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Fernandes KE, Dong AZ, Levina A, Cokcetin NN, Brooks P, Carter DA. Long-term stability and the physical and chemical factors predictive for antimicrobial activity in Australian honey. PLoS One 2024; 19:e0303095. [PMID: 38776281 PMCID: PMC11111008 DOI: 10.1371/journal.pone.0303095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 04/18/2024] [Indexed: 05/24/2024] Open
Abstract
The growing burden of expired medicines contributes to environmental contamination and landfill waste accumulation. Medicinal honey, with its non-toxic nature and potentially long shelf-life, represents a promising and underutilised therapeutic that avoids some of these issues. However, limited knowledge on how its antimicrobial properties change over time combined with a lack of reliable processes in the honey industry for measuring antimicrobial potential, hinder its clinical adoption. Using a diverse selection of 30 Australian honey samples collected between 2005 and 2007, we comprehensively evaluated their antibacterial and antifungal activity and pertinent physical and chemical properties with the aims of assessing the effect of long-term storage on activity, pinpointing factors associated with antimicrobial efficacy, and establishing robust assessment methods. Minimum inhibitory concentration (MIC) assays proved superior to the standard phenol equivalence assay in capturing the full range of antimicrobial activity present in honey. Correlations between activity and a range of physical and chemical properties uncovered significant associations, with hydrogen peroxide, antioxidant content, and water activity emerging as key indicators in non-Leptospermum honey. However, the complex nature and the diverse composition of honey samples precludes the use of high-throughput chemical tests for accurately assessing this activity, and direct assessment using live microorganisms remains the most economical and reliable method. We provide recommendations for different methods of assaying various honey properties, taking into account their accuracy along with technical difficulty and safety considerations. All Leptospermum and fourteen of seventeen non-Leptospermum honey samples retained at least some antimicrobial properties after 15-17 years of storage, suggesting that honey can remain active for extended periods. Overall, the results of this study will help industry meet the growing demand for high-quality, medicinally active honey while ensuring accurate assessment of its antimicrobial potential.
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Affiliation(s)
- Kenya E. Fernandes
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Andrew Z. Dong
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Aviva Levina
- School of Chemistry, University of Sydney, Sydney, New South Wales, Australia
| | - Nural N. Cokcetin
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Peter Brooks
- School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| | - Dee A. Carter
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
- Sydney Institute for Infectious Diseases, University of Sydney, Sydney, New South Wales, Australia
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Lozada Lawag I, Green KJ, Khairul Islam M, Locher C, Hammer KA. Bioactivities and Phenolic Profiles of Honeys Derived from Plants of the Goldfields, Esperance and Wheatbelt Regions of Western Australia. Chem Biodivers 2023; 20:e202301678. [PMID: 37968896 DOI: 10.1002/cbdv.202301678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 11/14/2023] [Accepted: 11/14/2023] [Indexed: 11/17/2023]
Abstract
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.
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Affiliation(s)
- Ivan Lozada Lawag
- Cooperative Research Centre for Honey Bee Products Limited (CRC HBP), Yanchep, WA, 6035, Australia
- Division of Pharmacy, School of Allied Health, The University of Western Australia, Crawley, 6009, Australia
| | - Kathryn J Green
- Cooperative Research Centre for Honey Bee Products Limited (CRC HBP), Yanchep, WA, 6035, Australia
- Marshall Centre for Research and Training, School of Biomedical Sciences, UWA, Crawley, 6009, Australia
| | - Md Khairul Islam
- Cooperative Research Centre for Honey Bee Products Limited (CRC HBP), Yanchep, WA, 6035, Australia
- Division of Pharmacy, School of Allied Health, The University of Western Australia, Crawley, 6009, Australia
| | - Cornelia Locher
- Cooperative Research Centre for Honey Bee Products Limited (CRC HBP), Yanchep, WA, 6035, Australia
- Division of Pharmacy, School of Allied Health, The University of Western Australia, Crawley, 6009, Australia
| | - Katherine A Hammer
- Cooperative Research Centre for Honey Bee Products Limited (CRC HBP), Yanchep, WA, 6035, Australia
- Marshall Centre for Research and Training, School of Biomedical Sciences, UWA, Crawley, 6009, Australia
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Grabek-Lejko D, Hyrchel T. The Antibacterial Properties of Polish Honey against Streptococcus mutans-A Causative Agent of Dental Caries. Antibiotics (Basel) 2023; 12:1640. [PMID: 37998842 PMCID: PMC10669562 DOI: 10.3390/antibiotics12111640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 11/08/2023] [Accepted: 11/10/2023] [Indexed: 11/25/2023] Open
Abstract
Streptococcus mutans is considered the main pathogen responsible for dental caries, one of the major infectious diseases, affecting more than 4 billion people worldwide. Honey is a natural product with well-known antibacterial potential against several human pathogens. The aim of the study was to evaluate the antibacterial efficacy of Polish honey against S. mutans and analyze the role of some bioactive substances on its antibacterial action. The antibacterial potential of different honey varieties (goldenrod, buckwheat, honeydew, and lime) was analyzed using a microdilution assay. Manuka and artificial honey were used as controls. The content of GOX, hydrogen peroxide, total polyphenols, and antioxidant potential was assayed in honey. The influence of catalase and proteinase K on antibacterial activity as well as antibiofilm action was also determined. The strongest antibacterial activity was observed for buckwheat, honeydew, and manuka honey, which were also characterized by the highest antioxidant activity and polyphenols content. Catalase treatment decreases the antibacterial activity of honey, while proteinase K treatment influences the antibacterial potential of honey slightly less. Obtained results suggest that honey can be a good natural product against S. mutans, and hydrogen peroxide was identified as a crucial contributor to its antimicrobial action.
