Dengue Fever is one of the world's most dangerous tropical diseases, infecting more than 400 million people each year, with no promise of a cure or vaccine. Until now. In groundbreaking research at the University of Nottingham's Malaysia Campus (UNMC), two teams of researchers are investigating unique treatment methods produced from the leaves of the papaya and tobacco plants.
A mosquito-born viral infection, Dengue Fever is found in tropical and sub-tropical climates and tends to be concentrated in urban and semi-urban areas. The virus causes flu-like symptoms – severe headaches, muscle and joint pain, fever and rashes – and can develop into the potentially fatal Dengue Haemorrhagic Fever. As incidences worldwide grow dramatically, researchers are applying new approaches to traditional herbal remedies to find a plant-based cure for this prevalent disease.
A traditional herbal remedy using papaya leaf juice has long been used in areas of India and South East Asia as a treatment for Dengue Fever. A compound in the juice is known to help with blood clotting and can restrict internal bleeding caused by the disease. With funding from the Malaysian Ministry of Higher Education, a team of chemical engineers at UNMC are tackling the challenge of extracting this compound, carpaine, to use in a pill to treat the infection.
Associate Professor Dr Ching Lik Hii said: "Dengue has been a big issue in Malaysia and other countries for over 20 years. More people are being infected and dying as the Aedes mosquito population grows. This global problem inspired me to investigate a well-known traditional plant-based remedy and make it much easier to process and consume.
"We're targeting the active bio-compound carpaine, which we know can increase blood platelets and therefore helps reduce internal bleeding. We're also looking at whether younger leaves or older leaves contain more carpaine, and whether the stems of the papaya plant could also be useful."
Crude carpaine material is extracted using an acid-based procedure, and refined through purification steps to produce solid carpaine that is at least 95% pure. By the end of the project, the team hopes to have identified which parts of the papaya plant are best to use and developed the best processing method to achieve the highest yield of carpaine. Eventually, the team aim to work with industry partners in Malaysia and beyond to produce a carpaine medication to treat Malaysia's most infectious disease.
In a further groundbreaking research project, a team of scientists at UNMC have discovered a way to create disease-fighting proteins from tobacco plants, which could lead to the development of a safe and cost-effective vaccine for Dengue Fever.
Professor Sandy Loh commented: "Vaccines are created from proteins, with research usually focusing on mammalian cell, bacterial cell or fungus. Using plants for this process is a new platform to emerge that has the potential to provide a vaccine that can be used in orally-taken medicine. Other than tobacco plants, we're also working on edible plant species, such as lettuce, which we hope will lead to vaccines in the future.
"Using plants to develop a vaccine in this way offers many advantages, including lower production costs, easier distribution methods and better safety, as there are no animal or human pathogens which increases the biosafety aspect."
The project has produced a vaccine antigen (protein) within the plant that neutralises the Dengue virus using a unique transient expression process called Agroinfiltration. During the process, a defective plant virus is combined with Agrobacterium to make an expression vector that delivers the Dengue vaccine antigen into the leaf of the tobacco plant. It is then incubated and harvested after a few days, when the vaccine antigen can be extracted and purified for use as a vaccine. The findings of the project have verified that antibodies produced in response to the plant-based vaccine can neutralise the Dengue virus. The next stage of the research will involve virus challenge studies to determine the protection efficacy of the vaccine.
One of the unique aspects of this research is the speediness at which vaccines can be created using the Agroinfiltration method. Professor Loh explains: "For developing countries, a cost-effective vaccine produced from plants would have a significant impact as it would mean they can develop their own local vaccines to combat endemic diseases. For diseases like flu, which can mutate quickly, the speed at which we could potentially develop a vaccine is as rapid as one month, which means specific vaccines can be produced for any potential pandemic outbreaks. Providing vaccines in this way will undoubtedly save lives."
Improving lives in Malaysia and beyond
These innovative research projects are part of a host of new research projects launched at the University's Malaysia Campus to help improve the lives of people in Malaysia and beyond. With a focus on addressing the challenges facing Southeast Asia, our world-renowned academics are pioneering research into improving healthcare, providing sustainable methods of food production and protecting our environment.
Professor Deborah Hall, Vice-Provost (Research and Knowledge Exchange) commented: "Our researchers are applying their capabilities to ensure a positive impact on economic, social and cultural wellbeing within ASEAN and the broader region.
"Particular research strengths include securing the future of food through the discovery and cultivation of new and underutilised crops, advancing new ways to save lives through techniques to detect breast cancer, and working to preserve the ecology and conservation of elephants in their natural habitat. All of this wouldn't be possible without our staff and students. These talented people underpin our capability in delivering high-quality research and impact to our local community and beyond."
Posted on Thursday 31st May 2018