Traditional Chinese Medicine herb is a potent cancer killer

Researchers have used an herb used in Traditional Chinese Medicine (TCM) to develop a compound that is 1,200-times more effective at killing cancer cells than current chemotherapy drugs.

Tomikazu Sasaki and colleagues at the University of Washington attached a chemical homing device to the anti-malarial drug artemisinin, which is derived from the sweet wormwood plant (Artemisia annua L). Tests showed that the compound was highly selective and effective at killing human leukemia cells. Preliminary results suggest that the compound is similarly effective at selectively killing human breast and prostate cancer cells.

The compound works by exploiting the high iron content of cancer cells. Artemisinin is highly toxic in the presence of iron, and the reaction that occurs between it and iron leads to the generation of free radicals, which ultimately kill off the cell. Artemisinin is actually very effective at killing cancer cells on its own; however by adding the chemical homing device the scientists were able to significantly improve its selectivity for cancer cells.

The majority of chemotherapy drugs that are currently available are non-selective, which means that they are extremely toxic to healthy cells, typically destroying one healthy cell for every five to ten cancer cells. However, the new compound selectively targets cancer cells, and was shown to destroy just one healthy cell for every 12,000 cancer cells. Thus suggesting that the compound would have minimal side effects.

Sweet wormwood has been used in TCM, where it is known as qing hao, for more than 2,000 years.

Oh S, Kim BJ, Singh NP, Lai H, Saskai T. Synthesis and anti-cancer activity of covalent conjugates of artemisinin and a transferrin-receptor targeting peptide. Cancer Letters. In Press. Available online 5 October 2008.

News release: Scientists develop new cancer-killing compound from salad plant. University of Washington Website. October 13th 2008.