Antimicrobial activity of honey from the stingless beeTrigona carbonariadetermined by agar diffusion, agar dilution, broth microdilution and time-kill methodology

Evaluation of the polyphenolic profile of native Ecuadorian stingless bee honeys (Tribe: Meliponini) and their antibiofilm activity on susceptible and multidrug-resistant pathogens: An exploratory analysis

Biofilms are associated with infections that are resistant to conventional therapies, contributing to the antimicrobial resistance crisis. The need for alternative approaches against biofilms is well-known. Although natural products like stingless bee honeys (tribe: Meliponini) constitute an alternative treatment, much is still unknown. Our main goal was to evaluate the antibiofilm activity of stingless bee honey samples against multidrug-resistant (MDR) pathogens through biomass assays, fluorescence (cell count and viability), and scanning electron (structural composition) microscopy. We analyzed thirty-five honey samples at 15% (v/v) produced by ten different stingless bee species (Cephalotrigona sp., Melipona sp., M. cramptoni, M. fuscopilosa, M. grandis, M. indecisa, M. mimetica, M. nigrifacies, Scaptotrigona problanca, and Tetragonisca angustula) from five provinces of Ecuador (Tungurahua, Pastaza, El Oro, Los Ríos, and Loja) against 24-h biofilms of Staphylococcus aureus, Klebsiella pneumoniae, Candida albicans, and Candida tropicalis. The present honey set belonged to our previous study, where the samples were collected in 2018-2019 and their physicochemical parameters, chemical composition, mineral elements, and minimal inhibitory concentration (MIC) were screened. However, the polyphenolic profile and their antibiofilm activity on susceptible and multidrug-resistant pathogens were still unknown. According to polyphenolic profile of the honey samples, significant differences were observed according to their geographical origin in terms of the qualitative profiles. The five best honey samples (OR24.1, LR34, LO40, LO48, and LO53) belonging to S. problanca, Melipona sp., and M. indecisa were selected for further analysis due to their high biomass reduction values, identification of the stingless bee specimens, and previously reported physicochemical parameters. This subset of honey samples showed a range of 63-80% biofilm inhibition through biomass assays. Fluorescence microscopy (FM) analysis evidenced statistical log reduction in the cell count of honey-treated samples in all pathogens (P <0.05), except for S. aureus ATCC 25923. Concerning cell viability, C. tropicalis, K. pneumoniae ATCC 33495, and K. pneumoniae KPC significantly decreased (P <0.01) by 21.67, 25.69, and 45.62%, respectively. Finally, scanning electron microscopy (SEM) analysis demonstrated structural biofilm disruption through cell morphological parameters (such as area, size, and form). In relation to their polyphenolic profile, medioresinol was only found in the honey of Loja, while scopoletin, kaempferol, and quercetin were only identified in honey of Los Rios, and dihydrocaffeic and dihydroxyphenylacetic acids were only detected in honey of El Oro. All the five honey samples showed dihydrocoumaroylhexose, luteolin, and kaempferol rutinoside. To the authors' best knowledge, this is the first study to analyze stingless bees honey-treated biofilms of susceptible and/or MDR strains of S. aureus, K. pneumoniae, and Candida species.

Antioxidants Discovery for Differentiation of Monofloral Stingless Bee Honeys Using Ambient Mass Spectrometry and Metabolomics Approaches

Stingless bee honey (SBH) is a natural, sweet product produced by stingless bees (Meliponini tribe) that has been used as a traditional medicine to treat various illnesses. It has been shown that SBH has high nutritional value and health-promoting properties due to the presence of plant bioactive compounds from different botanical flora of the foraged nectar. In this study, the antioxidant activities of seven monofloral honeys from acacia, agarwood, coconut, dwarf mountain pine (DMP), Mexican creeper (MC), rubber, and starfruit botanical origins were investigated. The antioxidant properties of SBH studied had a range from 19.7 to 31.4 mM TE/mg for DPPH assays, 16.1 to 29.9 mM TE/mg for ABTS assays, 69.0 to 167.6 mM TE/mg for ORAC assays, and 45.5 to 89.3 mM Fe²⁺/mg for FRAP assays. Acacia honey showed the highest level of antioxidant properties. The models built from mass spectral fingerprints from direct ambient mass spectrometry showed distinct clusters of SBH by botanical origin and correlated with the antioxidant properties. An untargeted liquid chromatography-mass spectrometry (LC-MS) metabolomics approach was undertaken to identify the antioxidant compounds that could explain the unique antioxidant and compositional profiles of the monofloral SBH by its botanical origin. The antioxidants that were identified predominantly consisted of alkaloids and flavonoids. Flavonoid derivatives, which are potent antioxidants, were found to be key markers of acacia honey. This work provides the fundamental basis for the identification of potential antioxidant markers in SBH associated with the botanical origin of the foraged nectar.

A review of stingless bees' bioactivity in different parts of the world

Stingless bees, also known as meliponines, live in beehives. However, reports on the distribution of stingless bees are scattered, resulting in a lack of precision. Honey and propolis are the main components that can be harvested from their beehive, with a great commercial value of up to 610 million USD. Despite the enormous potential profits, discrepancies in their bioactivities have been observed worldwide, leading to a lack of confidence. Therefore, this review provided oversight on the potential of stingless bee products and highlighted the differences between stingless bees in Asia, Australia, Africa, and America. The bioactivity of stingless bee products is diverse and exhibits great potential as an antimicrobial agent or in various diseases such as diabetes, cardiovascular disease, cancers, and oral problems.

An Insight into the Endophytic Bacterial Community of Tomato after Spray Application of Propiconazole and Bacillus subtilis Strain NBRI-W9