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Affiliation(s)
- Dorota Grabek-Lejko
- Department of Bioenergetics, Food Analysis and Microbiology, Institute of Food Technology and Nutrition, University of Rzeszow, Zelwerowicza 4 Street, 35-601 Rzeszow, Poland;
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Bucekova M, Godocikova J, Gueyte R, Chambrey C, Majtan J. Characterisation of physicochemical parameters and antibacterial properties of New Caledonian honeys. PLoS One 2023; 18:e0293730. [PMID: 37906561 PMCID: PMC10617706 DOI: 10.1371/journal.pone.0293730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 10/18/2023] [Indexed: 11/02/2023] Open
Abstract
Honey is an attractive natural product with various health benefits. A few honey-based commercial products have successfully been adopted in clinics to improve wound healing. However, screening of other potential sources of medical-grade honey, in particular, honeys from territories with high floral species diversity and high endemicity, is highly needed. The goal of this study was to characterise the physicochemical and antibacterial properties of New Caledonian honey samples (n = 33) and to elucidate the major mechanism of their antibacterial action. Inhibitory antibacterial activity of honeys against Staphylococcus aureus and Pseudomonas aeruginosa was determined with a minimum inhibitory concentration (MIC) assay. Enzymatic activity of glucose oxidase and the content of hydrogen peroxide (H2O2) in honey samples were analysed. Furthermore, total protein content of honeys together with their electrophoretic protein profiles were also determined in the study. The antibacterial efficacy of 24% of the tested honey samples was slightly superior to that of manuka honey with unique manuka factor 15+. The antibacterial activity of catalase-treated honey sample solutions was significantly reduced, suggesting that H2O2 is a key antibacterial compound of diluted honeys. However, the kinetic profiles of H2O2 production in most potent honeys at a MIC value of 6% was not uniform. Under the experimental conditions, we found that a H2O2 concentration of 150 μM in diluted honeys is a critical concentration for inhibiting the growth of S. aureus. In contrast, 150 μM H2O2 in artificial honey solution was not able to inhibit bacterial growth, suggesting a role of phytochemicals in the antibacterial activity of natural honey. In addition, the continuous generation of H2O2 in diluted honey demonstrated an ability to counteract additional bacteria in re-inoculation experiments. In conclusion, the tested New Caledonian honey samples showed strong antibacterial activity, primarily based on H2O2 action, and therefore represent a suitable source for medical-grade honey.
