Antioxidative, Antibacterial and Antiproliferative Properties of Honey Types from the Western Balkans

Synergistic Antibiofilm Effects of Chestnut and Linden Honey with Lavender Essential Oil Against Multidrug-Resistant Otitis Media Pathogens

BACKGROUND/OBJECTIVES

Bacterial resistance to antibiotics is a major problem in healthcare, complicated by the ability of bacteria to form biofilms. Complementary therapy for infectious diseases can rely on natural substances with antibacterial activity, e.g., essential oils and honeys. The aim of the study was to investigate the effects of linden and chestnut honeys, lavender essential oil, and their combinations against the multidrug-resistant otitis media pathogens Haemophilus influenzae, H. parainfluenzae, Moraxella catarrhalis, Pseudomonas aeruginosa, and Streptococcus pneumoniae. The efficacy of these natural substances was compared with each other and antibiotics used in clinical practice.

METHODS

Microscopic pollen analysis and physicochemical traits were used to confirm the botanical origin of honey samples. The antibiotic sensitivity of bacteria was tested with a disk diffusion assay. Minimum inhibitory concentrations were determined using a microdilution assay. A 24 h immature biofilm eradication test was performed with a crystal violet assay. The efficacy of combinations was tested with a checkerboard titration method. The DNA release of damaged bacterial cells was measured using a membrane degradation assay.

RESULTS

Lavender essential oil displayed more potent antibacterial activity compared to the honey samples. However, honey-essential oil combinations showed higher inhibition rates for biofilm eradication, with P. aeruginosa being the most resistant bacterium. The combined use of chestnut honey and lavender oil resulted in a higher degree of membrane degradation in a shorter time, and their synergistic effect was proven with checkerboard titration.

CONCLUSIONS

The combination of linden or chestnut honey with lavender essential oil was shown to be effective in the eradication of a 24 h immature biofilm formed by H. parainfluenzae, M. catarrhalis, and S. pneumoniae.

Release of elements and phenolic and flavonoid compounds from herbs and spices into acacia honey during infusion

Acacia honey was infused with basil, oregano, marjoram, dill, garlic or cinnamon at infusion rates of 0-5% by mass for a 6 months period. After removal of the infusates, macro and micro element concentrations were measured by Inductively Coupled Plasma Optical Emission Spectrometry. Total phenolic and flavonoid contents were determined spectroscopically. The greatest release of elements, phenols and flavonoids, (% release/1% infusion rate) were for phenols (1.22-3.74, respectively), flavonoids (0.12-2.18), K (0.39-0.78), P (0.14-0.87), and S (0.07-0.85). The least release was for Ba (0.04-0.17), Fe (0.03-0.41) and B (- 0.006 to 2.33). Dill showed the most important effect on the Na concentration of honey enriched (at 5.00%) with > 90 times higher content (328 ± 4 mg/kg) compared to control honey (3.46 ± 0.07 mg/kg). Sr content was more than 50 times higher in honey enriched with marjoram (1383 ± 10 µg/kg), and honey enriched with dill showed more than 30 times higher Fe content (4112 ± 14 µg/kg). Enrichment with dill had the greatest effect on Ca, Cu, K, Mg, Na and Fe content of control honey, and garlic had the most important effect on the B, P, S, Zn, TP and TF content. Enrichment with these herbs and spices resulted in increases in element, total phenolic and flavonoid content of acacia honey.

3D printed cacao-based formulations as nutrient carriers for immune system enhancement

This study explores the feasibility of using raw Greek honey-infused cacao-based formulations for three-dimensional printing (3DP). It evaluates their physicochemical properties, thermal stability, and rheological behaviour. Three honey varieties, one of which was Lavender Honey (LH), were incorporated into cacao printlets to assess their impact on structural integrity and compatibility with Vitamin D3 (VitD3), a bioactive compound known for immune system enhancement. Including honey aims to improve the nutritional profile, enhance the taste, and potentially increase the bioavailability of VitD3, which is limited by its hydrophobic nature and low oral absorption. Thermal analysis showed that honey-infused cacao printlets maintain a liquid-like state under ambient conditions and exhibit stability up to the printing temperature of 38 °C. Rheological assessments demonstrated that both individually and in combination, increased honey concentrations and VitD3 incorporation enhance viscosity. These changes improve printability and structural integrity during 3DP. While raw LH demonstrated antibacterial activity, no antibacterial efficacy was observed in the LH-based printlets after incubation. LH at a 10% concentration emerged as the optimal formulation, demonstrating balanced structural properties and effective miscibility with VitD3. This study highlights how raw Greek honey produced without chemical miticides, has the potential to enhance the functionality and palatability of 3D-printed health supplements. It utilises honey's antimicrobial properties and taste benefits while promoting immune system support through VitD3 integration. The findings highlight the versatility of honey-infused cacao printlets in developing personalized health supplements and pharmaceuticals, suggesting their promising role as delivery systems in personalized medicine. Honeys widely accepted sensory qualities and its application in food products are the basis for the proposition that it enhances palatability. These attributes imply that honey could positively influence the acceptability of the product.