Propiconazole (PCZ) is a commonly sprayed fungicide against fungal pathogens. Being systemic in action, it reaches subcellular layers and impacts the endophytes. Although PCZ is a fungicide, it is hypothesized to exert an inhibitory effect on the bacterial endophytes. Therefore, this study aims to get an insight into the perturbations caused by the systemically acting antifungal agents PCZ and Bacillus subtilis (W9) and the consequences thereof. The current study compared the 16S rRNA microbial diversity, abundance, and functions of the endophytic bacterial community of tomato in response to PCZ, W9, and PCZ+W9 application. The implications of these treatments on the development of bacterial speck disease by Pseudomonas syringae were also studied. The culturable endophyte population fluctuated after (bio)fungicide application and stabilized by 72 h. At 72 h, the endophyte population was ~3.6 × 103 CFUg-1 in control and ~3.6 × 104 in W9, ~3.0 × 102 in PCZ, and ~5.3 × 103 in PCZ+W9 treatment. A bacterial community analysis showed a higher relative abundance of Bacillales, Burkholderiales, Rhizobiales, Pseudomonadales, and Actinomycetales in the W9 treatment compared with that in the PCZ treatment and control. Phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis showed enhanced metabolic pathways related to secretion, stress, chemotaxis, and mineral nutrition in the W9 treatment. Disease severity was greater in PCZ than that in the W9 treatment. Disease severity on tomato plants showed strong negative correlations with Sphingomonas (r = -0.860) and Janthinobacterium (r = -0.810), indicating that the natural biocontrol communities are agents of plant resistance to diseases. Outcomes show that systemic chemicals are a potential threat to the nontarget endophytes and that plants became susceptible to disease on endophyte decline; this issue could be overcome by the application of microbial inoculums. IMPORTANCE Endophytes are plant inhabitants acting as its extended genome. The present study highlights the importance of maintaining plant endophytes for sustainable disease resistance in plants. The impact of chemical fungicides and biofungicides was shown on tomato endophytes, in addition to their implications on plant susceptibility to bacterial speck disease. The observations point toward the deleterious effects of systemic pesticide application on endophyte niches that disrupt their diversity and functions compromising plant immunity.

Flavonoids and Phenylethylamides Are Pivotal Factors Affecting the Antimicrobial Properties of Stingless Bee Honey

Despite the recent approval of stingless bee honey to the Argentine Food Code, there are still many gaps in information. Likely, the main reason for this is that multiple ecological and chemical factors influence their production and antimicrobial properties. This work combined metabolomic, microbiological, and physicochemical analyses to characterize the honey ofTetragonisca fiebrigifrom Northeastern Argentina. The antimicrobial activity tests showed that honey samples (n = 24) inhibited some Gram-positive and Gram-negative bacteria at different sensitivity levels. Furthermore, samples selected for their high bioactivity revealed crystallizations, a positive correlation with fungal growth, and the presence of flavonoids. The major polyphenols annotated by liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis and supported by metabolomic tools were quercetin 3,4'-dimethyl ether, pachypodol, jaceoside, irigenin trimethyl ether, corymboside, chrysoeriol 7-neohesperidoside, and corymboside. In contrast, samples missing antimicrobial activity did not crystallize, lacked flavonoids, and were enriched in phenylethylamides. Based on these findings, we discuss the significance of flavonoids and phenylethylamides on honey's antimicrobial activity and food quality and how they may indeed reflect essential parameters of the hive, such as microbial balance and eubiosis.

A comparative study of antibacterial and antivirulence activities of four selected honeys to Manuka honey

Background and Objectives

Honey has excellent antibacterial properties against various microorganisms of several different species. To date, there is no comparative evaluation of the antibacterial activity of Jarrah honey (JH), Kelulut Madu honey (KMH), Gelam honey (GH), and Acacia honey (AH) with that of Manuka honey (MH). The purpose of this study was to conduct such study and to compare the antibacterial activity of JH, KMH, GH, and AH with that of MH against Pseudomonas aeruginosa and Streptococcus pyogenes.

Materials and Methods

Activity was assessed using broth microdilution, time kill viability, microtiter plate, scanning electron microscope (SEM) and Quantitative Real-Time Polymerase Chain Reaction (RT-qPCR).

Results

The susceptibility tests revealed promising antibacterial activities of all honeys against both bacteria. The MICs of JH, KMH, GH, and AH ranged from 20% to 25% compared to MH (12.5%) against both bacteria. The MBCs of JH, KMH, GH, and AH ranged from 20% to 50% compared to MH (20%) against both bacteria. Treatment of both bacteria with 2× MIC (Minimum inhibitory concentration) of MH, JH, KMH, GH, and AH for 9 hours resulted in reduction in colony-forming unit (CFU/ml). SEM images showed that the morphological changes, cell destruction, cell lysis and biofilm disruption in both bacteria after exposure to all honeys. RT-qPCR analysis revealed that the expression of all genes in both bacteria were downregulated following treatment with all honeys. Among the all-tested honeys, MH showed the highest total antibacterial and antivirulence activities.

Conclusion

Our results indicate that all honeys activity included inhibition of both bacteria due to a decrease in expression of essential genes associated with both bacteria, suggesting that all honeys could potentially be used as an alternative therapeutic agent against certain microorganisms particularly against P. aeruginosa and S. pyogenes.

Genome shuffling of Lactobacillus plantarum 163 enhanced antibacterial activity and usefulness in preserving orange juice

Lactic acid bacteria have been used to inhibit the growth of spoilage bacteria in food and animal feeds. For instance, Lactobacillus plantarum 163 can inhibit efficiently the growth of both gram-positive and gram-negative bacteria. In our study, the antibacterial activity of L. plantarum 163 was further improved significantly by genome shuffling. The optimal conditions for protoplast formation and regeneration were 20 mg ml^-1 lysozyme and 5 mg ml^-1 mutanolysin for 30 min at 37°C using 0·5 mol l^-1 sucrose as stabilizer. The protoplasts were inactivated under ultraviolet light for 120 s or heated at 58°C for 20 min. After two rounds of genome shuffling, the inhibitory activity of strain F2-14 was improved by 2·45- and 1·99-fold, respectively, as compared to their parent strains. The prepared antibacterial peptides supernatant (APS) was added to the orange juice to inhibit spores of Alicyclobacillus acidoterrestris (SAA) at 45 and 28°C. Results showed that the growth of A. acidoterrestris was significantly inhibited, and the decrease in total soluble solids, OD value and pH value was also delayed. After treatment with APS, the thermal sensitivity of spores was increased and its D value was reduced to 13·78, 3·87 and 1·47 min at 80, 90 and 95°C respectively.

Antibacterial activity of honeys from Amazonian stingless bees of Melipona spp. and its effects on bacterial cell morphology

BACKGROUND

Stingless bee honey has great therapeutic potential, especially as an antimicrobial agent. In the present study, we evaluated the in vitro antibacterial potential of honey from Melipona spp. with occurrence in Rio Branco-AC and Xapuri-AC from the Amazonian region. Samples were collected from the species Melipona eburnea, Melipona grandis, Melipona flavolineata and Melipona seminigra. The antibacterial activity of the honey samples was tested against standard Gram-positive and Gram-negative bacteria and two strains isolated from bovine mastitis.

RESULTS

In the agar diffusion assay, we observed antibacterial activity for the four honeys against the tested strains. The honey from M. flavolineata showed a minimmum inhibitory concentration (MIC) lower than 3.12% (v/v). The minimum bactericidal concentration values were larger than the MIC for most of the microorganisms tested. Scanning electron microscopy (SEM) showed the damaging effect of the honey of M. flavolineata on Staphylococcus aureus cells, as well as its inhibitory effect on cell division.

