Leaf extraction

A UK team has identified three chemical processes that can be used to produce the anti-malaria drug artemisinin in an environmentally friendly way.


Malaria is one of the world’s most widespread diseases, infecting over 400 million people each year and causing about three million deaths.


The most effective drug against malaria is artemisinin, an extract from the herb Sweet Wormwood; most patients taking it improve within 24 hours.


But artemisinin has a big drawback – it is produced using the petroleum-derivative hexane, a toxic and potentially explosive substance which damages the environment.


Now a team of specialists at Bath University has identified three extraction processes that can compete economically with the traditional hexane method, as well as being better for the environment.


The research team found that technologies using supercritical carbon dioxide, hydrofluorocarbon and ionic liquids, all of which are non-flammable solvents, gave faster extraction times and a more complete extraction of the useful substances in the leaf.


These solvents are also considerably safer, with no risk of explosions, and are also much greener, having a lower environmental impact.


The reserchers have designed and built a small-scale demonstrator to test the new extraction technologies and they expect soon to be able to invite users from many countries to test it.


‘Increased production of artemisinin is now happening in many countries around the world but, if we are to reduce the costs of the final drugs, we need to increase yield and introduce new, more efficient, safer and more environmentally- friendly extraction systems,’ said Dr Alexei Lapkin, who is leading the project in the university’s department of chemical engineering.


The Bath project is being co-ordinated by FSC Development Services and funded by Medicines for Malaria Venture. It is a collaboration with Ineos Fluor.