Growing catnip, mosquito repellence, and economic prosperity in Uganda

Impact Acceleration Account (IAA) funding and cross-school collaboration have enabled the development of a novel mosquito repellent made from catnip, supporting local economies while redefining malaria prevention for generations to come.

Dr Peter Randerson and Dr Simon Scofield, Senior Lecturers at the School of Biosciences, together with Professor John Pickett from the School of Physical, Chemical and Environmental Sciences, are using essential oils extracted from catnip to create a sustainable, plant-based mosquito repellent that is grown locally to the communities where it will make the greatest difference.

Since 2016, the team has received several awards for translational research, including three Impact Acceleration Account (IAA) awards.

Peter’s interest in developing agri-business in Uganda and a £1,000 grant from the Welsh Government’s Wales and Africa scheme were the catalyst for a decade of research. His work has been the foundation for local Ugandan populations to support themselves through farming – while growing the very crops that will help to repel mosquitoes and protect them against malaria.

“It was all about mint in the early days,” he recalls. “It was a crop which the local people of Uganda could produce on site. In 2016, we saw an opportunity to introduce a new crop that is easy to extract valuable essential oils from.

“Mint extracts – particularly menthol and carvone, which is the smell that you get from peppermint and chewing gum – go into so many products worldwide: everything from tea to toothpaste.

“Once you’ve got your mint extracted at low cost, there are all sorts of potential applications,” Peter says. His initial funding enabled the production of mint-flavoured food, drinks, and scented shampoo.

“Mint can be inter-cropped – grown between other crops without taking any additional ground space – which maximises Ugandan farmers’ income,” Peter explains.

Peter’s subsequent work has explored using plant-based essential oils in other ways. “The mint family of plants, which includes lavender, basil, and catnip, produces a wide variety of chemicals that can be extracted as essential oils – and some of those chemicals are very valuable.”

By 2017, Dr Simon Scofield had established a collaboration with Peter, bringing plant biotechnology and genetics to the project, along with Professor John Pickett, who specialises in biological chemistry.

Global Challenges Research Fund (GCRF) grants enabled the team to explore variations of mint plants and the potential of a chemical found in catnip: nepetalactone.

“Following a GCRF grant, we travelled to Uganda to build on Peter’s existing collaborations, and while there, we saw a clear need for an alternative personal mosquito repellent.

“Standard options like DEET are very expensive in Uganda, as it is made and imported from South Africa. Globally, malaria is a huge problem, but particularly in the Budaka district of eastern Uganda that we are working in.

“Current malaria prevention efforts see money being poured into mosquito nets, but sometimes they’re not well used. We saw piles of nets waiting to be distributed in the Budaka health clinic, but nets sometimes become used by local people for other purposes such as fishing, rather than putting them on their beds,” says Dr Scofield.

“And you may be protected from being bitten while you’re under a mosquito net in bed, but mosquitoes bite from the late-afternoon onwards.

“So what about when Mum is preparing the evening meal and the kids are running around playing in the yard, or people are socialising outside after a day’s work?”

This motivated Simon and Peter to adapt their mint plantations and distillation equipment, focusing their efforts on developing catnip oil as a sustainable mosquito repellent.

The team set out to examine whether their catnip oil could deliver results.

“John has already well documented in his scientific literature that catnip oil has insect-repellent qualities. But we wanted to know whether the specific strain we were using, grown in Uganda and distilled with our equipment, would work,” Dr Scofield explains.

Their Ugandan academic partners, Professor Ivan Mukisa of Makerere University, and Charles Batume, who now works for the Ugandan Virus Research Institute at the Entebbe Research Station, were able to show great results in the lab.

The team tested practical application with a catnip oil hand lotion. Studies showed that the repellent effect from a single application lasted four to five hours.

Impact Acceleration Account (IAA) funding enabled the team to carry out human efficacy trials.

Simon explained how the grant was used to answer some important questions:

“We wanted to know how the repellent worked in the field. If we put it on somebody, will it help them in the evening walking around Uganda? So we conducted some quite large-scale field trials where we used a technique called the ‘human landing catch assay’.

“A participant sits out in the field in a chair, covered from head to toe with only the calf of one leg exposed. They have the lotion put on their leg, and then they count the number of mosquitoes that land in a four-hour period. They use a pooter to suck up the insect and capture it. And then we count them and identify what species it is.”

To test the effectiveness of the catnip lotion, the team compared it with DEET and with a control lotion that had neither DEET nor nepetalactone mixed in.

Two separate field trials in two different locations gathered data over three nights. It showed that when the lotion was tested with concentrations of 2% catnip oil and 6% catnip oil, 6% was as effective as DEET – and 2% only slightly less so.

“It sounds like it’s not much of a difference, 2% to 6%, but 6% would require three times as much oil to produce as the 2%, which isn’t as cost-effective,” says Simon.

A field trial participant using the human landing catch assay technique.

Repelling mosquitoes wasn’t the project’s only success.

“We had ethical approval for all the trials from both Cardiff University and a hospital research ethics committee in Uganda,” Simon says. “The American USDA has also done several studies on toxicity reactions of the lotion to the skin, and it’s completely harmless.”

The lotion was then given to locals to try. “They really liked it. It’s so easily absorbed by the skin. They told us they liked the feel of it, the smell of it, the texture, everything,” Dr Scofield enthused.