CONCLUSION

The results of the present study demonstrate that the honey from stingless bees possesses in vitro antimicrobial activity against pathogenic bacteria. The effects observed by SEM show that honey from the Amazonian stingless bee M. flavolineata has promising therapeutic potential as a future antimicrobial agent. © 2020 Society of Chemical Industry.

The stingless bee honey protects against hydrogen peroxide-induced oxidative damage and lipopolysaccharide-induced inflammation in vitro

Oxidative stress, DNA damage, and unresolved inflammation are the predisposing factors of many chronic and degenerative diseases, including cancer. Stingless bee honey (SBH) is recognized to have high medicinal value by traditional medicine practitioners and has been used to treat various illnesses traditionally. This study aimed to determine the antioxidant, anti-inflammatory, and genoprotective effects of SBH by using in vitro cell culture models. The sugar content, total phenolic content, radical scavenging activity, and ferric reducing antioxidant power (FRAP) of SBH were determined in this study. Then, the protective effect of SBH against hydrogen peroxide (H₂O₂)-induced cell death and DNA damage was studied by using WIL2-NS human lymphoblastoid cell line, while the lipopolysaccharide (LPS)-induced RAW 264.7 murine macrophages cell line was used to study the anti-inflammatory effects of SBH. Results from this present study showed that the major sugar contents of SBH were fructose (19.39 + 0.01%) and glucose (14.03 ± 0.03%). Besides, the total phenolic content, the radical scavenging activity, and the FRAP value of SBH were 15.38 ± 0.02 mg GAE/100 g of honey, 34.04 ± 0.21%, and 206.77 + 1.76 μM AAE/100 g honey respectively. Pretreatment with SBH protected WIL2-NS cells from H₂O₂-induced cell death and DNA damage (p < 0.001). Moreover, SBH was also able to attenuate the production of nitric oxide by inhibiting the expression of inducible nitric oxide synthase in LPS-induced RAW 264.7 cells (p < 0.001). In conclusion, SBH is rich in total phenolic content and possesses strong antioxidant, anti-inflammatory, and genoprotective properties. Our current findings suggest that SBH might be useful in the prevention and treatment of many diseases caused by oxidative stress and inflammation assuming the observed effects are also achievable in vivo.

The Antibacterial Potential of Honeydew Honey Produced by Stingless Bee (Heterotrigona itama) against Antibiotic Resistant Bacteria

Scientific studies about the antibacterial effects of honeydew honey produced by the stingless bee are very limited. In this study, the antibacterial activities of 46 blossom and honeydew honeys produced by both honey bees and stingless bees were evaluated and compared. All bacterial isolates showed varying degrees of susceptibility to blossom and honeydew honeys produced by the honey bee (Apis cerana) and stingless bee (Heterotrigona itama and Geniotrigona thoracica) in agar-well diffusion. All stingless bee honeys managed to inhibit all the isolates but only four out of 23 honey bee honeys achieved that. In comparison with Staphylococcus aureus, Escherichia coli was found to be more susceptible to the antibacterial effects of honey. Bactericidal effects of stingless bee honeys on E. coli were determined with the measurement of endotoxins released due to cell lysis. Based on the outcomes, the greatest antibacterial effects were observed in honeydew honey produced by H. itama. Scanning electron microscopic images revealed the morphological alteration and destruction of E. coli due to the action of this honey. The combination of this honey with antibiotics showed synergistic inhibitory effects on E. coli clinical isolates. This study revealed that honeydew honey produced by H. itama stingless bee has promising antibacterial activity against pathogenic bacteria, including antibiotic resistant strains.

Antibacterial properties of selected Malaysian Tualang honey against Pseudomonas aeruginosa and Streptococcus pyogenes

BACKGROUND AND OBJECTIVES

Tualang honey (TH) is a Malaysian multifloral jungle honey. In recent years, there has been a marked increase in the number of studies published in medical databases regarding its potential health benefits. The study aimed to investigate the effect of TH against Pseudomonas aeruginosa and Streptococcus pyogenes.

MATERIALS AND METHODS

The effect of TH on both bacteria was investigated using MIC, MBC, growth curve, time-kill curve, scanning electron microscopy (SEM) and RT-qPCR.

RESULTS

The MIC of TH against P. aeruginosa and S. pyogenes was 18.5% (w/v) and 13% (w/v) respectively and MBC was 25% (w/v) for both bacteria. Spectrophotometric readings of at least 90% inhibition yielded MIC90 values of TH, 18.5% (w/v) and 15% (w/v) for P. aeruginosa and S. pyogenes respectively. A time-kill curve demonstrated a bactericidal with a 4-log reduction estimated within 8 hours. Using SEM, loss of structural integrity and marked changes in cell shape were observed. RT-qPCR analysis showed that TH reduced the pattern of gene expression in both bacteria, with a trend toward reduced expression of the virulence genes of interest.

CONCLUSION

This study suggests that TH could potentially be used as an alternative therapeutic agent for microbial infection particularly against these two organisms.

Characterization of a non-glycosylated fraction from honey proteins of Melipona beecheii with antimicrobial activity against Escherichia coli O157:H7

AIMS

To analyse the non-glycosylated protein fraction from Melipona beecheii honey for antimicrobial activity against Escherichia coli O157:H7.

METHODS AND RESULTS

The proteins from M. beecheii honey were separated according to their degree of glycosylation using Concanavalin A-affinity chromatography. The total protein extract and its fractions were analysed by 1D and 2D electrophoresis. We also determined the antimicrobial and antihaemolytic activities of the total protein extract and the non-glycosylated fraction. Furthermore, we evaluated the effect of this non-glycosylated fraction for the expression of the Stx1, Stx2, EAE and HlyA pathogen genes. Melipona beecheii honey contained at least 24 proteins with molecular weights ranging between 7·6 and 95 kDa and isoelectric points between 3 and 10, three proteins from the 24 are non-glycosylated. The non-glycosylated fraction had an MIC₉₀ of 1·128 µg ml^-1 , and this fraction inhibited the haemolytic activity of the pathogen, as well as reduced the expression of Stx1, Stx2 and HlyA. The MbF1-2 protein from the non-glycosylated fraction was sequenced and identified as a homologue of the royal jelly-like protein of Melipona quadrifasciata.

