Kānuka trees grow throughout New Zealand and have long been a part of traditional Māori healing or rongoā. With antimicrobial, anti-fungal and anti-inflammatory properties, historically, the leaves of kānuka were ground and extracted into a tea to help with gastrointestinal pain, or turned into a paste to help with skin infections. Its steam vapours were used to treat respiratory problems.
Now scientists are looking at what else the bio-active ingredients in this native plant might help. Already, a 2022 New Zealand clinical trial, has identified that adding kānuka essential oil to an emollient cream made it more effective at treating moderate-to-severe eczema than using the cream on its own.
Now, there is an even more intriguing potential for kānuka. Exploratory science conducted here suggests that it may have a part to play in the ongoing quest to extend human lifespan.
This finding is the result of a partnership between Wellington’s Te Herenga Waka – Victoria University of and Ruatōria-based Hikurangi Bioactives, which develops products derived from kānuka oil.
Dr Andrew Munkacsi, a senior lecturer in biological sciences at the university, has been working with his team on different aspects of steam-extracted oil from kānuka leaves harvested on the East Coast.
“The aim was to get a better understanding of it and build on all the traditional knowledge that already exists,” he explains. “And also, perhaps find an unsuspected new mechanism and potential use.”
Researchers first looked at the chemical profile of their kānuka oil. One of the compounds found was nerolidol. This is a terpene, present in the essential oils of other plants, and part of their natural defence mechanism.
Nerolidol was already being investigated for its potential as a therapeutic and now Munkacsi’s experiments, using strains of yeast, have uncovered for the first time that it has a synergy with the drug rapamycin, which is very much a part of the longevity landscape, since it targets the cellular effects of ageing.
“Rapamycin is probably going to be the next lifespan-extending drug,” says Munkacsi. “It has already been shown to extend the lifespan of yeast and mice.”
While rapamycin was developed initially as an immunosuppressant to prevent organ rejection in transplant patients, the drug is now seen as a promising therapy for everything from cancer to cardiovascular disease, and there is excitement around its potential to slow the ageing process. It is currently being trialled in dogs and humans. However, rather than waiting for conclusive data, some people are already using it as an anti-ageing biohack.
Rapamycin mimics the effects of calorie restriction, inhibiting a pathway called mTOR and thus enhancing cellular repair processes. But there is a problem. At clinically effective doses rapamycin can be toxic, with side effects including anaemia, high blood sugar levels and kidney problems. It can also reduce the body’s ability to fight off infection.
“The billionaires around the world who use it to extend their life are cautious about the amount they take,” says Munkacsi.
One longevity-obsessed tech entrepreneur, Bryan Johnson, recently announced that he had stopped taking rapamycin because of worrying side effects including delayed wound healing, raised cholesterol, spikes in blood sugar, mouth ulcers and a higher resting heart rate. Johnson believes he may even have accelerated his speed of ageing.
He may be among those interested to hear that, thanks to its similar signature, Munkacsi’s kānuka extract seems to increase the bioavailability of rapamycin, which could mean that when used in combination with the drug, it would lower the dose required and avoid nasty side effects.
So far, this has been shown only in a preliminary study involving yeast. The next step would be to examine the effect of the kānuka/rapamycin combination in animal cells. Munkacsi concedes it is entirely possible that, even with small doses, the same unwanted side effects might happen. “This is a first step,” he says. “But there is a lot of interest in taking the next one and seeing it tested in mammalian cells.” l
