Relationship among the minor constituents, antibacterial activity and geographical origin of honey: A multifactor perspective

Reactive Oxygen Species (ROS)-Mediated Antibacterial Oxidative Therapies: Available Methods to Generate ROS and a Novel Option Proposal

The increasing emergence of multidrug-resistant (MDR) pathogens causes difficult-to-treat infections with long-term hospitalizations and a high incidence of death, thus representing a global public health problem. To manage MDR bacteria bugs, new antimicrobial strategies are necessary, and their introduction in practice is a daily challenge for scientists in the field. An extensively studied approach to treating MDR infections consists of inducing high levels of reactive oxygen species (ROS) by several methods. Although further clinical investigations are mandatory on the possible toxic effects of ROS on mammalian cells, clinical evaluations are extremely promising, and their topical use to treat infected wounds and ulcers, also in presence of biofilm, is already clinically approved. Biochar (BC) is a carbonaceous material obtained by pyrolysis of different vegetable and animal biomass feedstocks at 200-1000 °C in the limited presence of O2. Recently, it has been demonstrated that BC's capability of removing organic and inorganic xenobiotics is mainly due to the presence of persistent free radicals (PFRs), which can activate oxygen, H2O2, or persulfate in the presence or absence of transition metals by electron transfer, thus generating ROS, which in turn degrade pollutants by advanced oxidation processes (AOPs). In this context, the antibacterial effects of BC-containing PFRs have been demonstrated by some authors against Escherichia coli and Staphylococcus aureus, thus giving birth to our idea of the possible use of BC-derived PFRs as a novel method capable of inducing ROS generation for antimicrobial oxidative therapy. Here, the general aspects concerning ROS physiological and pathological production and regulation and the mechanism by which they could exert antimicrobial effects have been reviewed. The methods currently adopted to induce ROS production for antimicrobial oxidative therapy have been discussed. Finally, for the first time, BC-related PFRs have been proposed as a new source of ROS for antimicrobial therapy via AOPs.

Evaluation of the generation of reactive oxygen species and antibacterial activity of honey as a function of its phenolic and mineral composition

The antibacterial activity (ABA) of honey is associated with the generation of reactive oxygen species (ROS), where polyphenols (PFs) play a key role due to their pro-oxidant action modulated by metallic cations. In this work, the contents of PFs, H₂O₂, OH radicals, Cu, Fe, Mn, Zn, and ABA against Staphylococcus epidermidis and Pseudomonas aeruginosa were determined in honeys from central Chile. Then, their relationships were evaluated through partial least squares regression. The average contents of phenolic acids, flavonoids and metals in honey ranged from 0.4 to 4 μg/g, 0.3-1.5 μg/g and 3-6 μg/g, respectively. All honeys showed accumulation of H₂O₂ (1-35 μg/g) and OH radicals. The PLS showed that gallic acid, p-coumaric acid, chrysin, kaempferol, Fe, and Mn stimulate the generation of ROS. Quercetin, Cu, and Zn showed marginal antioxidant effects. PFs favor the ABA of honey against both bacteria and H₂O₂ against S. epidermidis.

Antibacterial and wound-healing action of Ulmo honey (Eucryphia cordifolia) of differing degrees of purity

Introduction

Antibacterial properties of honey vary according to its floral origin; few studies report the percentage of pollen types in honey, making it difficult to reproduce and compare the results. This study compares the antibacterial and wound-healing properties of three kinds of monofloral Ulmo honey with different percentages of pollen from Eucryphia cordifolia.

Methods

The pollen percentage of the honey was determined by melissopalynological analysis, and they were classified into three groups: M1 (52.77% of pollen from Eucryphia cordifolia), M2 (68.41%), and M3 (82.80%). They were subjected to chemical analysis and agar diffusion test against Staphylococcus aureus. A total of 20 healthy adult guinea pigs (Cavia porcellus) of both sexes were randomly assigned to four groups for experimental burn skin wound (uninfected) production and treatment with Ulmo honey. On day 10 post-injury, biopsies were obtained, and histological analysis was performed to assess wound-healing capacity following the treatment with honey.

Results

The chemical analysis showed that M3 differed significantly from M1 in terms of pH (P = 0.020), moisture (P = 0.020), total sugars (P = 0.034), and total solids (P = 0.020). Both strains of Staphylococcus aureus were susceptible to M1 and M2 at 40% w/v but were resistant to M3 at all concentrations. All groups (I-IV) were in the initial proliferative phase, with complete or partial re-epithelialization of the epidermis.

