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ONE of the most valuable weapons in the war on malaria is artemisinin, a drug derived from the leaves of sweet wormwood. Its discovery, inspired by wormwood’s use as a herbal remedy for the disease, brought Tu Youyou, the scientist responsible for making it, the first Nobel prize for medicine awarded to a researcher working in China. Artemisinin has, though, proved stubbornly difficult to synthesise chemically, meaning that extract-of-wormwood is still the main source of supply. That is a problem, for wormwood plants take between 190 and 240 days to mature. Moreover, yields are not huge—a mere half a milligram per gram of dried wormwood leaves. Alternative sources would thus be welcome.
One is to engineer relevant genes into yeast cells. That works, but only up to a point. The commercial process based on this method turns out artemisinic acid, not artemisinin. Further chemical treatment is needed to produce the drug, and the end product has had difficulty competing with artemisinin derived from plants. However, Shashi Kumar of the International Centre for Genetic Engineering and Biotechnology, in New Delhi, is proposing a different approach, using a plant instead of a fungus. As he reports in Molecular Plant, he has engineered tobacco to make artemisinin faster and better than wormwood can.
The article's full-text is available here.