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Affiliation(s)
- Marcela Bucekova
- Laboratory of Apidology and Apitherapy, Department of Microbial Genetics, Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Jana Godocikova
- Laboratory of Apidology and Apitherapy, Department of Microbial Genetics, Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Romain Gueyte
- Beekeeping Center, ADECAL Technopole, Noumea Cedex, New Caledonia
| | - Céline Chambrey
- Beekeeping Center, ADECAL Technopole, Noumea Cedex, New Caledonia
| | - Juraj Majtan
- Laboratory of Apidology and Apitherapy, Department of Microbial Genetics, Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
- Department of Microbiology, Faculty of Medicine, Slovak Medical University, Bratislava, Slovakia
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Jones ZJM, Huang Y, Green KJ, Hammer KA. Changes in antibacterial activity, colour, and hydrogen peroxide content of Western Australian Jarrah and Marri honeys after storage at different temperatures over time. J Appl Microbiol 2023; 134:lxad164. [PMID: 37505452 DOI: 10.1093/jambio/lxad164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 06/08/2023] [Accepted: 07/28/2023] [Indexed: 07/29/2023]
Abstract
AIMS This study aimed to evaluate the effects of storage and different temperatures on the antibacterial activity and physicochemical characteristics of several types of honey. METHODS AND RESULTS Honeys stored for 16 weeks at 37 and 45°C showed significant declines in antibacterial activity determined by minimum inhibitory concentrations, the loss of hydrogen peroxide, decreases in honey pH, and increases in honey colour, with changes most pronounced at 45°C. In contrast, honeys stored for 16 weeks at ambient (∼22°C) and cold (4, -20, and -80°C) temperatures showed only minor changes. In a second set of 12 honeys stored for 16-32 months at ambient temperature and then 4°C, honeys showed minor changes in antibacterial activity, increases in colour, and decreases in pH. For a third set of 17 honeys stored for five years at ambient temperature, the honeys showed almost complete loss of hydrogen peroxide and were all significantly darker in colour, but showed varied changes in antibacterial activity. CONCLUSIONS Heat was detrimental to the antibacterial activity of honeys, as was long-term storage at ambient temperatures for some honeys but not others.
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Affiliation(s)
- Zachary J M Jones
- School of Biomedical Sciences, The University of Western Australia, Crawley WA 6009, Australia
| | - Yina Huang
- School of Biomedical Sciences, The University of Western Australia, Crawley WA 6009, Australia
| | - Kathryn J Green
- School of Biomedical Sciences, The University of Western Australia, Crawley WA 6009, Australia
- Cooperative Research Centre for Honey Bee Products Limited (CRC HBP), The University of Western Australia, Crawley 6009, Australia
| | - Katherine A Hammer
- School of Biomedical Sciences, The University of Western Australia, Crawley WA 6009, Australia
- Cooperative Research Centre for Honey Bee Products Limited (CRC HBP), The University of Western Australia, Crawley 6009, Australia
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, Crawley 6009, Australia
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Dong AZ, Cokcetin N, Carter DA, Fernandes KE. Unique antimicrobial activity in honey from the Australian honeypot ant ( Camponotus inflatus). PeerJ 2023; 11:e15645. [PMID: 37520253 PMCID: PMC10386826 DOI: 10.7717/peerj.15645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 06/05/2023] [Indexed: 08/01/2023] Open
Abstract
Honey produced by the Australian honeypot ant (Camponotus inflatus) is valued nutritionally and medicinally by Indigenous peoples, but its antimicrobial activity has never been formally studied. Here, we determine the activity of honeypot ant honey (HPAH) against a panel of bacterial and fungal pathogens, investigate its chemical properties, and profile the bacterial and fungal microbiome of the honeypot ant for the first time. We found HPAH to have strong total activity against Staphylococcus aureus but not against other bacteria, and strong non-peroxide activity against Cryptococcus and Aspergillus sp. When compared with therapeutic-grade jarrah and manuka honey produced by honey bees, we found HPAH to have a markedly different antimicrobial activity and chemical properties, suggesting HPAH has a unique mode of antimicrobial action. We found the bacterial microbiome of honeypot ants to be dominated by the known endosymbiont genus Candidatus Blochmannia (99.75%), and the fungal microbiome to be dominated by the plant-associated genus Neocelosporium (92.77%). This study demonstrates that HPAH has unique antimicrobial characteristics that validate its therapeutic use by Indigenous peoples and may provide a lead for the discovery of novel antimicrobial compounds.