Physicochemical Characteristics, Phenolic Components, and Antioxidant Capacities of Lavender Honey (Lavandula Spp.) from Isparta Region of Türkiye

Lavender honey is one of the most desirable blossom honeys for its unique taste and aromatic qualities and can vary significantly from one region to another. In this study, melissopalynological, physicochemical and antioxidant properties of lavender honey from the Isparta region of Türkiye were investigated. The ration of the Lavandula spp. pollen were identified ranging from 9 % to 76 % in the thirteen samples. The average pH, conductivity, moisture, Hunter Lab* and proline values were 3.72, 0.22 mS/cm, 17.17 %, L*: 66.56, a*: 66.32, b*:18.41 and 576.92 mg/kg, respectively. The average F+G and F/G were 67.66 % and 1.02, respectively. The average of total phenolic (TP) and flavonoid (TF) substance were found to be 39.40 mg GAE/100 g and 3.23 mg QUE/100 g, respectively. The average total antioxidant capacity (FRAP) and DPPH radical scavenging activity values were found to be 178.28 μmol FeSO4 ⋅ 7H2O/100 g and 53.09 mg/mL, respectively. In the phenolic component analysis performed with HPLC-PDA, p-OH-benzoic acid, p-coumaric acid, chrysin and pinocembrin were detected as common polyphenols in the samples. Conclusively, despite considerable variability in their monofloral characteristics, no significant differences were observed in the physicochemical and antioxidant properties of lavender honeys.

Antibacterial activity of Hungarian varietal honeys against respiratory pathogens as a function of storage time

Today, antibiotic therapies that previously worked well against certain bacteria due to their natural sensitivity, are becoming less effective. Honey has been proven to inhibit the biofilm formation of some respiratory bacteria, however few data are available on how the storage time affects the antibacterial effect. The activity of black locust, goldenrod, linden and sunflower honeys from three consecutive years (2020, 2021, 2022) was analyzed in 2022 against Gram-negative (Haemophilus influenzae, H. parainfluenzae, Pseudomonas aeruginosa) and Gram-positive (Streptococcus pneumoniae) bacteria using in vitro microbiological methods. After determining the physicochemical parameters of honey, broth microdilution was applied to determine the minimum inhibitory concentration of each honey type against each bacterium, and crystal violet assay was used to test their antibiofilm effect. The possible mechanism of action was explored with membrane degradation test, while structural changes were illustrated with scanning electron microscopy. Honeys stored for one or two years were darker than fresh honeys, while older honeys had significantly lower antibacterial activity. The most remarkable inhibitory effect was exerted by linden and sunflower honeys, and P. aeruginosa proved to be the most resistant bacterium. Based on our results, honey intended for medicinal purposes should be used as fresh as possible during a treatment.

Bioactivities and Phenolic Profiles of Honeys Derived from Plants of the Goldfields, Esperance and Wheatbelt Regions of Western Australia

The aim of this study was to examine a collection of 79 honeys derived from plants endemic to several Western Australian unique bioregions for bioactivity and physicochemical characteristics. For physicochemical analyses, total phenolic content, high performance thin layer chromatography (HPTLC) fingerprints, pH, Brix, colour and hydrogen peroxide generation were examined. Brix (82.6±1.3) and pH (4.34±0.24) values were within expected ranges, whereas hydrogen peroxide levels determined using an o-dianisidine/horseradish peroxidase assay were relatively low, ranging from 0-244 μM. Antibacterial activity determined by the broth microdilution assay showed that Moort (Eucalyptus platypus) and Yate (Eucalyptus occidentalis) honeys had the highest overall activity with mean minimum inhibitory concentrations of 24.8 % and 25.1 % (w/v) honey, respectively. Yate honey also had the highest overall antioxidant activity (4.38±0.58 mmol Fe2+ /kg of honey), followed by Mallee honeys from various eucalypts, as determined by FRAP (Ferric reducing antioxidant power) and DPPH⋅ (2,2-Diphenyl-1-picrylhydrazyl) assays. This study identified new sources of honeys with potentially useful therapeutic properties from bioregions within Western Australia.

Antibacterial and Antibiofilm Effect of Unifloral Honeys against Bacteria Isolated from Chronic Wound Infections

Honey is known as an alternative remedy for the treatment of wounds. To evaluate the potential of five Hungarian honey types against wound-associated bacteria, in vitro microbiological assays were conducted on Pseudomonas aeruginosa, Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus (MRSA). Minimum inhibitory concentration (MIC) was determined with the broth macrodilution method, and biofilm degradation capacity was tested with a crystal violet assay. To understand the underlying mechanisms, the effects of honey treatments were assessed on bacterial membrane integrity and quorum sensing (QS). The highest antibacterial activity, indicated by the lowest MIC values, as well as the highest biofilm inhibition rates and membrane disruption, was displayed by chestnut and linden honeys. The most sensitive bacterium was S. epidermidis. Bacterial membrane degradation took place 40 min after treatment with honey solutions of at least a 40% concentration. Each honey sample exhibited anti-QS activity, which was most pronounced in the case of chestnut honey. It was concluded that the antibacterial, biofilm-inhibiting and anti-QS activities of linden and chestnut honeys were superior to those of acacia, goldenrod and milkweed honeys. In addition to the floral source, the antibacterial effect of honey is influenced by the microbial species treated. The use of honey in wound treatment can be justified by its diverse antibacterial mechanisms.

