Contribution of hydrogen peroxide to the antibacterial activity of Western Australian honeys

Project Supervisor: Dr Kate Hammer

Western Australia is a biodiversity hot spot and has unique endemic plants. When bees forage on each unique plant species, they collect pollen and nectar, and from these they produce a wide variety of floral honeys. Unique WA honeys, known as monofloral or varietal honeys, include Jarrah, Marri, Blackbutt, Moort, Banksia, Mallee, Wildflower and a range of other distinct honeys.

Honey has been used as a medicinal agent for centuries and has useful medicinal properties including antimicrobial and anti-oxidant activity. Some honeys, such as Manuka honey from New Zealand are well characterised for their beneficial properties whilst other honeys, including those from WA remain less investigated.

Aims

The aim of this research is to examine the role of hydrogen peroxide in the antibacterial activity of Western Australian honeys.  Hydrogen peroxide is produced in honey after the addition of water and is catalysed by the bee-derived enzyme glucose oxidase.  Levels of hydrogen peroxide produced vary between honeys and also vary over time and with the concentration of honey.

The aims of this project are to:

  1. Quantify levels of hydrogen peroxide produced in several Western Australian honeys
  2. Examine how the generation of hydrogen peroxide impacts on antibacterial activity
  3. Assess different antibacterial assays for their capacity to detect changes in bioactivity
  4. Evaluate the overall contribution of hydrogen peroxide activity to total activity

Techniques

  1. A broth microdilution method will be used to assess antibacterial activity
  2. An agar diffusion method will be evaluated to determine whether minor changes in bioactivity are detectable
  3. Time kill assays will be used to further investigate bioactivity
  4. A colorimetric assay will be used to quantify hydrogen peroxide levels

Reference(s)

Irish J, Blair S, Carter DA (2011). The antibacterial activity of honey derived from Australian flora. PLoS One, 6(3), e18229.

Kwakman PH, te Velde A, de Boer L, Vandenbroucke-Grauls CMJE, Zaat, SAJ. (2011). Two major medicinal honeys have different mechanisms of bactericidal activity. PLoS One, 6(3), e17709.

Brudzynski K1, Abubaker K, St-Martin L, Castle A. (2011) Re-examining the role of hydrogen peroxide in bacteriostatic and bactericidal activities of honey. Front Microbiol. 2011 25;2:213.

Roshan N, Rippers T, Locher C, Hammer KA. (2016) Antibacterial activity and chemical characteristics of several Western Australian honeys compared to manuka honey and pasture honey. Archives of Microbiology Accepted for publication DOI 10.1007/s00203-016-1308-3.