Discussion

The antibacterial activity showed a wide range of variation in the different types of honey studied, with no significant differences between wound healing and pollen percentage in the groups studied. Higher pH and the absence of Tineo in M3 conferred a lower antibacterial capacity but not a lower wound healing capacity. Despite its variability in the percentage of Eucryphia cordifolia like primary pollen in Ulmo's monofloral honey, this has the same properties in relation to wound healing.

A review on the phytochemical composition and health applications of honey

Background

Though honey has long been used as medicine, there is a scarcity of knowledge on how it interacts with the body.

Scope and approach

While different types of honey have different chemical and medicinal properties according to their origin, this narrative review seeks to analyse the current knowledge on the chemical composition and therapeutic use of honey. With numerous chemical components, honey has a range of health benefits in multiple disciplines of medicine, and provides an interesting prospect in chemical analysis with regards to identification of its origin.

Key findings and conclusions

There is a great potential for the use of honey in medicine, primarily due to its antioxidant and antimicrobial properties. Recent studies on the phenolic and enzymatic components of honey have made honey's therapeutic method of action in relation to the above properties clearer, still more research needs to be conducted and more innovations need to be tested, for the full potential of honey to be understood.

Honeys with anti-inflammatory capacity can alter the elderly gut microbiota in an ex vivo gut model

The anti-inflammatory effect of different sourced honeys and the impact on elderly gut microbiota were studied in terms of chemical compositions, anti-inflammatory effect and gut microbiota modulating capacities. All four honeys suppressed the production of pro-inflammatory markers NO, IL-1β and IL-6 induced by lipopolysaccharide and promoted the expression of anti-inflammatory cytokines IL-10 in RAW 264.7 cells. Moreover, in the ex vivo batch gut model using elderly fecal microbiota (referred to as microcosm), it was showed that the addition of honeys increased the abundance of beneficial lactobacilli, decreased the abundance of potentially harmful Gram negative enteric bacteria, and exerted a beneficial effect on the production of short chain fatty acids. The concentration of gallic acid in honeys was positively correlated with the expression level of IL-10 and the abundance of lactobacilli. These findings indicate honeys with anti-inflammatory capacity have great potential for regulating the elderly gut microbiota which would lead to health benefits.

Characterization of Various Honey Samples from Different Regions of Morocco Using Physicochemical Parameters, Minerals Content, Antioxidant Properties, and Honey-Specific Protein Pattern

Honey is a bee product relatively expensive; therefore, it has been a target of adulteration by many sweeteners. In this work, we evaluated the good quality, authenticity, and content in bioactive molecules of twenty-two Moroccan honey from different botanical origins and geographical areas. For that, the following analyses were determined: the content in total protein and especially the major royal jelly protein (apalbumin 1), the analysis of total acidity, free acidity, lactonic acidity, pH, ash, Pfund, electrical conductivity, and moisture. In addition, the content of sodium, potassium, calcium, and magnesium, the dosage of polyphenols, flavones, and flavonols, and the antioxidant activities were assessed. All analyzed samples had good antioxidant activities and present a source of antioxidant compounds, the predominant mineral in all honey samples was potassium, and the physicochemical parameters are in line with the standards’ recommended limits. The content of honey samples in total protein and apalbumin 1 ranged between 212 μg/g and 4121.2 μg/g and between 27.4 μg/g and 790.82 μg/g, respectively. Overall, the detection of apalbumin 1 in all honey samples and the results of physicochemical parameters, minerals, bioactive compounds, and antioxidant activities confirm the authenticity and no adulteration of Moroccan honey.

Honey: An Advanced Antimicrobial and Wound Healing Biomaterial for Tissue Engineering Applications

Honey was used in traditional medicine to treat wounds until the advent of modern medicine. The rising global antibiotic resistance has forced the development of novel therapies as alternatives to combat infections. Consequently, honey is experiencing a resurgence in evaluation for antimicrobial and wound healing applications. A range of both Gram-positive and Gram-negative bacteria, including antibiotic-resistant strains and biofilms, are inhibited by honey. Furthermore, susceptibility to antibiotics can be restored when used synergistically with honey. Honey’s antimicrobial activity also includes antifungal and antiviral properties, and in most varieties of honey, its activity is attributed to the enzymatic generation of hydrogen peroxide, a reactive oxygen species. Non-peroxide factors include low water activity, acidity, phenolic content, defensin-1, and methylglyoxal (Leptospermum honeys). Honey has also been widely explored as a tissue-regenerative agent. It can contribute to all stages of wound healing, and thus has been used in direct application and in dressings. The difficulty of the sustained delivery of honey’s active ingredients to the wound site has driven the development of tissue engineering approaches (e.g., electrospinning and hydrogels). This review presents the most in-depth and up-to-date comprehensive overview of honey’s antimicrobial and wound healing properties, commercial and medical uses, and its growing experimental use in tissue-engineered scaffolds.

