Honeys Research Articles

Improving DNA isolation from honey for the botanical origin identification

Honey is a natural product highly consumed due its known association with health benefits. Monofloral honeys are perceived as better quality products, being the most appreciated by consumers, thus attaining higher market values. Therefore efficient tools are needed as alternatives to the classical microscopic analysis presently used for the botanical origin identification of honey. In the present work, the use of DNA-based methods for the botanical species identification of honey is proposed. For this purpose, five DNA extraction methods (the kits NucleoSpin Plant (methods A and B) and DNeasy Plant Mini Kit, and the in-house CTAB-based and Wizard methods) combined with three different sample pre-treatments were applied to four honey samples (3 monofloral honeys of Calluna vulgaris, Lavandula spp. and Eucalyptus spp. and one multifloral honey). The 15 DNA extraction protocols were compared in terms of DNA integrity, yield and purity, as well as capacity of amplification targeting universal and adh1 specific genes of C. vulgaris. The results demonstrated the superior efficacy of the Wizard method in terms of DNA quality and amplification capacity, when combined with the sample preparation treatment with a mechanical disruption step of pollen to improve DNA yield. Although with considerable lower DNA yields, the CTAB and DNeasy methods were also successful because both were able to clearly amplify heather DNA from the monofloral heather honey.

Does gamma irradiation affect physicochemical properties of honey?

Honey is a supersaturated solution of sugars, enriched with proteins, minerals, vitamins, organic acids and polyphenols. Gamma irradiation is a physical technique of food preservation which protects the honey from insects' and microbial contamination during storage. We investigated the effect of gamma irradiation on physicochemical properties in two types of Malaysian honey, Gelam and Nenas. Both honeys were irradiated at the dose 25 kGy in a cobalt-60 irradiator. The physicochemical properties pH, moisture, acidity, color, and sugar content as well as vitamins C and E, hydroxymethylfurfural (HMF) and mineral contents, for the irradiated and non-irradiated honeys were assessed. The results revealed that pH, acidity, minerals and sugar contents in both types of honey were not affected significantly by gamma irradiation, while moisture, vitamin E contents and HMF level decreased significantly with gamma irradiation. However, significant increased in color intensity and vitamin C were observed after gamma irradiation for both types of honey. In summary, gamma irradiation treatment of honey (in the dose mentioned above) did not cause significant changes in the physicochemical and mineral contents, except for significant alterations in color intensity, moisture, vitamins (C and E), and HMF contents.

Characterization of Estonian honeys by botanical origin

This study characterizes Estonian honeys based on their physico-chemical properties and chemical composition. Melissopalynological analysis was carried out to determine the botanical origin of each honey. According to pollen analysis, 39% of the honeys analysed appeared to be unifloral rape (Brassica napus), raspberry (Rubus idaeus), or heather (Calluna vulgaris) honeys. Fluorescence spectroscopy was used to estimate both the physico-chemical parameters and floral content of each honey sample by comparing these estimates with experimental data measured using standard techniques. The r 2 correlation between estimated values and experimental data was above 0.7 for several parameters, including free acidity with an r 2 of 0.919.

The Antioxidant Activity of Acacia and Lime Romanian Honeys

Normal 0 MicrosoftInternetExplorer4 Two types of h oney, acacia and lime honey, collected in the south-eastern region of Romania , were investigated for their total phenolic content, total flavonoid content, free radicals scavenging activity and reducing power activity. Acacia honey sample presented the highest amount of total phenolic compounds when compared to lime honey, which possessed good radicals scavenging activity and the highest amount of total flavonoids. The results suggest a relationship between honey total polyphenols and free radicals scavenging activity determinated by chemiluminescent assay. Moreover, the concentration of honey phenolics and flavonoids seemed to correlate with honey reducing power activity.

Contribution of botanical origin and sugar composition of honeys on the crystallization phenomenon

The present work provides information regarding the statistical relationships among the palynological characteristics, sugars (fructose, glucose, sucrose, melezitose and maltose), moisture content and sugar ratios (F+G, F/G and G/W) of 136 different honey types (including bramble, chestnut, eucalyptus, heather, acacia, lime, rape, sunflower and honeydew). Results of the statistical analyses (multiple comparison Bonferroni test, Spearman rank correlations and principal components) revealed the valuable significance of the botanical origin on the sugar ratios (F+G, F/G and G/W). Brassica napus and Helianthus annuus pollen were the variables situated near F+G and G/W ratio, while Castanea sativa, Rubus and Eucalyptus pollen were located further away, as shown in the principal component analysis. The F/G ratio of sunflower, rape and lime honeys were lower than those found for the chestnut, eucalyptus, heather, acacia and honeydew honeys (>1.4). A lower value F/G ratio and lower water content were related with a faster crystallization in the honey.

