Photo by Jorge Ferreira,
via Wikimedia Commons
Artemisia annua L.
by Shana Potash
Today's best treatments for severe malaria are based on the potent drug, artemisinin. A treasure from China's medicine chest, it was rediscovered by Chinese scientists who transformed a centuries-old herbal remedy into a new class of drugs that have helped hundreds of millions of malaria sufferers around the world.
The story begins in the 1960s, during the Vietnam War and China's Cultural Revolution under Communist Party Chairman Mao Zedong. Malaria was rebounding in Asia as parasites that cause the mosquito-borne disease were becoming resistant to the available medicines. North Vietnam, in jungle warfare with the U.S., asked China for help developing new antimalarials for its troops. China launched a secret program investigating both known chemicals and traditional Chinese medicines. The chemical route quickly delivered new treatments to the battlefield. But scientists studying traditional medicines ultimately produced the powerful botanical artemisinin, several derivatives, and other drugs that can be combined with them.
Artemisinin is derived from the common plant, Qinghao, the Chinese name for Artemisia annua L., also known as sweet wormwood. It had been used in China for more than 2,000 years. The earliest record, from 168 B.C., was written on a piece of silk unearthed from a tomb and recommended the herb as a hemorrhoid therapy. A fourth century manuscript noted it as a malaria treatment and advised readers to take a handful of Qinghao, soak in 2 liters of water, strain the liquid and drink.
Throughout the 1970s, teams of Chinese scientists moved Qinghao from plant to drug. Early work produced a crude extract that was 100 percent effective against malaria in mice. Later, scientists isolated the extract's active component, and named it Qinghaosu, known in the West as artemisinin. They determined it had a chemical structure that was different from the existing antimalarials - which was important in solving the problem of resistance - and then tested it in clinical trials. China first used artemisinin-based drugs on the battlefield in 1979.
China did not disseminate information about artemisinin to the West during the Cultural Revolution. But when that period ended, news began to emerge and scientists in other countries, including the U.S., undertook their own studies. Western drug companies also became very interested.
Research inside and outside of China demonstrated that fast-acting artemisinin, combined with a longer-lasting partner drug, delivers the necessary one-two punch to clear parasites from the body. Today, artemisinin-based combination therapies are the WHO-recommended best available treatments for most patients with malaria, particularly in areas of parasite resistance.
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