Chemical Composition and the Anticancer, Antimicrobial, and Antioxidant Properties of Acacia Honey from the Hail Region: The in vitro and in silico Investigation

In consideration of the emergence of novel drug-resistant microbial strains and the increase in the incidences of various cancers throughout the world, honey could be utilized as a great alternative source of potent bioactive compounds. In this context, this study pioneers in reporting the phytochemical profiling and the antimicrobial, antioxidant, and anticancer properties of Acacia honey (AH) from the Hail region of Saudi Arabia, assessed using in vitro and molecular docking approaches. The phytochemical profiling based on high-resolution liquid chromatography-mass spectrometry (HR-LCMS) revealed eight compounds and three small peptide-like proteins as the constituents. The honey samples exhibited promising antioxidant activities (DPPH-IC₅₀ = 0.670 mg/mL; ABTS-IC₅₀ = 1.056 mg/mL; β-carotene-IC₅₀ > 5 mg/mL). In the well-diffusion assay, a high mean growth inhibition zone (mGIZ) was observed against Staphylococcus aureus (48.33 ± 1.53 mm), Escherichia coli ATCC 10536 (38.33 ± 1.53 mm), and Staphylococcus epidermidis ATCC 12228 (39.33 ± 1.15 mm). The microdilution assay revealed that low concentrations of AH could inhibit the growth of almost all the evaluated bacterial and fungal strains, with the minimal bactericidal concentration values (MBCs) ranging from 75 mg/mL to 300 mg/mL. On the contrary, high AH concentrations were required to kill the tested microorganisms, with the minimal bactericidal concentration values (MBCs) ranging from approximately 300 mg/mL to over 600 mg/mL and the minimal fungicidal concentration values (MFCs) of approximately 600 mg/mL. The AH exhibited effective anticancer activity in a dose-dependent manner against breast (MCF-7), colon (HCT-116), and lung (A549) cancer cell lines, with the corresponding IC₅₀ values of 5.053 μg/mL, 5.382 μg/mL, and 6.728 μg/mL, respectively. The in silico investigation revealed that the observed antimicrobial, antioxidant, and anticancer activities of the constituent compounds of AH are thermodynamically feasible, particularly those of the tripeptides (Asp-Trp-His and Trp-Arg-Ala) and aminocyclitol glycoside. The overall results highlighted the potential of AH as a source of bioactive compounds with significant antimicrobial, antioxidant, and anticancer activities, which could imply further pharmacological applications of AH.

A Review on Recent Progress of Stingless Bee Honey and Its Hydrogel-Based Compound for Wound Care Management

Stingless bee honey has a distinctive flavor and sour taste compared to Apis mellifera honey. Currently, interest in farming stingless bees is growing among rural residents to meet the high demand for raw honey and honey-based products. Several studies on stingless bee honey have revealed various therapeutic properties for wound healing applications. These include antioxidant, antibacterial, anti-inflammatory, and moisturizing properties related to wound healing. The development of stingless bee honey for wound healing applications, such as incorporation into hydrogels, has attracted researchers worldwide. As a result, the effectiveness of stingless bee honey against wound infections can be improved in the future to optimize healing rates. This paper reviewed the physicochemical and therapeutic properties of stingless bee honey and its efficacy in treating wound infection, as well as the incorporation of stingless bee honey into hydrogels for optimized wound dressing.

Honey Bees (Apis mellifera Hymenoptera: Apidae) Preferentially Avoid Sugar Solutions Supplemented with Field-Relevant Concentrations of Hydrogen Peroxide Despite High Tolerance Limits