Physicochemical characteristics of minor monofloral honeys from Tenerife, Spain

Physicochemical parameters (moisture, water activity, electrical conductivity, colour, hydroxymethyl furfural, acidity, pH, proline, diastase and invertase) and sugar composition (fructose, glucose, sucrose, maltose, isomaltose, trehalose, turanose and melezitose) were determined in 85 honeys belonging to nine minor monofloral honeys such as avocado (Persea americana), barrilla (Messembryanthemum crystallinum), heather (Erica arborea), agave o pitera (Agave americana), poleo (Bystropogon origanifolius), relinchón (Hirstfeldia incana), tedera (Aspalthium bituminosum), malpica (Carlina xeranthemoides) and oregano (Origanum virens) from Tenerife in order to typify them for the first time. Most of the studied honeys are characterized because their specific pollens are under-represented. All the honey samples showed values of all the parameters determined within the legally established intervals. All the physicochemical and sugar composition parameters, with the exception of diastase, presented significant differences in the mean values between the honeys analyzed. Applying univariate statistical analysis, the following parameters (moisture, acidity, electrical conductivity, fructose, sucrose and melezitose) allow to distinguish all the types of honeys studied without overlap. Heather and avocado honeys showed the most differential physicochemical characteristics with respect to the rest of monofloral honeys.

The Antimicrobial Activity of Honey Against Common Equine Wound Isolates

AimsThe aim of this study was to determine if shop‐bought honey was free from contamination and suitable for use on equine wounds, and to investigate the effect of a number of different types of uncontaminated honey on the growth of equine pathogens.MethodsTwenty‐eight honeys were collected from sources ranging from supermarkets to bee keepers, and were cultured on sheep blood and MacConkey agar. Ten bacteria were collected from equine wounds, these included: methicillin‐resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Escherichia coli, Streptococcus equi, S. equi subsp. zooepidemicus, Enterococcus faecalis, Acinetobacter baumannii, methicillin‐resistant Staphylococcus epidermis (MRSE), Staphylococcus sciuri, and Pseudomonas aeruginosa. Uncontaminated honey was incorporated into agar at a variety of concentrations and the plates were inoculated with the 10 bacterial isolates.ResultsOf the 28 honeys tested, 18 were contaminated with bacteria and/or fungi including Bacillus sp. and Proteus sp. Of the uncontaminated honeys, 8/11 were effective against all 10 isolates at concentrations from 4 to 16%. Overall, Manuka 20+ and heather honey performed best.ConclusionsThese findings suggest that many honeys have antimicrobial properties, and may be effective in the treatment of wound infections. The concentrations at which honey samples inhibited microbial growth, were typically less than 16%, much lower than is likely to occur at the surface of an infected wound treated with honey.Practical significanceThe use of shop‐bought honey on wounds should be avoided, as contamination with potentially pathogenic microbes appears to be common. Honey sourced within the UK is as, and in some cases more, effective than medical grade honey sourced in New Zealand. In many regions of the world access to expensive antimicrobial drugs are limited; therefore, honey may provide a local, inexpensive alternative.Ethical animal researchStudy approved by University of Glasgow Ethics and Welfare Committee. Sources of funding: Study funded by Glasgow Vet School and Kruuse UK Ltd. Competing interests: None.

Characterisation of honeys according to their content of phenolic compounds using high performance liquid chromatography/tandem mass spectrometry

A simple, fast and specific high performance liquid chromatography separation with an electro-spray ionisation tandem mass spectrometry detection in a negative single reaction ion monitoring scan mode was developed and used for the characterization of Polish honeys according to the content of phenolic acids, including caffeic, chlorogenic, p-coumaric, ferulic, homogentisic, p-hydroxybenzoic and vanillic acids, and flavonoids, i.e., apigenin, genistein, hesperetin, kaempferol, luteolin, rhamnetin, rutin, tricetin and quercetin. Target compounds were isolated and pre-concentrated from the honey matrix by means of the solid phase extraction using Strata X (500mg) cartridges. Analysed honeys did not contain tricetin and genistein. Hesperetin was determined for the first time in heather and linden honeys while rutin in rape honey.

