Enhancing essential oil feedstocks and high-value products from Mentha species for local Ugandan economies.

Lead Research Organisation: Cardiff University
Department Name: School of Biosciences


Several aromatic oil compounds (essential oils) of high commercial value are produced naturally by the leaves of mint plants (Mentha). Mint oil extracts are promoted for their health benefits and are used to flavour drinks, ice cream, chewing gum, as well as in cosmetics and personal care products such as toothpaste and shower gel. Menthol is a key component of mint essential oils, particularly those isolated from peppermint Mentha x piperita, and has a large international market with a value of around $800m p.a. Another chemical component, nepetalactone, a potent natural insect repellent normally found in catnip, has recently been identified in the pineapple mint species Mentha suaveolens. As part of a previous collaborative project, the potential for mint as a non-food crop for Ugandan farmers has been explored, a mint garden with selected varieties established near Kampala, and pilot-scale distillation equipment constructed to extract oil from a harvested spearmint crop. This suggests that wide-scale commercial cultivation of mint crops in Uganda could represent a viable resource for globally competitive production of mint essential oils. This project aims to develop novel mint varieties for cultivation in Uganda to produce high yields of essential oils containing menthol or nepetalactone which will be used to develop locally-produced products for the benefit of the rural Ugandan economy.
This application, involving partnerships between Cardiff (Wales) and Makerere (Uganda) Universities, seeks to maximise the production of selected essential oils using two parallel strategies. Firstly, we will screen a range of mint varieties to identify those with naturally high yields of menthol or nepetalactone using biochemical analysis (chromatography) of extracted oils, and those with the largest abundance of oil-bearing glandular leaf hairs (trichomes) by microscopic analysis of the leaf surface. The second strategy will be to manipulate key genes involved in the biosynthesis of essential oils in the leaf, with the aim of creating new 'elite' mint varieties by up-regulating the production of menthol. Such genetic modifications are feasible, due to recent advances in scientific understanding of the biochemical pathway leading to menthol production in mint oil. The most promising mint varieties will be selected for subsequent field trials to determine their viability for growth under potentially conditions of water availability, shading and soil type, in three regions of Uganda.
Together with our partners in Uganda, we will create local Community Enterprise (CE) groups to propagate and distribute plant material to farmers, and provide the necessary training to cultivate/harvest the crop, ensuring agricultural best practice. In turn, this will improve local systems of agricultural production, harvesting and extraction technology and result in substantive up-skilling of the local rural population. In addition, we will devise agro-economic models of mint crop production, and develop business plans and marketing strategies to guide emerging local business ventures. This project will ensure that sustainable financial benefits accrue principally to local communities in Uganda, via CE groups set up to grow, harvest and exploit new mint crops. The project will explore the development of products for sale in collaboration with local-based partners, enabling rural populations in Uganda to benefit sustainably from science-based enhanced production of mint essential oils.

Technical Summary

This multi-facetted proposal aims to increase production of the natural oil compounds, menthol and nepetalactone, in Mentha species and then utilise these terpenoids to create as high-value products for the rural Ugandan economy.
We will build a collection of Mentha species and characterise their natural oils and suitability for growth in Uganda. Correlation of trichome density with oil production will allow a simple method to be used in Uganda to identify promising new species. We will also use metabolic engineering to increase menthol yields by genetic modification in the M.x piperita and M. longifolia backgrounds. Based on current knowledge and flux control theory, four genes will be targeted for overexpression individually and in combination and the outputs assessed. From this work, tissue-culture regenerated vegetative plantlets will be produced which can be transported to Uganda for further evaluation.
Ugandan field trials will explore different growth conditions and we will measure biomass, oil yield and oil composition. These trials will include M.suaveolens that produces nepetalactone isomers in high amounts. The latter compound is a promising insect repellent and will be evaluated against mosquitos and other important disease vectors using WHO protocols with DEET as a control.
Building on the optimised production of menthol and nepetalactone will be their commercial utilisation in the local Ugandan economy. Menthol will be utilised in selected food/drink products to replace expensive imported material. Nepetalactone will be examined for safety and effectiveness in lotions or as sprays for bedding and clothes. These will represent significant additions to the rural economy. At the same time, there will be important transfer of technology and training of Ugandan scientists, enabling them to benefit sustainably from the project outputs.

Planned Impact

Local communities in Sub-Saharan Africa face many social and economic challenges that contribute significantly to poverty and low life expectancy. These include depressed agriculture through falling prices of traditional crops, inefficient agricultural practices among rural farmers, adverse effects of climate change, high levels of school drop-outs, youth unemployment and rural de-population. However, there are significant opportunities to improve living standards. In particular, the good quality soils and environmental conditions, coupled with large areas of available arable land and a skilled rural labour force, could enable African communities to cultivate and market feedstocks produced from locally-grown crop plants, generating financial revenue, employment and improved quality of life.
Our vision for improving social conditions in rural Uganda takes of account these challenges and opportunities of the region. This project will combine a high-quality scientific research programme with engagement, training and commercialisation activities to enable local rural Ugandan communities to develop and market essential oil feedstocks from Mint (Mentha) plants, with the aim to develop novel products containing mint oils for local commercial benefit. Collaboration with academic partners in Makerere University, Kampala, Uganda is an essential component of the project, and will involve sharing of skills in plant molecular biology, analytical chemistry, crop viability trials, insect repellence trials and food technology. Cardiff School of Biosciences will offer training to researchers in the current methodology for metabolic engineering to create transgenic plant lines, which will enable them to put such techniques into practice in the newly equipped (World Bank funded) molecular biology lab facilities in MaRCCI (Regional Centre for Crop Improvement).
As our collaborative partner in a previous project CEMPOP Uganda Ltd met with women's groups and community leaders in rural Uganda confirming the need to provide employment and sustainable incomes in rural communities. In response to such local needs, in 2013 our Ugandan partners initiated economically successful schemes producing high value crops of strawberries, ginger and red papaya by youth and women on small holding farm. Fertile land is available for small-scale cultivation, with low opportunity cost or at low rental, due to recent falls in world prices for Uganda's cash crops. This creates the opportunity to utilize now-dormant agricultural land to grow novel non-food crops for industrial markets. CEMPOP's role in the Project will include liaison with local community leaders and groups, as they have over the past 2 years, to establish mint farming as a new income source and to create Community Enterprise groups to manage the emerging business ventures based on mint oil products being developed by this project.
Market research indicated a rising demand for health foods/drinks and personal care products which is currently met by imported products and materials. Such demand is coupled with rising incomes and lifestyles in Kampala but is evident also to a limited extent in rural communities. This confirms the opportunity for sustainable production of plant essential oils as a feedstock for locally produced alternatives to imported goods. Both farming communities and new business ventures would benefit by exploiting such novel markets. We favour the model of Community Enterprise groups to empower local people to create novel business ventures. Although community cooperatives have been formed to support tourism-related activities, social enterprise groups growing novel "industrial" crops such as plant oils do not currently exist in Uganda. We will exploit this opportunity in this proposal, with the aim to use high-quality science to capitalise on the large market ($800m p.a.) for mint oil products through community enterprise to improve the lives of rural Ugandan communities.