Honey bees (Apis mellifera L. Hymeoptera: Apidae) use hydrogen peroxide (synthesized by excreted glucose oxidase) as an important component of social immunity. However, both tolerance of hydrogen peroxide and the production of glucose oxidase in honey is costly. Hydrogen peroxide may also be encountered by honey bees at high concentrations in nectar while foraging, however despite its presence both in their foraged and stored foods, it is unclear if and how bees monitor concentrations of, and their behavioral responses to, hydrogen peroxide. The costs of glucose oxidase production and the presence of hydrogen peroxide in both nectar and honey suggest hypotheses that honey bees preferentially forage on hydrogen peroxide supplemented feed syrups at certain concentrations, and avoid feed syrups supplemented with hydrogen peroxide at concentrations above some tolerance threshold. We test these hypotheses and find that, counter to expectation, honey bees avoid glucose solutions supplemented with field-relevant hydrogen peroxide concentrations and either avoid or don't differentiate supplemented sucrose solutions when given choice assays. This is despite honey bees showing high tolerance for hydrogen peroxide in feed solutions, with no elevated mortality until concentrations of hydrogen peroxide exceed 1% (v/v) in solution, with survival apparent even at concentrations up to 10%. The behavioral interaction of honey bees with hydrogen peroxide during both within-colony synthesis in honey and when foraging on nectar therefore likely relies on interactions with other indicator molecules, and maybe constrained evolutionarily in its plasticity, representing a constitutive immune mechanism.

In Vitro Antibacterial and Antibiofilm Activity of Hungarian Honeys against Respiratory Tract Bacteria

Honey is a rich source of carbohydrates, while minor compounds such as amino acids and polyphenols contribute to its health-promoting effects. Honey is one of the oldest traditional remedies applied for microbial infections, due to its antibacterial, anti-inflammatory, and antioxidant properties. The aim of this study was to investigate the antibacterial and antibiofilm effects of Hungarian black locust, linden, and sunflower honeys against the most common biofilm-forming respiratory tract pathogens Haemophilus spp., Pseudomonas aeruginosa, and Streptococcus pneumoniae. The unifloral character of all three honey types was confirmed by melissopalynological analysis. The antibacterial activity of each honey sample against each bacterium strain was proven with agar well diffusion assay and thin layer chromatography—direct bioautography. Kinetics and mechanisms of antibacterial action were clarified with time-kill assay and membrane degradation study. The anti-biofilm activity was evidenced using crystal violet assay. In each assay, linden honey was the most effective, followed by sunflower and black locust honey. In addition, each honey sample had greater potential to suppress respiratory tract bacteria, compared to major sugar components. In conclusion, honey in general and linden honey in particular, can have a role in the treatment of respiratory tract infections caused by biofilm-forming bacteria.

Safflomin A: A novel chemical marker for Carthamus tinctorius L. (Safflower) monofloral honey

Monofloral safflower honey (MSH), produced from nectar of the medicinal Carthamus tinctorius L., has been shown with excellent nutritional value and biological activity. However, current MSH authenticity verification is insufficient. Herein, we fully characterized MSH from a metabolomic perspective and proposed a chemical marker for its authentication. Using palynological analysis, we confirmed the botanical origin of MSH. Ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC/Q-TOF-MS) was applied further to compare MSH/safflower components. MSH and safflowers shared 1297 tentatively identified compounds, of which safflomin A was identified as a reliable characteristic indicator. When applied to commercial non-safflower honeys, none tested safflomin A positive. Solid phase extraction coupled UHPLC/Q-TOF-MS method revealed the LOD and LOQ of safflomin A in MSH to be 0.006 and 0.02 mg/kg, respectively, with concentrations ranging from 0.86 to 3.91 mg/kg. Collectively, safflomin A can be applied as a chemical marker for fingerprinting the botanical origin of safflower honey.

Promising Antimicrobial Properties of Bioactive Compounds from Different Honeybee Products

Bee products have been known for centuries for their versatile healing properties. In recent decades they have become the subject of documented scientific research. This review aims to present and compare the impact of bee products and their components as antimicrobial agents. Honey, propolis, royal jelly and bee venom are bee products that have antibacterial properties. Sensitivity of bacteria to these products varies considerably between products and varieties of the same product depending on their origin. According to the type of bee product, different degrees of activity were observed against Gram-positive and Gram-negative bacteria, yeasts, molds and dermatophytes, as well as biofilm-forming microorganisms. Pseudomonas aeruginosa turned out to be the most resistant to bee products. An analysis of average minimum inhibitory concentration values for bee products showed that bee venom has the strongest bacterial effectiveness, while royal jelly showed the weakest antibacterial activity. The most challenging problems associated with using bee products for medical purposes are dosage and safety. The complexity and variability in composition of these products raise the need for their standardization before safe and predictable clinical uses can be achieved.