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Affiliation(s)
- Andrew Z. Dong
- School of Life and Environmental Sciences, University of Sydney, Camperdown, NSW, Australia
| | - Nural Cokcetin
- Australian Institute for Microbiology and Infection, University of Technology, Sydney, NSW, Australia
| | - Dee A. Carter
- School of Life and Environmental Sciences, University of Sydney, Camperdown, NSW, Australia
- Sydney Institute for Infectious Diseases, University of Sydney, Camperdown, NSW, Australia
| | - Kenya E. Fernandes
- School of Life and Environmental Sciences, University of Sydney, Camperdown, NSW, Australia
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Lertsriwong S, Boonvitthya N, Glinwong C. Schwanniomyces etchellsii, acid-thermotolerant yeasts from urban city soil. World J Microbiol Biotechnol 2023; 39:159. [PMID: 37067620 DOI: 10.1007/s11274-023-03602-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 04/02/2023] [Indexed: 04/18/2023]
Abstract
Acid-tolerant yeasts are one of the important keys to producing ethanol from acidic substrates, especially from molasses and agricultural waste. In this study, selected cultivars of yeasts isolated from a variety of locations such as botanical gardens in Thailand urban areas, which are often found highly polluted in the air such as carbon dioxide which is a cause of acid rain. There is limited information about how tolerant yeasts, are or their functional properties related to the environment. Yeast species were determined by using the 18S rDNA sequence guide. The level of acid tolerance was evaluated by adding to the culture medium lactic acid (300-900 mM), acetic acid (100-400 mM), and propionic acid (25-100 mM). 18S rDNA analysis has shown a %similarity of the nucleotide sequence higher than 98.65% compared to the database. Schwanniomyces etchellsii strains found in urban city soil were notable for their tolerance of lactic acid up to 100 mM. There are two main types of yeasts in overall acid tolerance: S. etchellsii, which is recognized as an osmotic pressure-resistant species that is highly resistant to fermentation inhibitors and produces ethanol; and Schizosaccharomyces pombe, which cell wall has been reported to be characterized by accumulation of α-(1,3)-glucan and malic acid can be used in metabolic pathways. The results show that S. pombe, isolated from rice paddy fields, can grow efficiently in acetic and propionic acid up to 400 mM and 100 mM, respectively. This species could be cultured in ethanol at a concentration of 12.5% (v/v). Moreover, it presented high ethanol and acetic acid production of 14.5-15.9 g/L and 7-10 g/L, respectively, with or without acidic conditions. In comparison, S. etchellsii, isolated from the botanical garden soil, which is grown in acetic, propionic, and lactic acid, was also indicated to be an organic acid-tolerant species.
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Affiliation(s)
- Supattra Lertsriwong
- Program in Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
- Biofuels By Biocatalysts Research Unit, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | | | - Chompunuch Glinwong
- Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.
- Biofuels By Biocatalysts Research Unit, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.
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Green KJ, Lawag IL, Locher C, Hammer KA. Correlation of the antibacterial activity of commercial manuka and Leptospermum honeys from Australia and New Zealand with methylglyoxal content and other physicochemical characteristics. PLoS One 2022; 17:e0272376. [PMID: 35901185 PMCID: PMC9333225 DOI: 10.1371/journal.pone.0272376] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 07/18/2022] [Indexed: 01/22/2023] Open
Abstract
Variation in the antibacterial potency of manuka honey has been reported in several published studies. However, many of these studies examine only a few honey samples, or test activity against only a few bacterial isolates. To address this deficit, a collection of 29 manuka/Leptospermum honeys was obtained, comprising commercial manuka honeys from Australia and New Zealand and several Western Australian Leptospermum honeys obtained directly from beekeepers. The antibacterial activity of honeys was quantified using several methods, including the broth microdilution method to determine minimum inhibitory concentrations (MICs) against four species of test bacteria, the phenol equivalence method, determination of antibacterial activity values from optical density, and time kill assays. Several physicochemical parameters or components were also quantified, including methylglyoxal (MGO), dihydroxyacetone (DHA), hydroxymethylfurfural (HMF) and total phenolics content as well as pH, colour and refractive index. Total antioxidant activity was also determined using the DPPH* (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing–antioxidant power) assays. Levels of MGO quantified in each honey were compared to the levels stated on the product labels, which revealed mostly minor differences. Antibacterial activity studies showed that MICs varied between different honey samples and between bacterial species. Correlation of the MGO content of honey with antibacterial activity showed differing relationships for each test organism, with Pseudomonas aeruginosa showing no relationship, Staphylococcus aureus showing a moderate relationship and both Enterococcus faecalis and Escherichia coli showing strong positive correlations. The association between MGO content and antibacterial activity was further investigated by adding known concentrations of MGO to a multifloral honey and quantifying activity, and by also conducting checkerboard assays. These investigations showed that interactions were largely additive in nature, and that synergistic interactions between MGO and the honey matrix did not occur.