Suitability of three-dimensional synchronous fluorescence spectroscopy for fingerprint analysis of honey samples with reference to their phenolic profiles

The suitability of a right-angle geometry three-dimensional synchronous fluorescence spectroscopy (3D-SFS) for the differentiation and classification of different honey types, including acacia, buckwheat, heather, linden, multiflower and rape honeys, was evaluated with reference to their phenolic profiles. The fraction of phenolic compounds was initially isolated and pre-concentrated from analyzed samples by means of polymeric reversed phase Strata X solid phase extraction (SPE) cartridges. A thoughtful analysis of 3D-SF spectra of resulting methanolic extracts of honey samples containing the separated fraction of phenolics and standards of phenolic acids and flavonoids revealed that the proposed methodology based on SPE and 3D-SFS is capable of discriminating honey samples due to different floral sources in a fast and straightforward way.

The antimicrobial activity of honey against common equine wound bacterial isolates

Delayed healing associated with distal limb wounds is a particular problem in equine clinical practice. Recent studies in human beings and other species have demonstrated the beneficial wound healing properties of honey, and medical grade honey dressings are available commercially in equine practice. Equine clinicians are reported to source other non-medical grade honeys for the same purpose. This study aimed to assess the antimicrobial activity of a number of honey types against common equine wound bacterial pathogens. Twenty-nine honey products were sourced, including gamma-irradiated and non-irradiated commercial medical grade honeys, supermarket honeys, and honeys from local beekeepers. To exclude contaminated honeys from the project, all honeys were cultured aerobically for evidence of bacterial contamination. Aerobic bacteria or fungi were recovered from 18 products. The antimicrobial activity of the remaining 11 products was assessed against 10 wound bacteria, recovered from the wounds of horses, including methicillin resistant Staphylococcus aureus and Pseudomonas aeruginosa. Eight products were effective against all 10 bacterial isolates at concentrations varying from <2% to 16% (v/v). Overall, the Scottish Heather Honey was the best performing product, and inhibited the growth of all 10 bacterial isolates at concentrations ranging from <2% to 6% (v/v).Although Manuka has been the most studied honey to date, other sources may have valuable antimicrobial properties. Since some honeys were found to be contaminated with aerobic bacteria or fungi, non-sterile honeys may not be suitable for wound treatment. Further assessment of gamma-irradiated honeys from the best performing honeys would be useful.

Physicochemical Characterization and Antioxidant Activity of Commercial Portuguese Honeys

The present study evaluated the physicochemical characteristics and antioxidant activity of 13 commercial honeys from diverse floral origin, produced in Portugal. The values of electrical conductivity of cardoon and pennyroyal honeys were superior to the maximum limits defined by European legislation. Citrus, strawberry tree, and 1 sample of lavender honeys had values of diastase activity below those determined by European legislation. Strawberry tree, pennyroyal, and cardoon honeys had the highest amounts of potassium that coincided with the highest electrical conductivity. Strawberry tree honey was the most effective as antioxidant along with cardoon and heather honeys. This ability was strongly correlated with the amounts of phenols and flavonoids and not with the levels of vitamin C or proline.

Nutraceutical properties of Romanian heather honey

Purpose – The main purpose of this study is to create a complete physico‐chemical characterisation of Romanian heather honey.Design/methodology/approach – A total of 30 samples of heather honey were harvested from three different geographical areas (Fântânele, Calaţele, Marisel) from Transylvania region (Romania). This study contains a complete characterization of heather honey regarding its physico‐chemical composition, total phenols content, flavonoids content, antioxidant activity (expressed as radical scavenging activity – RSA) and micro‐ and macroelements content.Findings – The results obtained for the total phenols content and total flavonoids demonstrate that honey samples have good bioactive properties and the antioxidant activities are similar to those of dark honeys. Heather honeys normally have a high content of minerals, having their origin in soil. All quantified minerals in heather honey presented values higher that those reported for other types of honey.Practical implications – Heather hon...