Fraud in Animal Origin Food Products: Advances in Emerging Spectroscopic Detection Methods over the Past Five Years

Animal origin food products, including fish and seafood, meat and poultry, milk and dairy foods, and other related products play significant roles in human nutrition. However, fraud in this food sector frequently occurs, leading to negative economic impacts on consumers and potential risks to public health and the environment. Therefore, the development of analytical techniques that can rapidly detect fraud and verify the authenticity of such products is of paramount importance. Traditionally, a wide variety of targeted approaches, such as chemical, chromatographic, molecular, and protein-based techniques, among others, have been frequently used to identify animal species, production methods, provenance, and processing of food products. Although these conventional methods are accurate and reliable, they are destructive, time-consuming, and can only be employed at the laboratory scale. On the contrary, alternative methods based mainly on spectroscopy have emerged in recent years as invaluable tools to overcome most of the limitations associated with traditional measurements. The number of scientific studies reporting on various authenticity issues investigated by vibrational spectroscopy, nuclear magnetic resonance, and fluorescence spectroscopy has increased substantially over the past few years, indicating the tremendous potential of these techniques in the fight against food fraud. It is the aim of the present manuscript to review the state-of-the-art research advances since 2015 regarding the use of analytical methods applied to detect fraud in food products of animal origin, with particular attention paid to spectroscopic measurements coupled with chemometric analysis. The opportunities and challenges surrounding the use of spectroscopic techniques and possible future directions will also be discussed.

The Changes of Flavonoids in Honey during Storage

The purpose of this study was to determine the changes in the contents of flavonoids that were the most prevalent in acacia and multifloral honey during one year of storage. Samples were stored in transparent glass containers, at room temperature, on open shelves exposed to light during daytime. Eight individual flavonoids identified and quantified using HPLC-Diode Array Detector (DAD) belongs to three subgroups: flavonols (quercetin, luteolin, kaempferol and galangin), total flavanons (hesperetin and pinocembrin) and total flavones (apigenin and chrysin). Obtained results revealed that multifloral honey had more total flavonoids than acacia samples did. On average from all of the samples, multifloral honey had more of quercetin, hesperetin, luteolin, kaempferol and apigenin than acacia honey did. Content of flavonoids increased in samples between the 1st and 6th month of storage and then started to decrease until the 9th month, when they remained relatively constant all the way until the 12th month of storage. In conclusion, acacia and multifloral honey after one-year of storage still can be a valuable source of flavonoids.

Evaluation of physicochemical properties of Qinling Apis cerana honey and the antimicrobial activity of the extract against Salmonella Typhimurium LT2 in vitro and in vivo

Apis cerana honey collected from the Qinling Mountains in China has been widely used for its antimicrobial property in traditional Chinese medicine. However, its antibacterial mechanism against Salmonella Typhimurium LT₂ is still uncertain. A total of 52 volatile components were identified using headspace-gas-chromatography-ion-mobility, and Qinling A. cerana honey exhibited more abundant aromas than monofloral honeys. The phenolic extracts of honey sample F exhibited the lowest minimum inhibitory concentration (5 mg/mL), and chlorogenic acid exhibited the highest (155.91 ± 0.79 mg/kg), followed by caffeic acid, and rutin. After being treated with the extract, cell membranes of S. Typhimurium LT₂ significantly shrunk and further collapsed. The extract treatment on mice caused a significant decrease in S. Typhimurium LT₂, and a dramatic increase in the potential prebiotic Lactobacillus in both the caecum and colon. The results demonstrate that the Qinling A. cerana honey extract could effectively inhibit S. Typhimurium in vitro and in vivo.

Comprehensive tropane alkaloids analysis and retrospective screening of contaminants in honey samples using liquid chromatography-high resolution mass spectrometry (Orbitrap)

A wide-scope analytical method was developed and validated for the determination of tropane alkaloids (TAs) in honey samples. A simple and fast extraction procedure, using a mixture of methanol/water/formic acid (75/25/0.4, v/v/v) as extraction solvent, followed by a clean-up with graphitized black carbon (GBC) and magnesium sulphate was optimized, and compounds were analysed by liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS-Orbitrap). Validation of the proposed method provided adequate linearity (R² > 0.99), trueness (recoveries 71-120%) and precision (relative standard deviation, RSD ≤ 20.1%), with limits of quantitation (LOQs) at 20 µg/kg (except anisodamine and scopolamine at 40 µg/kg) and a significant matrix effect (≤-50%). Nineteen honey samples were analysed, but only one was positive, containing 27 µg/kg of scopolamine. Additionally, a post-targeted screening was performed, and 47% of samples were contaminated with different herbicides, insecticides and veterinary drugs. Therefore, the proposed analytical method is a powerful tool for both targeted TAs and post-targeted contaminant analyses.