Natural Honeys Research Articles

Vitamin C Enhances the Antibacterial Activity of Honey against Planktonic and Biofilm-Embedded Bacteria.

Multifactorial antibacterial action is an important feature of honey; however, its bactericidal efficacy against biofilm-embedded bacteria is limited. The aim of this study was to investigate the impact of vitamin C (Vit C) on the antibacterial activity of natural honeys against planktonic as well as biofilm-embedded bacterial pathogens. The antibacterial activity of four honey samples supplemented with Vit C was expressed as the minimum inhibitory concentration (MIC). At sub-MICs, Vit C significantly increased the antibacterial activity of the tested honeys against Pseudomonas aeruginosa in planktonic cultures. However, after supplementation, honeydew honey, the most active honey, was ineffective against Staphylococcus aureus. On the other hand, when 100% honeydew honey was supplemented with Vit C (100 mg/g of honey) in a multispecies wound biofilm model, complete eradication of almost all bacterial isolates, including S. aureus, was observed. Furthermore, a mixture of honey and Vit C was partially effective against Enterococcus faecalis, whereas honey alone exhibited no antibacterial activity against this bacterium. Vit C counteracted hydrogen peroxide in honey solution and, thus, eliminated the major antibacterial compound present in honey. It is likely that a combination of honey with Vit C may trigger the intracellular production of reactive oxygen species in bacterial cells, but the exact cellular mechanisms warrant further investigations.

Spatial distribution of environmental pollutants in natural honeys collected from some regions of Saudi Arabia

Natural honeys produced in some regions located in Saudi Arabia (KSA) were characterized on the basis of their physicochemical properties and the contents of heavy metals and pesticide residues. Some of the investigated samples fit most of the national and international specifications with geographical and seasonal variations. The levels of Pb2+, Cd2+, and Cu2+ in most of the tested samples were below the guideline values of 0.1, 0.05, and 5 mg/kg, respectively; however, Zn2+ and Fe3+ levels in most of the tested samples exceeded the guideline values of 5 and 15 mg/kg, respectively. The high levels of Mn2+ and Ni2+ have been found in all the tested samples which can be attributed either to the production stages of honey or the region from where the honey has been taken. Also, the present results revealed that some pesticides such as chlorothalonil, carbaryl, dicofol, and monocrotophos residues were detected in some samples. It can be concluded that some metals and pesticide residues are not in safety baseline levels for human consumption and may pose a health risk to consumers.

Determining Honey Adulteration by Seeding Method: an Initial Study with Sunflower Honey

In the present study, a novel method was developed to determine honey adulteration. Natural sunflower honey (A), adulterated honey (B), indirectly adulterated honey obtained by feeding of bee colonies using sugar syrup (C), mixtures of them (AB and AC), and two additional natural sunflower honey samples coming from different geographical regions (D and E) were examined after seeding at different levels (1, 5, 10%, w/w) of crystallized honey. The physico-chemical property, FT-IR spectra, thermodynamic property (Tp and ΔH), flow behavior [storage (G′) and loss (G″) modulus], and microstructural changes of the samples were investigated. According to the obtained results, natural sunflower honeys showed different visco-elastic and flow behaviors from adulterated honeys. The microstructure properties were also different and more homogeneous, and faster crystallization was detected in natural honey (A). The results of this study notably show that honey adulteration can be determined by examining honey crystallization behaviors. Therefore, it is thought that the industry will benefit from this easy and simple method instead of time-consuming, expensive, and complex methods used for determining honey adulteration.

In vitro antimicrobial activities of Saudi honeys originating from Ziziphus spina-christi L. and Acacia gerrardii Benth. trees.

