Adding a drug derived from the Chinese herbal medicine known as sweet wormwood boosts the effectiveness of standard malaria treatment, even in some areas where malaria parasites are resistant to frontline drugs. This finding comes from an analysis of 16 studies that examined wormwood-derived artesunate.
Twelve of the studies were done in Africa, three in Thailand, and one in Peru. Some participants in the studies took a typical antimalarial drug, such as chloroquine, as well as artesunate.
Others got a standard drug plus an inert pill.
On average, people whose treatment included artesunate were about one-fourth as likely to still be infected with malaria when checked 2 and 4 weeks after treatment, compared with the patients getting a standard drug plus a placebo, the researchers report in the Jan. 3 Lancet. Generally, people who cleared the parasite from their systems did so about twice as fast if their therapy included artesunate. In Thailand, where resistance to the malaria drug mefloquine is high, adding artesunate to such treatment sharply lowered the rate of relapse, two of the studies showed.
Artesunate appears to kill off the bulk of the malaria parasites “with the other drugs mopping up,” says study coauthor Paul Garner of the Liverpool School of Tropical Medicine in England. Other studies have shown that artesunate’s effect wears off within a week if the extract is used alone.
In a commentary accompanying the new report, Patrick E. Duffy of the Seattle Biomedical Research Institute and Theonest K. Mutabingwa of the London School of Tropical Medicine and Hygiene note that artesunate is chemically unrelated to quinine or other antimalarial drugs. “Combination [drug-plus-artesunate] therapy is a logical—and urgent—next step” against malaria, they conclude.
However, artesunate costs roughly $1 per treatment, while chloroquine and sulfadoxide-pyrimethamine, another standard antimalarial, cost 15 cents and 25 cents, respectively.