What is activity?
The term "activity" in the context of bioactive honeys is used to refer to the strength or potency of the honey in inhibiting bacterial or microbial growth.
There are two different types of activity: peroxide and non-peroxide activity honeys. Although different in their chemical composition, both peroxide and non-peroxide honeys produce an antimicrobial effect and thus comparable health benefits and immune support.
Western Australian honeys such as the Jarrah, Red Gum and Blackbutt are peroxide honeys (with their active component being enzymatic hydrogen peroxide), while Manuka is a non-peroxide honey (with its active component being methylglyoxal or MGO).
Comparison table
Studies have been conducted to test the level of non-peroxide activity and their corresponding level of MGO in Manuka honey. The following comparison table is based on those studies and research on Manuka honey being sold on the market today.
| TA / UMF | MGO |
|---|---|
| 5 | 83 |
| 10 | 263 |
| 15 | 514 |
| 20 | 829 |
| 25 | 1,200 |
| 28 | 1500 |
| 31 | 1700 |
(NB: there is no Manuka honey sold commercially in Australia that is marketed as higher than UMF 31+ / MGO 1,700+)
The different units of activity
Total Activity (or TA) is a measure of both peroxide and non-peroxide activity.
There are two alternative grades of activity that are well known in the market today - UMF and MGO, which are both used in the marketing of Manuka honey.
UMF (or Unique Manuka Factor) is a grading system that incorporates the measurement of non-peroxide activity levels in Manuka honey, as well as certifying the claim that the honey is Manuka honey.
MGO is simply a measurement of the concentration of MGO in a sample of honey in mg/kg as an indicator of the honey's non-peroxide activity.
Testing methods
The method used to measure the level of activity in TA and UMF is called "radial diffusion assay". Honey is placed into a well on an agar plate and the amount (distance) that it diffuses through the agar and inhibits the growth of the bacteria (Staphylococcus aureus) is compared to a standard material (phenol). The total activity results are reported as a % phenol equivalent.
A calibration curve is generated by the dilution of the phenol, with the upper standard being 35% - thus, the maximum TA or UMF value that can be reported is ">35%".
This method of measurement of activity measures the antimicrobial effect of the honey rather than the causal agent, and so for the purpose of comparing activity level, TA can be compared with UMF on a like-for-like basis.
UMF also takes into account the presence of two other compounds found in Manuka honey, being Leptosperin and dihydroxyacetone (or DHA), which are indicators to support the claim that the honey is Manuka honey.
To measure MGO, the actual concentration of MGO in the honey is measured using liquid chromatography mass spectrometry. The MGO compound is separated out from the rest of the honey during the analysis, and the instrument response is quantified against a series of MGO calibration standards. The actual concentration of MGO in the honey is then reported in mg/kg.
How to read activity levels
In general, any activity level beyond a TA or UMF of 10, or an MGO of 263, is considered therapeutically active.
A Buzz from the Bees ensures that each batch of honey sold is tested by the Australian National Measurement Institute, an Australian government body, for Total Antimicrobial Activity (or TA). With a range of honeys that are measured beyond TA15+, our customers can be confident that they are provided with only the highest quality and highest activity Western Australian honey.
If you have any questions relating to activity, please feel free to contact us.
Sources
Cokcetin et al. The Antibacterial Activity of Australian Leptospermum Honey Correlates with Methylglyoxal Levels. PLOS ONE, December 2016.
Adams et al. Isolation by HPLC and characterisation of the bioactive fraction of New Zealand manuka (Leptospermum scoparium) honey. Carbohydrate Research, March 2008.