Honeys originating from Sidr (Ziziphus spina‐christi L.) and Talh (Acacia gerrardii Benth.) trees in Saudi Arabia exhibited substantial antimicrobial activity against pathogenic gram‐positive bacteria (Bacillus cereus, Staphylococcus aureus), gram‐negative bacteria (Escherichia coli, Salmonella enteritidis), and a dermatophytic fungus (Trichophyton mentagrophytes). The diameter of zones of inhibition represents the level of antimicrobial potency of the honey samples. Precisely, Talh honey showed significantly higher antibacterial activity against all tested bacteria than Sidr honey. The antifungal activity of Talh and Sidr honey types was significantly at par against a dermatophytic fungus. The water‐diluted honey types (33% w/v) significantly induced a rise in the antimicrobial activity from that of the natural nondiluted honeys. Microbial strains displayed differential sensitivity; gram‐positive bacteria were more sensitive and presented larger inhibition zones than gram‐negative bacteria and the fungus. The sensitivity was highest in B. cereus and S. aureus, followed by T. mentagrophytes, E. coli, and S. enteritidis. The antimicrobial activity of water‐diluted honeys (Sidr and Talh) was high than that of broad‐spectrum antibacterial antibiotics (tetracycline and chloramphenicol) against bacterial strains, but these honeys were relativity less potent than antifungal antibiotics (flucoral and mycosat) against a fungal strain. Our findings indicate the antimicrobial potential of Saudi honeys to be considered in honey standards, and their therapeutic use as medical‐grade honeys needs further investigations.

Bal: kısa tıbbi bakış ve kronik yara bakımı

Utilities of honey-bee and its products have been always a moot point in medicine. Honey, pollen, royal jelly, propolis, bee venom and beeswax are all in a different chemical composition and efficiency. Even though honey itself has a great potential of both local and systemic medical usage, nowadays, honey dressings and honey itself are involved in routine medical procedures especially for chronic wound care and plastic surgery. In clinical research studies about natural honeys obtained from various climatic and geographic conditions; its acidity, hydrogen peroxide content, osmotic effect, nutritional and antioxidant contents and many other research-phase contents were observed to have antibacterial effect, immunomodulatory effect, increasing effect on wound healing and epitelization and decareasing effect on scar formation,. However, its pharmacological activity, potency and ingredients strongly vary according to climatic and geographic conditions, storage method, bee species and pre-usage processings on honey. In addition, risk of contamination is a major problem. So, it is hard to state that every honey is suitable for medical purposes and medicinal honeys must be pre-processed before its medical usage.

Comparative Assessment on Selected Physicochemical Parameters and Antioxidant and Antimicrobial Activities of Honey Samples from Selected Districts of the Amhara and Tigray Regions, Ethiopia.

The composition and properties of natural honeys differ with plant species on which the bees forage and the climatic conditions of the production areas. In Ethiopia, Amhara and Tigray are neighboring regions consisting of different agricultural activities and blossoms from different types of vegetations which may influence the natural composition and hence the properties of honey. So, the aim of the current study was to assess the quality of honey from selected districts of the two regions. In the study, 18 composited honey samples were collected from six selected districts and analyzed for selected physicochemical parameters and antioxidant and antimicrobial activities. The analyses of physicochemical parameters were carried out following standard procedures of IHC and QSAE. The antioxidant activity was determined by analyzing the RSA using DPPH while the antibacterial activities were determined by the agar well diffusion method. The moisture, ash content, electrical conductivity, pH, free acidity, reducing sugar, and sucrose content of the honey samples were found to be in the range 16.34 ± 0.26 to 19.83 ± 0.43 %, 0.08 ± 0.00 to 0.45 ± 0.03 %, 0.19 ± 0.00 to 0.89 ± 0.03 mS/cm, 3.79 ± 0.04 to 4.20 ± 0.01, 19.56 ± 1.13 to 38.11 ± 1.54 meq/kg, 62.10 ± 0.48 to 66.37 ± 0.20 %, and 1.35 ± 0.08 to 5.96 ± 0.10 %, respectively. The total phenolic content ranged from 1165.60 ± 23.45 to 1854.83 ± 10.47 mg/kg with antioxidant activity of 21.64 ± 0.26 to 36.12 ± 0.52 AEAC/100 g. The total phenolic contents showed strong correlation with RSA. Furthermore, all honey samples showed an antibacterial activity varying from 23.23 ± 0.12 to 28.84 ± 0.24 mm.

