The herb Ashwagandha, used for centuries as a part of traditional Indian medicine, is a potent killer of cancer cells, according to researchers in Japan. Ashwagandha has been a staple of the 5,000-year-old system of medicine known as Ayurveda. It has been prescribed for stress relief, pain, and diseases ranging from rheumatoid arthritis to diabetes. Researchers have recently discovered that a leaf extract from the plant also can inhibit the growth of cancer cells. In a recent study published in Cancer Letters, the researchers injected nude (hairless) mice with bone cancer (osteogenic sarcoma) and connective tissue cancer (fibrosarcoma) cells, and then treated the mice with Ashwagandha leaf extracts.
They found that the extract was able to selectively kill cancer cells without harming normal cells. "It is highly effective. Cancer cells stop growing. They do not form any colonies, and the progression of tumors was effectively suppressed in the mice model," says Renu Wadhwa, PhD, head of the Cell Proliferation Research Group, Research Institute for Cell Engineering at the National Institute of Advanced Industrial Science & Technology in Japan. The herbal extract works primarily by inducing the activity of p53, a protein that has anti-cancer properties, Dr. Wadhwa says. Ashwagandha prevents cancer cells from multiplying by stopping their growth, or by triggering a natural form of programmed cell death called apoptosis.
Ashwagandha also works by other mechanisms, which Dr. Wadhwa and her colleagues plan to report on soon. Although this study looked specifically at osteogenic sarcoma and fibrosarcoma cells, other cancer cells also appear to respond well to Ashwagandha. "We have also examined colon cancer, lung cancer, breast cancer, and brain cancer," says Dr. Wadhwa. "It works for all kinds of cancers tested so far." What's more, the herbal extract appears to be very safe.
The researchers found no toxic effects in the mice used in this study, even when the mice were fed with large doses of the herb. Ashwagandha is available in supplement form; however, it is unknown at this time what dose of the supplement might be most effective against cancer in humans. And although Ashwagandha is generally safe, it is always best to check with a doctor before using any supplements, because some herbs can interact with medications and cause reactions.
More will be known about Ashwagandha's cancer-fighting capabilities when researchers conduct additional studies on the herb. Dr. Wadhwa says that she and her research team are planning to launch studies in human patients in the near future. Source: Widodo N, Takagi Y, Shrestha B, Ishii T, Kaul SC, Wadhwa R. Selective killing of cancer cells by leaf extract of Ashwagandha: components, activity and pathway analyses. Cancer Letters, 2008.
