Native bee honey stops every bacterium tested in new study

The study, by PhD candidate Jasmin Li and research fellow Kenya Fernandes, both of the University of Sydney, tested honey and propolis from the small black bee, which is found along Australia's east coast from tropical Queensland to temperate New South Wales, against 16 types of disease-causing bacteria and fungi.

Drug-resistant infections are on the rise, and developing new drugs is difficult, expensive and slow, which has pushed researchers to look beyond conventional medicines. Australia is home to 11 of the world's roughly 550 stingless bee species, and Indigenous Australians have long valued the honey of this one, known as sugarbag, as food and medicine for itchy skin and sores.

Unlike honeybees, stingless bees build almost everything from propolis, a blend of plant resin and their own wax, and store their runny honey in small sealed pots made of this material. The honey is about a quarter water, compared with at most a fifth in honeybee honey, yet much of it stays free of harmful microbes.

Most honey relies on hydrogen peroxide, a natural antiseptic produced by enzymes the bees produce, but in honeybee honey that burst lasts only hours. Native bee honey can keep producing peroxide for up to a week, and it stayed active after heating destroyed the peroxide. Even samples kept in a fridge for 18 years, which had lost their peroxide entirely, retained their antimicrobial activity. One possibility is that plant compounds called phenolics, some of which fight microbes, are involved. Another is that, compared with honeybee honey, it contains a different mix of proteins, some of which may attack microbes directly.

The propolis was a different kind of weapon. Extracts from eight nests stopped the fungi behind ringworm and athlete's foot, plus a mould called Rhizopus behind rare but dangerous infections, at concentrations roughly equal to a pinch of salt in a ten-litre bucket, while doing nothing at all against some other fungi. Every sample showed the same pattern. One possibility is that the bees' chemical defences help protect the nest from harmful microbes without disrupting beneficial fungi, and the effect on human skin fungi may be a lucky side effect.

Medical-grade honey is already used in wound care, giving honey-based products a head start over entirely new drugs. But the authors say the next steps are to develop suitable formulations, investigate storage, and test safety and effectiveness for specific uses, and that supply is a challenge because stingless bee colonies produce relatively small amounts of honey. Growing interest in keeping native bees could create opportunities to increase production sustainably, they add, and identifying the compounds behind these effects could reveal new molecules to inspire future antimicrobial treatments. The next treatment for a grazed knee gone bad, they suggest, might come from a native bee nest rather than a pharmaceutical lab.