Pollen Analysis of Natural Bee Honeys from Different Regions of Sri Lanka

Pollen analysis plays an important role when identifying the botanical and geographical origins of bee honey. The aim of the present study was to identify the major plant sources that contribute to the increase of yield of honey which was obtained from selected regions of Sri Lanka such as Ella, Elpitiya, Welimada, Minipe, Loggaloya, Anuradhapura, Kothmale, Haputhale and Nuwara Eliya. The morphology of pollen was observed with light microscope and total pollen counts were expressed in pollen percentage frequency. Based on the analysis, Welimada, Haputhale, Nuwara Eliya and Loggaloya samples were categorized as unifloral honey and remaining honeys were multifloral. Nuwara Eliya, Elpitiya, and Kothmale bee honey samples were categorized as good quality honey because they had absolute pollen count >1,000,000/10g. There were 82 pollen types belonging to 29 families identified through the study. Among different plant families, Myrtaceae, Fabaceae, Asteraceae, Poaceae, and Malvaceae families highly contributed for nectar and pollen sources of honey bee in the areas examined in this study. Through identifying the major plant sources for honey bees, this study demonstrated the potentiality for expanding and sustainable bee keeping practices in Sri Lanka.

Evaluation of Radical Scavenging Capacity of Polyphenols Found in Natural Malaysian Honeys by Voltammetric Techniques

AbstractAs minor constituents present in natural honey, polyphenols have the capacity as antioxidant by donating electron to halt detrimental actions of free radicals. The present work aims to analyze the electrochemical behaviour of polyphenols identified in Malaysian Apis and Trigona honey samples, determine and compare their reducing strengths as well as qualitatively evaluate the radical scavenging capacity of these phenolics in Malaysian honey samples. Six flavonoids, eight phenolic acids, and tannin pentagalloyl glucose (PGG) dissolved in 0.1 M PBS pH 7 were studied by cyclic voltammetry (CV). Seventeen Malaysian honey samples were analyzed using differential pulse voltammetry (DPV). Cyclic voltammograms revealed that polyphenols with catechol moiety in their structure exhibited Ep1a at low potentials, ranging between +0.173 V and +0.404 V. PGG and quercetin may have equal tendency to donate electron (same Ep1a) but higher peak current was observed for the former indicates its higher reducing strength, suggesting PGG as the strongest antioxidant among studied polyphenols. From DP voltammograms, oxidation of honey phenolics occurred in all honey samples with predominant catechol‐bearing peak P1 observed in nanas N1, kelulut K3 and tualang T1 honeys. The varied peak current intensities observed for P1‐P3 in all analyzed Malaysian honey samples suggested that these honey samples can act against free radicals at varying degree and thus are good sources of natural antioxidants.

Physicochemical Analysis of Several Natural Malaysian Honeys and Adulterated Honey

Physicochemical analysis is one of the methods used to measure the quality and authenticity of honey. Quality and authenticity of honey are crucial to ensure only a high quality of natural honey is offered to consumers and to avoid any health complications in the future. However, relatively few physicochemical data is available on the Malaysian honey. In this study, selected physicochemical analyses were conducted on several local honey. Seven honey samples i.e. Tualang honey, Rubber honey, Acacia honey, Kelulut 1 honey, Kelulut 2 honey, adulterated honey 1 and adulterated honey 2 were used and their physicochemical properties measured. Natural honey samples exhibited varying physicochemical characteristics compared to adulterated honey. The adulterated honey 1 had the highest HMF level (164.55 ± 27.14mg/kg), with a low level of pH (3.2 ± 0.02), free acidity (20.8 ± 0.17) and electrical conductivity (0.003 ± 0.00) compared to the natural honey. These preliminary data could serve as a basis for the identification and characterisation of Malaysian honey based on the physicochemical analysis. Moreover, the data can support enforcement activities by the authorities in preventing adulterated honey production and trading in the future.

Checking syrup adulteration of honey using bioluminescent bacteria and chemometrics

Accomplishing the Italian law to verify honey quality is onerous, because it requires measuring many chemical and physical parameters. On the contrary, bioluminescence-based analytical methods allow for rapid and inexpensive analysis. Bioluminescence has never been applied before to verify honey adulteration. The application of chemometrics to analytical methods based on bioluminescence has been here explored for this scope. Several honey samples were prepared, in which sugar syrup was added without exceeding legal limits: in this case, univariate analysis prescribed by the law cannot reveal the fraud. All samples were subjected to measurements of parameters prescribed by the law and also to bioluminescence analysis, executed using the Vibrio fischeri bacterium, one of the most common bioluminescent bacteria. Principal components analysis, linear discriminant analysis, and partial least square regression were applied to discriminate sugar-added honeys with respect to natural honeys, both by regulated physicochemical parameters and by bioluminescence ones. The feasibility of combining bioluminescence and multivariate analysis for a rapid screening of honey authenticity was demonstrated.

