A plant grown in the South Pacific and consumed by islanders for its mild sedative effects appears to prevent smoking-induced lung cancer, according to researchers at the University of Minnesota.

Their findings, published last week in the journal Cancer Prevention Research, suggest that an extract made from kava root suppresses the growth of tumors in mice. They’ve applied for a patent on a blend of the active ingredients that they believe is the preventive agent.

Lung cancer results in about 150,000 deaths and 160,000 new cases a year in the United States. The five-year survival rate is just under 17 percent. Smoking greatly increases the chance of developing lung cancer. Yet studies in such islands as Fiji and Western Somoa have found very low lung cancer rates despite relatively heavy tobacco use.

Earlier studies found an inverse correlation between the amount of kava consumed and the cancer rate among smokers, indicating that the earthy beverage might be blocking tumor growth. But kava was banned in Europe, where it had been used to treat anxiety, after reports suggesting it causes liver damage. The U’s researchers found those reports questionable and say their own kava extract did not harm the liver. However, further study is needed to establish its safety in human clinical settings, they said.

The American Botanical Council said in a statement that while it generally does not comment on studies conducted on mice and other animals, the U’s kava research warrants attention. It quoted Rick Kingston, a U pharmacy professor and president of Regulatory and Scientific Affairs at SafetyCall International in Minneapolis, as saying the research is “unprecedented in its potential impact.”

An editorial accompanying the study said that “although the ultimate success of kava will depend on the outcomes of further … studies, this herb exemplifies the principle of ‘nature to bench to bedside’ and supports the identification and … testing of natural agents for cancer chemoprevention.”