of 'jurema-preta' (Mimosa tenuiflora, Leguminosae, Mimosoideae).

CONCLUSION

'Jurema-preta' shoot apices are likely resin sources of RN propolis. The chemical characteristics and antioxidant property of RN propolis provide promising prospects for the introduction of this type of propolis into the apicultural market. © 2017 Society of Chemical Industry.

Nanostructured lipid systems modified with waste material of propolis for wound healing: Design, in vitro and in vivo evaluation

Propolis, a natural compound that can accelerate the wound healing process, is mainly used as ethanolic extract. The extractive solution may also be obtained from the propolis by-product (BP), transforming this waste material into a pharmaceutical active ingredient. Even if propolis does not show toxicity, when used as an extract over harmed skin or mucosa, the present ethanol content may be harmful to the tissue recovering, besides hindering the drug release. This study describes the development of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) as topical propolis delivery systems and the investigation of their in vitro and in vivo activities. The extracts were evaluated to guarantee their quality, and the lipid dispersions were characterized with respect to morphology (cryo-TEM), size and diffractometry (X-ray) properties. The occlusive capacity of formulations was also evaluated by an in vitro technique, which determines the occlusion factor. The drug entrapment efficiency (EE), as well as the in vitro drug release profile from the nanoparticulate systems was investigated as well. The size analysis performed through 90days was favorable to a topical administration and the polydispersity index, though not ideal in all cases due to the high content of resins and gums from the extracts, were relatively stable for the SLN. The propolis extract contributes to the occlusive potential of the formulations. The human immortalized keratinocytes presented good cell viability when tested with both extracts (propolis and BP) freely or entrapped in the systems. SLN modified with propolis material provided an acceleration of the in vivo wound healing process.

Are Russian propolis ethanol extracts the future for the prevention of medical and biomedical implant contaminations?

BACKGROUND

Most studies reveal that the mechanism of action of propolis against bacteria is functional rather than structural and is attributed to a synergism between the compounds in the extracts.

HYPOTHESIS/PURPOSE

Propolis is said to inhibit bacterial adherence, division, inhibition of water-insoluble glucan formation, and protein synthesis. However, it has been shown that the mechanism of action of Russian propolis ethanol extracts is structural rather than functional and may be attributed to the metals found in propolis. If the metals found in propolis are removed, cell lysis still occurs and these modified extracts may be used in the prevention of medical and biomedical implant contaminations.

STUDY DESIGN

The antibacterial activity of metal-free Russian propolis ethanol extracts (MFRPEE) on two biofilm forming bacteria: penicillin-resistant Staphylococcus aureus and Escherichia coli was evaluated using MTT and a Live/Dead staining technique. Toxicity studies were conducted on mouse osteoblast (MC-3T3) cells using the same viability assays.

METHODS

In the MTT assay, biofilms were incubated with MTT at 37°C for 30min. After washing, the purple formazan formed inside the bacterial cells was dissolved by SDS and then measured using a microplate reader by setting the detecting and reference wavelengths at 570nm and 630nm, respectively. Live and dead distributions of cells were studied by confocal laser scanning microscopy.

RESULTS

Complete biofilm inactivation was observed when biofilms were treated for 40h with 2µg/ml of MFRPEE. Results indicate that the metals present in propolis possess antibacterial activity, but do not have an essential role in the antibacterial mechanism of action. Additionally, the same concentration of metals found in propolis samples, were toxic to tissue cells. Comparable to samples with metals, metal free samples caused damage to the cell membrane structures of both bacterial species, resulting in cell lysis.

CONCLUSION

Results suggest that the structural mechanism of action of Russian propolis ethanol extracts stem predominate from the organic compounds. Further studies revealed drastically reduced toxicity to mammalian cells when metals were removed from Russian propolis ethanol extracts, suggesting a potential for medical and biomedical applications.

Identification of Free Radical Scavengers from Brazilian Green Propolis Using Off-Line HPLC-DPPH Assay and LC-MS

Brazilian green propolis is known as an appreciable natural antioxidant with abundant polyphenolic compounds. For quality control, a fingerprint-efficacy study of Brazilian green propolis was carried out in this work. Chemical fingerprints of Brazilian green propolis from 22 different sources were determined by HPLC and investigated by similarity analysis. The fingerprint-efficacy relationships between chemical fingerprint and DPPH radical-scavenging activity were established. The results showed that 14 characteristic common peaks were identified, and 9 compounds were discovered with free radical-scavenging activities. Caffeoylquinic acids and artepillin C might be the major effective components for quality control of Brazilian green propolis due to their specificity and strong antioxidant activity. This study provides new markers for the quality assessment of Brazilian green propolis and its derived products.

Natural products isolated from Tetragonula carbonaria cerumen modulate free radical-scavenging and 5-lipoxygenase activities in vitro

Background

Propolis and cerumen are plant-derived products found in honeybees and stingless bees, respectively. Although propolis is an ancient folk medicine, the bioactivities of cerumen obtained from Australian native stingless bees (Tetragonula carbonaria) have not been widely studied. Therefore, we investigated selected anti-oxidant and anti-inflammatory properties of T. carbonaria cerumen.