CONCLUSIONS

The non-glycosylated protein fraction from M. beecheii honey greatly contributes to antibacterial activity and it is composed of at least three proteins, of which MbF1-2 provided over 50% of the antimicrobial activity.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study showed significant antimicrobial activity from several proteins present in the honey of M. beecheii. Interestingly, the non-glycosylated protein fraction demonstrated antihaemolytic activity and adversely affected the expression of virulence genes in Escherichia coli O157:H7; these proteins have the potential to be used in developing therapeutic agents against this bacterium.

In vitro antibacterial activity of honey against multidrug-resistant Shigella sonnei

BACKGROUND AND PURPOSE

The health benefits of honey as an oral therapeutic agent for the treatment of diarrhoea caused by Shigella sonnei depend on the ability of honey to withstand human gastrointestinal conditions. This study aimed to investigate whether honey could withstand and inhibit the growth of Shigella sonnei under such conditions.

MATERIALS AND METHODS

We initially evaluated the survival of Shigella sonnei in human simulated gastric conditions (SGC) and simulated intestinal conditions (SIC). This was followed by determination of the susceptibility of Shigella sonnei to Manuka and Talah honey under gastrointestinal conditions. The colony forming units (CFU) of Shigella sonnei and minimum inhibitory concentrations (MICs) of honey were calculated.

RESULTS

Shigella sonnei was unable to survive in the acidic environment of the stomach without food matrix and survived only when inoculated with a food source, resulting in 1.5 × 10⁵ ± 0.2 CFU at 60 min and 1.7 × 10⁵ ± 0.3 CFU after 120 min of incubation. In SIC, it survived both with and without food matrix at the same CFU (1.2 × 10⁷ ±0.4) at 60 min and 1.7 × 10⁷ ±0.2 CFU after 120 min of incubation. Growth of Shigella sonnei was not observed in SGC in the presence of either honey at different concentrations without a food source. In the presence of a food source, Manuka honey inhibited the growth of Shigella sonnei at 10% v/v and Talah honey at 20% v/v dilutions in SGC. In SIC, Manuka honey inhibited the growth of Shigella sonnei at 15% and 20% v/v dilutions, whereas Talah honey inhibited Shigella sonnei at 20% and 25% v/v dilutions without and with food sources, respectively.

CONCLUSION

Shigella sonnei can survive in the acidic environment of the stomach if inoculated with a food source. Acidic pH and pepsin had no deleterious effects on the antibacterial capability of honey. However, bile reduced the antibacterial activity of honey in the intestinal environment.

Antioxidant and Antibacterial Activity of Selected Indonesian Honey against Bacteria of Acne

Honey has natural bacteriostatic and bactericide activities; thus, it could be active compounds as an antibacterial against Propionibacterium acnes, the main bacteria in acne forming state. Our study aims to determine phenolic and flavonoid contents (qualitative and quantitative), antioxidants, along with antibacterial activity against P. acnes of selected Indonesian honey. Honey used in this study, including honeybees and stingless bees, were collected from Sumbawa, Riau, Belitung, Sukabumi, Banyuwangi, Bogor, and South Sulawesi. In the method, the quantitative content of phenols and flavonoid were measured using a spectrophotometer. Further, DPPH (2, 2’-diphenylpicryl hydrazyl) and ABTS (2’-azino-bis (3- ethylbenzothiazoline-6-sulfonic acid) assays were used to measure the antioxidant activities, and subsequently microdilution method was applied to determine antibacterial activity. The results showed that Indonesian honey contains phenolics and flavonoids in the range of 49.5-67.3 μg Gallic Acid Equivalent (GAE)/g and 766.5-1509.5 μg Quercetin Equivalent (QE)/g, respectively. All honey samples also show antioxidant and antibacterial activities. Of note, Apis cerana honey from Banyuwangi has the highest antioxidant and antibacterial activity compared to others. It has the Inhibition Concentration (IC50), Trolox Equivalent Antioxidant Capacity, Minimum Inhibitory Concentration (MIC) and Minimum Bactericide Concentration (MBC) values of 59.85 mg/L, 122 μg Trolox/g, 125 mg/mL, and 500 mg/mL respectively. Our study reveals that Indonesian honey can inhibit and kill P. acnes as well. Nonetheless, the phenolic content of honey is not always linear with antioxidant and antibacterial activities.

Antioxidant-Based Medicinal Properties of Stingless Bee Products: Recent Progress and Future Directions

Stingless bees are a type of honey producers that commonly live in tropical countries. Their use for honey is being abandoned due to its limited production. However, the recent improvements in stingless bee honey production, particularly in South East Asia, have brought stingless bee products back into the picture. Although there are many stingless bee species that produce a wide spread of products, known since old eras in traditional medicine, the modern medical community is still missing more investigational studies on stingless bee products. Whereas comprehensive studies in the current era attest to the biological and medicinal properties of honeybee (Apis mellifera) products, the properties of stingless bee products are less known. This review highlights for the first time the medicinal benefits of stingless bee products (honey, propolis, pollen and cerumen), recent investigations and promising future directions. This review emphasizes the potential antioxidant properties of these products that in turn play a vital role in preventing and treating diseases associated with oxidative stress, microbial infections and inflammatory disorders. Summarizing all these data and insights in one manuscript may increase the commercial value of stingless bee products as a food ingredient. This review will also highlight the utility of stingless bee products in the context of medicinal and therapeutic properties, some of which are yet to be discovered.

Physical characteristics and antimicrobial properties of Apis mellifera, Frieseomelitta nigra and Melipona favosa bee honeys from apiaries in Trinidad and Tobago

Background

Honey is a versatile and complex substance consisting of bioactive chemicals which vary according to many bee and environmental factors. The aim of this study was to assess the physical and antimicrobial properties of five honey samples obtained from three species of bees; two stingless bees, Frieseomelitta nigra and Melipona favosa and one stinging bee, Apis mellifera (fresh and aged honey). Samples were acquired from apiaries across Trinidad and Tobago. An artificial honey, made from sugar, was also used for comparison.

Methods

Physical properties such as appearance, pH, moisture content, sugar content and specific gravity were determined. Antimicrobial activity was assessed utilizing the agar diffusion assay and comparison to a phenol equivalence. The broth microdilution test was performed to determine the minimum inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs) of the five honey samples against four common pathogens, including Staphylococcus aureus, Escherichia coli, Streptococcus pyogenes and Haemophilus influenzae.