Spanish honeys protect against food mutagen-induced DNA damage

Honey contains a variety of polyphenols and represents a good source of antioxidants, while the human diet often contains compounds that can cause DNA damage. The present study investigated the protective effect of three commercial honey samples of different floral origin (rosemary, heather and heterofloral) from Madrid Autonomic Community (Spain) as well as an artificial honey on DNA damage induced by dietary mutagens, using a human hepatoma cell line (HepG2) as in vitro model system and evaluation by the alkaline single-cell gel electrophoresis or comet assay. Rosemary, heather and heterofloral honeys protected against DNA strand breaks induced by N-nitrosopyrrolidine (NPYR), benzo(a)pyrene (BaP) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), but none of the honey samples tested prevented DNA strand breaks induced by N-nitrosodimethylamine (NDMA). Heterofloral and heather (unifloral) honeys with higher phenolic content were most effective in protecting HepG2 cells against DNA damage induced by food mutagens. Heterofloral honey was more protective against NPYR and BaP, while heather honey was more protective against PhIP. Artificial honey did not show a protective effect against DNA damage induced by any of the food mutagens tested, indicating that the protective effects of honeys could not be due to their sugar components. The results suggest that the protective effect of three kinds of Spanish honey of different floral origin could be attributed in part to the phenolics present in the samples. Honeys with higher phenolic content, i.e. heather and heterofloral honeys, were most effective in protecting against food mutagen-induced DNA damage in HepG2 cells. In addition, a possible synergistic effect between other minor honey components could also be involved.

Effect of Erica sp. Honey against Microorganisms of Clinical Importance: Study of the Factors Underlying this Biological Activity

This study aimed to determine the factors (phenolic compounds, flavonoids, sugars or H2O2) that contribute the most to the antimicrobial activity of heather honey samples against four yeasts and four bacteria with medical importance. To discard the effect of H2O2 in the antimicrobial activity, catalase was added. To evaluate the osmotic pressure’s effect, artificial honey was also used. Phenolic compounds and flavonoids were determined and Pearson’s correlation analysis was performed to assess whether these correlated with antimicrobial activity. The amount of phenolic compounds ranged from 630.89 ± 5.21 GAE kg−1 to 718.92 ± 4.41 GAE kg−1, while the flavonoids varied between 450.72 ± 5.67 CAE kg−1 and 673.98 ± 4.33 CAE kg−1. For the bacteria, the minimum inhibitory concentration (MIC) of the honey without catalase ranged from 1.01 ± 0.50% to 10.00 ± 4.72% and was between 2.00 ± 0.94% and 13.27 ± 5.23% for honey with catalase. Concerning the yeasts, the MICs was between 13.16 ± 4.08% and 20.00 ± 5.09% for honey without catalase and between 14.95 ± 4.16% and 25.67 ± 5.50% for honey with catalase. The elucidation of the antimicrobial factors and action mechanisms is essential for the correct use of honey in therapeutic applications.

Classification of Honeys from Pará State (Amazon Region, Brazil) Produced by Three Different Species of Bees using Chemometric Methods

Vinte e sete amostras de mel, produzidas em dez cidades do Estado do Para (Regiao Amazonica, norte do Brasil) por tres especies diferentes de abelhas (Apis mellifera, Melipona fasciculata e Melipona flavoneata), foram analisadas em seus teores de elementos minerais (Al, As, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Sr e Zn) e alguns parâmetros fisicoquimicos (cor, umidade, densidade, pH, solidos insoluveis e soluveis totais, cinzas, condutividade eletrica, indice de formol, acidez livre, hidroximetilfurfural, acucares redutores e totais e sacarose). Os teores minerais foram determinados via espectrometria de emissao atomica por plasma acoplado indutivamente (ICP OES) e as analises dos parâmetros fisico-quimicos seguiram metodologias oficiais. Os resultados das analises fisico-quimicas apresentaram-se de acordo com a legislacao nacional e internacional, bem como com outros trabalhos similares ao redor do mundo. A analise estatistica multivariada (analise por agrupamento hierarquico (HCA) e por componentes principais (PCA)) foi aplicada aos resultados dos teores metalicos e aos parâmetros fisico-quimicos, sendo possivel a separacao das amostras de mel conforme a especie produtora.

Antiproliferative and apoptotic effects of spanish honeys

Background:Current evidence supports that consumption of polyphenols has beneficial effects against numerous diseases mostly associated with their antioxidant activity. Honey is a good source of antioxidants since it contains a great variety of phenolic compounds.Objective:The main objective of this work was to investigate the antiproliferative and apoptotic effects of three crude commercial honeys of different floral origin (heather, rosemary and polyfloral honey) from Madrid Autonomic Community (Spain) as well as of an artificial honey in human peripheral blood promyelocytic leukemia cells (HL-60).Material and Methods:HL-60 cells were cultured in the presence of honeys at various concentrations for up to 72 hours and the percentage of cell viability was evaluated by MTT assay. Apoptotic cells were identified by chromatin condensation and flow cytometry analysis. ROS production was determined using 2´,7´-dichlorodihydrofluorescein diacetate (H2DCFDA).Results:The three types of crude commercial honey induced apoptosis in a concentration and time dependent-manner. In addition, honeys with the higher phenolic content, heather and polyfloral, were the most effective to induce apoptosis in HL-60 cells. However, honeys did not generate reactive oxygen species (ROS) and N-acetyl-L-cysteine (NAC) could not block honeys-induced apoptosis in HL-60 cells.Conclusion:These data support that honeys induced apoptosis in HL-60 cells through a ROS-independent cell death pathway. Moreover, our findings indicate that the antiproliferative and apoptotic effects of honey varied according to the floral origin and the phenolic content.

