The compound, extracted from sweet wormwood Artemisia annua L, cut the development of breast cancer by 40 per cent in rats that had been given a cancer-causing agent.
Artemisinin has previously been shown to selectively kill cancer cells, and is already used as an effective anti-malaria treatment. "With the results of this study, it's an attractive candidate for cancer prevention," said researcher Henry Lai.
The study, published in the January 2006 issue of Cancer Letters (vol 231, issue 1, pp 43-48), used rats treated with a single dose of DMBA (50 mg per kg), a compound known to induce multiple breast cancer. The rats were then randomly divided into two groups, with one group's feed supplemented with 0.02 per cent artemisinin.
The rats with the supplemented feed showed a 40 per cent lower incidence of breast cancer formation than the control group. In addition, the tumours that did develop in the case group were smaller and fewer.
"Since artemisinin is a relatively safe compound that causes no known side effects even at high oral doses, the present data indicate that artemisinin may be a potent cancer-chemoprevention agent," said the researchers.
Artemisinin works by reacting with iron in the body and forming free radicals that attack the cells from within. Cancer cells replicate at a higher rate than normal cells and so have a higher concentration of iron. This makes artemisinin highly toxic to the cancer cells.
The same mechanism is responsible for its anti-malarial properties. The parasite that causes malaria cannot eliminate the iron from the blood cells it eats and stores it. The artemisinin makes the stored iron poisonous to the parasite.
Artemisinin is now a major component in the treatment of malaria is China, Vietnam and other areas of Asia and Africa.
But the results of the present study were greeted with guarded optimism by Dr Emma Knight, science information officer for British charity Cancer Research UK.
She told NutraIngredients.com: "These findings in rats are very interesting but more work is needed to assess whether artemisinin could have a role in cancer prevention in humans."
Dr Knight stressed the importance of investigating naturally occurring compounds, however, and exploiting the potential health benefits that may be on offer.
"Contrary to popular belief, a number of anti-cancer drugs are derived from natural sources. The periwinkle, yew tree and African bush willow are just some of the plants that have an important place in the treatment of cancer today," she said.