Results

All honey samples were acidic, with pH values ranging from 2.88 (M. favosa of Tobago) to 3.91 (fresh A. mellifera). Sugar content ranged from 66.0 to 81.6% with the highest values detected in stinging bee honeys of the A. mellifera (81.6 and 80.5°Bx). Moisture content ranged from 16.9% for aged A. mellifera honey (from Trinidad) to 32.4% for F. nigra honey (from Tobago). The MICs (2 to 16%) and MBCs (2 to 32%) of stingless bee honeys were lower than that of stinging bee and artificial honeys (16 to > 32%). Stingless bee honeys also exhibited a broad spectrum of antimicrobial activity against both Gram-positive and Gram-negative organisms with higher phenol equivalence values (4.5 to 28.6%) than the A. mellifera honeys (0 to 3.4%) against the isolates tested. M. favosa honey of Tobago displayed the greatest antimicrobial activity as indicated by the high phenol equivalence and low MIC and MBC values.

Conclusions

Stingless bee honeys from Tobago showed the greatest antimicrobial activity when compared to the other honeys used in this study. M. favosa honey of Tobago showed the most potential for use as medicinal honey.

Effects of phenolic and protein extracts from Melipona beecheii honey on pathogenic strains of Escherichia coli and Staphylococcus aureus

Antimicrobial effects of Melipona beecheii honey have been attributed to diverse factors, in this sense, certain components such as proteins and phenolics could explain relevant aspects of its antimicrobial activity. The aim of this study was to evaluate the antibacterial activity of phenolic and protein extracts from M. beecheii honey against two bacterial pathogens: Staphylococcus aureus and Escherichia coli. With respect to phenolic content, HPLC analysis allowed the identification of phenolic acids like chlorogenic acid, caffeic acid, and flavonoids like catechin, myricetin, quercetin and apigenin. On the other hand, seven bands with molecular weight from 7.6 to 95 kDa were detected in protein extract by SDS-PAGE system. It was determined the antibacterial activity of both extracts, with MICs lower than 145 µg/mL and 60 µg/mL for the phenolic and protein extracts respectively. These results indicate that phenolic and protein components of M. beecheii honey contribute significantly to the antibacterial activity.

Stingless Bee Honey Improves Spatial Memory in Mice, Probably Associated with Brain-Derived Neurotrophic Factor (BDNF) and Inositol 1,4,5-Triphosphate Receptor Type 1 (Itpr1) Genes

This study was conducted to evaluate the effects of stingless bee honey (SBH) supplementation on memory and learning in mice. Despite many studies that show the benefits of honey on memory, reports on the nootropic effects of SBH are still lacking, and their underlying mechanism is still unclear. SBH is a honey produced by the bees in the tribe of Meliponini that exist in tropical countries. It features unique storage of honey collected in cerumen pots made of propolis. This SBH may offer a better prospect for therapeutic performance as the previous report identifies the presence of antioxidants that were greater than other honey produced by Apis sp. In this study, SBH was tested on Swiss albino mice following acute (7 days) and semichronic (35 days) supplementation. Experiments were then conducted using Morris water maze (MWM) behaviour analysis, RT-PCR for gene expression of mice striatum, and NMR for metabolomics analysis of the honey. Results indicate spatial working memory and spatial reference memory of mice were significantly improved in the honey-treated group compared with the control group. Improved memory consolidations were also observed in prolonged supplementation. Gene expression analyses of acutely treated mice demonstrated significant upregulation of BDNF and Itpr1 genes that involve in synaptic function. NMR analysis also identified phenylalanine, an essential precursor for tyrosine that plays a role at the BDNF receptor. In conclusion, SBH supplementation for seven days at 2000 mg/kg, which is equivalent to a human dose of 162 mg/kg, showed strong capabilities to improve spatial working memory. And prolonged intake up to 35 days increased spatial reference memory in the mice model. The phenylalanine in SBH may have triggered the upregulation of BDNF genes in honey-treated mice and improved their spatial memory performance.

Purification and characterization of proteins in multifloral honey from kelulut bee (stingless bee)

The kelulut bee (Meliponini) is a subfamily of stingless bees that produce honey. A total of 89 species out of a total of 500 species of kelulut bees are known to originate from the Indo-Australian region. Kelulut bees do not have quality standards so they still refer to the Codex and EU Directive which basically only applied for Apis honey. The Codex and EU Directive are formed by several psychochemical parameters, one of it is diastase activity. Diastase activity in kelulut honey is known not to meet existing standards or even undetectable. Therefore, this study aimed to explore proteins inside kelulut honey and investigate the possibility of using a specific protein as a biomarker to differentiate honey produced by kelulut bee from other honey. This research can also be considered as an initial step to optimize the exploration of protein in kelulut honey. This research is divided into two sections which are the preliminary research and the research expansion. From preliminary section, glucose dehydrogenase enzyme (GDH) was found to be present inside Tetragonula spp honey. A further examination of GDH enzyme was made in four kelulut bee honeys namely Tetragonula leaviceps, T. biroi, Heterotrigona itama, and Geniotrigona thoracica. The preliminary research has five stages that are exactly the as expansion research section except it didn't include GDH activity measurement. The research includes seven main stages. First honeys were dialyzed to remove the sugar content followed by centrifugation. The samples were then purified using liquid chromatography with anion exchanger column. The molecular weight of proteins was analysed by SDS-PAGE method. The GDH activity was measured using spectrophotometer followed by qualitative analysis using LC-MS/MS. The peptide sequences resulted from LC-MS/MS were then matched with Uniprot to identify the unknow protein. The results showed that only T. biroi and T. laeviceps had GDH enzyme activity of 0,1891 U/mL and 0,1652-1,579 U/mL, respectively. Bands from both species were also qualitatively identified as GDH. With these results, it can be concluded that the GDH enzyme cannot be used as a biomarker to distinguish the kelulut honey.

In vitro evaluation of methicillin-resistant and methicillin-sensitive Staphylococcus aureus susceptibility to Saudi honeys

Background

Honey has been increasingly recognized as a potential therapeutic agent for treatment of wound infections. There is an urgent need for assessment and evaluation of the antibacterial properties against wound pathogens of honeys that have not yet been tested.

Methods

Ten Saudi honeys collected from different geographical locations were screened initially for their antibacterial potential against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) by the agar well diffusion method. Manuka honey (UMF-12) was used for comparison. Of the tested honeys, the honey that exhibited the greatest antibacterial activity in the agar well diffusion assay was further evaluated for its minimum inhibitory concentration (MIC) against ten MRSA clinical isolates and three American Type Culture Collection (ATCC) reference strains by the microbroth dilution method.