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Affiliation(s)
- Kathryn J. Green
- School of Biomedical Sciences, The University of Western Australia (UWA), Crawley, Western Australia, Australia
- Cooperative Research Centre for Honey Bee Products Limited (CRC HBP), Yanchep, Western Australia, Australia
| | - Ivan L. Lawag
- Cooperative Research Centre for Honey Bee Products Limited (CRC HBP), Yanchep, Western Australia, Australia
- Division of Pharmacy, School of Allied Health, UWA, Crawley, WA, Australia
| | - Cornelia Locher
- Cooperative Research Centre for Honey Bee Products Limited (CRC HBP), Yanchep, Western Australia, Australia
- Division of Pharmacy, School of Allied Health, UWA, Crawley, WA, Australia
| | - Katherine A. Hammer
- School of Biomedical Sciences, The University of Western Australia (UWA), Crawley, Western Australia, Australia
- Cooperative Research Centre for Honey Bee Products Limited (CRC HBP), Yanchep, Western Australia, Australia
- The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, UWA, Crawley, WA, Australia
- * E-mail:
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Guttentag A, Krishnakumar K, Cokcetin N, Hainsworth S, Harry E, Carter D. Inhibition of Dermatophyte Fungi by Australian Jarrah Honey. Pathogens 2021; 10:194. [PMID: 33670403 PMCID: PMC7918412 DOI: 10.3390/pathogens10020194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/03/2021] [Accepted: 02/05/2021] [Indexed: 12/24/2022] Open
Abstract
Superficial dermatophyte infections, commonly known as tineas, are the most prevalent fungal ailment and are increasing in incidence, leading to an interest in alternative treatments. Many floral honeys possess antimicrobial activity due to high sugar, low pH, and the production of hydrogen peroxide (H2O2) from the activity of the bee-derived enzyme glucose oxidase. Australian jarrah (Eucalyptus marginata) honey produces particularly high levels of H2O2 and has been found to be potently antifungal. This study characterized the activity of jarrah honey on fungal dermatophyte species. Jarrah honey inhibited dermatophytes with minimum inhibitory concentrations (MICs) of 1.5-3.5% (w/v), which increased to ≥25% (w/v) when catalase was added. Microscopic analysis found jarrah honey inhibited the germination of Trichophyton rubrum conidia and scanning electron microscopy of mature T. rubrum hyphae after honey treatment revealed bulging and collapsed regions. When treated hyphae were stained using REDOX fluorophores these did not detect any internal oxidative stress, suggesting jarrah honey acts largely on the hyphal surface. Although H2O2 appears critical for the antifungal activity of jarrah honey and its action on fungal cells, these effects persisted when H2O2 was eliminated and could not be replicated using synthetic honey spiked with H2O2, indicating jarrah honey contains agents that augment antifungal activity.
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Affiliation(s)
- Annabel Guttentag
- Marie Bashir Institute, School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia; (A.G.); (K.K.)
| | - Krishothman Krishnakumar
- Marie Bashir Institute, School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia; (A.G.); (K.K.)
| | - Nural Cokcetin
- ithree Institute, University of Technology Sydney, Sydney, NSW 2007, Australia; (N.C.); (E.H.)
| | | | - Elizabeth Harry
- ithree Institute, University of Technology Sydney, Sydney, NSW 2007, Australia; (N.C.); (E.H.)
| | - Dee Carter
- Marie Bashir Institute, School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia; (A.G.); (K.K.)
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Guttentag A, Krishnakumar K, Cokcetin N, Harry E, Carter D. Factors affecting the production and measurement of hydrogen peroxide in honey samples. Access Microbiol 2021; 3:000198. [PMID: 34151153 PMCID: PMC8209695 DOI: 10.1099/acmi.0.000198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 12/17/2020] [Indexed: 11/18/2022] Open
Abstract
Many Australian native honeys possess significant antimicrobial properties due to the production of hydrogen peroxide (H2O2) by glucose oxidase, an enzyme derived from the honeybee. The level of H2O2 produced in different honey samples is highly variable, and factors governing its production and stability are not well understood. In this study, highly active Australian honeys that had been stored for >10 years lost up to 54 % of their antibacterial activity, although almost all retained sufficient activity to be considered potentially therapeutically useful. We used a simple colourimetric assay to quantify H2O2 production. Although we found a significant correlation between H2O2 production and antibacterial activity across diverse honey samples, variation in H2O2 only explained 47 % of the variation observed in activity, limiting the assay as a screening tool and highlighting the complexity of the relationship between H2O2 and the killing power of honey. To further examine this, we tested whether H2O2 detection in honey was being inhibited by pigmented compounds and if H2O2 might be directly degraded in some honey samples. We found no correlation between H2O2 detection and honey colour. Some honey samples rapidly lost endogenous and spiked H2O2, suggesting that components in honey, such as catalase or antioxidant polyphenols, may degrade or quench H2O2. Despite this rapid loss of H2O2, these honeys had significant peroxide-based antibacterial activity, indicating a complex relationship between H2O2 and other honey components that may act synergistically to augment activity.
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Affiliation(s)
- Annabel Guttentag
- School of Life and Environmental Sciences and the Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW 2006, Australia
| | - Krishothman Krishnakumar
- School of Life and Environmental Sciences and the Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW 2006, Australia
| | - Nural Cokcetin
- ithree Institute, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Elizabeth Harry
- ithree Institute, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Dee Carter
- School of Life and Environmental Sciences and the Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW 2006, Australia
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