Ground-up artemisia plants, from which the anti-malaria drug artemisinin is derived, appear to work much better than the refined drug does by itself, according to research at the University of Massachusetts.
Artemisinin, discovered by Chinese scientists in a project started by Mao Zedong to help the North Vietnamese, has become the newest malaria miracle cure. But parasites resistant to it have emerged.
Scientists infected mice with two strains of rodent malaria — one that is already artemisinin-resistant and one that is not, but is biologically similar to Plasmodium falciparum, the deadliest strain of human malaria. They then fed the mice pure artemisinin or dried artemisia annua plants bred for high drug content at Worcester Polytechnic Institute.
The study was published this month by the Proceedings of the National Academy of Sciences.
The whole plant cured mice with artemisinin-resistant malaria. In mice with the dangerous strain, parasites resistant to the plant failed to emerge even after 49 successive infections — three times as many as it took for parasites resistant to artemisinin alone to evolve.
“We don’t know what the precise mechanism is,” said Stephen M. Rich, a University of Massachusetts microbiologist and the paper’s lead author, but the plant contains dozens of toxic chemicals that repel or kill fungi, bacteria, insects and even rival plants. Some may protect the artemisinin from being broken down by the liver. Also, he said, malaria parasites share an ancestor with plants and contain vestigial versions of the chlorophyll-producing organelles. The natural herbicides some plants use to kill rivals may also work on them, he said.