Results

Locally produced honeys exhibited variable antibacterial activity against the tested isolates in the agar well diffusion assay. They were unable to exhibit antibacterial activity against MSSA and MRSA at 25% dilutions (w/v) in catalase solution. However, Sumra and Talha honeys showed a zone of inhibition at 50% dilutions (w/v) in catalase solution. This finding means that both honeys possess weak non-peroxide-based antibacterial activity. Moreover, Sumra honey showed a larger inhibition zone at 50 and 25% dilutions (w/v) in distilled water than Manuka honey against both MSSA and MRSA. This result demonstrates that Sumra honey has more hydrogen peroxide-related antibacterial activity or total antibacterial activity than Manuka honey. In addition, MIC results obtained through a microbroth dilution assay showed that Sumra honey inhibited the growth of all MRSA clinical isolates (n = 10) and reference strains [MRSA (ATCC 43300) and MSSA (ATCC 29213)] at lower concentrations (12.0% v/v) than those required for Manuka honey-mediated inhibition (14.0% v/v). This result means that Sumra honey has more peroxide or synergistic antibacterial activity than Manuka honey. An equivalent MIC (15.0% v/v) was observed for E. coli (ATCC 25922) between Manuka honey and Sumra honey.

Conclusions

Sumra honey may be used as an alternative therapeutic agent for infected wounds and burns, where additional hydrogen peroxide-related antibacterial activity is needed. In the future, the physiochemical characteristics of Sumra honey may be evaluated and standardized.

Therapeutic Properties of Stingless Bee Honey in Comparison with European Bee Honey

Both honeybees (Apis spp.) and stingless bees (Trigona spp.) produce honeys with high nutritional and therapeutics value. Until recently, the information regarding potential health benefits of stingless bee honey (SBH) in medical databases is still scarce as compared to the common European bee honey (EBH) which is well known for their properties as therapeutic agents. Although there have been very few reports on SBH, empirically these products would have similar therapeutic quality as the EBH. In addition, due to the structure of the nest, few studies reported that the antimicrobial activity of SBH is a little bit stronger than EBH. Therefore, the composition of both the types of honey as well as the traditional uses and clinical applications were compared. The results of various studies on EBH and SBH from tissue culture research to randomised control clinical trials were collated in this review. Interestingly, there are many therapeutic properties that are unique to SBH. Therefore, SBH has a great potential to be developed for modern medicinal uses.

Biophysical Studies of Some Bee Products as Radioprotectors.. [DOI: 10.1101/472233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

The study had been planned to evaluate some antioxidant ingredients in honey and propolis. Also, a study on ionizing gamma irradiated rats was done to assess these antioxidants as radioprotectors. Bioactive ingredients, such as phenols, flavonoids and trace elements, were explored using FTIR, UV-Vis and AAS spectroscopic techniques. Animals were exposed to fractionated gamma radiation doses. Honey, propolis and their combination were administrated before and during the irradiation period. Serum levels of total protein, albumin and uric acid were estimated. Also, the osmotic fragility of Red Blood Corpuscles (RBCs) membranes and a microscopic examination of blood films were investigated. The analysis demonstrated that the level of phenolic, flavonoid and trace elements are higher in propolis than honey. The levels of total protein and albumin decreased post irradiation while the level of uric acid increased. Likewise, osmotic fragility of RBCs membranes was increased with a sticking forming RBCs aggregation. It had been found that administration of the natural antioxidants induced amelioration in most of the studied parameters. It can be concluded that natural antioxidants produced a modulation against oxidative stress induced by ionizing radiation.

Summary Statement

Assessment of some antioxidant ingredients in honey and propolis. Also, a study on ionizing gamma irradiated rats was done to assess these antioxidants as radioprotectors.

In vitro and in vivo activity of Manuka honey against NDM-1-producing Klebsiella pneumoniae ST11

Aim: To determine the therapeutic potential of Manuka honey against New Delhi metallo-β-lactamase-1-producing Klebsiella pneumoniae ST11 in vitro and in vivo. Materials & methods: Carbapenamases and metallo-β-lactamases-producing K. pneumoniae ST11 isolated from blood culture was confirmed by VITEK-2® system, matrix-assisted laser desorption ionization–time of flight and multilocus sequence typing, followed by determination of minimum inhibitory concentration (μg/ml) using VITEK-2 system. Genetic analysis of bla NDM-1 was done by PCR, pulsed-field gel electrophoresis and DNA hybridization. In vitro and in vivo efficacy of Manuka honey was performed by microbroth dilution assay and BALB/c mice model respectively. Results: K. pneumoniae ST11 displayed resistance to commonly used antibiotics. bla NDM-1 was located on 150 and 270kb plasmids. Minimum inhibitory concentration and minimum bactericidal concentration of Manuka honey was 30% (v/v) and substantial reduction of bacterial mean log value (>1 log) was observed in mice. Histological analysis of mice liver and kidneys demonstrated mild to moderate inflammation. Conclusion: Manuka honey can be used as an alternate therapeutic approach for management of New Delhi metallo-β-lactamase-producing pathogens.

Role of Honey in Topical and Systemic Bacterial Infections

BACKGROUND

The development of bacterial resistance to antibiotics has made it more difficult and expensive to treat infections. Honey is getting worldwide attention as a topical therapeutic agent for wound infections and potential future candidate for systemic infections.

OBJECTIVES

The purpose of this review was to summarise different antibacterial bio-active compounds in honey, their synergistic interaction and their clinical implications in topical and systemic infections. In addition, contemporary testing methods for evaluating peroxide and non-peroxide antibacterial activity of honey were also critically appraised.

DESIGN

MEDLINE, EMBASE, Cochrane Library, Pub Med, reference lists and databases were used to review the literature.

RESULTS

Honey contains several unique antibacterial components. These components are believed to act on diverse bacterial targets, are broad spectrum, operate synergistically, prevent biofilm formation, and decrease production of virulence factors. Moreover, honey has the ability to block bacterial communication (quorum sensing), and therefore, it is unlikely that bacteria develop resistance against honey. Bacterial resistance against honey has not been documented so far. Unlike conventional antibiotics, honey only targets pathogenic bacteria without disturbing the growth of normal gastrointestinal flora when taken orally. It also contains prebiotics, probiotics, and zinc and enhances the growth of beneficial gut flora. The presence of such plethora of antibacterial properties in one product makes it a promising candidate not only in wound infections but also in systemic and particularly for gastrointestinal infections. Agar diffusion assay, being used for evaluating antibacterial activity of honey, is not the most appropriate and sensitive assay as it only detects non-peroxide activity when present at a higher level. Therefore, there is a need to develop more sensitive techniques that may be capable of detecting and evaluating different important components in honey as well as their synergistic interaction.

