A report published by the Western Australian Department of Agriculture and Food in September 2011 conducted a series of tests from 342 honey samples from commercial beekeepers in the south west region of Western Australia from 1999 to 2004. The honey was tested against Staphylococcus aureus ‘Golden Staph’.
It found that the two native Western Australian honeys derived from Marri (Corymbia calophylla) and Jarrah (Eucalyptus marginata) trees were found to have consistently high antimicrobial activity of all honeys surveyed. The activity of the two endemic species was about 90% greater than the average activity of New Zealand’s manuka honey.
Marri and Jarrah, had high average antimicrobial activity of 31.1% and 30.2% (w/v) phenol equivalent, respectively against S. aureus. The activity was significantly higher than New Zealand’s manuka honey, which averaged 15.8% phenol
Previous research conducted by Dr Rob Manning and Nola Mercer of the Department of Agriculture in Feburary 2002, showed that Western Australian honey had some of the highest activity levels in the world due to a naturally occurring enzyme in the honey. Upon dilution of honey, the enzyme glucose oxidase produces low concentrations of hydrogen peroxide which is the source of its antimicrobial activity. It is different to Manuka (Leptospermum scoparium) honey from New Zealand which is termed a ‘non-peroxide’ honey because it’s activity is derived from a chemical called methylglyoxal (MGO)
Both Jarrah and Manuka honeys are active and healing honeys, meaning that they have antibacterial properties. However, Jarrah honey also has antimicrobial activity meaning it can also fight off virus pathogens whereas Manuka is only antibacterial.
The taste profiles of Jarrah and Manuka are also very different which is explained by the active enzymes within each honey that allows it to be classified as medicinal. Manuka’s active compound methylglyoxal contributes to the grainy, earthy and bitter taste. Whereas jarrah’s active compound is the naturally occurring hydrogen peroxide and this does not affect taste or texture allowing it to remain a smooth and subtly sweet dark amber honey, which typically is associated with a high concentration of antioxidant properties and healing enzymes.
The level of antimicrobial activity is measured by a term called “Total Activity” or TA. This number represents the antimicrobial strength of the honey, meaning the higher number on the scale, the greater antimicrobial strength of that honey. Total activity considers the medicinal properties from both peroxide activity and also non peroxide activity. Jarrah Honey gets almost all of its medicinal properties from peroxide activity whereas Manuka honey gets all of its medicinal properties from an enzyme called methylglyoxal (MGO) which is considered non peroxide activity.
The MGO forms over time in the honey from the interaction of a chemical called dihydroxyacetone (DHA), which originates from the nectar of the Manuka flower, and other naturally-occurring proteins and amino acids in the honey.
Beekeepers that produce Manuka have two ways to identify the activity of the Manuka honey they produce that often confuse the consumer due to their widely differing numbers. The UMF (Unique Manuka Factor) is a trademarked term to describe the non peroxide activity in honey and typically ranges from 5+ to 20+. The MGO value, which is the methylgloxal content in mg/kg values range from about 100 to 1,000. The table above shows approximate equivalent values of TA - UMF - MGO to try and help consumers understand the wide range of ratings that ultimately measure the same activity variable.
Molan P (2006) The evidence supporting the use of honey as a wound dressing. The International Journal of Lower Extremity Wounds. 5(1), 40-54.
Irish J, Blair S, Carter DA. The antibacterial activity of honey derived from Australian flora. PLoS One. 2011;6(3):e18229. Published 2011 Mar 28. doi:10.1371/journal.pone.0018229
Manning, R J. (2011), Research into Western Australian honeys. Department of Primary Industries and Regional Development, Western Australia, Perth. Report.