Antimicrobial activity of different Finnish monofloral honeys against human pathogenic bacteria

The antimicrobial activity and phenolic compounds of five Finnish honey products against important human pathogens Streptococcus pneumoniae, S. pyogenes, Staphylococcus aureus, and methicillin-resistant S. aureus were analyzed. Microbroth dilution method and HPLC-DAD were used in antimicrobial testing and phenolic compound determination, respectively. Significant antimicrobial activity (p < 0.01) against all the tested pathogens was found from willow herb (Epilobium angustifolium), heather (Calluna vulgaris), and buckwheat (Fagopyrum esculentum) honeys. This is the first report on antimicrobial activity of Finnish monofloral honeys against streptococcal and staphylococcal bacteria. To our knowledge this is also the first report on the antimicrobial effect of honey against S. pneumoniae.

Nutritional value and antioxidant activity of honeys produced in a European Atlantic area

One hundred eighty-seven honey samples from an Atlantic European area were studied to determine their nutritional compositions and antioxidant capacities, as well as the relationships between them. The results showed that heather, polyfloral, blackberry, and eucalyptus honeys had the highest carbohydrate contents, whereas honeydew and chestnut honeys had the lowest. There were some important differences among the honey types, which were related to the presence of minor components. The protein contents were significantly higher in honeydew and chestnut honeys, and the same results were obtained for mineral contents. Related to the presence of several antioxidant compounds, heather honey had the highest phenolic content, whereas honeydew and chestnut honeys had the highest flavonoid contents. Multivariate analysis showed that some variables, such as the amounts of flavonoids, minerals, proteins, and phenols, were significantly correlated with antioxidant activity. The regression analysis produced a significant model (R2=0.716; F=154.680; P<0.001) that related the antioxidant activity and the flavonoids, K, and P contents.

Botanical Origin Causes Changes in Nutritional Profile and Antioxidant Activity of Fermented Products Obtained from Honey

Honey as rich source of enzymatic and nonenzymatic antioxidants serves as health-promoting nutrient in the human body. Here, we present the first time a comparative study of nutritional profiles (e.g., acidities, sugar, organic acid profile, total polyphenolic, flavonoid content) for different unifloral, multifloral honeys and their fermented products, in correlation with their antioxidant activity. Additionally, an optimized method for HPLC separation of organic acids from honey was established. The total phenolic content of honey samples varied widely among the honey types compared to fermented products. High amounts of total flavonoids were quantified in heather honey, followed by raspberry, multifloral, black locust, and linden honey. A positive correlation between the content of polyphenols, flavonoids, and antioxidant activity was observed in honey samples. After fermentation, the flavonoid content of dark honey fermented products decreased significantly. Black locust and linden honeys are more suitable for fermentation because the decrease in antioxidant substances is less pronounced.

Changes in the volatile fractions and sensory properties of heather honey during storage under different temperatures

A comparative study of the temperature effect on the physicochemical parameters, volatile composition and sensory quality of heather honey stored during 1 year was performed. The temperatures evaluated were refrigerated (10 °C), room (20 °C) and high temperatures (40 °C). The cooling storage of heather honey presented advantages such as the retention of compounds like lilac aldehyde and lower looses of terpene derivatives, β-damascenone, benzaldehyde and phenylacetaldehyde, compared with other storage temperatures. Heather honey stored under room temperature showed significant increases in levels of 2-furanmethanol, furaneol, 2-methyl furancarboxylate, maltol and 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one (DDMP). These compounds, whose concentrations were extremely high in honeys submitted at 40 °C, are suggested as useful indices of unsuitable storage temperature. Moreover, the occurrence of methyl cyclotene and ethyl cyclotene are proposed as new markers indicatives of over-heating treatment of honey. Sensory analysis showed that off-flavours such as medicine and toasted, detected in honeys submitted at 40 °C, began to be perceived in the samples stored at room temperature, while heather honeys refrigerated (10 °C) kept the organoleptic profile and quality similar to fresh heather honey.