CONCLUSIONS

Keeping in view the current guidelines for treatment of diarrhea, honey is considered one of the potential candidates for treatment of diarrhea because it contains a natural combination of probiotics, prebiotics, and zinc. Therefore, it would be worthwhile if such a combination is tested in RCTs for treatment of diarrhea.

Stingless Bee Honey, the Natural Wound Healer: A Review

<b><i>Background:</i></b> The stingless bee is a natural type of bee that exists in almost every continent. The honey produced by this bee has been widely used across time and space. The distinctive feature of this honey is that it is stored naturally in the pot (cerumen), thus contributing to its beneficial properties, especially in the wound healing process. <b><i>Methods:</i></b> In this article, several studies on stingless bee honey that pointed out the numerous therapeutic profiles of this honey in terms of its antioxidant, antimicrobial, anti-inflammatory, as well as moisturizing properties are reviewed. All of these therapeutic properties are related to wound healing properties. <b><i>Results:</i></b> Antioxidant in stingless bee honey could break the chain of free radicals that cause a detrimental effect to the wounded area. Furthermore, the antimicrobial properties of stingless bee honey could overcome the bacterial contamination and thus improve the healing rate. Moreover, the anti-inflammatory attribute in this honey could protect the tissue from highly toxic inflammatory mediators. The moisturizing properties of the honey could improve wound healing by promoting angiogenesis and oxygen circulation. <b><i>Conclusion:</i></b> The application of honey to the wound has been widely used since ancient times. As a result, it is essential to understand the pharmacological mechanism of the honey towards the physiology of the wounded skin in order to optimize the healing rate in the future.

Antibacterial activity and chemical characteristics of several Western Australian honeys compared to manuka honey and pasture honey

The physicochemical parameters and antibacterial activity of 10 Western Australian (WA) and two comparator honeys were determined. Honeys showed a pH range of 4.0-4.7, colour range of 41.3-470.7 mAU, methylglyoxal levels ranging from 82.2 to 325.9 mg kg^-1 and hydrogen peroxide levels after 2 h of 22.7-295.5 µM. Antibacterial activity was assessed by the disc diffusion assay, phenol equivalence assay, determination of minimum inhibitory and bactericidal concentrations and a time-kill assay. Activity was shown for all honeys by one or more method, however, activity varied according to which assay was used. Minimum inhibitory concentrations for WA honeys against 10 organisms ranged from 4.0 to >32.0% (w/v). Removal of hydrogen peroxide activity by catalase resulted in decreased activity for several honeys. Overall, the data showed that honeys in addition to those derived from Leptospermum spp. have antimicrobial activity and should not be overlooked as potential sources of clinically useful honey.

Propolis from the Stingless Bee Trigona incisa from East Kalimantan, Indonesia, Induces In Vitro Cytotoxicity and Apoptosis in Cancer Cell lines

BACKGROUND

Previously, stingless bee (Trigona spp.) products from East Kalimantan, Indonesia, were successfully screened for in vitro antiproliferative activity against human cancer derived cell lines. It was established that propolis from T. incisa presented the highest in vitro cytotoxicity against the SW620 colon cancer cell line (6% cell survival in 20 μg/mL).

MATERIALS AND METHODS

Propolis from T. incisa was extracted with methanol and further partitioned with n-hexane, ethyl acetate and methanol. The in vitro cytotoxicity of the extracts was assessed by the MTT assay against human colon (SW620), liver (Hep-G2), gastric (KATO-III), lung (Chago) and breast (BT474) cancer derived cell lines. The active fractions were further enriched by silica gel quick column, absorption and size exclusion chromatography. The purity of each fraction was checked by thin layer chromatography. Cytotoxicity in BT-474 cells induced by cardanol compared to doxorubicin were evaluated by MTT assay, induction of cell cycle arrest and cell death by flow cytometric analysis of propidium iodide and annexin-V stained cells.

RESULTS

A cardol isomer was found to be the major compound in one active fraction (F45) of T. incisa propolis, with a cytotoxicity against the SW620 (IC50 of 4.51±0.76 μg/mL), KATO-III (IC50 of 6.06±0.39 μg/mL), Hep-G2 (IC50 of 0.71±0.22 μg/mL), Chago I (IC50 of 0.81±0.18 μg/mL) and BT474 (IC50 of 4.28±0.14 μg/mL) cell lines. Early apoptosis (programmed cell death) of SW620 cells was induced by the cardol containing F45 fraction at the IC50 and IC80 concentrations, respectively, within 2-6 h of incubation. In addition, the F45 fraction induced cell cycle arrest at the G1 subphase.

CONCLUSIONS

Indonesian stingless bee (T. incisa) propolis had moderately potent in vitro anticancer activity on human cancer derived cell lines. Cardol or 5-pentadecyl resorcinol was identified as a major active compound and induced apoptosis in SW620 cells in an early period (≤6 h) and cell cycle arrest at the G1 subphase. Thus, cardol is a potential candidate for cancer chemotherapy.

Antibacterial synergic effect of honey from two stingless bees: Scaptotrigona bipunctata Lepeletier, 1836, and S. postica Latreille, 1807

Several studies have tested antimicrobial activity of combinations of honey and various substances. In this study, we tested a combination of two stingless bee honeys against various bacterial strains. In particular: the antibacterial activity of honeys produced by Scaptotrigona bipunctata (SB) and Scaptotrigona postica (SP) was evaluated against Gram-positive and Gram-negative bacterial strains by agar well diffusion assays, minimum inhibitory concentration (MIC) assessment, construction of growth and viability curves and scanning electron microscopy (SEM). The interaction of the two honeys was also evaluated by the checkerboard assay. Inhibition zones ranged from 8 to 22 mm. The MIC values of the individual honeys ranged from 0.62 to 10% (v v(-1)) and decreased to 1/4 to 1/32 when the honeys were combined. SEM images showed division inhibition and cell wall disruption for the SB and SP honeys, respectively, and these alterations were observed in same field when the SB and SP honeys were combined. This study demonstrated that the natural honeys possess in vitro antimicrobial activity against Gram-positive and Gram-negative bacteria, including multidrug-resistant strains. Combination of the SB and SP honeys could lead to the development of new broad-spectrum antimicrobials that have the potential to prevent the emergence of resistant bacterial strains.

Determination of interglycosidic linkages in O-glycosyl flavones by high-performance liquid chromatography/photodiode-array detection coupled to electrospray ionization ion trap mass spectrometry. Its application to Tetragonula carbonaria honey from Australia

RATIONALE

Tetragonula carbonaria pot-honeys are highly valued as a food source and for their biological activities in Australia, and there is a growing interest to know its composition. Phenolic metabolites, which could be related to their beneficial properties, have not been studied in depth yet.