Determination of Quality Criteria that Allow Differentiation Between Honey Adulterated with Sugar and Pure Honey

This study used various parameters of honey to develop a potentially more robust approach to the detection of adulterated honey. For this purpose, 25 multifloral, natural honey samples and 20 samples of adulterated honey produced by bees that had been fed supplementary sucrose syrup were analysed. The mean total phenolic content of the natural honeys was considerably higher than in the adulterated honeys at 157 ± 13 and 35.2 ± 7.3mg GAE/100g, respectively. Similarly, considerable variation was determined between natural and adulterated honeys in terms of total flavonoids (3.3 ± 0.3 and 2.1 ± 0.4mg QE/100g, respectively), antiradical activity (87.9 ± 12 and 163 ± 11mg/mL, respectively) and proline content (202 ± 26 and 71.1 ± 21.6mg/kg, respectively.) The potassium, phosphorus, calcium and magnesium contents of natural honeys were also higher than in adulterated honeys (P < 0.01). In conclusion, the determination of the proline level, phenolic content, antioxidant activity and mineral profile may collectively provide a more holistic method approach to the differentiation of natural and adulterated honey, and also for comparing their food values.

Antimicrobial and antioxidant properties of some commercial honeys available on the Polish market

Six commercial natural honeys available on the Polish market were characterised with respect to their geographical and floral origins, physicochemical parameters and microbial properties. The study focused on a determination of the activity of the main enzymes, antioxidant capacity and identification of antimicrobial effects. Fructose was the predominant sugar in all tested honeys. The largest amount of hydroxymethylfurfural (HMF) was found in eucalyptus honey. It was found that thyme honey was characterised by the highest values of diastase number, invertase activity, antioxidant capacity and total phenolic content. A very week correlation between the antioxidant properties of tested honeys and their antimicrobial action against tested bacteria was observed. M. luteus and P. putida were resistant to most honey samples. All tested honeys showed antibacterial activity against E. coli and P. myxofaciens. B. subtilis was resistant only to eucalyptus honey.

Physicochemical properties of honey from Serbia in the period 2014-2016

Honey is a viscous, aromatic, sweet food that is consumed and enjoyed by people around the world due to its unique nutritional and medicinal properties. The physicochemical parameters of natural honeys, such as moisture, reducing sugars, sucrose, hydroxymethylfurfural (HMF), free acidity, diastase activity, water-insoluble content and electrical conductivity are strictly defined and constitute the quality indicators which characterize individual honey varieties. The present study shows results of honey quality investigation from various regions of Serbia, which were evaluated according to the Serbian Regulation. A total of 372 honey samples (132 acacia honey, 221 blossom honey and 19 honeydew honey) were obtained from the Serbian market. All applied methods were performed according to the Harmonized Methods of the International Honey Commission. Summarizing the results presented, the most important parameters for detecting honey that was non-compliant with the regulation were HMF content along with diastase activity and sugar content. Results show that in 2014 and 2015, a great number of honey samples were of insufficient quality to satisfy regulatory requirements. In 2016, the situation on the Serbian honey market improved and became more under control.

In vitro activity of some natural honeys against Entamoeba histolytica and Giardia lamblia trophozoites.

