Last year, Waikato University researcher Merilyn Manley-Harris showed that methylglyoxal was responsible for New Zealand Mānuka honey’s antibacterial properties.

The antibacterial wound-healing properties of Mānuka honey are proven, but research has also shown that this antibacterial activity is only present in some Mānuka honeys.

Further investigation at a specialist laboratory in Singapore has also examined the active fractions in Mānuka honey.

Honey with knife

The results show the existence of a formerly unknown synergist, a molecule that combines with the methylglyoxal molecule and other fractions in the honey to create the powerful antibacterial activity Mānuka honey is known for.

Scientists believe this discovery will also be the key to understanding why the honey’s antibacterial activity is so effective and why bacteria fail to develop resistance to it.

Further research is now underway to confirm the mode of action of the synergist and to understand its interaction with other fractions, including methylglyoxal. This will provide a full scientific understanding of Mānuka honey’s antibacterial properties.

“Not all Mānuka honeys are equal, and the way to test potency has been an issue for some time,” Professor Peter Molan of Waikato University says.

“My original assay uses a simple test method of comparing the bacterial kill-zone of a honey sample to that of a standard antiseptic. For a variety of reasons, this can’t be perfect and is open to interpretation and a margin of error. The ideal is to have a simple chemical test that can be carried out by any lab, but this isn’t possible until we know what we’re trying to measure. Discovering the synergist was the key,” Professor Molan explains.

Current work includes developing an algorithm to find the strength of a honey’s antibacterial activity by measuring the level of the synergist and the level of methylglyoxal present. It will then be possible to precisely determine the non-peroxide activity of Mānuka honey by chemical analysis.