METHODS

Mass spectrometry (MS) coupled to liquid chromatography (LC) is an advanced technique for the study of complex flavonoids present in difficult food matrices that hampers their isolation and purification. This allows the tentative characterization of diglycosides/triglycosides establishing the position of the O-glycosylation on the sugar moiety by the study of the MS data in T. carbonaria pot-honeys from Australia.

RESULTS

Their spectra obtained by high-performance liquid chromatography/photodiode-array detection/electrospray ionization ion trap mass spectrometry (HPLC/DAD/ESI-MS(n) ) revealed for the first time 19 quercetin, kaempferol and isorhamnetin O-glycosides. These compounds were clustered in flavonoid triglycosides, diglycosides and monoglycosides. The first cluster contained one flavonoid trihexoside, two -3-O-(2-hexosyl, 6-rhamnosyl)hexosides and their isomers and two -3-O-(2,6-di-rhamnosyl)hexosides. In the second cluster, eleven flavonoid diglycosides such as three -3-O-(2-hexosyl)hexosides, four -3-O-(2-rhamnosyl)hexosides and one -3-O-(6-rhamnosyl)hexoside as well as two -3-O-(2-pentosyl)hexosides and one tentative -3-O-(3-pentosyl)hexoside were detected. In the monoglycoside group, only one flavonoid -3-O-hexoside was identified.

CONCLUSIONS

The occurrence of this large number of flavonoid glycosides could be due to the low glucosidase activity previously reported in stingless bee honey.

In vitro antibacterial phenolic extracts from "sugarbag" pot-honeys of Australian stingless bees (Tetragonula carbonaria)

Australian stingless bee honeys have been shown to exert antioxidant and in vitro antimicrobial properties; however their bioactive factors remained unidentified. This study investigated the antibacterial properties of phenolic extracts from Tetragonula carbonaria honeys. Honeys were harvested from beehives in three sites of South East Australia. Liquid-liquid extractions yielded the phenolic concentrates, for analyses by liquid and gas chromatography mass spectrometry. Antibacterial assays were conducted against Staphylococcus aureus and Klebsiella pneumoniae by in vitro agar diffusion and broth dilution assays. The phenolic extracts averaged to 5.87 mg/100 g of raw honeys, and constituents were 3-phenyllactic acid, lumichrome, diglycosylflavonoids, norisoprenoids. The honeys did not contain methylglyoxal, dihydroxyacetone or phenolics characteristic of Leptospermum nectars. Hydrogen peroxide content amounted up to 155.8 μM in honeys. Beside the bactericidal effects of hydrogen peroxide at 760 μM, other antibacterial factors were the phenolic extracts of "sugarbag" honeys that were active at minimum bactericidal concentrations of 1.2-1.8 mg/mL.

Methylglyoxal is associated with bacteriostatic activity of high fructose agave syrups

Three α-ketoaldehydes, potentially present in high fructose agave syrups (HFASs) as intermediates of the Maillard reaction, were determined. A previously reported HPLC-FLD procedure based on pre-column derivatisation with 4-methoxy-o-phenylenediamine was adopted, yielding the method quantification limits 0.11 mg/kg, 0.10mg/kg, 0.09 mg/kg for glyoxal, methylglyoxal (MGo) and diacetyl, respectively. The obtained results revealed high concentrations of methylglyoxal in HFASs (average 102 ± 91 mg/kg, range 15.6-315 mg/kg) as compared to commercial Mexican bee honeys or corn syrups. Hydrogen peroxide was generated in all HFASs upon dilution, yet to less extent than in bee honeys. HFASs presented bacteriostatic activity against Bacillus subtilis and Escherichia coli; catalase addition had minimum effect on the assay results in syrups with elevated MGo. Principal component analysis revealed direct association between growth inhibition and MGo. It is concluded that elevated concentration of MGo in HFASs is at least in part responsible for their non-peroxide bacteriostatic activity.

Anti-staphylococcal activity of C-methyl flavanones from propolis of Australian stingless bees (Tetragonula carbonaria) and fruit resins of Corymbia torelliana (Myrtaceae)

Propolis of Australian stingless bees (Tetragonula carbonaria, Meliponini) originating from Corymbia torelliana (Myrtaceae) fruit resins was tested for its antimicrobial activities as well as its flavonoid contents. This study aimed at the isolation, structural elucidation and antibacterial testing of flavanones of C. torelliana fruit resins that are incorporated into stingless bee propolis. Flavanones of this study were elucidated by spectroscopic and spectrometric methods including UV, 1D and 2D NMR, EI-MS, ESI-MS and HR-MS. The results indicated known C-methylated flavanones namely, 1 (2S)-cryptostrobin, its regioisomer 2 (2S)- stroboponin, 3 (2S)- cryptostrobin 7-methyl ether, and 6 (2S)- desmethoxymatteucinol, and known flavanones 4 (2S)- pinostrobin and 5 (2S)- pinocembrin as markers for C. torelliana fruit resins and one propolis type. Ethanolic preparations of propolis were shown to be active against Staphylococcus aureus (ATCC 25923) and to a lesser extent against Pseudomonas aeruginosa (ATCC 27853). C. torelliana flavanones inhibited the growth of S. aureus therefore contributing to the antibacterial effects observed for Australian stingless bee propolis extracts.

Topical anti-inflammatory activity of a monofloral honey of Mimosa scabrella provided by Melipona marginata during winter in southern Brazil

Melipona marginata is an endangered species of stingless bee from Brazil that produces honey with particular physicochemical features and a remarkable exotic flavor. To the best of our knowledge, this is the first report devoted to exploring the medicinal potential of this honey. Thus, the aim of this paper was to investigate the potential anti-inflammatory activity of honey extract from M. marginata on skin inflammation. The honey sample was classified as a monofloral honey of Mimosa scabrella. The presence of 11 phenolic compounds as kaempferol and caffeic acid was detected using the high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-UV-ESI-MS) method. The anti-inflammatory activity was measured using a 12-O-tetradecanoylphorbol-13-acetate-induced ear edema model of inflammation in mice. The topical application of the M. marginata honey extract (1.0 mg/ear) was able to reduce ear edema with an inhibitory effect of 54 ± 5%. This extract decreased the myeloperoxidase activity in 75 ± 3%, which suggests a lower leucocyte infiltration that was confirmed by histological analysis. This extract also provided a reduction of 55 ± 14% in the production of reactive oxygen species. This anti-inflammatory activity could be due to a synergic effect of the phenolic compounds identified in the honey sample. Taken together, these results open up new possibilities for the use of M. marginata honey extract in skin disorders.