Considering the potentiality of honey in combating diseases, the present study was carried out aiming to assess the in vitro antiprotozoal activity of several honeys (Ziziphus spina-christi, Acacia nilotica, Acacia seyal, and Cucurbita maxima) against Entamoeba histolytica and Giardia lamblia by employing the sub-culture method. All the tested honeys inhibited the growth of trophozoites, and the level of inhibition varied according to the assayed concentrations and incubation times. Acacia seyal honey had completely stopped motility of E. histolytica trophozoites at a concentration ≤ 50 µg/ml after incubation for 72 h. Ziziphus spina-christi, Acacia seyal, and Acacia nilotica honeys had completely inhibited the growth of Giardia lamblia trophozoites at concentration ≤ 200 µg/ml after 72 h. These inhibitory activities were similar to that of Metronidazole™ which showed IC50 = 0.27. The mammalian cytotoxicity of these honeys against normal Vero cell line which determined by applying MTT method verified the nontoxicity of the examined honeys. Also the proximate composition of the samples indicated compliance with the natural honey standards. The findings of the study indicate the need for in vivo studies and further investigations to identify active principles with antiprotozoal activities from natural honeys.

A palynological study of natural honeys from the Bongaigaon district of Assam, northeast India

ABSTRACTPalynological examination of 18 honey samples (BG-1–18) procured from nine localities in the Bongaigaon District, Assam, India, produced a assemblage of pollen in terms of quantity and diversity. According to palynological assessment of the honey samples, 12 were unifloral (five in terms of Brassica campestris, two from Elaeocarpus rugosus and one each from Mimosa pudica, Xanthium strumarium, Syzygium cumini, Salmalia malabaricum and Meliaceae). Six were multifloral; the dominant taxa include Mimosa, Brassica, Coriandrum, Ziziphus mauritiana and Salmalia. Taxa such as Cassia fistula, Acacia catechu, Toona ciliata, Butea monosperma, Lagerstroemia parviflora, Lamiaceae, Malvaceae and Oleaceae were minor sources of nectar and bee forage, as indicated by low frequencies of their pollen. The numerous pollen types and their diversity show that bees travel considerable distances to collect nectar for honey production. The study could be helpful in evaluating the allergenicity of some honeys in the area of investigation, causing hay fever, asthma, dermatitis and other disorders, where composition is mainly of ‘Compositae allergic’ pollen such as Xanthium (BG-2; 57.78%; unifloral) and Eupatorium (BG-4; 37.64%; unifloral).

천연꿀과 사양꿀의 성분 분석

천연꿀과 사양꿀의 성분 분석

In Vitro Antibacterial Activity of Some Natural and Trade Iraqi Honey against MRSA Staphylococcus Heamolyticus Isolated from Some Burned Patients in Misan City

The study is aimed to evaluate the antibacterial activity of both natural Iraqi honeys (Sidr, Eucalyptus) and trade honey sample against MRSA Staphylococcus heamolyticus isolated from burned patients in alsader hospital-misan city then were analyzed between (October to December in 2015). The samples were taken in order to determine the bacterial profile and antibiotic susceptibility. The isolates of Staphylococcus heamolyticus were tested against 5 different antibiotics by a disk diffusion method 100% of the Staphylococcus heamolyticus isolates were resistant to the Optochin, Lincomycin, Ampicillin, Amphotercin, while the inhibitory effect of Amikacin antibiotic were (24mm) on MRSA Staphylococcus heamolyticus. Total antibacterial activity was evaluated by measuring the clear zone around the well. Honey samples were tested in different concentration (75%, 50 %, 25%, 10% and 100%). However, the results showed the absences of inhibitory zone to both natural and trade honeys type on MRSA Staphylococcus heamolyticus tested bacteria after dilution of(25% Sidr honey sample, 50% Eucalyptus honey sample, 50% Trade honey sample), while Sidr honey sample have more effective in 75%v/v concentration against MRSA Staphylococcus heamolyticus tested bacteria. The minimum inhibitory concentration (MIC) of the Sidr honey sample were also determined. Finally cytotoxicity evaluating toward human RBC, the results revealed the Iraqi honeys sample have not any cytotoxicity in all concentration. The good antimicrobial potency of sidr and Eucalyptus Iraqi honeys could potentially be used as therapeutic against MRSA Staphylococcus heamolyticus as an alternative to the costly antibiotics.

Honey-sensitive Pseudomonas aeruginosa mutants are impaired in catalase A.

