A nondescript, leafy plant might offer a much-needed edge in the fight against cancer.

Called Indian mustard, or Brassica juncea to be precise, this flowering plant draws up minerals from soil, concentrating trace elements such as selenium within it. And scientists have found that selenium not only may prevent cancer, but also may reduce the side effects of chemotherapy and improves tumor control in those who already have cancer.

That’s why City of Hope researchers are testing whether giving certain cancer patients selenium from Indian mustard — along with chemotherapy — can help them better battle their disease.

“Selenium is an essential nutrient found in many foods,” said Stephen Shibata, M.D., director of the Gastrointestinal Cancer Program and associate professor of medical oncology at City of Hope. “It’s part of our everyday daily diet. But studies have suggested that in high doses, it has specific anticancer effects.”

Several large studies are under way nationwide testing selenium’s ability to prevent malignancies such as prostate and lung cancers.

Now Shibata is leading a phase I clinical trial incorporating selenium into treatment for patients with advanced cancers that didn’t respond to standard therapies. The trial pairs selenium pills along with the chemotherapy drugs irinotecan and capecitabine. Both drugs are increasingly used against cancer, particularly colon cancer.

Unfortunately, these chemotherapies and others can cause significant side effects, including diarrhea, mouth irritation and drops in blood cell counts. These problems often limit the dose of drugs that doctors can safely give patients. But researchers hope that pairing selenium along with the drugs will help patients tolerate treatment better, allowing physicians to give patients higher doses of the chemotherapy — which might make for more successful treatment.

“We think selenium might work in partnership with chemotherapy and control tumor growth, as well,” Shibata said. “This clinical trial and others will help answer this question.”

Indian mustard, a pungent part of Southern cooking and some Asian cuisines, is just one of a number of plants with natural healing potential. The leaves and bark of the willow tree, for example, contain a substance called salicin, which is similar to acetylsalicylic acid — the chemical name for aspirin. And the chemotherapy drug paclitaxel, known by the trade name Taxol, originates from a toxin found in the bark of the Pacific yew tree.

“People are finding that natural products may have anti-cancer properties,” Shibata said, “and we are looking for those that can bring additional cancer-fighting options to our patients.”