Methods

A methanolic extract was prepared from the combined cerumen of 40 T. carbonaria hives, and HPLC was used to screen for chemical constituents that scavenged 2,2-azobis(2-methylpropionamidine) dihydrochloride (AAPH). The ability of cerumen extracts to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) and to interfere with leukotriene B₄ (LTB₄) production in ionomycin-stimulated human neutrophils was also examined.

Results

The extract dose-dependently scavenged DPPH (EC₅₀ = 27.0 ± 2.3 μg/mL); and inhibited the 5-lipoxygenase (5-LOX)-mediated oxidation of linoleic acid (IC₅₀ = 67.1 ± 9.6 μg/mL). Pre-treatment of isolated human neutrophils with the methanolic cerumen extract additionally inhibited the ionomycin-stimulated production of LTB₄ from these cells (IC₅₀ = 13.3 ± 5.3 μg/mL). Following multi-solvent extraction, the free radical-scavenging and 5-LOX-inhibiting activities of the initial cerumen extract were retained in a polar, methanol-water extract, which contained gallic acid and a range of flavonone and phenolic natural products.

Conclusions

The findings identify free radical scavenging activity, and interference by extracts of T. carbonaria cerumen in 5-LOX–LTB₄ signaling. Further investigation is needed to determine whether the extracts will provide therapeutic benefits for medical conditions in which oxidative stress and inflammation are implicated, including cardiovascular disease and impaired wound healing.

Antitumoral and Antioxidant Potential of Egyptian Propolis Against the PC3 Prostate Cancer Cell Line

It has been shown previously that nutritional supplements rich in polyphenolic compounds play a significant role in prostate cancer chemoprevention. Propolis is a natural, resinous hive product that has several pharmacological activities including antimicrobial, antioxidant, anti-inflammatory, and antitumoral activities. The aim of this study was to compare the cytotoxic, antioxidant and antitumoral activities of an ethanolic extract of Egyptian propolis (EEP) in vitro with an established chemotherapeutic drug such as doxorubicin (DOX), and the effects of their combination against the PC3 human prostate cancer cell line. Cellular viability and IC50 levels with EEP, DOX and their (v/v) combination were detected by sulphorhodamine-B (SRB) assay after incubation of PC3 cells for 72 h with different doses (0, 0.01, 0.1, 1, 10 and 100 μg/ml). Two selected doses of IC50 and IC25 were applied to cells for 24h for antitumor evaluation assay of treatment compounds. EEP and its (v/v) combination with DOX showed significant antitumor potential besides high antioxidant properties of superoxide dismutase (SOD), total antioxidant capacity (TAC), catalase (CAT), nitric oxide (NO) and reduced glutathione (GSH) levels when compared with the control untreated cells. DNA fragmentation assay and semi quantitative RT-PCR analyses for p53 and Bax genes showed that EEP activated cellular apoptosis and increased the mRNA expression levels more than other treatment. In conclusion, EEP alone or in combination with DOX at both doses used here showed greater antioxidant, antiproliferative and apoptotic effects against the PC3 cell lines as compared to treatment with DOX alone. Therefore, EEP could be considered as a promising candidate for prostate cancer chemotherapy.

The mechanism of action of Russian propolis ethanol extracts against two antibiotic-resistant biofilm-forming bacteria

The interaction between antibiotic-resistant Staphylococcus aureus and antibiotic-sensitive Escherichia coli biofilm-forming bacteria and Russian propolis ethanol extracts was evaluated. In this study, bacterial cell death occurred when the cell membranes of bacteria interacted specifically with the antibacterial compounds found in propolis. In order to understand the Russian propolis ethanol extract mechanism of action, microscopy and bacterial lysis studies were conducted. Results uncovered from these experiments imply that the mechanism of action of Russian propolis ethanol extracts is structural rather than functional. The results obtained throughout this study demonstrate cell membrane damage, resulting in cell lysis and eventually bacterial death.

SIGNIFICANCE AND IMPACT OF THE STUDY

Most strains of bacteria and subsequently biofilms, have evolved and have altered their chemical composition in an attempt to protect themselves from antibiotics. The resistant nature of bacteria stems from the chemical rather than the physical means of inactivation of antibiotics. The results uncovered in this work demonstrate the potential application of Russian propolis ethanol extracts as a very efficient and effective method for bacterial and biofilm inactivation.

Propolis: a potential natural product to fight Candida species infections

AIM

To evaluate the effect of propolis against Candida species planktonic cells and its counterpart's biofilms.

MATERIALS & METHODS

The MIC values, time-kill curves and filamentation form inhibition were determined in Candida planktonic cells. The effect of propolis on Candida biofilms was assessed through quantification of CFUs.

RESULTS

MIC values, ranging from 220 to 880 µg/ml, demonstrated higher efficiency on C. albicans and C. parapsilosis than on C. tropicalis cells. In addition, propolis was able to prevent Candida species biofilm's formation and eradicate their mature biofilms, coupled with a significant reduction on C. tropicalis and C. albicans filamentation.

CONCLUSION

Propolis is an inhibitor of Candida virulence factors and represents an innovative alternative to fight candidiasis.