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Description Large collection of mint varieties established. Phylogenetic relationships investigated with DNA bar coding and phylogenetic trees generated. Many DNA constructs created for generating transgenic mint and Arabidopsis plants using Golden Gate modular gene cloning. DNA constructs transformed into mint, Arabidopsis and protoplasts. Comprehensive oil composition analysis performed across all varieties. Regeneration condition optimisation. Initial lines selected for field trials in Africa. Oil distilled from African-grown mint plants. Used to formulate locally produced lotions, soap and food and beverage flavourings, as well as hand-sanitizer, face masks and early-stage insect repellent. These products will be sold and the profits will accrue directly to local rural farmers and other Ugandan stakeholders involved in development, helping to fulfill the ODA goal of economic impact, together with training and upskilling of local farmers and researchers which will have a positive societal impact. Further details are given in narrative impact section. We are also about to publish two papers from this award. One relating to the phylogenetics and biochemistry of different mint varieties, and one which is a review of transgenic approaches to mint metabolic engineering. One paper on biosynthetic pathways and one about transgene expression already published.
Exploitation Route The transgenic mint varieties can be used for cultivating high yielding plants and will be disseminated to more African farmers. The products generated can be used to provide income for local rural farmers. Researchers can use our constructs/ varieties for further work into the biosynthesis of essential oil components. We have also secured additional funds to further develop the nepetalactone-based insect repellent and to continue with the generation of transgenic lines.
Sectors Agriculture, Food and Drink,Chemicals,Communities and Social Services/Policy,Creative Economy,Education,Environment,Manufacturing, including Industrial Biotechology

URL https://twitter.com/DrJonesWales?ref_src=twsrc%5Egoogle%7Ctwcamp%5Eserp%7Ctwgr%5Eauthor
Description Work on this project is still underway despite the project officially finishing last year. We have had a significant impact on rural farming communities in Uganda who are growing our mint varieties to extract essential oils. These oils are being used to develop locally-produced products that can be sold on local and national markets for profit, which accrues directly to the farmers. Products being developed include soaps, lotions and flavourings. Such products have yet to reach market but are in advanced stages of development and will help achieve ODA goals of economic improvement. The project has indirectly supported local metal and brick manufacturers who are building the infrastructure needed for oil extraction and refinement (fabricated steel distillation unit and brick building to house the still) in line with ODA goals of improving local economy and society. Many local women farmers inolved in mint cultivation, helping to promote gender balance. We have also given talks to secondary school pupils on the project and about science generally. The team were interviewed by local and national Ugandan press. Meetings with Budaka district regional officials held to discuss project impact in local area. We also have an excellent collaboration with Makerere University (male and female researchers) and have undertaken a knowledge exchange to Uganda with a reciprocal visit to cardiff last year by Ugandan researchers. We have developed a mint-scented hand-sanitizer, face masks and a preliminary formulation of a nepetalactone-based hand sanitizer.
First Year Of Impact 2019
Sector Agriculture, Food and Drink,Creative Economy,Education,Manufacturing, including Industrial Biotechology
Impact Types Cultural,Societal,Economic

Description Maximising mint metabolites for improved health and economic prosperity in Uganda
Amount £30,000 (GBP)
Funding ID 523515 
Organisation Cardiff University 
Sector Academic/University
Country United Kingdom
Start 11/2022 
End 03/2023
Description Cardiff University (UK) and Makerere University (Uganda) 
Organisation Makerere University
Country Uganda 
Sector Academic/University 
PI Contribution Acquisiation of funding. Design of research programme. Project oversight. Scientific training.
Collaborator Contribution Development of food, beverage, cosmetic and medical products. Field trials of mint varieities.
Impact Food and beverage products. Insect repellent. Hand-sanitiser.
Start Year 2019
Description Research team visit to Uganda: visiting academic partners, civic leaders, local and national press, University students, secondary school students and local farmers 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Visited stakeholders in Uganda. Met with academic partners at Makerere University to discuss research and way forward for project. Gave talks/lectures to undergraduate and graduate students. Gave talks to secondary school pupils at Kamonkoli college about importance of science. Interviewed by local and national press about project. Met with local farming communities to discuss best practice and how to maximise oil yields. Met with Budaka district officials to discuss project and potential regional impact and developed plans for future collaborations.
Year(s) Of Engagement Activity 2019