The bespoke lotion was then formulated by colleagues at the Ugandan Government Research Institute in Kampala, to include emollients and antibacterial agents that act as a lotion preservative, and the oil percentage specified by Simon, Peter, and John.

The team’s thoughts then turned to securing the longevity of the project and upscaling production, supported by a Strategic Impact Fund IAA award.

“We wanted to optimise extraction of the oil, so we tried lots of different techniques, including extracting the plants directly into the ingredients used to make the repellent instead of distilling the oil,” Simon tells. “But, ultimately, we found that oil distillation is the best way to get the high concentration that we need.”

Simon and Peter then employed Cardiff-based business consultants Lisk and Jones to develop their business plan and calculate the associated costs of expanding their manufacturing.

“We wanted to increase our land acreage to install and modify automated irrigation equipment, to produce 3,000 bottles of repellent, which we would then roll out across the district for free.

“We’ve also met with local practitioners in the malaria clinics, and they were very excited about the possibility of the locals having this product. So our next stage is about infrastructure and capacity-building,” Simon explained.

“Once we know we can produce this at a scale where we can distribute it, it’s a case of just expanding in a modular way. We take on another field, expand the irrigation system a little bit further. Then we can produce more bottles every year.

“Initially, it will cost more to produce if we’re only producing a few thousand bottles. But by the time we’re producing half a million bottles, the idea is it would be much, much cheaper – and all from plants grown by local farmers who benefit from selling the crop.”

The ultimate goal of the project is to become independent of grant funding and to sell the lotions to the Ugandan local authority for free distribution. Their expanded business plan also covers packaging, distribution, and marketing, using radio adverts and promotional leaflets to generate income for local businesses.

Through established contacts and a 2025 Knowledge Exchange Partnership IAA award, the team were also able to gather support from the Ugandan government. After meeting with the Science, Technology and Innovation Secretariat, the project was given Level 2 support, which gives access to government infrastructure in order to roll the product out.

“We met with the regional officials, and once they’re on board, it’s easy to get the tribal leaders on board. The local community put their trust in those people.”

“Through multiple IAA awards, we were able to use smaller amounts of funding to keep the momentum of our project going.”

Dr Simon Scofield explains how his work with Peter and John was made possible by Impact Acceleration Account (IAA) funding.

Learn more about IAA funding

Simon, Peter, and John are focused on the economic stability of the Ugandan communities they work with and setting them up for the future.

“This is about all of the people involved, the stakeholders in every chain of the pipeline – from the farmers, to the people harvesting material, to the people distilling the oil and formulating the lotions.

“Plant oils have a lot of uses. We could have made something with more commercial value, like perfume, but then there wouldn’t be this additional healthcare benefit,” Simon emphasises.

To support local development, Dr Randerson founded partner organisation Community Enterprise Model for Plant Oil Production (CEMPOP) in 2016, led by Sarah Mutaka Logose.

“We bring in the grants, but CEMPOP run the show in Uganda,” Peter says. “They oversee how the money is spent and organise everything.”

Over the last ten years, Simon and Peter’s projects have employed over 70 people in various capacities, from brick makers to metal fabricators, with emphasis on employing women and young people. This is especially important for the younger generations who would otherwise have to travel to larger cities in search of stable income.

“The man who built our first distillation house fabricated his own bricks, which he now sells and builds other buildings with. He also employs local young people to make his bricks, keeping his business turning over,” Peter says.

Their mint oil distillation project also enabled a local response to the immediate global threat of the coronavirus (COVID-19) outbreak: mint-scented hand sanitiser was put into production. The legacy of this allowed a local woman to create her own sanitiser business and build economic stability, enabling her to educate her children and pursue a Pharmacy degree.

Dr Scofield revisited the project site in October 2025 and was overjoyed by the impact on the community: “I was just so impressed with the scale of what’s been achieved, the number of people involved, and how far they've come with it. It's something people are really keen to be a part of.”

That civic pride led to the mosquito lotion’s brand name, DSK. Dison Stephen Kalebo was a prominent community leader and local employer, and the lotion is named in his memory.

The next move for the team includes aspirations to roll out similar projects in neighbouring countries, and, eventually, the global north.

“Once we have fully launched in Uganda, the idea is to support projects in surrounding countries such as Kenya and Tanzania. We then may be able to bring our lotion to the global north as a marketable product for profit. We can then funnel the funds back to where it all started,” Simon hopes.

The project is already subject to wider interest, with the team giving talks about their work globally, from Ukraine to Italy, and gaining coverage from The Guardian: “As a locally grown, plant-based lotion, it’s a very attractive product. These things are not only important for sustainability but also to consumers.”

The team are also planning an awareness campaign for Parthenium hysterophorus, or ‘Santa Maria feverfew’ weed: a wild plant that attracts mosquitoes, evidenced by field and laboratory observations by John. High in sugar, the plant serves as a popular food source before the mosquito searches for a blood meal.

Native to the American tropics, the Santa Maria feverfew has become an invasive species in many regions across the globe, including Africa. It has contributed to recent surges of malaria in Uganda, Simon explains: “This plant is everywhere. It’s outside the malaria clinics. It’s outside the schools. It’s outside people’s houses. But locals had no idea why so many mosquitoes were being brought in.”

The awareness campaign will focus on encouraging locals to destroy the weeds on site, reducing the draw of mosquitoes and, in turn, the risk of infection.

Simon, Peter, and John’s work has changed local economies and now has the potential to expand malaria care into pragmatic action and sustainable products that will benefit future generations.