Manuka Honey/2-Hydroxyethyl Methacrylate/Gelatin Hybrid Hydrogel Scaffolds for Potential Tissue Regeneration

Scaffolding biomaterials are gaining great importance due to their beneficial properties for medical purposes. Targeted biomaterial engineering strategies through the synergy of different material types can be applied to design hybrid scaffolding biomaterials with advantageous properties for biomedical applications. In our research, a novel combination of the bioactive agent Manuka honey (MHo) with 2-hydroxyethyl methacrylate/gelatin (HG) hydrogel scaffolds was created as an efficient bioactive platform for biomedical applications. The effects of Manuka honey content on structural characteristics, porosity, swelling performance, in vitro degradation, and in vitro biocompatibility (fibroblast and keratinocyte cell lines) of hybrid hydrogel scaffolds were studied using Fourier transform infrared spectroscopy, the gravimetric method, and in vitro MTT biocompatibility assays. The engineered hybrid hydrogel scaffolds show advantageous properties, including porosity in the range of 71.25% to 90.09%, specific pH- and temperature-dependent swelling performance, and convenient absorption capacity. In vitro degradation studies showed scaffold degradability ranging from 6.27% to 27.18% for four weeks. In vitro biocompatibility assays on healthy human fibroblast (MRC5 cells) and keratinocyte (HaCaT cells) cell lines by MTT tests showed that cell viability depends on the Manuka honey content loaded in the HG hydrogel scaffolds. A sample containing the highest Manuka honey content (30%) exhibited the best biocompatible properties. The obtained results reveal that the synergy of the bioactive agent, Manuka honey, with 2-hydroxyethyl methacrylate/gelatin as hybrid hydrogel scaffolds has potential for biomedical purposes. By tuning the Manuka honey content in HG hydrogel scaffolds advantageous properties of hybrid scaffolds can be achieved for biomedical applications.

Antiviral and Antibacterial Effect of Honey Enriched with Rubus spp. as a Functional Food with Enhanced Antioxidant Properties

The aim of this study was to investigate the effect of blackberry and raspberry fruits (1 and 4%) and leaves (0.5 and 1%) on the biological activities of rape honey. Honey and plant material extracts were analyzed regarding total phenolic, flavonoid, anthocyanin contents, HPTLC and HPLC polyphenol profiles, as well as antioxidant activity. The antiviral potential was analyzed against bacteriophage phi 6-a coronavirus surrogate-whereas antimicrobial was tested against S. aureus and E. coli. Blackberry extracts were more abundant in antioxidants than raspberry extracts, with better properties found for leaves than fruits and for cultivated rather than commercial plants. The addition of both Rubus plant additives significantly increased the antioxidant potential of honey by four-fold (for 4% fruits additive) to five-fold (for 1% of leaves). Honey with the addition of fruits possessed higher antiviral potential compared with raw rape honey (the highest for 4% of raspberry fruit and 1% of blackberry leaf additive). Honey enriched with Rubus materials showed higher antibacterial potential against S. aureus than rape honey and effectively inhibited S. aureus biofilm formation. To summarize, honey enriched with Rubus fruit or leaves are characterized by increased pro-health value and can be recommended as a novel functional food.

The effectiveness of forest honey toward symptoms of atrophy patients: Study of ear nose and throat-head neck and dermatology venereology

The effectiveness of forest honey in Total Nasal Symptom Score (TNSS) improvement in allergic rhinitis patients and index Scoring Atopic Dermatitis (SCORAD) in Atopic Dermatitis (AD) patients were discovered. It was an experimental study with a pretest-posttest design. A total of 20 people with atopy (15 people with allergic rhinitis and five people with AD) were given forest honey in the morning (1 ml × 10 ml dose) for 8 weeks and 20 atopy patients without forest honey. TNSS and SCORAD index were evaluated before the intervention, week 2, week 4, and after the intervention (week 8). The mean TNSS before treatment was higher in the honey group, namely 7.73, and a significant decrease after 8 weeks of intervention, namely 2.73 with P = 0.000. The nonhoney group showed that there was no significant difference after 8 weeks with P = 0.888. The SCORAD values of the honey and nonhoney groups had significantly different values from week 0 to week 4 (P = 0.003) and week 0 to week 8 (P = 0.003). Forest honey can give as an additional therapy for patients with allergic rhinitis and AD.