The antimicrobial power of honey seems to be ascribable to several factors, including oxidative and osmotic stress. The aim of this study was to find genetic determinants involved in the response to honey stress in the opportunistic pathogen Pseudomonas aeruginosa, chosen as model micro-organism. A library of transposon mutants of P. aeruginosa PAO1 was constructed and only four mutants unable to grow in presence of fir honeydew honey were selected. All four mutants were impaired in the major H2O2-scavenging enzyme catalase A (KatA). The knockout of katA gene caused sensitivity, as expected, not only to hydrogen peroxide but also to different types of honey including Manuka GMO 220 honey. Genetic complementation, as well as the addition of PAO1 supernatant containing extracellular catalase, restored tolerance to honey stress in all the mutants. As P. aeruginosa PAO1 catalase KatA copes with H2O2 stress, it is conceivable that the antimicrobial activity of honey is, at least partially, due to the presence of hydrogen peroxide in honey or the ability of honey to induce production of hydrogen peroxide. The katA-deficient mutants could be used as tester micro-organisms to compare the power of different types of natural and curative honeys in eliciting oxidative stress mediated by hydrogen peroxide.

Molecular Mechanisms of Natural Honey Against H. pylori Infection Via Suppression of NF-κB and AP-1 Activation in Gastric Epithelial Cells

Natural honey has been used as a medicine since ancient times. Honey is widely known for its antibacterial properties against H. pylori; however, the mechanisms of its antibacterial activity are not fully known. The present study was performed to examine the molecular mechanisms by which natural honey can inhibit H. pylori infection in gastric epithelial cells. Electrophoretic mobility shift assay was used to measure NF-κB- and AP-1-DNA binding activity. Western blotting was used to detect IκB-α and COX-2 expression. H. pylori induced NF-κB and AP-1 DNA-binding activity in gastric epithelial cells. Manuka honey inhibited H. pylori-induced NF-κB and AP-1 in a time- and dose-dependent manner. Maximum inhibition of H. pylori-induced NF-κB and AP-1 by manuka honey was observed at concentrations of 20% at 1-2h. Pre-treatment of AGS cells with other commercial natural honeys also inhibited H. pylori-induced NF-κB and AP-1 DNA-binding activity. Honey prevented H. pylori-induced degradation of IκB-α protein and downregulated COX-2 protein levels. Our findings suggest that natural honey exerts its inhibitory effects against H. pylori by inhibiting NF-κB and AP-1 activation and downregulation of COX-2 expression. These results provide new mechanistic insights into honey effects in the suppression of H. pylori infection.

Antibiofilm efficacy of honey and bee-derived defensin-1 on multispecies wound biofilm.

Many clinically relevant biofilms are polymicrobial. Examining the effect of antimicrobials in a multispecies biofilm consortium is of great clinical importance. The goal of this study was to investigate the effect of different honey types against bacterial wound pathogens grown in multispecies biofilm and to test the antibiofilm activity of honey defensin-1 (Def-1) in its recombinant form. A modified Lubbock chronic wound biofilm formed by four bacterial species (Staphylococcus aureus, Streptococcus agalactiae, Pseudomonas aeruginosa and Enterococcus faecalis) was used for evaluation of honey and recombinant bee-derived Def-1 antibiofilm efficacy. Recombinant Def-1 was prepared by heterologous expression in Escherichia coli. We showed that different types of honey (manuka and honeydew) were able to significantly reduce the cell viability of wound pathogens (Staphylococcus aureus, Streptococcus agalactiae and Pseudomonas aeruginosa) in mature polymicrobial biofilm. None of the tested honeys showed the ability to eradicate Enterococcus faecalis in biofilm. In addition, recombinant Def-1 successfully reduced the viability of Staphylococcus aureus and Pseudomonas aeruginosa cells within established polymicrobial biofilm after 24 and 48 h of treatment. Interestingly, recombinant Def-1 did not affect the viability of Streptococcus agalactiae cells within the biofilm, whereas both natural honeys significantly reduced the viable bacteria. Although Enterococcus faecalis was highly resistant to Def-1, Def-1 significantly affected the biofilm formation of Enterococcus faecalis and Streptococcus agalactiae after 24 h of treatment, most likely by inhibiting its extracellular polymeric substances production. In conclusion, our study revealed that honey and Def-1 are effective against established multispecies biofilm; however, Enterococcus faecalis grown in multispecies biofilm was resistant to both antimicrobials.