A naturally-derived drug has shown promise in treating a lethal form of brain tumor, scientists have reported.

Researchers from the University of Alabama at Birmingham (UAB) have presented results from Phase II clinical trial of AT-101, a pill produced from a compound found in cottonseed that appears to overcome the abnormal growth patterns of tumor cells.

They studied 56 patients who were largely unresponsive to traditional treatments for the brain cancer known as glioblastoma multiforme which included surgery, chemotherapy and radiation.

However, after about three weeks taking the pill, many of the patients experienced a significant slowdown in the growth of their tumors which persisted for several months, the scientists reported.

Dr John Fiveash, an associate professor in the UAB Department of Radiation Oncology and the lead researcher on the study, says AT-101 would likely work best in combination with radiation and chemotherapy to boost the cancer-fighting properties of those treatments.

He noted that the added benefit of the orally-delivered drug is that it appears to be well tolerated by patients.

In order to avoid serious health complications such as cancer, some people have turned to nutritional supplements containing antioxidants.