Honey made by ants could treat some bacterial and fungal infections

Honey produced by a type of ant in Australia has antimicrobial properties that could one day lead to new treatments against some bacterial and fungal infections.

Australian honeypot ants (Camponotus inflatus) are found in arid regions of central and western parts of the country. Their colonies are made up of ordinary worker ants and a specialised group of workers called repletes. These gather nectar that they stuff into their extended abdomens, giving them a glassy, amber hue.

“They are basically the holding vessels of the nectar that is brought in,” says Andrew Dong at the University of Sydney, Australia. By regurgitating the nectar, the replete ants produce a honey that feeds the rest of colony.

For thousands of years, Indigenous Australians have eaten this honey and used it to treat sore throats, wounds and skin ulcers, says Danny Ulrich, an Indigenous Australian who assisted the researchers.

In a laboratory experiment, Dong and his colleagues exposed a range of bacterial and fungal pathogens to different doses of the honey. They found that a water solution made up of 8 per cent honey killed the bacterium Staphylococcus aureus – a leading cause of skin and soft tissue infections that can also lead to pneumonia or enter the blood, bones or joints.

At a 16 per cent concentration, the honey killed some fungi species, such as Aspergillus fumigatus and Cryptococcus deuterogattii, which can both cause serious medical complications.

When the researchers compared the ant honey to types of bee honey with known antimicrobial properties, such as Manuka, the ant honey killed a narrower range of bacteria and fungi. For example, it was ineffective against fungi such as Candida albicans, which can cause thrush, and bacteria like Escherichia coli, a cause of food poisoning. Manuka and other types of bee honey killed both of these pathogens.

Most honey made by bees contains hydrogen peroxide, which is thought to be the source of its antimicrobial properties. Ant honey contains much less of this molecule, suggesting that there is something chemically unique about it, says team member Kenya Fernandes at the University of Sydney. “We hypothesise that it’s most likely to be an antimicrobial peptide that is being produced by the ants.”

Ant honey is rare and culturally significant to Indigenous Australians, says Fernandes. It is therefore unlikely to ever be used directly in medicines, she says. The team hopes to identify the honey’s active compounds so these can one day be replicated when developing new treatments, says Fernandes.