Discovery could lead to a more stable supply of the compound artemisinin, which is used when other therapies fail.

Shoring up the erratic supply of artemisinin, a malaria drug extracted from the sweet wormwood plant, remains a struggle. But that could change, thanks to a discovery that the synthesis of the compound is less restricted in the plant than thought.

For decades, researchers thought that artemisinin was secreted solely by the plant’s microscopic glands, which can yield only so much of the compound. De-Yu Xie and his colleagues at North Carolina State University in Raleigh bred a variety of sweet wormwood (Artemisia annua) that lacks glands when the plants are young. When the researchers examined the seedlings’ glandless leaves, they were surprised to find artemisinin and many of its chemical precursors in the plant’s long-overlooked non-glandular cells.

The team also obtained glandless mutant versions of A. annua that were previously reported to lack artemisinin. In these plants, too, the researchers were able to detect the drug.

The findings, the team says, could lead to a more stable supply of the potent drug, which is widely used to treat malaria that is resistant to other drugs.